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Group Title: Circular Florida Cooperative Extension Service
Title: Raising dairy replacement heifers
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Permanent Link: http://ufdc.ufl.edu/UF00014508/00001
 Material Information
Title: Raising dairy replacement heifers
Alternate Title: Circular 770 ; Florida Cooperative Extension Service
Physical Description: 18 p. : ill. ; 28 cm.
Language: English
Creator: Harris, Barney Jr.
Shearer, Jan K.
Publisher: Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 1988
 Subjects
Subject: Heifers -- Breeding   ( lcsh )
Dairy cattle -- Breeding   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )
 Notes
Statement of Responsibility: Barney Harris, Jr. and Jan K. Shearer.
General Note: Cover title.
 Record Information
Bibliographic ID: UF00014508
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: ltqf - AAA6948
ltuf - AFE9102
oclc - 18896275
alephbibnum - 001065047

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Full Text





Circular 770


Raising Dairy

Replacement

Heifers
Barney Harris, Jr. and
Jan K. Shearer


Florida Cooperative Extension Service / Institute of Food and Agricultural Sciences
University of Florida, Gainesville / John T Woeste, Dean for Extension


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Barney Harris, Jr. is Professor and Extension Nutrition Specialist, Dairy Science Department and Jan K. Shearer is
Associate Professor, Dairy Cattle Extension Specialist, College of Veterinary Medicine, IFAS, University of Florida,
Gainesville.







Table of Contents

Introduction . . . . . . . . . . . . . . . . . . . . . 1

Caring for the Cow and Calf at Calving ........................... 1
Care of Navels at Birth...................................... 1
Feeding Colostrum ... .. ............................ .. . .. 1
Evaluating Colostrum Quality. ................................ 2
Detecting the Colostrum-Deprived Calf . . . . . . . . . . . . . 3

Starting the Nutrition Program . . . . . . . . . . . . . . . .3
Once- Versus Twice-Daily Feeding ................................ 4
Early Weaning Calves .... ................................... 4
Calves Need Fresh Water .................................... 4
The Calf Starter Ration ....... ...............................4
The Growing Ration ....................................... 5
Hay Feeding . . . . . . . . . . . . . . . . . . . . . . 6
Minerals and Vitam ins ...................................... 6
Antibiotics Used as Feed Additives ...............................6

H o using . . . . . . . . . . . . . . . . . . . . . . . 7

G rouping Heifers . . . . . . . . . . . . . . . . . . . . .7
Things to Do Before Grouping .................................. 7
D ehorning . . . . . . . . . . . . . . . . . . . . . .7
Identification . . . . . . . . . . . . . . . . . . . . .8
Removing Extra Teats...................................... 8
Age-Based Grouping System ................................... 8

The Growing Dairy Heifer .................................... 8
Avoid Underfeeding or Overfeeding ............................... 8
W hen to Breed . . . . . . . . . . . . . . . . . . . . . 9

Diseases of Dairy Replacements................................ 10
Septicemic Collibacillosis ................................... 10
Diarrhea (Scours).. . . . . .. .. .. ..... .. . .. . . . . . . .. 11
Enterotoxic Collibacillosis.................................... 11
Rota and Coronavirus ..................................... 11
Salm onella . . . . . . . . . . . . . . . . . . . . . 11
Sudden Death Syndrome (Enterotoxemia) .......................... 12
Pneum onia in Calves ...................................... 12

Parasite Problems of Dairy Replacements . . . . . . . . . . . .. 12
Protozoal Parasites....... ........................ .... .. .. 12
C occidiosis . . . . . . . . . . . . . . . . . . . . . 12
Cryptosporidiosis . . . . . . . . . . . . . . . . . . . 13
Nem atode Parasites ......................................13
General Life Cycle of Nematodes ..............................13
Stomach (Abomasum) Worms ................................14
Intestinal W orm s ......... ....................... .. ... .14
Lungworm s . . . . . . . . . . . . . . . . . . . ....14
Trematode and Cestode Parasites ...............................15
Liver Fluke Infection (Fascioliasis).............................15
Tapew orm s . . . . . . . . . . . . . . . . . . . ....17

External Parasites . . . . . . . . . . . . . . . . . . . 17
L ice . . . . . . . . . . . . . . . . . . . . . . . 17


F lies . . . . . . . . . . . . . . . . . . . . . . . 17


Sum m ary......................


9 18












Introduction
Raising replacement dairy heifers provides excel-
lent opportunities and challenges in building for the
future. Records show that about 25-35% of the
milking herd must be replaced annually. Therefore,
to maintain herd size and improve genetic potential
for high milk production, quality replacements must
be continuously available.
Good management is essential to raising healthy
calves. Reducing death losses of newborn calves to
less than 5% and raising strong, healthy heifers
large enough to breed at 14 to 16 months of age
are sound management objectives. Calves stunted
from underfeeding or diseases may not develop into
healthy and profitable cows.
Estimates are that some herds lose 15 to 25% of
live-born calves consistently. This is excessive and
costly to the dairy industry. Some dairy farmers
consistently lose less than 2 to 3% of live-born
calves. Careful attention to feeding, housing, and
health management practices are key elements in
successful raising of replacements.
In general, the younger the calf, the greater its
risk of dying from disease. Most deaths occur in
calves less than one month old. Therefore, sanita-
tion during the pre-calving, calving and early post-
calving periods is crucial.

Caring for the Cow and Calf at Calving
A good calving environment reduces the exposure
of cows and newborn calves to infectious disease
organisms. Well-drained grass lots or pastures
visible from the barn are ideal calving areas. In
cooler climates maternity stalls are used, particular-
ly during periods of unfavorable weather. In either
situation, a clean and comfortable area that
provides cows with good footing minimizes the
potential for injuries. Calving areas should be
selected or landscaped to allow for adequate drain-
age. Shade structures are recommended. University
of Florida studies have shown a detrimental effect
on fetal growth rate and milk production in subse-
quent lactations when cows are not sheltered from
heat stress.
Calf mortality is closely related to the dam's
health during gestation, and fewer problems arise if
dietary intake is monitored (see IFAS Circular 623-
Dry Cow Feeding and Management). Studies indi-
cate that 4 to 5% of calves are born dead or die
within 24 hours of birth, and losses can be as high
as 15% or more in herds where calving management


practices are poor. Table 1 shows the causes of
death in calves less than 24 hours old for one Flor-
ida study.
Table 1. Cause of death in calves less than 24 hours old
in a Florida dairy (939 calvings).
Number of % of total % of total
calves deaths calvings
Premature deliveries
and near-term abortions 10 18 1.6
Dystocia
(assisted births) 23 40 2.4
Stillbirth or calf
found dead 24 42 2.5

