Management of dairy cattle in Florida

Material Information

Management of dairy cattle in Florida
Series Title:
Bulletin University of Florida. Agricultural Experiment Station
Arnold, P. T. Dix, 1902-
Becker, R. B ( Raymond Brown ), 1892-1989
Spurlock, A. H
Place of Publication:
Gainesville Fla
University of Florida Agricultural Experiment Station
Publication Date:
Copyright Date:
Physical Description:
56 p. : ill. ; 23 cm.


Subjects / Keywords:
Dairy farming -- Florida ( lcsh )
Milk yield -- Florida ( lcsh )
bibliography ( marcgt )
non-fiction ( marcgt )


Includes bibliographical references.
General Note:
Cover title.
Bulletin (University of Florida. Agricultural Experiment Station)
Statement of Responsibility:
P.T. Dix Arnold, R.B. Becker, A.H. Spurlock.

Record Information

Source Institution:
Marston Science Library, George A. Smathers Libraries, University of Florida
Holding Location:
Florida Agricultural Experiment Station, Florida Cooperative Extension Service, Florida Department of Agriculture and Consumer Services, and the Engineering and Industrial Experiment Station; Institute for Food and Agricultural Services (IFAS), University of Florida
Rights Management:
All applicable rights reserved by the source institution and holding location.
Resource Identifier:
027116273 ( ALEPH )
18254202 ( OCLC )
AEN6198 ( NOTIS )


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Full Text

November 1949


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Bulletin 464


Frank M. Harris, Chairman, St. Petersburg
N. B. Jordan, Quincy
Hollis Rinehart, Miami
Eli H. Fink, Jacksonville
George J. White, Sr., Mount Dora
W. F. Powers, Secretary, Tallahassee


J. Hillis Miller, Ph.D., President of the
Harold Mowry, M.S.A., Director
L. 0. Gratz, Ph.D., Asst. Dir., Research
W. M. Fifield, M. S., Asst. Dir. Admin.
Geo. F. Baughman, M.S., Business Manager3
Claranelle Alderman, Accountant3



C. V. Noble, Ph.D., Agri. Economist1 3
R. E. L. Greene, Ph.D., Agri. Economist
Zach Savage, M.S.A., Associate
A. H. Spurlock, M.S.A., Associate
D. E. Alleger, M.S., Associate
D. L. Brooke, M.S.A., Associate
M. R. Godwin, Ph.D., Associate
H. W. Little, M.S., Assistant
Tallmadge Bergen, B.S., Assistant
Orlando, Florida (Cooperative USDA)
G. Norman Rose, B.S., Asso. Agr. Economist
J. C. Townsend, Jr., B.S.A., Agr.
J. B. Owens, B.S.A., Agr. Statistician2
J. F. Steffens, Jr., B.S.A., Agr. Statistician2


Frazier Rogers, M.S.A., Agr. Engineer' a
J. M. Johnson, B.S.A.E., Asso. Agr.
J. M. Myers, B.S., Asso. Agr. Engineer
R. E. Choate, B.S.A.E., Assistant. Agr.
A. M. Pettis, B.S.A.E., Asst. Agr. Engineer12


Fred. H. Hull, Ph.D., Agronomist'
G. E. Ritchey, M.S., Agronomist2
G. B. Killinger, Ph.D., Agronomist3
H. C. Harris, Ph.D., Agronomist3
R. W. Bledsoe, Ph.D., Agronomist
W. A. Carver, Ph.D., Associate
Darrel D. Morey, Ph.D., Associate
Fred A. Clark, B.S., Assistant
Myron C. Grinnell, B.S.A.E., Assistant
M. N. Gist, Collaborator2


J. Francis Cooper, M.S.A., Editor3
Clyde Beale, A.B.J., Associate Editor3


R. S. Glasscock, Ph.D., An. Husbandman3
J. E. Pace, B.S.A., Asst. An. Husbandman
S. John Folks, B.S.A., Asst. An.
T. J. Cunha, Ph.D., Assoc. An. Husbandman
G. K. Davis, Ph.D., Animal Nutritionist3
R. L. Shirley, Ph.D., Biochemist
Katherine Boney, B.S., Asst. Chem.

E. L. Fouts, Ph.D., Dairy Technologist' 3
R. B. Becker, Ph.D., Dairy Husbandman3
S. P. Marshall, Ph.D., Asso. Dairy Husb.3
W. A. Krienke, M.S., Asso. in Dairy Mfs.3
P. T. Dix Arnold, M.S.A., Assistant Dairy
L. E. Mull, M.S., Asst. in Dairy Tech.

A. N. Tissot, Ph.D., Entomologist'
L. C. Kuitert, Ph.D., Assistant
H. E. Bratley, M.S.A., Assistant

Ouida D. Abbott, Ph.D., Home Econ.1
R. B. French, Ph.D., Biochemist

G. H. Blackmon, M.S.A., Horticulturist'
F. S. Jamison, Ph.D., Horticulturist3
Albert P. Lorz, Ph.D., Asso Hort.
H. M. Reed, B. S., Chem., Veg. Processing
R. K. Showalter, M.S., Asso. Hort.
R. A. Dennison, Ph.D., Asso. Hort.
R. H. Sharpe, M. S., Asso. Hort.
R. J. Wilmot, M.S.A., Asst. Hort.
R. D. Dickey, M.S.A., Asst. Hort.
Victor F. Nettles, Ph.D., Asst. Hort.
L. H. Halsey, M.S.A., Asst. Hort.
F. S. Legasse, Ph.D., Asso. Hort.'

Ida Keeling Cresap, Librarian

W. B. Tisdale, Ph.D., Plant Pathologist' 3
Phares Decker, Ph.D., Plant Pathologist
Erdman West, M.S., Mycologist and Botanist
Howard N. Miller, Ph.D., Asso. Plant Path.
Lillian E. Arnold, M.S., Asst. Botanist
Robert W. Earhart, Ph.D., Plant Path.2

N. R. Mehrhof, M.Agr., Poultry Husb.1
J. C. Driggers, Ph.D., Asst. Poultry Husb.3
F. B. Smith, Ph.D., Microbiologist1
Gaylord M. Volk, Ph.D., Chemist
J. R. Henderson, M.S.A., Soil Technologist3
J. R. Neller, Ph.D., Soils Chemist
Nathan Gammon, Jr., Ph.D., Soils Chemist
R. A. Carrigan, Ph.D., Biochemist3
Ralph G. Leighty, B.S., Asso. Soil Surveyor
Geo. D. Thornton, Ph.D., Asso.
H. W. Winsor, B.S.A., Assistant Chemist
R. E. Caldwell, M.S.A., Asst. Chemist3
V. W. Cyzycki, B.S., Asst. Soil Surveyor
R. B. Forbes, M.S., Asst. Soils Chemist
W. L. Pritchett, M.S., Asst. Chemist4
James H. Walker, M.S.A., Asst. Soil
Walter J. Friedmann, M.S.A., Asst.
O. E. Cruz, B.S.A., Asst. Soil Surveyor

D. A. Sanders, D.V.M., Veterinarian1
M. W. Emmel, D.V.M., Veterinarians
C. F. Simpson, D.V.M., Asso. Veterinarian
L. E. Swanson, D.V.M., Parasitologist
Glenn Van Ness, D.V.M., Asso. Poultry
G. E. Batte, D.V.M., Asso. Parasitologist


J. D. Warner, M.S., Vice-Director in Charge
R. R. Kincaid, Ph.D., Plant Pathologist
L. G. Thompson, Ph.D., Soils Chemist
W. C. Rhoads, M.S., Entomologist
W. H. Chapman, M. S., Asso. Agron.
Frank S. Baker, Jr., B.S., Asst. An. Husb.
Mobile Unit, Monticello
R. W. Wallace, B.S., Associate Agronomist
Mobile Unit, Marianna
R. W. Lipscomb, M.S., Associate Agronomist
Mobile Unit, Chipley
J. B. White, B.S.A., Associate Agronomist
Mobile Unit, Pensacola
R. L. Smith, M.S., Associate Agronomist

A. F. Camp, Ph.D., Vice-Director in Charge
W. L. Thompson, B.S., Entomologist
J. T. Griffiths, Ph.D., Asso. Entomologist
R. F. Suit, Ph.D., Plant Pathologist
E. P. Ducharme, M.S., Asso. Plant Patho.'
R. K. Voorhees, Ph.D., Asso. Horticulturist
C. R. Stearns, Jr., B.S.A.. Asso. Chemist
J. W. Sites, M.S.A., Horticulturist
H. 0. Sterling, B.S., Asst. Horticulturist
J. A. Granger, B.S.A., Asst. Horticulturist
H. J. Reitz, M.S., Asso. Horticulturist
Francine Fisher, M.S., Asst. Plant Path.
I. W. Wander, Ph.D., Soils Chemist.
A. E. Wilson, B.S.A., Asso. Biochemist
J. W. Kesterson, M.S., Asso. Chemist
R. N. Hendrickson, B.S., Asst. Chemist
Wallace T. Long, M.S.A., Asst. Hort.
J. C. Bowers, B.S., Asst. Chemist
D. S. Prosser, Jr., B.S., Asst. Horticulturist
R. W. Olsen, B.S., Biochemist
F. W. Wenzel, Jr., Ph.D., Supervisory Chem
Alvin H Rouse, M.S., Asso. Chemist
L. W. Faville, Ph.D., Asst. Chemist

R. V. Allison, Ph.D., Vice-Director in Charge
F. D. Stevens, B.S., Sugarcane Agronomist
Thomas Bregger, Ph.D., Sugarcane
J. W. Randolph, M.S., Agricultural Engineer
W. T. Forsee, Jr., Ph.D., Chemist
R. W. Kidder, M.S., Asso. Animal Hush.
T. C. Erwin, Assistant Chemist
Roy A. Bair, Ph.D., Agronomist
C. C. Seale, Asso. Agronomist
N. C. Hayslip, B.S.A., Asso. Entomologist
E. H. Wolf, Ph.D., Asst. Horticulturist
W. H. Thames, M.S., Asst. Entomologist
W. N. Stoner, Ph.D., Asst. Plant Path.
W. A. Hills, M.S., Asso. Horticulturist
W. G. Genung, B.S.A., Asst. Entomologist
Daniel W. Beardsley, B.S., Asst. An. Husb.
W. D. Hogan, M. S., Asst. Plant Path.


Geo. D. Ruchle, Ph.D., Vice-Dir. in Charge
D. 0. Wolfenbarger, Ph.D., Entomologist
Francis B. Lincoln, Ph.D., Horticulturist
Robt. A. Conover, Ph.D., Asso. Plant Path.
Milton Cobin, B.S., Asso. Horticulturist
R. W. Harkness, Ph.D., Asst. Chemist


William Jackson, B.S.A., Animal Husband-
man in Charge2


W. G. Kirk, Ph.D., Vice-Director in Charge
E. M. Hodges, Ph.D., Agronomist
D. W. Jones, B.S., Asst. Soil Technologist
E. M. Kelly, B.S.A., Asst. An. Husb.


R. W. Ruprecht, Ph.D., Vice-Dir. in Charge
J. W. Wilson, Sc.D., Entomologist
Ben. F. Whitner, Jr., B.S.A., Asst. Hort.
P. J. Westgate, Ph.D., Asso. Hort.


C. E. Hutton, Ph.D. Agronomist'
H. W. Lundy, B.S.A., Associate Agronomist



G. K. Parris, Ph.D., Plant Path. in Charge

Plant City

A. N. Brooks, Ph.D., Plant Pathologist


A. H. Eddins, Ph.D., Plant Path. in Charge
E. N. McCubbin, Ph.D., Horticulturist


A. M. Phillips, B.S., Asso. Entomologist2
John R. Large, M.S., Asso. Plant Path.
J. R. Beckenbach, Ph.D., Hort. in Charge
E. G. Kelsheimer, Ph.D., Entomologist
David G. Kelbert, Asso. Horticulturist
E. L. Spencer, Ph.D., Soils Chemist
Robert O. Magie, Ph.D., Gladioli Hort.
J. M. Walter, Ph.D., Plant Pathologist
Donald S. Burgis, M.S.A., Asst. Hort.


Warren O. Johnson, B.S., Meterologist2

'Head of Department.
-In cooperation with U. S.
SCooperative, other divisions, U. of F.
On leave.