Cows at or near calving should be separated and
observed frequently. Heifers will normally deliver
their calves within 12 hours after the onset of
labor. The interval from onset of labor to birth in
cows is usually six to eight hours. Difficulties
occur in slightly more than 3% of calvings among
dairy cattle. If the labor and delivery process is
prolonged or an abnormal presentation is detected
(such as the appearance first of a tail, head or one
leg) corrective procedures may be needed. Common
causes for calving difficulties are excessive calf size
and abnormal calf posture or position. Beginning
with the cow's third calf, milk fever (also called
parturient hypocalcemia) should be suspected any-
time the labor process seems particularly slow or
appears to have stopped. A cow with milk fever
will often be wobbly or unable to rise. Milk fever
can be treated rapidly and effectively by adminis-
tering calcium-containing preparations.
Experience is an important prerequisite for the
identification of problems or potential problems in
managing calving. The calf has a better chance for
survival if stress during the birth process is min-
imized.

Care of Navels at Birth
Calves' navels should be dipped in disinfectant at
birth using a product such as two percent tincture
of iodine. Failure to do so increases the oppor-
tunity for the development of potential fatal sep-
ticemia (invasion of the bloodstream by bacterial
organisms). Further, bacteria associated with navel
infections in calves may lead to serious arthritis
that is difficult to treat and may result in the need
for premature culling of affected calves.

Feeding Colostrum
The calf should receive colostrum as soon as
possible after birth. The gut of the newborn calf is









able to absorb maternally-derived immunoglobulins
(antibodies) contained in colostrum and transport
them into the bloodstream. Antibodies transferred
from the dam to the calf in this way are referred
to as "passive" antibodies. The ability of the calf
to absorb these colostral antibodies is greatest
within the first hour following birth and remains
fairly good for up to six hours. After this, there is
progressive loss in the calf's ability to absorb colo-
stral antibodies. After 24 hours a calf may be able
to absorb little or none at all.
Colostrum's chief importance is providing antibod-
ies which give the newborn calf resistance to dis-
ease. In addition, colostrum acts as a mild laxative
which aids in removing digestive residue from the
gut of the newborn calf. Colostrum is also high in
nutrient value, especially vitamin A or its precursor
carotene, B vitamins, proteins and minerals. The
total solids and protein content of colostrum is
about 23.9% and 14% as compared to 12.9% and 3.6%
for normal milk.
Evaluating Colostrum Quality- Several factors affect
the passive transfer of colostral antibodies to the
calf: The immunoglobulin mass ingested, time delay
after birth of ingestion of colostrum, the method of
feeding and genetic, physiological, and environmen-
tal influences. Of these, the most important are
mass of colostral antibody consumed and the length
of time after birth before ingestion.
In the late 1970s researchers at the University of
Arizona developed a method to estimate the an-
tibody content of colostrum. The device used,
known as a colostrometer, was designed for on-farm
use and has become particularly valuable to dairies
that store colostrum for hand-feeding newborn
calves. The colostrometer is simply a hydrometer
specially calibrated to provide a measure of colo-
strum specific gravity which is directly related to
antibody concentration (Figure 1). Using this tool,
dairy farmers can estimate the protective quality of
the colostrum they collect from cows and thus
selectively feed or store that which is of an ac-
ceptable value.


Florida field trial results demonstrate the impor-
tance of monitoring colostrum quality (Figure 2). A


(Number in Catagory/Number Examined)


over 50


21-50


(96/891)


(159/891)


20 or less -


(631/891)
0 10 20 30 40 50 60 70 80 90 100
% of Samples


Figure 2. Colostrum scores at first milking from field
trial at a Florida dairy.
total of 891 first-milking colostrum samples were
scored with the colostrometer in a Florida dairy
over a one-year period. As shown in Figure 2 only
96 (10.8%) of the colostrum samples examined at
first milking contained 50 mg/ml or more of colos-
tral antibody. This suggests that indiscriminate
collection of first milking colostrum and pooling
with other sources may result in storage of inferior
quality colostrum. When possible, at least two
liters of colostrum scoring in the zone over
50mg/ml should be preserved for each newborn calf.
Colostrum may be fed by nipple bottle, but most
dairies find it more convenient and expedient to
feed colostrum by esophageal feeder or stomach
tube (Figure 3). Colostrum with lower than optimal


Figure 1. The colostrometer is a specially calibrated
hydrometer.


Figure 3. Feeding a calf with a stomach tube.









antibody levels may be fed as is or diluted for
feeding to older calves.

Detecting the Colostrum-Deprived Calf Several
methods can be used to determine if a calf has
absorbed adequate levels of protective antibodies
from colostrum. A popular procedure for large
dairies is measurement of serum total proteins.
This is by far the most efficient and practical met-
hod for routine screening of large numbers of cal-
ves and can easily be performed on the dairy by a
veterinarian or dairy personnel.
Previous studies demonstrate that blood antibody
levels correlate well with serum total proteins in
calves at 2-10 days of age. Serum fractions from
calves containing less than 5.0 gm/100 ml indicate
insufficient colostral antibody absorption (Table 2).
Table 2. Interpretation of serum total proteins.
Less than 5.0 mg/dl------------colostrum deprived
5.0 5.5 mg/d----------------------"-------suspect" deprived
5.5 7.5 mg/dl---- --------- colostrum satisfied
greater than 7.5 mg/d------"-------suspect" (dehydration)
* Clinical signs of septicemia, diarrhea or other problems
should be noted at the time of sampling.

Total protein values in excess of 7.5 gm/100 ml are
suggestive of dehydration and may be cause for
concern. Herds experiencing severe losses in calves
under two weeks of age should evaluate calves to
determine if colostrum deprivation is a problem. In
very large herds we can oftentimes determine how
successful the neonatal calf management program is
by monitoring a sample of the calves between 2-10
days as opposed to checking all calves.

Starting the Nutrition Program
The milk feeding period in most calf operations is
4 to 5 weeks for large breed calves and 5 to 6
weeks for small breed calves. Liquid feeds com-
monly used are whole milk, milk replacers and colo-
strum. The choice of which to use depends on
availability, practicability and cost.
Regularity in calf feeding is important. Too much
milk at one feeding is likely to cause loose bowels
which may develop into scours. For best results,
weigh or measure the milk at each feeding.
Most dairy farmers prefer to feed milk to calves
at about body temperature (90 to 100F). How-
ever, research has shown that temperature may vary
from slightly warm to about 100F. Apparently, the


temperature of the milk is relatively unimportant so
long as a similar pattern is followed each day.
a) Whole Milk This is the most common liquid
for calves. It is usually fed twice a day but
in recent years has been fed once a day with
success. Calves should receive from 6 to 10
lbs per day depending on the size of animal
(about 8-10% of body weight at birth).
b) Milk Replacer Some of the primary concerns
in the selection of a milk replacer is cost,
physical properties and the nutritional value of
the product. Milk replacers should mix easily,
not settle out to any objectionable degree on
standing and have milk-like appearance in dry
and liquid form. The major difference between
brands of milk replacers is usually the source
of protein casein, soy flour, etc. Select a
good quality milk replacer.
c) Fresh Colostrum In many dairy operations,
more colostrum is available than can be fully
utilized by newborn calves. Rather than dis-
card a valuable product, it can be preserved by
freezing and fed as needed. Colostrum's laxa-
tive properties, coupled with its extra total
solids may increase the incidence of scours in
calves unless diluted with water.
d) Mastitic Milk Milk from cows with mastitis,
which cannot be marketed, may be fed to
calves with good success. Such milk should be
fed to calves in individual pens to prevent the
possible spreading of organisms since calves in
community pens tend to nurse each other after
drinking milk.
e) Fermented Colostrum In recent years some
dairy farmers have used fermented colostrum
(sometimes called pickled milk or sour colos-
trum) to feed dairy calves. Research shows
that colostrum can be successfully stored as a

fermented product for a month or longer and
remain readily acceptable to calves. The aci-
dity of sour colostrum is reduced from 6.5 to a
pH of about 4.0 which preserves the material.
The increased acidity prevents the growth of
harmful bacteria. For good results, store in a
plastic or non-corrosive container. Colostrum
milk from other cows freshening within a few
days can be added and mixed with the batch
as needed. Start a new container when colos-
trum milk has not been added daily. Do not
add milk from a cow being treated for mastitis
because the antibiotics stop fermentation and
the milk will not sour properly. Mix the sto-









red colostrum before feeding. Feed a minimum
of one quart (two pounds) and preferably three
pounds of fermented colostrum diluted with
about one-third water twice a day. Fermented
colostrum appears to be a satisfactory nutrient
source for calves when 4 to 6 pounds of colo-
strum is fed daily. Weight gains have been
equal to calves receiving whole milk or milk
replacer.

Once- Versus Twice-Daily Milk Feeding
During the past few years several studies have
shown that milk may be fed to calves once instead
of the usual twice per day. The once-daily feeding
has not increased the number of digestive and hea-
lth problems as compared to twice daily feeding.
Calves receiving milk once daily remain active and
consume their portion of liquid feed. Amounts up
to 10% of body weight (8 to 12 lbs per calf) are
consumed readily by larger calves.

An important question, particularly in Florida, is
whether calves fed once daily during hot weather
can perform as well as calves fed twice daily with-
out supplemental water. An Ohio study showed that
once daily fed calves provided with supplemental
water gained an average of 4.5 pounds more than
calves not given water. Consumption of calf starter
averaged 7.0 pounds more at 30 days of age for the
water-supplemented calves and resulted in greater
efficiency of growth and increased body weight
gain.
Once daily feeding reduces the time required for
milk or milk replacer preparation and feeding pail
washing. Food management makes the program
work. Even though calves may be fed milk once
daily, they should be observed at least twice daily
for health and general management problems. Early
detection of problems is an important aspect of any
young animal management system.

Early Weaning Calves
Calves may be successfully weaned from milk or
milk replacers at 3 to 6 weeks of age depending on
breed and appetite. Smaller breed calves should
receive milk a little longer than Holsteins and all
calves should have been eating a minimum of 1 to 2
lbs of calf starter (grain mix) daily for the 7 to 10
days prior to weaning. Those consuming less may
lose weight and do poorly for several days after
weaning. To encourage starter consumption, reduce
milk fed by about one-half a few days prior to
weaning. (Table 3).


Table 3. Suggested pounds of milk to feed daily.a
Large breed Small breed
Age of calf (Ib per day) (Ib per day)

1 day Suckles cow or is fed colostrum
(first 24 hours)
2 7 days 8-10b 5-8
2nd week 10-12 6-9
3rd week 10-12 6-9
4th week 5-6 3-4
a If scours occur during milk feeding, the amount of milk
may be withheld or reduced to one-half. Provide an equal
amount of water to replace the milk withheld.
b One gallon of milk weighs 8.6 lb.


A special feed termed prestarter is commercially
available and has been used by some dairy farmers
to aid in early weaning. Experiments with the
program have shown that calves can be weaned as
early as two weeks and although growth is slower
for a few weeks it is non-significant at three
months of age. Calves respond differently to such
an early weaning program. Advantages in such a
program are reduction of labor and costs. Dis-
advantages are slower growth and possible increased
death losses.

Calves Need Fresh Water
Growing dairy calves should have access to clean,
fresh water at all times after they are weaned.
Most dairy farmers offer water during the milk
feeding period. Pail feeding fresh water is best.
Avoid feeding water just before feeding milk.
Young dairy calves have a higher requirement for
water than older animals per unit of body weight.
As calves get older, provide about one foot of
water space for each 10 heifers.


The Calf Starter Ration
The calf's appetite increases as it grows. Offer-
ing a small amount of good starter ration to the
calf at 2 to 3 days of age is an excellent way to
meet this increasing need (Figure 4). Also, unlike
milk, a starter ration will stimulate early rumen
function and the establishment of the rumen micro-
bial population and growth of the rumen papillae.
The grain starter is more effective than hay in
encouraging rumen development. Early rumen de-
velopment allows early weaning and helps the calf


4























Figure 4. Bucket for feeding a palatable starter ration
with water available.
overcome stresses associated with the milk feeding
period.
A calf starter should be palatable and chewy.
Some of the grain should be in the cracked, rolled
or whole form. Variety is more important in a calf
starter than in rations for the milking herd or older
heifers. Pelleting is another method of increasing
palatability when the ingredients are finely ground.
The calf starter ration should contain about 16 to
17% crude protein with added minerals and vitamins.
University of Florida studies show an advantage in
adding 10 to 15% cottonseed hulls to calf starter
rations. Such rations need only contain 15 to 16%
crude protein.