INTRODUCTION .. ... ..... .... ....... .... .. .. 5
THE DAIRY HERD: SIRE AND DAM .-.-- ---- -- 16
What Gives Value to a Cow? -- --- --- 16
Relation of Dam to Production of Daughters -- 18
Building on Cow Families 18
SELECTION OF A HERD SIRE .-.... .... .-.-- -- .- ... .. ... 19
Care and Management of the Bull 21
Sampling and Proving the Sire ---- ....... 25
Length of Useful Service .....-- --_ 26
Natural Causes of Termination of Usefulness -----...... 28
Keeping Dairy Records -- .... ... .............. ........ ...... ..... 29
Raising Dairy Calves .. ... ... .. .... 32
Raising Calves on Nurse Cows -..- ..--. ...-- .. .. 33
Colostrum as Calf Feed 33
The Nipple Bucket --- .. ..... ...... ........ ....... ... .. 33
Feeding Whole Milk and Skimmilk ---- 34
Limited Milk Feeding-Dry Method ---- -- 35
Liquid Milk Substitutes and Gruels ---- -- 35
Precautions in Calf Management 36
Feed from Weaning to Breeding Age 36
Age to Breed Heifers -.-. .- ...- ...... 36
Feed from Breeding to Calving Time 37
FACTORS AFFECTING MILK YIELD ............ .. .... 39
Season of Calving Affects Yearly Milk Yield 39
Age Influences Milk Production -._-.-- 41
Length of Dry Period Affects Milk Yield -41
Mineral Supplements as Related to Milk Yield 43
Managed Milking .............. 44
Variations in the Butterfat Content of Milk 45
Richness of Morning and Evening Milk 46
Age Influences Average Butterfat Test .---- 47
Season of Calving in Relation to Milk Sales ----.. 47
Relation of Production per Cow to Labor Required and to
Relative Cost of Milk ... ........................ 47
Raising versus Purchasing Replacements .. 49
Average Useful Life Span and Reasons for Replacements of
Dairy Cattle ---- ----- -------............. 52
Depreciation of Dairy Herds --- ---.. ....-.......... 54
ACKNOWLEDGEMENTS .------.....- ... ---...... 56

Management of Dairy Cattle in Florida
(A Revision of Bulletin 274)
Dairy Husbandry and Dairy Manufactures Department
Department of Agricultural Economics

The information assembled herein has been accumulated
from a number of sources, including experiments and observa-
tions of other state experiment stations and the Bureau of Dairy
Industry, U. S. Department of Agriculture. Records of the
associations fostering the pure breeds of dairy cattle have been
drawn upon. "An Economic Study of 249 Dairy Farms in
Florida" and subsequent surveys have furnished many facts
obtained from, and directly applicable to, the dairy herds of this
state. Records accumulated during the past 30 years from the
dairy herd at the Florida Agricultural Experiment Station have
furnished the evidence upon which many of the general state-
ments and recommendations are based. A part of these studies
has appeared in other publications from this station.

The dairy industry in Florida has made rapid progress in
recent years. Factors contributing to increased milk produc-
tion have been increased numbers of better dairy cows, more
local sources of good breeding stock, use of proper mineral sup-
plements, expanding acreage of improved and fertilized pastures,
and better management practices with dairy cattle. Supplies of
home-grown and locally produced feeds (such as citrus by-
products) have contributed to economical dairying. Marked ad-
vances have been made in developing pastures. Milk production
goals were exceeded during ever year of World War II, and milk
production is continuing to increase at present.
Dairying in Florida is divided into three distinct classes,
namely: the strictly commercial dairy, dairying as a part of
general farming, and the family-cow dairy. Many problems
apply alike to all classes of dairy farming, but each class has its
own special managerial problems.

Florida Agricultural Experiment Stations

There is marked need for a supply of milk for home use on
every farm, especially where there are children. When milk is
available, less money is required to buy groceries for the family
living; folks live better and are more healthy; and a higher
standard of living for the entire family is maintained, since
money saved on groceries is available for other needs of farm
life. Even a mediocre cow may render valuable service as a
family cow.

Fig. 1.-A fertilized pasture of White Dutch clover and grass can
provide a considerable proportion of the nutrients needed by dairy cows.
This scene is on Holly Hill Dairy near Jacksonville.

M *-j

"r 1 T1.

.aa i

Management of Dairy Cattle In Florida

The Cow's Contribution to Family Living in Florida
The contribution of dairying to the living of farm families in
Florida has been studied in several areas. A detailed survey of
220 specialized dairy farms adjacent to five population centers
of Florida by Bruce McKinley, as published in Station Bulletin
246, showed that the families of farm operators consumed milk
and milk products equivalent to 3,948 pounds (459.1 gallons) of
whole milk in a year. The average laborer on these farms used
an additional 896 pounds (104.2 gallons) per dairy farm.
Twenty-nine farms in a general farming area were surveyed on
which dairy cows were kept as a source of cash income from sale
of dairy products. One of these was a strictly dairy farm; the
others were general farms. The families of farm operators on
these general farms used 3,628 pounds of milk for home con-
sumption, and allowed an additional 318 pounds to laborers em-
ployed at various times during the year.
The contributions of the family cow dairies were studied by
Dr. J. E. Turlington and associates1 on 817 farms in 11 areas
where fruit, truck and other crops predominate as the sources of
cash incomes. In these various areas from 22 to 61 percent of
the farms had one or more cows which provided from 101 to 445
gallons of whole milk per farm, the average being 3,543 pounds
(412 gallons) per family per year on farms having family cows.
About one-fifth of these farms had only one cow, so that milk
was unavailable when the cow was dry.
Miss T. Roesel,2 home demonstration agent, found that milk
cows were owned on 85 of 105 Marion County farms which she
surveyed. Twelve were considered dairy farms, while the ma-
jority kept one or more cows mainly for family use. Only 37 of
these 85 farms had an adequate supply of milk throughout the
the year, an adequate supply being considered as a quart of
whole milk per child and a pint per adult each day. The feed for
the cows on many of these farms was largely home-grown, only
11 farms having spent as much as $25.00 to purchase dairy feeds
during the year when this study was made. The importance of
milk in the food supply is seen in the fact that consumption of

1 Florida Agricultural Extension Economist 1 (Nov. 1931) and 2 (May
2 Florida Agricultural Extension Economist 3 (April 1933).

Florida Agricultural Experiment Stations

milk and dairy products on these farms during a year was
equivalent to over 400 gallons of whole milk per family. A good
type of family cow is shown in Figure 2.

Fig. 2.-Family cows contribute much to the welfare of rural people.
Dr. J. E. Turlington found (mainly on truck and fruit farms) that these
cows yielded 3,543 pounds (412 gallons) of milk yearly per family. Bruce
McKinley observed on 29 general farms that these farm families used dairy
products equivalent to 3,628 pounds of whole milk, and on 220 strictly dairy
farms, 3,948 pounds of milk. This amount of whole milk and other dairy
products is an appreciable contribution to good living on these Florida

What Is a Profitable Cow?
How much milk should a cow produce in order to pay her
The answer to the above question must be based upon the
method of utilizing the dairy products. A family cow often
derives a large part of her feed requirements from grass. Her
care is largely by family labor which would not receive wages
otherwise at the same hours. Many medium or even low-
producing cows may save on the family budget and render a
real service by providing health-giving food at a minimum cash
outlay. Little capital is invested in the cow shelter or in equip-

Management of Dairy Cattle In Florida

Cows on general farms obtain part of their feed by gleaning
fields from which cash crops have been marketed. They convert
coarse parts of many crops into milk for the farm family and
for sale locally as dairy products. More equipment is necessary
to care for the dairy products on a general farm. Labor used
in the care of general farm cows is employed partly at other farm
work, so that the hours spent in caring for the livestock may
mean more efficient use of this labor. A large proportion of this
labor is performed by the operator and his family. To return a
net profit from the sale of dairy products alone, cows on such a
farm must be medium producers at least.

Only medium to high-producing cows will meet operating
expenses on a commercial dairy farm and leave any margin for
wages to the operator, who must earn a living from his cows.
Whether or not a particular cow will pay her way in a com-
mercial dairy depends entirely upon the feeding practices, cost
of feed, labor and other products, amount of labor and efficiency
in its use, and the distribution of management and overhead
operating costs of the particular dairy in question. Many of
these cost items have varied as much as 100 percent between
neighboring dairies.

High quality milk is produced by healthy, well-fed cows,
handled by healthy persons in a sanitary manner, and kept cold
until it is consumed. Production of quality milk requires more
and better equipment on commercial dairy farms than on general
farms. The commercial dairy requires more capital for equip-
ment and for buildings arranged to meet the exacting standard
requirements of city milk ordinances and state regulations for
the production and care of high quality market milk. The aver-
age valuation of dairy barns and milk houses on the 163 owner-
operated dairy farms surveyed in Florida during 1927 was 50
percent higher than on 27 owner-operated general farms. In the
general farm area studied, milk was sold mainly in bulk to a
manufacturing plant. The strictly dairy farms had a larger
additional investment in equipment for refrigeration, steriliza-
tion and washing of milk utensils than was needed on the general
farms. These are an essential part of the costs of producing
high quality market milk. The investment in buildings and
equipment to care for a family cow is a small item in Florida.


Florida Agricultural Experiment Stations

Management of dairy cows is affected materially by the
character of the market for dairy products. A commercial dairy
may furnish a steady supply of milk to an industrial community.
On the other hand, it may need peak production during a period
of tourist trade. The season of freshening for cows on general
farms may be such as to bring the larger part of the dairy
products at the time of highest market prices, or it may be
desirable to produce milk mainly from cheap crops such as pas-
tures or fields that are ready to be gleaned after the harvest of
cash crops. With two family cows, one may be dry while the
other is in milk, so as to provide an adequate supply over the
year. Some practices of dairy herd management apply to every
cow, while others meet specific situations.
The dairy herd on the general farm has a number of economic
factors which affect management of the dairy cows. These fac-
tors include the convenient distribution of labor between crop
production and care of the cows; amount of pasture and culti-
vated fields to be grazed by the cows; and the season at which
these are available; seasonal demand for whole milk or cream;
and the relative market price of these products from season to
The owners of family cows are interested in a steady supply
of milk from pasture grasses and from unmarketable parts of
crops. Only a limited amount of feed is purchased for the cow,
as in most instances an extra supply of milk is not desired
beyond the amount used by the family as whole milk, cream,
butter, cottage cheese, ice cream and for cooking purposes. Sur-
plus milk may be fed to calves, chickens or pigs.

Breeds of Dairy Cattle
The choice of a breed of cattle to be used in commercial
dairies is affected largely by preference of the individual owner,
and education of the consumers for milk of a particular quality.
Each breed has a large proportion of desirable cows, along with
some less desirable ones.
Jerseys were introduced into the Southern states shortly
after 1850, and have multiplied to the point where they predomi-
nate among the dairy cattle of the region. The other dairy
breeds represented are Holstein, Guernsey, Ayrshire, and Dutch

Management of Dairy Cattle In Florida

Belted. The trend has been toward an increase in Guernseys.
Recently a number of Brown Swiss have been introduced.
A brief discussion of the several dairy breeds of cattle will be
given. More detailed descriptions may be obtained in Farmers'
Bulletin 1443, Dairy Cattle Breeds, published by the U. S. De-
partment of Agriculture.
Southwestern Scotland has been noted as a dairy district for
over 160 years. The region is hilly, with considerable area de-
voted to pasture land. The climate is cool and moist in summer
and more rigorous in winter. Such is the ancentral home of the
Ayrshire, noted as a breed whose milk long has been used in the
manufacture of fine cheese.
Ayrshires were imported into the United States in 1822.
Some Ayrshire blood was introduced into herds of range cattle
in Alachua County over 70 years ago,3 traces of which still are
apparent in the horns and color markings of some of the descend-
ants in these herds.
Ayrshires usually are inclined to be of stocky build. The colors
are a mixture of white and red, sometimes shading to a rich
mahogany. The horns usually are wide spreading and tend to
curve upward and outward. The Ayrshire Digest stated re-
cently that 50 percent of Ayrshire cows in the United States
are dehorned. The udders tend to be quite symmetrical and are
attached closely to the body. A Polled strain is increasing in
popularity. In some individuals, the teats tend to be short,
though American breeders have eliminated this fault largely by
selection of breeding stock.
An average herd of Ayrshires under good farm conditions
should produce from 6,500 to 9,000 pounds of milk yearly per
cow with an average butterfat test of about 4.00 percent. Some
49,750 Ayrshires on Herd Improvement Register test during
10 recent years averaged 8,741 pounds of milk, 4.04 percent and
353 pounds of butterfat. Well-grown mature bulls should weigh
from 1,500 to 2,000 pounds and mature cows close to 1,050
pounds. Their calves weigh from 60 to 80 pounds at birth, males
averaging about 5 pounds more than females. These cattle are
rugged animals and are good grazers.
8 Florida Agricultural Experiment Station Bulletin 248, page 10.