The calf starter should be supplied in a very
small amount during the first week of life and then
gradually increased. Feed only the amount that the
calf will consume that day to help keep the feed
fresh. Some calves will be consuming 3 to 5 lbs of
calf starter daily at one month of age. Continue
feeding the calf starter until the calf is about two
months of age.

The Growing Ration
As calves increase in age and size, larger calves
may be limited to about 4 to 6 pounds of grain per
day and the smaller calves about 4 to 5 pounds per
day in order to encourage consumption of roughage,
especially hay (Table 4). When calves are older (8
to 10 weeks of age) and are consuming 4 to 5
pounds of calf starter daily, a more simple and
economical grain mixture may be used (Table 5).

Table 4. Dairy calves receiving hay and a concentrate
as the total ration.
Ib DM CP TDN CA P
b---------------------- b---------------------
Bermuda hay 2.00 1.76 0.14 0.80 0.00 0.00
Concentrate mix 4.50 1.35 0.63 3.12 0.03 0.02
Mineral 0.00 0.00 0.00 0.00 0.00 0.00
Totals 6.50 3.11 0.77 3.92 0.04 0.03
Requirements 0.79 3.92 0.04 0.02
(150 Ib body weight)


Table 5. Five simple 14-15% protein grain mixtures for supplementing grow-
ing heifers on pasture or other forages.
Ingredients* 1 2 3 4 5
b--------------------- b---------------------
Wheat, rolled 400
Soy hulls 300 300 300
Oats or barley, rolled 500 600 -
Citrus pulp 400 400 -
Molasses 100 150 100 -
Corn gluten feed 400 600 -
Wheat middlings 300 300
Soybean meal (49%) or peanut meal (50%) 290 130 260 40 180
Corn, cracked 870 470 1000 600 765
Urea 10 -
Defluorinated phosphate 20 10 5 0 10
Calcium carbonate 20 15 30 25
Salt, trace 20 20 20 20 20
* Add 6 8 million USP units of Vitamin A per ton.









Table 6 shows the amount of crude protein, total
digestible nutrients, calcium and phosphorus needed
for young growing heifers to make acceptable
weight gains. A calf pasture should contain a good
supply of clean water and some shade. Clip the ma-
ture plants and weeds occasionally. Mature plants
are less palatable and less nourishing than younger
growing plants.



Table 6. A feeding program for growing heifers
weighing 800 pounds.
lb DM CP TDN CA P
------------------------lb ---------------
Bermuda hay 5.00 4.40 0.40 2.00 0.01 0.01
Grass pasture 50.00 7.50 0.90 6.00 0.03 0.02
Grain mixture(2o%) 5.00 4.50 1.00 3.50 0.04 0.03
Mineral* 0.10 0.09 0.00 0.00 0.02 0.01
Totals 60.10 16.49 2.30 11.50 0.10 0.07
Requirements 2.22 11.49 0.06 0.05
(800 lb heifers)
Mineral contains 16% calcium, 8% phosphorus and 20% salt.



Calves on pasture should be supplemented with
some grain and minerals. A complete mineral mix-
ture containing about 20-30% salt, 8-10% phosphorus
and 14-18% calcium may be used. Also, one part
trace mineral salt mixed with one part defluorinated
phosphate provides extra minerals. The minerals
should be provided in a container or trough that
provides heifers free access.
A feeding program should give the dairy heifer
every opportunity to develop a healthy and strong
body. A well-developed heifer has a far better
chance of becoming a good producer than one poor-
ly fed and cared for. Varying amounts of roughage
and grain may be fed during the growing period,
with the amount of grain based on the desired
growth rates. A great deal of flexibility is possible
during this period and similar results can be ob-
tained by following one of several feeding plans.
There is no one best grain mixture for young
dairy calves and growing heifers. A 14% grain
mixture for dairy cows is satisfactory as a growing
ration for older calves. This is true even though
the grain mixture may contain some cottonseed hulls
and urea. The level of urea (0.5% of DM intake) as
recommended for mature cows also applies to grow-
ing heifers.


Hay Feeding
There have been a number of recommendations on
the age when hay should be offered to young dairy
calves. Some prefer to start feeding hay when
calves are as early as one week old, while others
recommend waiting until the calves are two months
old.
Most calves will eat very little hay before they
are two months old. A few, however, seem to have
a strong appetite for roughage and may need to be
fed some hay at an earlier age. For this reason,
we recommend some hay when the calf is one to
two months of age. Calves that select hay over
grain should have hay restricted until they are
consuming from one to two pounds of grain per day.
Calf starter rations containing 10 to 15% cottonseed
hulls provide adequate roughage during the first one
to two months of life.
Hay is important for normal rumen function and
should be made available to all calves over 1 to 2
months of age. More hay will be eaten if fresh hay
is provided each day. Do not let hay get packed in
hay racks for several days. Feed about the amount
the calf will eat each day. An exception is where
calves have free access to hay in round bales.

Minerals and Vitamins
Minerals and vitamins are important to all lives-
tock, especially growing heifers. A free-choice
commercial mineral containing calcium and phospho-
rus in about a 2:1 ratio with 20 to 25% salt and
added trace minerals and vitamins should be ade-
quate. Calves and heifers will consume less free-
choice mineral if they are receiving a grain mixture
containing a good balance of minerals. However, as
heifers get older and pasture becomes more avail-
able, a free-choice mineral should be provided.

Antibiotics Used as Feed Additives
Antibiotics may be useful in starter rations in
helping to reduce digestive disorders, increase feed
consumption and improve daily weight gain in baby
calves raised in some areas of Florida. In general,
though, healthy dairy calves do not benefit from
antibiotic supplementation.
Chlortetracycline (aureomycin) and oxytetracycline
(terramycin) are of greatest value for calves when
the untreated animals have had diarrhea or digestive
disturbances.








Housing
Calves need clean, well lighted, properly ven-
tilated quarters. Damp stalls, drafts, and wet
bedding may lower the calf's resistance to certain
diseases, especially pneumonia. Poorly ventilated
quarters usually lead to strong undesirable odors.
Individual, portable pens work very well in Florida.
Young calves should be placed in individual pens
until 6 to 12 weeks of age, depending on facilities.
The two most common types are portable and per-
manent pens. Permanent pens usually have wood-
slatted or expanded metal floors that require no
bedding and are easy to clean (Figure 5). Portable
pens are popular in Florida (Figure 6). In addition
to providing plenty of fresh air and shelter, they
are inexpensive to make. Structures known as calf
hutches are used in colder climates but are usually
not needed in Florida.


There is less danger in spreading disease when
calves are kept in individual pens. Portable pens
are usually placed on clean permanent pasture with
good drainage and a thick sod that serves as bed-
ding for the calves. It is best to move the pens on
a rotational basis every one to two weeks or as
often as needed.

Grouping Heifers
Ideally, heifers should be placed in groups of 10
to 12 heifers per lot as soon as they are removed
from individual pens. In most operations, this oc-
curs at two to three months of age and provides
ease in observing the heifers and detecting proble-
ms. Also, heifers tend to be more competitive at
the feed bunk and, as a result, grow faster (Figure
7). As heifers become ready to be put on pasture
at 5 to 6 months of age, larger groups are more
desirable.


Figure 5. Calves in individual pens with easy-to-clean
floors.


Figure 6. Portable pens can be moved to clean, dry
ground as needed and and are well-suited for use
in Florida's mild climate.


Figure 7. Weaned calves at feed bunk -- competition for
feed can speed growth.

Things to Do Before Grouping
Before calves leave the individual pens, they
should be dehorned, identified and extra teats
should be removed.
Dehorning is a necessary surgical procedure in
dairy calves. When performed early (at less than
one month of age) setback is minimal, however, if
the calf is near weaning age or beyond, dehorning
can be particularly stressful. The preferred meth-
ods are burning the horn buds with an electric
dehorner, or surgically removing them with specially
designed dehorning gouges. Both of these instru-
ments can be bought from most livestock supply
companies. An alternate method of horn removal is
chemical cautery. This must be performed with








great care in order to confine the caustic material
to the horn bud area. Not uncommonly, calves will
rub their heads on surrounding structures and inad-
vertently spread the caustic beyond the horn bud
area, causing severe chemical burns to the head and
face. When using caustics, calves should be isolated
to eliminate contact with other calves.
The method chosen will determine the age at
which dehorning is performed. Burning of horn
buds can be done as early as one to two weeks of
age on some calves. On others, horn buds may not
be distinct until three to four weeks of age or
older. Surgical removal requires a discernible horn
bud. With either method, failure to burn or remove
an adequate amount of the underlying horn bud
tissue may result in the development of horn scurs.
Aside from being unesthetic they can be trouble-
some and later require surgical removal. The best
time to remove horns is when the calves are about
one to two weeks old or as soon as the buttons can
be distinctly felt.
Identification may be accomplished with commer-
cially available numbered plastic ear tags as well as
tattooing a number in the ear.
Removing extra teats is sometimes necessary
because occasionally heifer calves are born with one
or more extra teats. Later, these detract from the
appearance of the udder and may interfere with
milking. Removal of these extra teats is conven-
iently performed at the same time as dehorning or
at least before the calf reaches six months of age.
Disinfect the cut area with tincture of iodine or
another antiseptic. If the extra teats cannot be
readily distinguished or are attached to one of the
regular teats, consult a veterinarian about removal.

Age-Based Grouping System
The following suggests a possible grouping system
for replacement heifers:
a) Weaning age to six months. This group re-
quires special attention and feeding to grow
well (Figure 7). Vaccination programs for
bangs and blackleg may be needed.
b) Six months to nine months. These calves need
grain supplementation and good pasture.
c) Nine months to breeding age. This group may
do well for short periods on quality forages
and a mineral supplement. However, some
grain may be needed for good growth.


d) Breeding age to springing heifers. Heifers in
this group require special attention for breed-
ing and mammary development (Figure 8).


Figure 8. Breeding age heifers can be pastured in larger
groups.

Provide adequate eating space for all heifers.
Usually, 12 inches of manger space is needed for
young calves and 18 inches for older heifers.

The Growing Dairy Helfer
Heifers are usually turned to pasture at five to
six months of age and should receive grain supple-
ments, the amount depending on the condition of
the heifers (Table 4). Generally, two to five pounds
of grain per day is needed for good growth. If the
pasture contains some legumes, such as clover, a
grain mixture containing 12 to 14% protein is ade-
quate. If the pasture consists of grasses, millets,
etc. the grain supplement should contain from 15
to 16% protein.
The desirable growth rate for large breed heifers
(Table 7) from birth to 14 months is about 1.7
lb/day. At 14 months these heifers should weigh
about 700 lbs.

Avoid Underfeeding and Overfeeding
Retardation of growth below recommended levels
as shown in Table 7 tends to shorten the productive
portion of the heifer's life. In some herds heifers
frequently reach three years of age before first
calving. The boarding bill for such heifers may
become quite large.
Acceleration of growth above two pounds per day
is also undesirable since lifetime milk production
and longevity decrease. Tennessee studies show
increased fatty infiltration of the mammary gland









Table 7. Daily nutrient requirements for growing heifers.a
Body Daily Est. Crude Minerals
Wt. Gain Age NE g+mb TDN Protein Ca Phos
(Ib) (Ib) (wk) (Mcal) (Ib) (Ib) (Ib) (Ib)
(Large breeds)
90 0.90 1 2.00 2.15 0.40 .032 .012
100 1.00 3 2.14 2.24 0.45 .035 .013
150 1.40 8 3.33 3.92 0.79 .037 .018
200 1.50 13 3.90 4.06 0.94 .040 .020
300 1.70 21 5.24 5.56 1.29 .043 .024
400 1.70 29 6.31 6.75 1.60 .046 .028
500 1.70 37 7.33 7.92 1.82 .050 .032
600 1.70 45 8.28 9.10 1.87 .053 .036
700 1.70 54 9.21 10.27 1.94 .056 .040
800 1.70 63 10.10 11.49 2.22 .058 .043
900 1.70 71 10.96 12.75 2.52 .060 .044
1000 1.70 80 11.79 14.07 2.84 .062 .045
1100 1.70 90 12.62 15.48 3.20 .064 .046
1200 1.50 100 12.93 16.09 3.41 .064 .046
1300 1.30 110 13.20 16.65 3.61 .064 .046
(Small breeds)
60 0.70 1 1.25 1.03 0.40 .020 .010
75 0.80 2 1.60 1.55 0.50 .020 .010
100 0.80 10 2.60 2.80 0.60 .036 .018
150 1.00 19 3.20 3.45 0.75 .038 .019
200 1.10 26 3.64 3.76 0.93 .040 .020
300 1.30 37 5.04 5.32 1.26 .043 .023
400 1.30 48 6.06 6.56 1.54 .046 .026
500 1.30 59 7.08 7.80 1.60 .049 .029
600 1.30 70 8.07 9.07 1.75 .052 .032
700 1.30 81 8.93 10.41 2.07 .055 .035
800 1.10 92 9.37 11.06 2.43 .058 .038
900 1.10 105 10.19 12.52 2.84 .060 .042
a NRC requirements 1988.
b Net energy for maintenance and growth.