Florida Agricultural Experiment Stations

Brown Swiss
The picturesque Swiss Alps are the native home of two
famous breeds of dairy cattle-Simmenthalers and Brown Swiss.
The latter breed was imported into the United States in 1869.
In their native home the cattle are housed in the valley farm-
steads in the winter, and some of them are moved onto the higher
mountain pastures during the summer months. Much of their
milk is used for manufacture of the famous Swiss cheese. Be-
cause of outbreaks of foot-and-mouth disease on the continent,
quarantine regulations have restricted shipments of livestock
from Europe. Less than 200 Brown Swiss cattle were imported
from which the breed multiplied. Some Brown Swiss have been
brought into the Southern states.
The cows are strong and rugged, some with a tendency toward
coarseness as compared with other more refined dairy breeds.
Mature cows weigh around 1,100 to 1,500 pounds and bulls from
1,600 to 2,000 pounds. Colors range from gray to light or dark
brown, seldom with any white markings. Horns, when allowed
to grow, are of medium size, curve outward and forward, and
often appear plain. Calves are large, many weighing 70 to 90
pounds or more at birth.
Brown Swiss cows are considered good producers of milk with
an average richness of about 4.00 percent butterfat. Some 8,337
purebred Brown Swiss cows on Herd Improvement Register test
recently yielded an average of 9,219 pounds of milk, 3.95 percent,
and 364 pounds of butterfat per year.
Dutch Belted
The Dutch Belted breed of dairy cattle is said to have some
ancestry in common with the Friesian, Oldenburg and other
breeds of cattle native to the Netherlands and the adjoining
provinces of northwestern Europe. They were owned and de-
veloped largely on estates of the ruling families of Holland, who
tried to select for perfection in color markings without losing
sight of dairy qualities. Their native country is a rich lowland
with verdant pasturage.
D. H. Haight imported a few Dutch Belted cattle into New
York state in 1838 and P. T. Barnum imported several in 1840 for
show purposes. Other importations were limited. The breed
has not become known widely in this country, although some

M. ilgement of Dairy Cattle In Florida

herds are found from New England to California. The largest
Dutch Belted herd in America is located near Miami, Florida,
and includes some of the good producers of the breed.
Dutch Belted cattle are black with wide white belts, which
sometimes extend sufficiently that white shows on the fore udder
and sometimes to markings on the hind feet. Common with
other black breeds of cattle, first-cross grades sometimes show an
outcrop of recessive red coloration.4 The white belt is a dominant
color marking among grades descended from this breed. Cows
are of good size, weighing from 1,000 to 1,500 pounds, and mature
bulls weigh from 1,500 to 2,000 pounds or more. Most of the
calves range between 70 and 90 pounds at birth.
Cows of this breed are said to be slightly lower producers of
milk, but with an average butterfat test above that of the Hol-
stein breed. The average richness of milk of the Dutch Belted
cows that have completed Advanced Registry tests is about 3.8
percent butterfat. With good care, cows of this breed should
produce above 8,500 pounds of milk yearly.

Jersey cattle originated on the Island of Jersey, one of the
Channel Islands in the English Channel. These islands long have
been famous because of the quality of milk produced by the
native cows. The fame of these cattle, and local pride in safe-
guarding purity of the breed, caused the islanders to promulgate
laws preventing introduction of any cattle for other than im-
mediate slaughter as early as 1789. French cattle brought by
the Germans during World War II were eliminated by the island
authorities after the surrender.
The first importation of Jerseys into the United States, from
which purebred cattle trace today, was made in 1850. Shortly
afterwards importations were made to New Orleans and other
Southern centers and thence became distributed widely. Because
of this early introduction in considerable numbers, Jerseys pre-
dominate in the Southeastern states.
Although a large proportion of Jerseys are solid fawn in
color, they vary from light cream to dark brown and black.
Admixtures of white with the other colors commonly occur.
Pigmentation of the nose and tongue is more frequently dark or
Journal of Heredity 24: 283-286. 1933.

Florida Agricultural Experiment Stations

black, and the switch is often black. Horns are small, short and
frequently incurving. Jerseys in most commercial dairies are
dehorned. The head is short and broad and the face dished at-
tractively. Mature cows weigh from 750 to 1,050 pounds and
bulls from 1,200 to 1,500 pounds. There is a tendency toward
selection of the larger sizes of Jerseys, since the larger cows
have been shown to be heavier producers on the average. Jersey
calves weigh from 40 to 60 pounds at birth. Because of this
small initial weight they are seldom used profitably for veal.
Jersey cattle have a good reputation as grazers, ranking with
the Ayrshire breed in this characteristic.
Jersey whole milk has a yellow color and is rich in butterfat,
the breed average being 5.35 percent butterfat in the milk. They
yield less milk per cow than do other dairy breeds, in part due to
small size of animals but also because of the high content of food
solids in the milk. Some 118,233 Jersey records on Herd Im-
provement Registry test in 10 years averaged 7,090 pounds of
milk, 5.36 percent and 379 pounds of butterfat per year. The
milk finds favor with consumers because of its richness and high
content of milk solids.
The Guernsey breed of cattle originated on the islands of
Guernsey, Alderney, Jethro, Sark and Herm, off the northwest
coast of France in the English Channel. These islands are in-
tensively cultivated and highly developed agriculturally, with
dairying as the third largest enterprise. This breed sprang from
ancestry similar to that of the Jersey breed on the adjacent
Island of Jersey, and resembles the latter breed in many re-
spects. Alderney was evacuated during World War II but the
cattle were restocked from Guernsey recently. Milk and butter
have been the chief forms in which dairy products are marketed
on the islands.
Guernsey cattle were introduced into America in the latter
part of the eighteenth century, along with Jerseys, under the
common name of Alderney. The earliest importations to be kept
pure came in 1830. In recent years, many grade and purebred
Guernseys have come into the South, and rank second in numbers
there among the dairy breeds.
Guernsey cattle usually are fawn and white, though some
solid fawn animals are seen. Noses and tongues are usually a

Management of Dairy Cattle In Florida

flesh color, dark pigmented noses occurring less frequently among
animals of the breed. A yellowish secretion of the skin is noted
especially in the wax of the ears, in the switch and on other parts
of the body. Horns are medium to small and of amber color.
Many Guernseys are dehorned. Mature cows should weigh from
900 to 1,400 pounds and bulls from 1,400 to 1,900 pounds. Calves
usually weigh from 55 to 70 pounds, males exceeding females by
about 5 pounds.
Some 25,482 Guernsey cows on Herd Improvement Register
test produced a yearly average of 8,531 pounds of milk, 4.89
percent and 417 pounds of butterfat. The yellow color of Guern-
sey milk has been widely advertised and finds favor with consum-
ers of bottled milk.
The Holstein-Friesian breed has existed for centuries on the
lowlands of northwestern Europe, which were famous for the
size of the cattle and for the manufacture and exportation of
cheese. On the highly productive pastures, Friesian cows were
bred and developed. Cattle from Holland were brought into New
York by early Dutch settlers so that the early cattle of that
region were commonly black and white.
The name Holstein-Friesian originated with the union of the
Holstein Breeders' Association with the Dutch Friesian Associa-
tion in this country in 1885. The term, Holstein, has come to be
the abbreviated name for this breed in America.
The first importation to which registered cattle trace came
into Massachusetts in 1861. Many were imported in the next
24 years, and few since that time, except from Canada. Quaran-
tine against foot-and-mouth disease prevented importations for
many years.
All registered Holsteins are black and white in color. Like
other breeds of black cattle, a few animals still carry the factor
for recessive red coloration,5 which crops out in the proportion of
one in three cases upon mating of animals that carry the factor
for recessive red coloration. Horns are medium in size, dark to
black in color, and usually curve forward and upward. Most
Holsteins now are dehorned. Mature cows should weigh between
1,000 and 1,600 pounds and bulls from 1,600 to 2,300 pounds. The

SWis. Agr. Exp. Sta. Bul. 313: 1-35. 1920.

Florida Agricultural Experiment Stations

calves are large at birth, usually between 75 and 105 pounds in
weight, the males being about 10 pounds heavier than females.
Because of large initial weight, many are vealed.
Holsteins are less noted as grazers on sparse pastures, thriv-
ing best where feed is plentiful. Some 103,627 records of Holstein
cows on Herd Improvement Registry in the past 10 years
averaged 11,379 pounds of milk and 395 pounds of butterfat.
Over 17 years, Holsteins in the Herd Improvement Register in-
creased from an average of 3.37 to 3.52 percent of butterfat in
their milk. The trend has been to select herd sires from medium
and high testing families. The milk has a pale color, due to
refraction of light from some of its colloidal constituents, inde-
pendent of the fat content. Holsteins are popular in cheese and
condensery districts, because of the desirable proportion of casein
to butterfat in their milk.

The Dairy Herd: Sire and Dam
What Gives Value to a Cow?
Selection of a dairy cow as the foundation of a dairy herd
should be made with as full a knowledge as available of a number
of facts, namely:
1. Ability of the cow to produce milk and butterfat.
2. Health-freedom from tuberculosis, infectious abortion,
mastitis, other communicable diseases and injurious parasites.
3. Condition of the cow as affected by previous feeding and
management, as well as mineral storage or state of nutrition.
4. She should have a satisfactory breeding history, as shown
by number of calves, date of last calving, subsequent service
record, quality of the sire by which she is with calf, and a
measure of her ability to transmit dairy qualities to her offspring.
5. Age of the cow affects the length of time that she yet may
be a producer.
6. The proper registration certificate with transfer inscribed
by the breed association should be supplied by the last owner, if
a cow is registered purebred.
7. Dairy conformation includes a good mammary system,
large feed capacity, spareness of natural fleshing and a rugged
constitution. An attractive appearance of head, body and lines
is desirable, though beauty is less essential than is producing

Management of Dairy Cattle In Florida

ability of a cow. An illustration of a good cow is shown in
Figure 3.

Fig. 3.-Observer Prescription 1089909 was purchased to add a new
female family to the station dairy herd. She possesses the qualities de-
sired in a good purebred dairy cow, namely: good breeding, type, produc-
tion and transmitting ability. She was sired by Afterglow's Observer
286446 (a good transmitting bull), from the cow Sybil Prudent Star 948765
-a Good Plus Silver Medal cow with two good Register of Merit records
and two Register of Merit daughters. Observer Prescription classified Very
Good for type; has three Register of Merit records averaging 9,372 pounds
of milk, 5.27 percent, 495 pounds of butterfat in 305 days, with a Silver
Medal as a junior two-year-old. She is a Tested Dam with three daughters
averaging 7,327 pounds of milk, 5.51 percent, 404 pounds of butterfat. She
has a daughter and two granddaughters in the herd.

Total valuation of a cow is the result of the entire combina-
tion of facts listed. Serious faults in a single point may be
sufficient to eliminate a cow from consideration. For example, a
cow advanced in age may be little longer of value as a potential
breeding animal.
The average productive life of a dairy cow has been calcu-
lated to be from 4.5 to 6.0 years after calving the first time.
This span of usefulness allows for cows eliminated by disease,
accidental death, sterility, culling and senility. Physical con-


Florida Agricultural Experiment Stations

edition and thrift of a cow should be considered, along with age,
in making selections.
Relation of Dam to Production of Daughters
Heredity is governed by the law of independent assortment
of genes (hereditary units). Probably few animals are suf-
ficiently pure in those hereditary characters which govern milk
producing capacity to transmit this capacity uniformly to all of
their progeny. This explains in part why many good producing
cows have few progeny their equal in producing ability. Very
high producing cows often are exceptions in a family of medium
to good producers. Yet the hope of a breeder is to locate an out-
standing producer that likewise proves to be a meritorious trans-
mitter on which to found a good cow family. When low-produc-
ing cows are mated with an average good purebred dairy bull,
the heifers usually are better than their dams. The daughters
of top cows usually excel the average, but frequently are not
quite equal to their dams.
An analysis of 200 pairs of dams and daughters in the Experi-
ment Station herd showed the relation existing between dams'
and daughter's daughter's production (see Table 1). The policy
during much of this time was to retain every daughter possible
through at least the first full lactation, so as to measure her
transmitting ability, however good or poor.

Number Daughters Dams
of Pairs Milk Butterfat Milk Butterfat
Pounds Pounds Pounds Pounds
12 4,861 247 2,683 134
14 5,320 284 3,983 183
35 5,809 295 4,598 228
49 6,140 309 5,424 274
50 5,970 309 6,301 325
23 6,623 339 7,223 375
11 6,305 324 7,763 413
6 7,085 348 8,842 468

Building on Cow Families
A herd is founded on purchased cows but its continuance and
success depend on the transmitting ability of the individual

Management of Dairy Cattle In Florida 19

animals. Ten foundation cows usually result in five cow families
10 years hence, under average conditions. When heifer calves
are being raised as replacements the herd records should be
studied so as to select those calves from good and medium pro-
ducing cows and from good cow families within the herd. Suc-
cess in breeding dairy cattle depends on continual study to
locate and multiply desirable families.
Between 1901 and 1948 41 registered Jersey females were
obtained by purchase and gift for the Station dairy herd. Some
cows or their descendants were dropped because of low produc-
tion, poor transmitting ability, lack of female progeny, disease
or other causes. Seventeen still are represented by progeny,
including six of the original females purchased since 1942. Early
culling was based on individuals, but elimination of poorer
families has been in progress also. An analysis of three good
and two poor families, when every heifer calf was saved to be
raised, will illustrate the family situation.
This analysis follows:

Foundation Generations Descendants Number of Average Production
Female of Progeny with Records Lactations Milk Butterfat
Pounds Pounds
A 4 12 50 6,261 326
B 3 5 21 6,497 344
C 4 10 37 5,060 260
D 4 9 32 6,455 330
E 5 21 62 5,319 273

Based on the information from Table 1 and a similar study of
2,165 pairs of cows in dairy herd improvement associations by
J. C. McDowell,6 the recommendation can be made to select heifer
calves out of the medium and higher producing cows. A few
exceptional animals will be discarded among the calves from low-
producing cows, but the majority from low producers develop to
be below average in milk and butterfat production.

Selection of a Herd Sire
A herd sire is the most important purchase made by a dairy-
man, since five to eight years hence a large proportion of his
milking cows may be progeny of this animal. Being of such
6 U. S. Dept. Agr. Dept. Circ. 368: 1-14. 1926.

Florida Agricultural Experiment Stations

importance to the dairyman who raises replacements, how can
the chances of getting a good bull be increased?
There is no sure way of selecting a young dairy bull with any
assurance that he will transmit high production to the major
portion of his progeny. Selection of young, untried sires is
always with the knowledge that the offspring may not prove
Copeland7 found the most satisfactory method of obtaining a
herd sire to be selection of a good proved bull, when available, or
a son of a good proved bull, out of a cow with good daughters and
10 or more good paternal half-sisters.
Careful scrutiny of the conditions of proving a sire includes
studying the dams and daughters, environment and management
while under test, and actual production records of both dams
and daughters. Computed averages sometimes may be mis-
leading, unless all conditions are known. Bull indexes are merely
guides based largely on an assumption that a cow's production
also measures transmitting ability-which too frequently is in-
Questions to consider when selecting a young bull are:
1. Has the sire transmitted producing ability to a large pro-
portion of his daughters? Do they equal or excel their dams in
average milk and butterfat production?
2. Has the dam been a satisfactory producer year after
year? Does she have sisters her equal, or is she a high pro-
ducing freak in a mediocre family? Does she have the constitu-
tion, capacity and mammary development desired? Is she better
than cows in the herd where the bull will be used? Has she
transmitted producing ability and desirable conformation to her
other progeny?
3. Desirable conformation in the bull includes good depth and
circumference of chest, length of body, depth of ribs, length of
rump, desirable placement of rudimentary teats, good size for
age, spareness inside the thighs, and a general appearance of
dairy temperament. These characteristics denote constitution,
capacity for feed, dairy temperament and mammary develop-
ment. Health of the animal and of the herd from which he

Journal of Dairy Science 17: 93-102. 1934.

Management of Dairy Cattle In Florida

comes is essential. Is he free from known hereditary defects?
An example of a good proved bull is shown in Figure 4.
Only good purebred dairy bulls should be used. Large num-
bers of dairy herd improvement association records analysed by
the Bureau of Dairy Industry, U. S. Department of Agriculture,
have shown that purebred dairy cows usually exceed grade cows
in producing ability. The desirable qualities of good grade cows
have come in large part from their purebred ancestors.
Care and Management of the Bull
Progress in improvement of a dairy herd depends to a large
extent upon transmitting ability of the herd sire, hence it is im-
portant that his ability be proved while yet living. He is the
most important animal in the herd, contributing one-half of the

Fig. 4.-The herd sire transmits one-half of the characters inherited by
his daughters. Consequently the quality of his immediate ancestors, indi-
viduality of the bull himself and the characteristics of all known progeny
should be considered prior to his purchase. This bull-Sophie 19th's Victor
81st 331031- was from good parents. He possessed good breed character,
constitution, capacity and general conformation. The entire 170 lactations
of his 67 daughters once in the station herd averaged 6,374 pounds of milk,
5.03 percent, 321 pounds of butterfat per lactation regardless of age. Thirty-
four of his sons have gone into Florida dairy herds. The majority of his
daughters and granddaughters have been profitable cows. Such an animal
is a desirable bull, to be used throughout his useful lifetime.
eww zlY

Florida Agricultural Experiment Stations

inheritance to all progeny. If a good proportion of daughters
excel their dams in producing ability, he is a valuable animal
worthy of use as long as he is serviceable.
Since bulls often become dangerous suddenly, special pro-
vision should be made for safe care and good management.
How can a bull be maintained safely, and as a satisfactory

A bull
septum of

should have a light copper ring inserted high in the
the nose while still young. This light ring should be
_-l replaced with a heavy
bronze cannon metal
ring when the animal is
two or three years old.
He should be trained to
lead, and to be tied,
while he is yet young
and tractable. Bulls al-
Bullr ways should be handled
paoddee firmly; never petted nor
teased. The gentle bull
is often the most dan-
Opinions differ as to
whether or not bulls
Fig. 5.-A safety breed- should be dehorned.
ing chute can be constructed They may be dehorned
in the corner of any paddock. with caustic potash
The gate swings inward to
admit, and remove, the cow while very young. Some
without the attendant having persons prefer to let
to enter the bull's pen. the horns grow for
the horns grow for
several months and
then perform the operation during cool weather.
It is thought that by this latter method the bull
is more cautious in the aggressive use of his head.
If the horns are allowed to remain, it is sometimes
desirable to round them off at the tips, so that he
is less likely to injure other animals.
A separate paddock, pasture or exercise lot,
adjacent to a shelter and to a safety breeding

Management of Dairy Cattle In Florida

chute (see Fig. 5) have proved satisfactory for handling and
housing bulls. Where two or more bulls are kept, each may
occupy a small shelter pen in which these animals are provided
with feed and water and access to a large paddock. A long
narrow paddock one-half acre or larger in size, from which a
bull can see out, is more conducive to exercise than a square pen.
Sometimes two congenial bulls may occupy the same paddock,
although there is risk of injury. Without exercise bulls get
sluggish and have been found less effective in service.
The feeds supplied to a bull should be of good quality and
such amount as to keep him in a vigorous thrifty condition, but
not fat. The quantity of roughage should be limited somewhat,
so as to avoid the bull becoming paunchy or heavy in the middle.
Good grazing and exercise may be provided in a strongly-fenced
pasture separate from the dairy herd. Good legume forage, with
an allowance of green pasture or soiling crops, is desirable.
There is a popular belief that the allowance of silage should be
limited in amount. Shade and water should be available in any
pasture or paddock.
Bulls require only a limited amount of concentrates. The
concentrates need not contain over 16 percent total crude protein,
and may be made up of such feeds as wheat bran, corn feed meal,
oats, cottonseed and linseed oil-meals. It is desirable to give
bulls access to common salt and such mineral matter as is needed
on the local soil areas. Too much feed and too limited exercise
shortens the useful life of many bulls.
Studies made at the South Carolina station showed that
dairy bulls were more effective in natural service when not used
over 12 times per month. With bulls under two or over eight
years of age, somewhat lighter service is desirable. With bulls
in artificial insemination units one collection of semen per week
is the present recommended practice. Breeding efficiency was
lower in herds where brucellosis was prevalent, or with cows
showing any abnormal vaginal discharge. Barring accidents,
the average good dairy bull may be expected, with good care, to
remain serviceable past 10 years of age. Although many bulls
are disposed of younger, a small number are known to have been
active and useful even until 19 years of age.
Failure of cows to conceive at first service often has been an
erroneous reason for discarding a good bull. A large number of
records were assembled from published literature and from the

Florida Agricultural Experiment Stations

Florida station herd relative to breeding efficiency in cattle. Of
4,819 pregnancies tabulated, 62 percent conceived at the first
service, 19 percent at the second service, and 9 percent at the
third service. Few extreme instances of conception beyond the
tenth service were noted. Large numbers of records showed
that two services per conception were not unusual. In eight
experiment station herd reports studied, an average of 1.78
services were required per conception.
At the Florida station 63 percent of the conceptions studied
were from a single service, 22 percent after the second service
and 7 percent from the third service. Five extreme instances out
of 1,000 conceptions between 1922 and 1947 were from the 9th
to 14th services. Heifers at the Ohio station conceived slightly
more readily than did older cows among a group of 340 Jersey
and 379 Holstein pregnancies. The Nebraska station analysed
their records for a period of longer than 30 years and found
under their conditions that 24 percent more services were re-
quired for heifers under two years of age than for cows. It has
been observed at the Florida station and in certain other areas
that the state of nutrition (total nutrients, minerals, protein,
vitamins) is a factor affecting the regularity of oestrum in cows
and heifers. State of health of the reproductive organs also
affects the readiness of conception.
Analyses of breeding records of cows in the Florida station
dairy herd over the years 1932 to 1948 have been made relative
to conceptions obtained during the various months. Generally,
fewer services per conception were required during spring
(March, April and May) when young grass was plentiful. In
autumn (September and October) the most services were re-
quired per conception. Since the market demand for milk is
great during the winter periods in most parts of Florida, many
dairymen try to have more of their cows freshen in time for the
heaviest production at that season. Conception to services
during November through February was equal to the average of
the year (see Table 2). Adequacy of good green forage may be
concerned in seasonal conception rate, hence the desirability of
improved fertilized pastures for use with dairy herds.
Regular management of a dairy herd requires that breeding
records be kept. The service dates may be listed consecutively
in a notebook and recorded from there into a small herdbook on
the separate record of each individual cow.

Management of Dairy Cattle In Florida


Total Number Number Not Percent Services per
Month Services Conceived Conceived Conceived Conception
January 155 76 79 49.0 2.0
February 163 74 89 45.5 2.2
March 161 79 82 49.1 2.0
April 163 78 85 47.9 2.0
May -. 171 78 93 45.6 2.2
June 146 74 72 50.7 2.0
July 150 65 85 43.3 2.3
August 162 70 92 43.3 2.3
September ... 130 58 72 44.6 2.2
October 128 51 77 39.8 2.5
November 120 51 69 42.5 2.4
December -..- 190 86 104 45.3 2.2

1,839 840 999 45.7 2.2
Nov.-Feb. .. 628 287 341 45.7 2.2
Mar.-May ._ 495 235 260 47.5 2.1
June-Aug. 458 209 249 45.6 2.2
Sept.-Oct.. 258 109 149 42.2 2.4

1,839 840 999 45.7 2.2

Sampling and Proving the Sire
Young bulls, selected with the best judgment, must be proved
before too great dependence is placed on their use. The cost of
raising heifers is so great and the chances of their turning out
satisfactory so variable that it is good business to sample junior
herd sires before too great dependence is placed on their heavy
and continuous use. The better practice is to breed junior sires
to a group of heifers pending the arrival of 10 or 12 heifer calves,
a number which Copeland" found sufficient to get a reasonable
measure on transmitting ability. The junior sire then may be
held in reserve or used where heifer calves are of less import-
ance until the heifers come into production. His feed bill from
two to 41/. years of age is much less than the loss incurred should
most of his female progeny prove undesirable. In the meantime,
older cows and heifers from the most promising families within

8 Copeland, L. The Jersey Bulletin and Dairy World 51: 7-8, 28, 30-32.
January 6, 1932.

Florida Agricultural Experiment Stations

the herd are reserved for the proved senior herd sire. Once a
junior sire has proved satisfactory, there is plenty of time to
rely on his extensive use with the good cows from which all
heifer calves are to be retained. The results of proving seven
Jersey bulls in the station herd are as shown in Table 3.
Daughters Increased
Over Dams
Daughter- Daughters Dams
Sire Dam Pairs Milk Test Fat Milk Test Fat Milk Fat
Lbs. % Lbs. Lbs. % Lbs. % %
A 13 4,531 4.96 230 5,092 5.12 262 46 46
B 8 3,123 5.28 168 6,008 5.06 302 13 13
C 67 6,374 5.03 321 5,412 5.28 286 70 58
D 32 6,286 5.09 320 6,180 5.02 310 44 53
E 17 6,445 5.07 327 5,767 5.17 298 53 47
F 5 4,806 4.97 239 6,610 5.27 349 0 0
G 13"* 6,214 5.10 317 4,781 5.28 252 77 77
Based on actual 365-day records in lactations at comparable ages.
Their records are all for the first and second lactations.
What information comes from proving bulls? This can be
seen by referring to Table 3. Bulls A, B and F decreased milk
yield of their daughters. The average butterfat tests was in-
creased only by bulls B and D. The daughters of bulls C, D, G
and E produced more butterfat per year than did their dams.
Bulls C, E and G truly were herd builders. Bull D was a valu-
able sire in that his daughters were able to maintain satisfactory
milk production and to increase butterfat yield, even when they
were out of good producing cows. Bull A did not justify being in a
commercial dairy herd, while bulls B and F transmitted ex-
tremely low production to their daughters. Fortunately, the
facts concerning Bulls B and F were determined early and
these two animals were butchered before too much expenditure
was made in raising heifers by them.