and reduced number of alveolar cells available for
milk synthesis. Greatest harm apparently occurs
during pre-puberty (prior to first heat) with little
to no detrimental effect on mammary growth post-
puberty (from about 11 months on). Michigan State
studies suggest that feeding high levels of energy to
accelerate growth from breeding to calving does not
inhibit formation of mammary secretary tissue, and
would probably allow maximum lifetime milk yields.

When to Breed
Optimum time for first breeding depends on the
feeding program and management system. Size is
more important than age in determining when heif-
ers should be bred. Often heifers are bred to
freshen at a particular time of the year to increase
milk sales when supply is low and price favorable.


Well-fed heifers can be bred at 14 to 15 months
of age and should weigh about 750 pounds (Holstein
and Brown Swiss). At this size, conception should
be good with little to no increase in calving dif-
ficulties. During the nine month gestation period,
heifers should gain from 400 to 500 pounds, 130
pounds of which is calf weight and associated tis-
sue. Until three months of age the average rate of
gain is seldom over one lb per day, so an average
daily gain of 1.8 lb per day is recommended from 3
to 14 months in order to obtain the desired breed-
ing size of 750 to 800 lb at 14 to 15 months of age.
The suggested sizes and ages at which heifers are
usually bred are given in Table 8.









Table 8. Age and weight to breed heifers and
gestation periods.
Approximate Approximate Gestation
Breed Weight Age (months) Period
Ayrshire 600-700 14-15 278
Brown Swiss 750-850 14-15 288
Guernsey 556-650 14-15 283
Holstein 750-850 14-15 278
Jersey 500-600 14-15 278

A recent Iowa study compared age at calving on
milk production of all first-lactation (305-2x-ME)
heifers from 2124 herds (DHI records). The results
are shown in Table 9.


Table 9. Holstein herds by average age at first
calving, showing level of production.
Age No. -----1st Lactation----- Rolling Herd
Yr-Mo Herds Milk (lb) Fat (Ib) Avg.(lb) Actual
1 -09 26 14,251 523 12,605
2 00 110 15,952 587 14,589
3 03 369 15,354 560 14,355
4 06 157 15,041 559 14,322
5 02 68 14,158 528 13,769


There is considerable cost in both time and money
in rearing replacement heifers to first calving.
Calving of replacement heifers at 23-24 months
minimizes the cost of raising replacements and
allows dairy farmers to begin receiving a return on
investments without affecting lifetime production.

Diseases of Dairy Replacements
The diseases that account for most calf illnesses
and deaths are septicemia, diarrhea, pneumonia and
parasitism. Their frequency and distribution in and
among herds reflects a complex interaction between
the calf's immune defense mechanisms,
environmental influences, and the capacity of
various infectious agents to produce disease. The
best solutions for herds experiencing excessive calf
loss lie in differentiating those management
practices which are beneficial from those which are
detrimental or of little value in promoting health
and preventing disease. For example, treatment of
all newborn calves with hyperimmune serums or
antibiotics is costly and of questionable value.
While these may be advised for short-term problems,
they are by no means a good substitute for


environmental sanitation and early colostrum intake.
Antibody-rich colostrum coupled with the highly
absorptive gut of the newborn calf provides an
unparalleled level of immunity to neonatal disease.
Today's progressive calf programs are founded upon
health management practices which augment this
natural system and not on systems which rely
primarily on treatment or vaccination schemes to
control disease.
The following are some of the more common
infectious diseases of calves from birth to weaning.
Septicemic Colibacillosis
Septicemia is the presence of bacteria and their
toxins (poisons) in the bloodstream. It is caused by
a wide variety of agents but when it occurs in
calves under five days of age the most probable
causes are invasive strains of E. coli.

The normal gut of calves and other animals is
populated with millions of E. coli which live har-
moniously with their host. Under certain condi-
tions, however, this delicate balance is upset and
the disease-producing strains increase. These or-
ganisms and their toxins multiply, cross through the
intestinal wall and move into the bloodstream where
they are distributed throughout the body. In un-
sanitary calving pens, invasive strains of E. coli can
also cause systemic infection by entering through
the navel of newborn calves.
Calves affected with septicemic colibacillosis
become rapidly depressed and weak. Diarrhea may
occur but is not a consistent feature of this
disease. Mortality is usually high due to a severe
endotoxic shock induced by circulating bacteria and
toxins and calves may die within 12 hours of the
onset of clinical symptoms. Death is often so
sudden that it may be the only sign of disease
observed.
Calves which survive the initial septicemic epi-
sodes may subsequently develop joint infections;
hence, the syndrome of swollen inflamed joints
caused by non-fatal cases of this disease are known
as joint ill. The infected joints are painful and
become arthritic. Severely affected calves may not
make profitable herd replacements. In herds with a
high incidence of septicemia, early culling of
severely affected young calves may be necessary.
Septicemic colibacillosis should be suspected when
there is excessive mortality in calves under five to
seven days of age. Successful treatment depends
upon prompt diagnosis. However, therapy is the
least effective way to deal with this disease.


10









Calves deficient in colostral antibodies are most
susceptible; dairy farmers who do not emphasize
colostrum management often lose many calves to
the disease. Calves born in a clean, dry calving
area and given an adequate amount of colostrum
soon after birth are less likely to suffer septicemia.
Properly disinfecting the navel and moving the calf
to a clean, dry individual pen will help ward off
septicemia.
Diarrhea (Scours)
Diarrhea is common, if not universal, in calves
under one month of age, and certainly not all cases
demand aggressive treatment. However, diarrheic
calves should be observed closely until stools return
to normal consistency. Diarrhea can be caused by a
variety of bacteria, viruses, and protozoa or may
also result from improper feeding practices as
discussed under "Starting the Nutrition Program."
The following discussion will be limited to the
infectious causes of diarrhea in young calves.