Length of Useful Service
How long can a desirable proved bull be used in service under
good care and management?
A nation-wide survey of dairy bulls allowed to live out their
period of natural service provided an answer. Since a bull is five

Management of Dairy Cattle In Florida

years or older by the time his daughters can be proved satis-
factory producers, only the records of bulls past that age and
born prior to January 1, 1932, were used. The average useful
life span and anticipated usefulness of bulls at different ages
is presented in Table 4.


Number Proportion of
of Bulls Total Number



Average Age at
Last Effective

Bulls born prior to January 1, 1932.
** Too few numbers to be significant.

As shown in Table 4, these 2,636 five-year-old dairy bulls lived
to an average useful age of 10.63 years at last effective service.
In other words, they still had 5.63 years (10.63-5.00) of useful-
ness ahead on their fifth birthdays. Of that total number, 61
percent still were in active service on their tenth birthdays and
were useful for an additional 2.34 years on the average. Those
bulls still fertile on their fifteenth birthdays amount to 4.3 per-
cent of the original group, and yet were effective for a little over
a year. Beyond this age more than one-half of these animals
passed out of service in each succeeding year, so the forecast of
future usefulness is highly uncertain.


Usefulness at

Florida Agricultural Experiment Stations

Natural Causes of Termination of Usefulness
Some 4.063 records of dairy bulls eliminated from service by
natural causes have been analysed to base recommendations for
extension of the useful life of such animals. The causes which
terminated service of this group are set forth in Table 5.


Sterility--- ---- --
Cause of death undiagnosed --
Accidents, injuries, rupture, etc. --
Old age (senility)-------- -.
Inability to breed, low fertility --
Foreign bodies, wire, nails, etc. ----
Lameness, poor feet and legs ---
Diseases of digestive tract, and bloat ---
Paralysis ---- -...
Other non-infectious causes -
Infectious causes:-
Lumpy jaw (actinimycosis) --
Brucellosis -----------
Tuberculosis and Johne's disease
Trichomoniasis -----
Tumors and abscesses ---
Pneumonia --------
Kidney and bladder conditions
Diseases of the reproductive tract
Miscellaneous infections --


Number of Animals Percent
...1,156 28.5
489 12.0
-- 392 9.7
S345 8.5
320 7.9
223 5.4
S 196 4.8
88 2.2
59 1.7
96 2.4





The onset of sterility, which terminated the usefulness of
28.5 percent of the bulls studied, may be delayed in some in-
stances. A number of causes may be involved: improper feeding,
insufficient exercise, excessive use, injuries in handling or ship-
ment, and pathological conditions.
Lameness, poor feet and legs, and accidents on slippery floors
sometimes could be prevented. Use of sand or cinders can cause
sufficient wearing of the hoofs to keep the feet in good condition.
Otherwise, they need regular attention and trimming when

Management of Dairy Cattle In Florida

Autopsies showed 5.4 percent of these dairy bulls had died
from injuries due to eating metal objects (wire, nails, staples and
similar material). An electromagnet at the feed mixer and care-
ful disposal of all bailing wire may reduce this hazard.
Miscellaneous non-infectious causes of loss included licking
wet lead paint, eating poisonous plants (second growth sorghum),
and bloat. Some of these are preventable, if considered in time.
Infectious causes accounted for 16.9 percent of the losses of
dairy bulls. Lumpy jaw, caused by a spore-forming fungus, led
this list. This can be corrected medically or removed surgically, if
recognized and treated in time. New cases can be reduced by
thorough disinfection of yards, feed mangers, drinking facili-
ties and places where the infection can be spread by rubbing.
This fungus can be communicated to man, and hence a case dis-
charging pus must be regarded with alarm and handled with care.
No bull can be expected to live forever, but good feeding,
management, care and sanitation can extend the useful life span
of many valuable animals. Observation and timely veterinary
care have prolonged the life of many animals.

Keeping Dairy Records
Good management of dairy herds centers around a simple
system of herd records so that a dairyman can know, without
question, all that it is possible to know about each cow. Any
good system of herd records should be sufficiently complete that
upon absence of the owner or manager another person can take
the records and answer the following questions from them re-
garding any individual in the herd:
1. Identification of each animal (tattoo, ear mark, neck strap
number or color markings).
2. Age of the animal.
3. Breeding record up to date, with identity of progeny in
the herd.
4. Production record up to date, either on the current monthly
milk sheet or in the herdbook.
Breeding records should be kept consecutively in a breeding
diary or notebook, as shown in Figure 6, in addition to being on

Florida Agricultural Experiment Stations

Cow Date of Date Herd Number
Number Service Herd Sire Calved Sex of Calf
3-F 12- 3-46 Gold Bond 9-12-47 Male 95-F
5-F 12- 7-46 Bets 9- 9-47 Female 94-F
4-F 12-15-46 Gold Bond rebred
6-F 12-18-46 Standard 9-15-47 Female 96-F
4-F 1- 6-47 Gold Bond cow killed June 8, 1947 (beef)
7-F 1-19-47 Bets
11-F 1-20-47 Bets rebred
9-F 2-12-47 Standard rebred
11-F 2-12-47 Bets
9-F 3- 2-47 Standard
8-F 3-11-47 Gold Bond

Fig. 6.-A breeding dairy shows dates, animals concerned and identity
of progeny. Any bound notebook can have the headings written at the top
of each page and will become a permanent record for use in management of
the herd.

each cow's individual record, as in Figure 7. By such a system
one may obtain quickly a list of the cows expected to calve in
any month and know when they should be turned dry to allow
a six-weeks' rest. Knowing when the calf may be expected, ar-
rangement may be made to segregate the cow and give her closer
attention about calving time. These records often call attention
to need for veterinary care.
Many kinds of herdbooks and record systems are available,
the majority of which are satisfactory when the records in them
are complete. A compact loose-leaf record book, devised at the
Oklahoma station, contains much of the information desired in a
record system. It includes name and date of birth of the animal,
provision for identification by color marks, tattoo or herd num-
ber, a brief pedigree, and the complete reproduction record on
the face of the looseleaf form. The back side of this form has
room for four lactation records, as long as 14 months' duration.
See Figure 7. Retail dairymen may wish only milk records, while
others may wish to use the butterfat tests on each cow at
monthly or bi-monthly intervals, so that butterfat production
may be computed. These total milk yields for each month are
taken from the monthly milk sheet kept at the dairy barn, either
by daily weights, once weekly, three times a month, or with a
single day's weight at the middle of each month. Daily milk
weights require slightly more work to obtain but allow a dairy-
man to watch any irregularity in the condition of the cows as
seen by variations in production from day to day.

Management of Dairy Cattle In Florida

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Fig. 7.-The loose-leaf herdbook form, devised at the Oklahoma Experi-
ment Station, allows for identification, short pedigree and reproduction
records on one side, and four yearly production records on the reverse side
of the sheet. Dates of calving, first and last weighed milkings are shown
for each lactation.

Raising Herd Replacements
Raising Dairy Calves
The annual replacement of cows in dairy herds ranges from
20 to 50 percent. High producing profitable cows are high in
price while reasonably priced cows often are those disposed of by
other dairymen for some reason. Average depreciation rates are
higher in herds maintained by purchased replacements than in

Florida Agricultural Experiment Stations

herds raising calves. Calves sired by a good purebred bull and
out of the better cows in the herd have the possibility of de-
veloping into high-producing milk cows that are profitable.
Danger of introducing diseases and parasites into a herd is
eliminated when home-raised calves are the source of replace-
ments. Two such Florida-raised heifers are shown in Figure 8.

Fig. 8.-Animals of this type make desirable replacements in dairy
herds. This boy raised these purebred Jersey heifers as a part of his 4-H
club work in Florida.

The calf should be born in clean, dry surroundings. A clean
grass lot or small pasture having shade or shelter, and apart
from other animals, is satisfactory. Muddy lots in which many
animals have been kept should be avoided.
An attendant should be near in case assistance is necessary
during calving. The animal's navel should be disinfected with
tincture of iodine soon after birth so as to eliminate infection


Management of Dairy Cattle In Florida

and dry up the navel cord. Calves given a good start the first
three days of life are likely to develop into thrifty, vigorous
Raising Calves on Nurse Cows
A number of Florida dairymen and family cow owners place
calves with nurse cows. A good nurse cow sometimes will supply
milk for two or more calves at a time. Some dairymen replace
the older calves with young calves after several months, depend-
ing on quantity of milk and the supplementary feed available for
older calves. This is an expensive method when there is a market
for whole milk but has been a means of starting calves off well
before they can subsist wholly on other feeds.
Colostrum as Calf Feed
Colostrum, or the first milk produced by the cow after calving,
is of special benefit to the new-born calf. Every calf should re-
ceive colostrum as soon after birth as possible for three reasons.
It is rich in vitamins. It is laxative and starts the digestive
tract functioning properly. Colostrum contains anti-bodies which
help to combat infections. Without colostrum, calves seldom
survive. Many cows produce much more colostrum than is
needed by their own calves. It should not be wasted, but may be
fed to other young calves. Colostrum may be stored frozen for
emergency feeding of calves whose dams do not supply a suf-
ficient amount.
Many herdsmen like to separate the calf when less than 24
hours old in.the belief that both cow and calf become less at-
tached to each other. The cow becomes accustomed to the barn
routine and the calf will learn to drink milk soon. Usually both
cow and calf do better when the calf is separated early.

The Nipple Bucket
The young calf, nursing normally, has its head extended and
gets milk in a small stream, which passes directly to the fourth
compartment of the stomach. The bucket fed calf has its head
down and swallows in large gulps which tends to allow milk to
enter the first compartment of the stomach. The first compart-
ment does not function in early calfhood and it is not the place
for digestion of milk. Any getting into it ferments, causing in-
digestion, diarrhea and unthriftiness.

Florida Agricultural Experiment Stations

Buckets or pails with detachable nipples have been designed
to hang on the pen or fence at a height which extends the calf's
neck. The nipple has a small opening and simple valve which
allows only a small amount of milk to pass at a time and closely
simulates the conditions of normal nursing. Nipple pails are
available from dairy supply companies. Nipples and valves
should be taken apart after each feeding, to be cleaned and
sterilized. Nipples should be replaced frequently, since the open-
ings in them become enlarged after long use and allow milk to
pass too freely, defeating the purpose for which they were in-
tended. Calves raised on nipple buckets tend to be more thrifty
and have less digestive troubles.
Feeding Whole Milk and Skimmilk
Calves need about one pound of whole milk for each 10 pounds
of live weight daily. A 50-pound Jersey heifer calf can be fed
21/2 pounds of whole milk at each feed, morning and evening. The
amount of milk may be increased in proportion to the gain in
body weight, at the rate mentioned above. When price levels
allow, it is desirable for calves to receive whole milk up until six
weeks of age, in addition to hay and dry grain. Skimmilk may
replace the whole milk when the calf is six weeks of age and its
use continued until six months of age. Some roughage is eaten
as early as two weeks after birth, the amount increasing as the
calf's digestive system develops. The offering of roughage may
be as much as will be eaten without waste, but the amount of
grain may be limited according to condition of the animal, never
exceeding four pounds daily when on good pasture.
Grain mixtures to accompany the milk and roughage de-
scribed above, in feeding calves under six months old, may con-
sist of the following:
Shelled corn 100 pounds Shelled corn 100 pounds
Whole oats 100 pounds Wheat bran 50 pounds
Cottonseed oilmeal 25 pounds
High grade sweet mule feed which consists of cracked corn,
crimped oats, alfalfa-and-molasses, and linseed oilmeal is also a
good concentrate for young calves. Mixed dairy feeds may be
reduced to 12 percent total crude protein by addition of citrus
pulp and shelled corn or corn feed meal. After the calf is six
months old its grain should be ground.

Management of Dairy Cattle In Florida

When whole milk is scarce or high in price the change to
skimmilk may be made at four weeks of age, though slower
growth will follow such an early change. Re-constituted skim-
milk may be made up by using a ratio of one pound of powdered
skimmilk or powdered sweet buttermilk with nine pounds of warm
water, to be fed at about body temperature. This re-constituted
skimmilk may be fed at the same rate as fresh skimmilk. Calves
always should be fed under sanitary conditions and in clean
Calves vary in the age at which they start to eat hay and dry
grain. Some will begin when less than two weeks of age; others
later. They may be offered up to one-half pound of supplemen-
tary dry grains before six weeks of age. The offering to older
calves should be limited according to growth and development,
not exceeding three to four pounds daily at any age.

Limited Milk Feeding-Dry Method
A number of calf meals are on the market for raising calves
when milk is scarce or high in price. These meals have proved
satisfactory when from 200 to 350 pounds of whole milk have
been fed during the first six weeks of the calf's life to insure a
proper start. The meals contain an appreciable percentage of
high quality animal protein (dried milk products, soluble blood
flour, fishmeals, etc.) and are adequate for raising thrifty calves
when used with high quality leafy hay and vitamin supplements.
Many calf meals contain vitamin supplements. At 16 to 18 weeks
of age a simple grain mixture may be fed with good hay or
pasture. Most calves raised this way tend to have rough hair
and be pot-bellied when six months of age, but if properly fed
and cared for between six and 15 months they will grow to
normal size and weight at breeding age.

Liquid Milk Substitutes and Gruels
Several substitutes for milk containing dried milk by-products
are on the market. They are substituted for milk at 10 days to
two weeks of age and are fed as a gruel early in the calf's life.
Later they may be fed dry if desired. Considerable time is in-
volved in preparing gruels and extreme care should be exercised
in cleaning and sterilizing the utensils and buckets. Such liquid
gruels are recommended to be fed up to six months of age.

Florida Agricultural Experiment Stations

Precautions in Calf Management
Always weigh or measure milk in proportion to weight of the
calf. A Jersey calf at birth needs about 1 to 11/2 quarts of milk
per feeding and the milk should be fed at body temperature and
at 12-hour intervals. Overfeeding or sudden changes often upset
the digestive system. At the first sign of digestive upset the
offering of milk should be reduced until the animal recovers.
Fresh clean water should be available continually. A limited
allowance of leafy hay or fresh green feed should be available.
All feeding utensils, pens and yards need to be kept clean.
A good calf man knows each individual animal and watches
all of them closely. The success of raising calves depends largely
upon his interest and skill in caring for each individual animal
regularly according to its needs.

Feed from Weaning to Breeding Age
Calves usually are considered old enough to wean from milk
products at four to six months of age, though if surplus milk is
at hand its use may be continued. Good pasturage and a good
grade of dry roughage, silage and mineral supplement may make
up the major portion of the feed for growing heifers. Mineral
supplements are essential, particularly where the pastures and
roughages are grown on certain light sandy and muck soils or
soils that respond to heavy phosphate fertilization, as will be
discussed later. Some mixed grain may be offered, but in limited
amounts. A mixed feed containing 12 to 16 percent total crude
protein is adapted for heifers at this stage of growth. Such a
feed may be made up of cornmeal, dried citrus pulp, wheat bran,
cottonseed meal and other similar feeds which are reasonable in
price. The amount of grain should vary inversely with the
amount and quality of roughage accessible to the heifers. Heifers
should be in vigorous growing condition, but not excessively fat,
at breeding age.
Age to Breed Heifers
Large vigorous heifers may be bred two or three months
younger than animals that are under-developed or in poor con-
dition. The average ages recommended for service vary with the
size and rate of maturity of the different breeds, and are as

Management of Dairy Cattle In Florida

Jersey -- 15 to 18 months
Guernsey ---- --- -- 16 to 20 months
Ayrshire --.-- 17 to 21 months
Holstein ... 18 to 22 months
Brown Swiss -..-----..-.- 20 to 25 months
Breeding practice followed with heifers in 249 Florida dairy
herds was such that 11.9 percent calved when under 24 months
of age, 41.4 percent between 24 and 30 months, and 46.7 percent
when 30 months of age or over. The average estimated weight
of all cows was only 736 pounds. Fifty-seven percent of the herds
were comprised of purebred or grade Jersey cows and another 37
percent had partly Jerseys, with some additional Holsteins,
Guernseys, Ayrshires or Dutch Belted cows.
Sufficient fertilized pasture, home-grown roughage and ade-
quate mineral matter, with limited allowance of concentrates,
will allow heifers to grow to good size. Extensive studies have
shown that within each breed the larger cows usually are the
heavier milk producers.
Feed from Breeding to Calving Time
The daily routine after a heifer is safely with calf should be
similar to that followed before breeding age. Roughage may
constitute the main part of the feed, this to be supplemented
with mineral matter as outlined below and with such limited
grain as the abundance and quality of roughage may require.
Two months before the heifer is due to freshen is not too early
for her to come into the stanchions for an extra allowance of
grain. The object of feeding extra grain is two-fold: (a) to get
the animal in condition for maximum milk production after
calving and (b) to accustom her to the stanchion and barn rou-
tine before she must be milked. This period of barn training
makes a heifer more tractable and also gives a dairyman oppor-
tunity to anticipate the time of calving. Access to mineral sup-
plements needs to be given especial attention in the period just
prior to calving, particularly on light sandy and muck soils.
Likewise, good skeletal storage of calcium and phosphorus needs
to be provided prior to the first lactation.

Mineral Supplements for Cattle
Calves, rapidly growing heifers, pregnant animals and cows
in milk have a high requirement for mineral matter. Mineral

Florida Agricultural Experiment Stations

elements are needed by these animals to build the red portion of
blood, muscles and organs, as well as the straw-colored part of
the blood, the skeleton, to stimulate appetite, and to provide for
the minerals in milk.

Cattle never should be allowed to suffer from mineral short-
ages. Feeds may be selected with a knowledge of the nutrients
which they provide
for growing animals
and milking cows.
Legumes usually con-
tain from three to
five times more lime
(calcium) than do
grasses or silage crops
(corn or sorghum)
grown on the same
land. Wheat bran and
several oilmeals are
high in phosphorus
content. Seeds and
grains usually contain
less iron than do the
leaves and stems of
plants, the amounts be-
ing related to richness
of soil in the element.

Fig. 9.-A three-compartment mineral box
where cattle may have free access, and the sup-
plements be protected from wind and rain. One
compartment is for common loose salt, one for
steamed bone meal (feeding grade), and the
third is for the iron-copper-cobalt supplement.
Separate access to these allows the animal to
use the one needed without forcing use of the
other supplements unnecessarily.

It is advisable un-
der most Florida con-
ditions to give cattle
free access to addi-
tional mineral matter
in a sheltered three-
compartment box, as
shown in Figure 9. The
first and second com-
partments may con-
tain common loose salt
and steamed bone
meal, respectively.

Management of Dairy Cattle In Florida

Either of the following mineral mixtures may be used in the
third compartment.
No. 1 No. 2
Common salt 100 lbs. Common Salt 50 lbs.
Red oxide of iron 25 lbs. Bone meal 50 lbs.
Pulverized copper sulfate 1 lb. Red oxide of iron 25 lbs.
Cobalt sulfate 1 oz. Pulverized copper sulfate 1 lb.
Cobalt sulfate 1 oz.

Mineral supplement No. 1 is for general use with animals on
light sandy and muck soils. The reduction in amount of salt,
and substitution with bone meal, adapts supplement No. 2 for
use with animals on areas near salt water or where the drinking
water is brackish. It is particularly desirable that the iron-
copper-cobalt supplement be used with calves, growing heifers
and pregnant cows at all times, on areas that are marginal or
deficient in any of these mineral elements.
Steamed bone meal (finely ground feeding bone meal) sup-
plies both calcium and phosphorus in a safe, palatable and
readily available form at relatively low cost. Its use is general
with dairy cows and also on ranges where cattle chew bones,
leather, oyster shells and similar objects. The presence of
broken ribs and hips in any dairy herd is an indication that
bone meal should be added to the ration. Cattle consume more
mineral matter in late fall, winter and early spring when on
mature fibrous pasture herbage. Heavily milking cows eat salt
and bone meal in larger amounts than do heifers and dry cows,
while cows advancing in pregnancy use more of the iron-copper-
cobalt supplement than do cows recently fresh.

Factors Affecting Milk Yield
Season of Calving Affects Yearly Milk Yield
The influence of season of freshening on milk yield was
measured by an analysis of 319 complete normal lactations of
Jersey cows milked twice daily in the Florida station herd.
These records were obtained over a 16-year period and showed
the general trend of seasonal production with cows freshening
at different seasons.
Cows fresh during the winter months (December to Febru-
ary) gave slightly more milk and were the more persistent pro-
ducers. Those calving in the autumn (October and November)

Florida Agricultural Experiment Stations

followed the first group very closely. Cows fresh in the summer
(June to September) ranked below these in milk yields, while the
spring calving group (March to May) produced the least. Only
very small differences were noted in the milk yields of the cows
fresh in autumn, winter and summer. However, the group of
cows freshening in spring produced less than did the groups
which calved during other times of the year.
The summer rainy season-a period of flush pastures-
exerted a noticeable influence in maintaining daily milk produc-
tion (see Fig. 10). The decline in daily milk yields was more
rapid just after the close of the rainy season, when pasture
turned dry and vegetation became scanty and fibrous. The time
of the rainy season in relation to the stage of lactation appeared
to be a significant factor in these differences in milk from season
to season. However, these differences were of smaller magnitude
than are those observed in other regions farther north where
there are greater seasonal differences in environment. A sum-

Tariatlons In daily ilk yield due tol
Sontbh In lactation -
Calendar onth -- --


. 10

months in actatlon
1 2 3 4 5 6 7 s 9 10 11 12
JTa b lirch April Iye Jam J1Uy iAV Sept Oct NOT .o

Fig. 10.-Daily milk yield was stimulated during spring and early
summer when young and succulent pasturage was available (see broken
line). Milk yield was depressed by advancing lactation (see solid line).
The latter influence was of greater magnitude than the former, as it affected
ultimate milk yields of individual cows in the herd.

Management of Dairy Cattle in Florida

mary of the average milk yields by cows fresh at different
seasons is given in Table 6.
1917 1932.
Season of Number of Total
Freshening Lactations Milk Yields
Spring 74 4,864
Summer 104 5,339
Autumn 70 5,436
Winter 71 5,445

Age Influences Milk Production
Studies of milk records in other parts of the United States
have shown that Jersey and Guernsey cows attain their peak of
milk production when seven to eight years of age, and the larger,
later-maturing breeds at about one year older. The average
percentage of butterfat of the milk of cows declines to a lesser
degree with advancing age than does milk production.
Length of Dry Period Affects Milk Yield
How long should cows be dry?
The answer to this question depends upon how the dry period
influences milk production and welfare in the next lactation, and
also upon the local demand for dairy products. In times of local
surplus of milk it may be desirable either to turn some cows dry
sooner or to cull out the less profitable animals. A survey showed
that Orlando dairymen turn their cows dry an average of 46
days, Tampa dairymen up to 60 days, and the average for the
state is 55 days.
Influence of length of dry period upon subsequent lactation
was measured by an analysis of 291 lactations of cows in the
Florida station herd, calving fairly regularly throughout dif-
ferent seasons of the year. Since these cows had received
rations low in calcium prior to 1929 and adequate in calcium
thereafter, it was desirable to summarize milk yields of these
groups separately. All records were divided into five groups,
namely: initial lactations and those preceded by dry periods of
30 days or less, 31 to 60 days, 61 to 90 days and over 90 days in

42 Florida Agricultural Experiment Stations

The group of 73 lactations following dry periods of 31 to 60
days showed the highest average milk yield per lactation. Since
this length of dry period also is the one generally used by suc-
cessful dairymen, this average milk yield (5,775.5 pounds) was
used as a base with which to compare the production of other
classes. Cows dry less than 30 days produced 7.6 percent less
milk; those dry 61 to 90 days, 5.3 percent less; and those dry
longer than 90 days, 11.2 percent less milk than the basal group.
First-calf heifers produced 8.1 percent less than did the group dry
31 to 60 days. It appears from this that the general practice of
allowing a dry period of 31 to 60 days favors optimum milk pro-
duction in commercial dairies.
The average production for each group of lactations is pre-
sented in Table 7.
Average Yields per Lactation
Number On On Percentage
of Low-Calcium Adequate Average of Base
Dry Period Lactations Rations Rations Yields
Pounds Pounds Pounds Percent
Initial lactations 53 4,632.0 -
15 -7,581.6
68 -- 5,306.0 91.87

30 days 10 4,806.2
or less 9 5,926.5
19 -- 5,335.6 92.38
31-60 days 54 5,188.1 -
22 7,185.1
76 5,775.5* 100.00

61-90 days 45 4.937.7 -
14 7,373.0
59 -- 5,468.0 94.68

91 days 56 4,690.9- -
or more 13 -6,878.0
69 5,126.9 88.77
Weighted 218 4,856.0 -
average 73 -7,092.7
291 5,420.9
Since a dry period of one to two months has been recommended popularly, the milk
yields for this group were used as a base with which to compare these groups.