Enterotoxic Colibacillosis
While septicemia and rapid death are the distin-
guishing features of septicemic colibacillosis,
enterotoxic colibacillosis is characterized by diar-
rhea, dehydration, and toxemia of varying severity.
It is caused by enterotoxigenic (intestinal toxin
producing) strains of E. coli (ETEC). These organ-
isms do not enter the bloodstream but attach them-
selves to the wall of the upper small intestine
where they multiply and produce large amounts of
enterotoxin (poison produced in the intestine).
These toxins drain fluid and electrolytes from the
blood and other body tissues. This results in severe
dehydration and a metabolic imbalance that will lead
to death if not corrected. Enterotoxic colibacillosis
is one of the most common forms of colibacillosis in
calves under one week old. Death can occur
suddenly before the development of diarrhea. Most
infected calves develop a watery diarrhea. The tail,
buttocks, and legs of an infected calf will usually
be stained or soiled with diarrheic manure. These
calves may refuse to suck, depending on the degree
of toxemia and dehydration, and may lie down and
refuse to rise as they grow weaker.
Whenever outbreaks of diarrheic diseases occur
every attempt should be made to isolate the af-
fected from the unaffected susceptible calves. As
new calves are born they should be housed as far
away as possible from sick calves. If possible,
assign separate work crews to feed and care for
each group so that the cross contamination poten-


tial can be minimized. Separate buckets or bottles
should be used for feeding rather than using the
same for all calves. Sanitation is a must in the
control of diarrheal diseases. Provisions to insure
that newborn calves receive colostrum are particu-
larly important for resistance to these diseases.
Promising results have been obtained from research
trials on immunization of the pregnant dry cow
against colibacillosis in calves. Vaccination of the
cow within 2-4 weeks of calving with vaccines
produced from strains of ETEC stimulates the pro-
duction of a greater concentration of specific
antibodies that, when given in colostrum at birth,
provides an extra margin of protection against
ETEC. More recently, with the development of a
vaccine containing monoclonal antibody to the pilus
antigen of ETEC, problem herds can get immediate
protection for calves in the face of colibacillosis
outbreaks. This must be administered as soon as
possible following birth (within the first 8-12 hours
at least) and is not effective as a treatment for
calves which are already infected. It can only
prevent the disease.


Rota and Coronavirus
Rotavirus is a frequent cause of diarrhea in
calves under 2 weeks of age; coronavirus more often
affects calves aged 2-4 weeks. As primary patho-
gens these viruses generally induce only a mild
diarrhea, but when combined with secondary bac-
terial infections they may become major contribu-
tors to mortality in calves one month old and
younger. Both viruses occur throughout the United
States and in many foreign countries. Recent stu-
dies in the U.S. indicate that these viruses are
present in most, if not all, herds and that the maj-
ority of calves eventually become infected by them.
These viruses survive in feces for long periods.
After ingestion they attack the epithelial cells
lining the small intestine. The loss of this cellular
barrier increases susceptibility to invasion by other
infectious agents. A vaccine against these viruses
is available for pregnant cows and newborn calves
and should be used where the viruses are particu-
larly troublesome. Some dairy managers have found
that feeding colostrum continually for a week after
birth reduces the incidence of serious diarrhea
caused by these viruses.
Salmonella
Salmonellosis causes at least three clinical syn-
dromes in cattle: septicemia, enteritis, and abortion.
Septicemic salmonellosis is most common in calves,


11









and typically occurs at 3-4 weeks of age. (septi-
cemic colibacillosis is more common in calves under
2 weeks of age.) Infected calves become weak and
occasionally show signs of incoordination, sugges-
ting involvement of the nervous system. The
disease may end in death within 24-48 hours of the
onset of illness. The typical mortality rate is 25%,
but it may approach 100%.
Methods of treatment are controversial, but
regardless of the therapeutic regimen chosen, treat-
ment must begin early in the course of the disease.
Control during outbreaks requires strict environ-
mental sanitation and isolation of affected calves.
Calves should be kept in individual pens, and feed-
ing utensils should be routinely disinfected.
Prevention using vaccines for salmonella have
yielded mixed results and cannot be universally
recommended at present.

Sudden Death Syndrome (Enterotoxemia)
The sudden death of an apparently healthy calf is
frequently due to enterotoxemia caused by Clos-
tridium perfringens. These organisms occur naturally
in the soil and may be found in the gut of normal
calves. Under certain conditions, clostridial organ-
isms multiply while in the intestinal tract and prod-
uce a potent enterotoxin that damages blood vessels
in the brain as well as other tissues. Death usually
occurs suddenly.

Overfeeding of grain and/or milk is one cause for
the rapid proliferation of Clostridia. Calves con-
suming considerable amounts of grain while still
receiving a full feeding of milk are most likely to
develop this disease, thus the incidence of sudden
death is generally highest for calves 3-8 weeks of
age. Since most calves are fed free choice and
feeding errors are sometimes made, dry cows and
calves should be routinely vaccinated with Clostri-
dium C and D toxoid. For dry cows being vac-
cinated for the first time, two injections should be
made 2-3 weeks apart. For calves, vaccinations
should be made at 1-2 weeks of age and repeated in
2-3 weeks.

Pneumonia in Calves
In cool climates, calf pneumonia is usually asso-
ciated with poor ventilation. In Florida, however,
calf pneumonia often occurs around weaning time
when calves are moved from individual to group
pens. The co-mingling of calves into group pens
increases the potential for their exposure to disease
organisms. Problems are compounded by stress


associated with pecking order establishment rituals.
Consequently, calves should be grouped according to
breed and body size and groups should contain no
more than 10-12 calves.
Some dairy farmers make the stress to calves
worse without meaning to by scheduling vaccination,
dehorning, and deworming procedures too close to
weaning for the sake of convenience or because it
may seem like the most appropriate time. It is
preferable to perform these procedures at least 1-2
weeks before or after weaning.
The infectious agents which most usually cause
respiratory disease in calves are the bacteria Pas-
teurella spp., Corynebacterium pyogenes, and Myco-
plasma spp.; and several viruses including infectious
bovine rhinotracheitis (IBR), parainfluenza-3 (PI3),
bovine virus diarrhea (BVD), and bovine respiratory
syncitial virus (BRSV). Calves are exposed to these
pathogens as they are put into group pens where
they share feed and watering facilities. Calves are
more likely to resist infection if weaning stress is
minimized. Vaccinating cows with IBR/PI3 and BVD
protects newborn calves who are fed colostrum of
from vaccinated cows (CAUTION: do not use modi-
fied live vaccines for IBR and BVD in pregnant
cows). The intranasal IBR/PI3 vaccine may provide
calves additional immunity to disease. Several res-
piratory disease complex vaccines are now being
developed. Pasteurella hemolytica vaccine, which
has been developed recently, may also be helpful in
preventing infection where this organism is a major
cause of pneumonia.