Management of Dairy Cattle in Florida

Mineral Supplements as Related to Milk Yield
Rations adequate in the mineral elements required in nutri-
tion of dairy cows are not benefitted by the addition of more
mineral matter. When dairy rations contain an adequate pro-
portion of high quality legume hay, corn silage and a grain
mixture which contains some wheat bran and an oil meal, no
additional mineral matter except salt is required by cows in
commercial dairies. Even with the best of rations, however,
high-producing cows require attention to the mineral content of
their feeds. Common salt is deficient frequently. On acid soils
or where the roughages are entirely grasses rather than legumes
calcium (lime) may be needed. Certain types of soils are low in
available phosphorus. Others may lack iron, copper and cobalt,
or there may be instances where two or more of these elements
may be deficient on the same land. Under these circumstances
cows respond to mineral supplements in the rations. The degree
to which these elements are lacking will affect the response that
may be anticipated when they are supplied.
The pasture and crop lands at the Florida station were on
acid sandy soil, low in available lime. The forages supplied to the
dairy herd were mainly silage crops and pasture grasses grown
on these unlimed lands. Under these conditions the rations
formerly fed were low in calcium content. The calcium content
of the rations was increased later by addition of 2 percent of
finely ground feeding steamed bone meal to the concentrates.
The higher producing cows received a limited offering of alfalfa
hay. These changes provided sufficient calcium to meet the re-
quirements of Jersey cows in commercial dairies. More recently,
1 percent each of bone meal and kalsite (marble dust) are being
used in place of 2 percent of bone meal. As mentioned in the
study of dry periods, the lactations were divided into two groups:
(a) those while the cows received rations low in calcium and (b)
those on rations adequate in calcium content. The records also
were grouped according to length of preceding dry period, al-
though the numbers in each group are so few that these averages
can be considered only indicative.
The average of 218 lactations while the cows received low
calcium rations was 4,856 pounds of milk. The 73 lactations on
rations adequate in calcium average 7,092 pounds of milk, or an

Florida Agricultural Experiment Stations

increase of 46 percent. While many of the animals appeared
only in one group, this difference compares closely with a
separate study which involved lifetime production of 12 cows
that had complete normal lactations under each set of conditions.
(See Table 7.)
Mixed dairy feeds marketed in the Southeast in recent years
contain supplementary bone meal and finely ground limestone,
so that in large part this deficiency of calcium is being corrected.
Application of lime on improved pastures also tends to correct
this deficiency. Where rations are home-mixed it is desirable to
consider this part of the ingredients carefully and to supplement
the ration with such elements as may be needed locally.

Managed Milking
From research on milk secretion and methods of milking by
W. E. Petersen and associates at the Minnesota station, milking
practices have evolved whereby the milk is obtained from the cow
in a minimum of time. The method has been described briefly,
as follows:
1. Prepare the cow's udder by washing with warm water
(about 125 degrees F.) or a good warm antiseptic solution. Warm
water stimulates the cow to release a hormone which causes the
udder to let down milk, requiring about 45 to 60 seconds. Draw
two streams from each teat into a strip cup to check for infec-
tion in any quarter and hence to prevent spread to other cows.
2. Begin milking one minute after stimulation of the udder.
Use the full-hand grasp in hand milking to prevent injury to teat
linings. In machine milking follow the manufacturer's instruc-
3. Milking should be completed in three or four minutes. With
machine milking, pull down on the teat cups when they tend to
crawl upward, to prevent closing off the teat canal from the milk
4. Most cows can be stripped by machine. As the final step,
pull down on the teat cups while massaging the udder downward
to complete the operation. Few cows require hand stripping.
5. Remove the teat cups as soon as milk stops flowing to
prevent injury to the delicate lining of teats and milk cisterns.

Management of Dairy Cattle in Florida 45

Factors affecting the Butterfat Content of Milk
Variations in the Butterfat Content of Milk
Butterfat content of the milk of any cow is affected by a
number of independent factors, most important of which is
heredity. The butterfat test of Jersey milk differs from that of
average Holstein milk. Within a breed, the butterfat content
likewise is governed by heredity, there being high, medium and
low testing individuals in every dairy breed. The milk of Holstein
cows on yearly Herd Improvement Registry test contained an
average of 3.47 percent butterfat, whereas that of Jersey cows
contained 5.36 percent butterfat. The average for Guernsey
records is 4.97 percent butterfat; for Ayrshire 4.04 percent; and
for the Brown Swiss breed 4.01 percent butterfat. These are
averages, about which the various individuals of these different
breeds may vary. It is possible to select strains within each of
the breeds that transmit a higher, or a lower, average butterfat
content in milk. In fact, by such definite selection the typical
butterfat test of Friesian cattle was increased more than 0.75
percent butterfat within a 40-year period because of the knowl-


i -4.5
YT=UlationB in fat percunt-ge d-3 ta,
mInths in lactation --_-^ .
.0 Calendar -Doth ------

0.5ntl in lactation

Fig. 11.-The butterfat content of Jersey milk tends to increase .in
cooler weather and also with advancing stage of lactation.

46 Florida Agricultural Experiment Stations
edge that with cows of equal size and milk yield, those with the
higher butterfat test produced butterfat more economically.
Two factors next in importance to heredity are the stage of
lactation and the season of the year (environment). Records of
purebred Jersey cows in the Florida station dairy herd were
analyzed to determine the influence of these two factors. The
result of these analyses is shown in Figure 11. The milk of pure-
bred Jersey cows tends to test low in the first two months after
calving and to increase gradually in richness as the lactation ad-
vances. This analysis was made in such a way as to distribute
evenly any seasonal influence.
Regardless of stage of lactation, Jersey milk tends to be
richer in butterfat in the winter months and lower during the
summer months. These ranges in butterfat content tend to
follow those noted in more northerly latitudes. When cool
weather is incident with the latter stages of lactation both fac-
tors operate together for a high fat percentage in the milk, and
the opposite may occur with cows freshening in warm weather.

Richness of Morning and Evening Milk
A group of 1,785 butterfat tests was obtained from 595 series
of three consecutive milkings from Jersey cows in the station
herd. It was observed from these that the average morning milk
tested 5.10 percent fat and the evening milk 5.72 percent fat in
this herd, the difference being 0.62 percent fat. Occasionally the
morning milk tested higher than the evening milk. A 14-hour
interval preceded the morning milkings and 10-hour interval the
evening milkings. Thus the lower butterfat tests were after the
longer interval between milkings. These observations are in ac-
cord with results of similar studies in other regions.
When the first butterfat test was above the average for the
Jersey breed, generally the next test tended to be lower. Follow-
ing an extremely low test, the general trend was toward a test in
the succeding milking near to, or above, average. Two consecu-
tive milkings from a single cow have varied from 2.4 to 8.1 per-
cent fat, although variations of more than 2.0 percent occurred
When milk samples are being taken to determine the per-
centage of butterfat therein, either for the herd record of a
single cow or in city milk inspection, it is well to remember that

Management of Dairy Cattle in Florida

the tests of morning and evening milk differ. Truly representa-
tive butterfat tests for such uses can be obtained only by using
both morning and evening milk from the same source.
Age Influences Average Butterfat Test
Cows advancing in age usually yield milk of slightly lower
butterfat content than do younger animals. Records of 22 cows
in the Florida station herd for eight or more lactations showed
this trend. These 22 cows had an average test of 5.17 percent
butterfat in their first lactations, as compared with 4.72 percent
in their eighth lactations. The decline in fat percentage with age
in Guernseys is similar to that with Jerseys. This decline is less
in the breeds producing milk of a lower butterfat content.
Economic Phases of Dairying
Season of Calving in Relation to Milk Sales
Dairymen generally try to have cows freshen at regular
intervals during the year, in order to meet the demand of their
market for milk. In towns having an important volume of
tourist trade the demand is seasonal and requires a larger pro-
portion of cows in heaviest milk during that period.
The survey made of commercial dairies in Florida by Bruce
McKinley showed that the peak of whole milk sales at that time
was in December in the St. Petersburg area and in January in the
Miami and Orlando areas. In the Jacksonville area peak milk
sales occurred during May and July, and in the general farming
area during March and May. The period of low milk sales was
mainly in August and September.
Management of the breeding program in respect to market
requirements for milk is reflected to a considerable extent in the
actual percentage distribution of calvings, as is shown in Table
8. These data, derived from reports of dairymen in various
parts of the state, show the peak months of calving as December
and January. Peak milk production generally occurs about six
weeks later than calving and this would be in the months of
January, February and March.
Relation of Production per Cow to Labor Required
and to Relative Cost of Milk
Some pertinent records were assembled from the survey of
dairies of the state by McKinley. A significant point was that
with equally careful management a herd of low-producing cows

Florida Agricultural Experiment Stations

(Average of four years: August, 1944, to July, 1948)
Month Cows Freshening
January -........... --------------- -- 10.1
February ---------------- 9.3
March .........---------------------- 9.1
A pril .. .. .. .. .- 7.6
May --------- 6.6
June ------- 6.6
July ......---------- 4.5
August -------------- -- 8.0
September ----------------- 9.2
October --.......---------- 8.8
November -------- 9.2
December ------- 11.0

Total .... .......------ 100.00
SReported by commercial and non-commercial dairymen to the U. S. Bureau of Agri-
cultural Economics at Orlando, Florida.
had almost the same overhead costs as did high-producing herds.
Thus, the overhead costs per 100 pounds of milk increased as
production per cow decreased; likewise, labor required per 100
pounds of milk increased as production per cow decreased when
other cost factors remained constant. This principle, as noted
in the 1927 study in the state, has been observed also in a later
study in North Carolina as shown in Table 9. These data show
labor in relation to sales of milk per cow. Milk sales were some-
what less than total production. Net costs of milk per 100
pounds sold also increased as production per cow decreased.
Cows producing less than 5,000 pounds of milk had total costs
35 percent higher than did those producing 6,200 pounds or more.

Number Average Labor per Net Cost of
Milk Sold per of Milk Sales 100 Pounds Milk Sold per
Cow Farms per Cow of Milk Sold 100 Pounds
Pounds Pounds Hours
Less than 5,000 --- 24 4,421 4.48 $3.58
5,000 to 6,199 --... 34 5,580 3.33 $3.05
6,200 or more ...- 31 6,991 2.50 $2.66

All Farms --- 89 5,868 3.14 $2.96
Adapted from R. E. L. Greene, North Carolina Agricultural Experiment Station
Bulletin 345. 1944.

Management of Dairy Cattle in Florida

Feed is the largest single item of cost of milk production.
Whether or not it pays to use a large amount of purchased feed
depends entirely upon prices of feed and dairy products. Some-
times, milk and feed price levels are such that it is desirable to
depend largely on home-grown roughages and pasture, balanced
with a minimum of concentrates. This will make the labor cost
per 100 pounds of milk somewhat higher. More frequently in the
past, price levels have been such that it was profitable to feed
more concentrates in the ration for a higher level of milk produc-
tion per cow and a lower overhead and labor cost per 100 pounds
of milk marketed.
From a study of 106 farms in Montgomery County, New York,
during 1944-1945,9 it was found that, "high output of milk per
worker was an important key to production efficiency and fi-
nancial success High output of milk per man was obtained
principally by these practices:
1. Keeping moderately large herds, which made possible,
2. Spending less than the average amount of time per cow to
do the dairy chores in the stable and yet
3. Having better-than-average producing cows."

Raising Versus Purchasing Replacements
Considering only original or first cost, it may be cheaper for
many Florida dairymen to purchase replacements than to raise
them. Many of the larger commercial dairies in the state, par-
ticularly those selling milk at wholesale, follow the practice of
buying cows from other areas to replace cows going out of the
herd. There are, however, many disadvantages in purchasing
cows, some of which even experienced buyers of cattle cannot
It is almost impossible to build up a high-producing herd from
purchased cows, because their ancestry is largely unknown and
selection and breeding of high-producing families cannot be
practiced. From a survey of 863 farms in Connecticut in 1928
it was found that farms using purebred bulls of known high-
producing ancestry obtained 10.6 percent more milk per cow

9 Farm Economics, Cornell University, No. 152, Sept. 1946. L. C.

Florida Agricultural Experiment Stations

yearly than did those using grade bulls (Table 10). High-
producing cows cost more per year to keep, but they make more
efficient use of their feed and produce milk at a lower cost per 100

Average Yield Percent
Percent of of Milk per of
Quality of Bulls Used Farms Owning Cow per Year Production*
Purebred, of known high-
producing ancestry __. 15.0 7,377 110.6
Purebred, ancestry of
unknown production -- 48.9 6,827 102.4
Grade 36.1 6,670* 100.0
SAdapted from "Statistical Summary of Dairy Survey of Connecticut, 1928." Connecticut
Agricultural College and Extension Service, Storrs, Connecticut. Mimeo.
The average production of herds headed by grade bulls was used as 100 percent.

It was found in the Connecticut study also that the prevalence
of abortion and udder trouble was higher in herds with pur-
chased replacements than in herds raising their replacements
(Table 11). There is the possibility of introducing brucellosis,
mastitis or other diseases into the herd from purchased cattle.

No Slight Serious
Evidence Evidence Trouble
Percent Percent Percent
Farms raising all their cows .---..- ---- 62.0 33.0 5.0
Farms raising 50 to 99 percent of their cows 55.5 30.7 13.8
Farms raising 1 to 49 percent of their cows --- 40.1 35.1 24.8
Farms purchasing all their cows 37.9 37.9 24.2
Udder Trouble
Farms raising all their cows ---.---.. 70.0 17.0 13.0
Farms raising 50 to 99 percent of their cows -_ 49.8 16.1 34.1
Farms raising 1 to 49 percent of their cows --- 44.2 19.4 36.4
Farms purchasing all their cows 52.1 11.6 36.2
1Adapted from "Statistical Summary of Dairy Survey of Connecticut, 1928." Con-
necticut Agricultural College, Extension Service, Storrs, Connecticut. Mimeo.

Cows purchased for replacements do not last as long on the
average in the service of the purchaser as raised stock. One

Management of Dairy Cattle In Florida

reason is that purchased cows sometimes have had one or more
lactations and some are eliminated soon because of disease, low-
production or other reasons. In 1945 and 1947 data were ob-
tained from about 60 dairymen in Florida on the rate of turnover
or replacement of cattle in their herds. Most of the commercial
dairies were buying all or a large part of their replacements.
From these data and from estimates by the dairymen as to a
cow's service life, it appears that purchased cows lasted about
three years in the herd. In the Miami area the period of useful-
ness was only about 2 to 21/. years and in the Tampa, Jackson-
ville and Orlando areas about three years. Cows in the largest
dairies had a shorter period of usefulness than in smaller dairies.
Cows in Florida dairies with raised replacements were found
to have an average life spar of 6.6 years, or about 4.1 years of
productive usefulness in the herd. This is 37 percent longer
service life than was obtained from purchased cows (Table 12).


(Excludes Cows Sold for Dairy or Breeding Purposes Only)
Number of Percent Average Anticipatec
Cows Still of Total Age at Usefulness
stained Age Living Number Disposal Different As

2.0 to 2.9 978
3.0 to 3.9 918
4.0 to 4.9 798
5.0 to 5.9 673
6.0 to 6.9 509
7.0 to 7.9 393
8.0 to 8.9 292
9.0 to 9.9 196
10.0 to 10.9 128
11.0 to 11.9 91
12.0 to 12.9 59
13.0 to 13.9* 35
14.0 to 14.9* 18
15.0 to 15.9* 14
16.0 to 16.9* 7
17.0 to 17.9* -
18.0 to 18.9: 2
19.0 to 19.9* 1
Insufficient numbers to be significant.








Florida Agricultural Experiment Stations

In Connecticut cows in herds raising replacements lasted 4.0
years and in herds purchasing replacements 2.6 years.1"
The longer period of usefulness of raised replacements, even
if their first cost is somewhat higher, may make their cost per
year of service and per 100 pounds of milk less than with pur-
chased cows. This is because their cost is spread over a longer
period of useful life and higher total milk production. A method
for calculating depreciation or cost per year is shown in a subse-
quent section.

Average Useful Life Span and Reasons for
Replacements of Dairy Cattle
Professor W. J. Fraser of Illinois has said, "It takes all the
profit a good cow can make in her first two years to pay off this
debt (of cost at first calving) and whether or not she will
prove a profitable cow will depend upon how many years she con-
tinues after this to return a good profit over the cost of her keep.
The length of her producing life has a great deal to do with the
profit she earns for the dairyman."
Data have been obtained from 13 commercial dairies in
Florida raising most of their replacements and covering the use-
ful life span of 978 cows. Records were obtained on the birth
date and disposal date of each cow, together with the reason for
disposal. The life span of 978 cows with the average life ex-
pectancy at different ages is shown in Table 12. No cows were
included which did not attain an age of two years and come into
the milking herd. Thus, the mortality experienced in raising
calves and heifers cannot be obtained from Table 12.
All cows averaged 6.6 years of life, or about 4.1 years of use-
fulness in the milking herd. At five years of age only 673, or
68.8 percent, of the original number remained in the herd. Cows
which reached 5 to 5.9 years of age, however, averaged 8.0 years
of life, and thus a dairyman could expect them to last about 2.5
years longer on the average. At age nine only 196, or 20 percent,
of the original 978 remained, with an additional life expectancy
of about 1.7 years. A larger number of observations is needed to
be conclusive but these observations should be helpful to dairy-
men, especially in the purchase of high-priced cattle in estimat-

la Published in Hoard's Dairyman, January 10, 1947. Data on 763
dairy farms, Connecticut.

Management of Dairy Cattle In Florida 53

ing how much longer a cow of a given age may be expected to
stay in the herd. It will be noted that a very high rate of loss or
culling occurs at ages of 4.0 to 7.9 years, with the highest rate at
6.0 to 6.9 years. The small proportion of older cows that are good
producers frequently have to pay the losses entailed by any
younger animals that have proven unprofitable.
The reasons for replacement of dairy cattle were known in
some cases where it was not possible to calculate their ages, thus
resulting in a larger number of observations for "reason for
disposal." In Table 13 are shown the principal reasons why 1,469
dairy cows left the herd. Cows which were sold for dairy or
breeding purposes were excluded.

(Excludes Cows Sold for Dairy or Breeding Purposes Only)
Number Percent
Reason for Disposal of Cows of Total
Mastitis and udder trouble .... .. ...... 309 21.0
Low production (culled) ...---.. 216 14.7
Reproductive troubles -....- ...... .... 137 9.3
Old age ----...----. ..... .... 29 2.0
Combination of above reasons -----. 66 4.5
Accidents and injuries ....... ...... 33 2.3
Diseases ---. .. ....-.......... ........... 50 3.4
Other reasons ..... ...-- --..-- .. ... 30 2.0
Unstated ... ... .. -- .... ..... 417 28.4
Diseases ---- ------.- 84
Reproductive troubles -..... 30
Accidental death 21
Old age ---- ----- 12
Unknown causes .----- -35

182 12.4

Total .- -- ----. ...... 1,469 100.0

Mastitis and udder trouble were responsible for 21 percent of
all disposals, or 24 percent of those disposed of before death.
This was the most serious cause of loss. Low production was
given as the reason for the sale of 14.7 percent; reproductive
troubles, 9.3 percent; and old age, 2 percent. Various combina-
tions of two or more of the above reasons were responsible for

Florida Agricultural Experiment Stations

the loss of 4.5 percent and accidents and injuries 2.3 percent. Dis-
eases accounted for 3.4 percent of the losses, of which Bang's
disease (brucellosis) caused about half and Johne's disease about
a fourth.
About 28 percent of the disposals, representing the largest
group, was for unknown reasons. It is probable that these cows
would be distributed among the above groups if the reasons for
their disposal were available.
Death caused the loss of 12.4 percent of all the cattle ob-
served. Various diseases, reproductive troubles, accidents and
old age were the important reasons for death.

Depreciation of Dairy Herds
No set rate of depreciation can be assigned to dairy cows that
will apply under all conditions. Depreciation rates change with
changes in the various factors which enter into depreciation
costs. These factors are:
1. Initial cost of cow at first calving or at time of purchase.
2. Length of useful life in years. This is apparently longer
for raised than for purchased animals. Purchased replacements
seem to have a service life after purchase of about three years
and raised cows about 4.1 years after first freshening.
3. Salvage value, which fluctuates with beef prices.
4. Death rate. This should be included in the depreciation
rate to avoid a separate calculation for deaths. Cows eliminated
by death are a total loss to the herd, and including average death
rates in depreciation makes allowance for this cost. In 1945 the
death rate was found to be about 3.9 per 100 cows in a number of
commercial dairies in the state which were purchasing most of
their replacements. It was found to be 4.6 percent on 249 dairy
farms in Florida in 1927 by McKinley.
When the initial cost, service life, salvage value and death
rate of dairy cows are known, the depreciation rate may be calcu-
lated by the following formula:
Cost 1 Deaths per 100
(- ) X Salvage value=Depreciation
No. years No. years 100 cost per year
of use of use in dollars.

Management of Dairy Cattle In Florida

With assumed factors, a method of calculating the rate of de-
preciation for a dairy herd is illustrated below:

Average value or cost per cow ..---------- $150
Average number of years of service life --- 3.0
Average salvage value ------------- $80
Death rate per 100 cows per year 3.9
$150 1 3.9
(- ----) X $80 = Depreciation per year
3 3 100
$50-[(.3333 .039) X $80] or
$50-($26.66 $3.12) or
$50-$23.54 $26.46, Average depreciation cost per year per cow

The depreciation cost in dollars divided by the average initial
cost of a cow and multiplied by 100 gives the annual rate of de-
preciation in percent:

-- X 100 = 17.6 percent

Should any of the factors affecting depreciation cost change,
the rate and amount will change. Thus, for a cow costing $300,
the annual depreciation would be $76.48, or 25.5 percent of her
cost, if other assumptions remain constant. For $150 cows with
4.1 years of service life and $80 salvage value, the depreciation
cost per year would be $20.20 or 13.5 percent.
No interest has been included in these calculations. Interest
costs would vary directly with the cost of the cow.
The effect of a cow's useful life span and of initial cost on
depreciation cost is shown in Table 14. The depreciation cost
per gallon has been calculated at three different levels of pro-
Thus, it can be seen that a longer useful life span is important
in keeping down annual depreciation cost per cow. Adding a year
to a cow's service life spreads the cost of her unproductive years
over a longer period.
The higher the initial cost of a cow, the higher her annual
depreciation, assuming a fixed life span and salvage value. De-
preciation cost per year increases more than proportionately
with increasing initial cost. This however, does not point toward
the use of low grade cows, as their productivity may also be low
and other costs higher.

Florida Agricultural Experiment Stations


Depreciation Depreciation Cost per Gallon
Useful Assumed Cost per 600 800 1,000
Life Valuation Year Gallons Gallons Gallons
Effect of Useful Life
1.0 $150 $73.12 $0.122 $0.091 $0.073
2.0 150 38.12 .064 .048 .038
3.0 150 26.46 .044 .033 .026
4.0 150 20.62 .034 .026 .021
5.0 150 17.12 .029 .021 .017
Effect of Initial Cost
3.0 100 9.79 .016 .012 .010
3.0 150 26.46 .044 .033 .026
3.0 200 43.13 .072 .054 .043
3.0 250 57.79 .096 .072 .058
3.0 300 76.46 .127 .096 .076

At any given life span and initial cost of a cow, depreciation
cost per gallon decreases directly as production per year in-
creases. The herdsman should strive for cows of higher produc-
tion and make every effort to extend their profitable service life
to obtain the lowest depreciation cost per gallon of milk produced.


The dairy herd records prior to June, 1928, were accumulated
under the supervision of Professor John M. Scott, formerly
Animal Industrialist and Vice-Director of the Florida Agri-
cultural Experiment Station. Many persons who have worked
with the dairy cows through this period of years are responsible
for the completeness and accuracy of the records upon which
these studies are based. A number of Florida dairymen, and
breeders of dairy cattle over the United States and Canada, have
cooperated in providing records concerning useful life span and
causes of losses of dairy cows and bulls under practical con-
ditions. Dr. D. A. Sanders aided with the discussion of two sec-
tions concerning dairy calves. The cover photograph was made
by J. Francis Cooper on Holly Hill Dairy in Duval County.