Parasite Problems of Dairy Replacements
Protozoal Parasites of Cattle
Coccidiosis: The acute form of coccidiosis, caused
by a protozoan, is characterized by bloody diarrhea
and anemia. Calves 3 weeks to 6 months old are
most susceptible to infection. The disease usually
strikes at weaning time when calves are moved to
overcrowded, dirty and wet pens. Feeding hay fed
from the ground or grain from low troughs which
are easily contaminated by fecal material increases
the likelihood of infection.
Once ingested, coccidia invade and destroy the
epithelial cells lining the intestine. Diarrhea,
sometimes bloody, and anemia are often observed in
clinically affected calves. Calves that survive
coccidiosis develop long-lasting immunity. Pens
should be maintained in dry areas with a sufficient
drainage system. Overcrowding should be avoided
and waterers and feeders should be constructed or


12









located so that fecal contamination can be averted.
Medicating feed and water supplies usually controls
the disease without interfering with the development
of immunity.
Cryptosporidiosis: These organisms are proto-
zoans like coccidia, and are capable of infecting a
variety of animals, including man. The disease is
reported to be common in calves up to one month
old; however, in Florida, it most frequently is
observed around 7-10 days of age. Recent surveys
on several Florida dairies have found a high in-
cidence of cryptosporidial infection in calves be-
tween 5 and 15 days of age.
Cryptosporidia damage epithelial cells of the small
intestine. This decreases the absorptive ability and
surface area of the gastrointestinal tract and causes
watery diarrhea. Because the infected calf cannot
digest and absorb nutrients, it loses weight.
The importance of cryptosporidia as a cause of
calf diarrhea is unclear, however it has increasingly
been reported as a finding in calves with diarrheal
disease. Less severe experimental infections often
clear up in 1-2 weeks, whereas naturally acquired
infections are often complicated by E. coli or
rotavirus and may lead to death. Like aforemen-
tioned pathogens, cryptosporidia are found in the

Grazing calves ingest
infective-stage larvae with
grass. Adult worms
inhabit the gastrointestinal
tract.











Infective stage larvae (L3)
on grass.



Migration from feces onto
grass.


gut of healthy calves. One study showed that
neonatal calves deficient in colostral antibody are
at increased risk of developing cryptosporidial-
associated diarrhea. The best current treatment is
good nursing care. The best prevention is to feed
calves colostrum at birth. Continued feeding of
colostrum through the first week of life may pro-
vide additional protection against cryptosporidia as
well as other pathogens likely to infect calves
during this period.
Nematode Parasites of Cattle
Nematode or worm infections in cattle usually
begin with first exposure to grass. Most young
animals have only a limited immunity to parasites,
and will develop overwhelming infections if not
carefully monitored. However, calves who recover
from these infections develop a long-lasting im-
munity that protects them into adulthood. In the
southeast, low immunity is often a result of mal-
nutrition or conditions conducive to extreme para-
site exposure.
General Life Cycle of Nematodes: The life cycles
of gastrointestinal parasites are similar in that none
needs an intermediate host (Figure 9). Mature
worms produce eggs that are passed in the feces.
After variable lengths of time these eggs hatch,





/ \Eggs passed out in feces.


Eggs hatch in feces to
first stage larvae (1).


Figure 9. Life cycle of the common gastrointestinal nematode parasites of cattle.


13









liberating the first of two free-living larval stages,
commonly known as L1 larvae. These larvae grow
and molt twice, giving rise to third stage "infective"
larvae (L3). This infective L3 remains in the manure
pat until it moves onto surrounding vegetation
following periods of rainfall or heavy dew. Cattle
become infected while grazing infected pasture and
ingesting infective L3. In general, survivability of
the infective L3 is most favorable during cooler
seasons in Florida, whereas survival is less certain
during the hotter and dryer times of the year. In
the gut, L3 undergo further development to an L4,
L5 and an adult stage. Once mature, they repro-
duce and the cycle repeats itself.
An understanding of this basic life cycle is fun-
damental to the development of rational control
strategies. The most effective control schemes are
based upon appropriate use of anthelmintics in a
deworming program designed to prevent contamina-
tion of pastures with infective stages of parasites.
This can be accomplished by deworming immediately
prior to movement to new grazing areas and again
three to four weeks later.
In the sections that follow are descriptions of the
disease syndromes resulting from common nematode
infections in cattle. These descriptions are
organized under general headings according to the
organ or organ system in which they occur.

Stomach (Abomasum) Worms: The stomach worms of
major significance in cattle, Ostertagia ostertagi,
Trichostrongylus axei, and Haemonchus spp., tend to
be the most pathogenic of the gastrointestinal
parasites and consequently the most important
economically.

Ostertagia, known as the brown stomach worm, is
capable of entering an arrested state of develop-
ment for as long as six months. Because of this
unique ability, two types (Type I and Type II) of
ostertagia infection are recognized. Type I oster-
tagiasis is most typically seen in the southeast
during the winter and spring in heifers during their
first season at grass. The clinical syndrome is
characterized by diarrhea, weight loss, decreased
appetite, and hypoproteinemia (low blood protein)
exhibited as submandibular edema (bottle jaw).
Damage to abomasal digestive glands in the stomach
is caused by both the larvae and adult worms during
their development, but in particular, by emergence
of the adult L5 from the glands.
Type II ostertagiasis occurs in young stock (year-
lings and first and second calf heifers) that have


had at least one grazing season. In the southeast
it is most commonly observed in late summer and
early fall. The clinical signs are similar to those
described above, but usually more severe. Also, it
differs from type I in that the occurrence is more
sporadic with smaller numbers of animals in a herd
affected. Type II disease is caused by the ac-
cumulation of arrested larvae acquired during the
late spring of the previous grazing season. Signs of
disease are evident in the fall as the adults emerge
from the glands as described earlier for Type I. An
early summer deworming with an anthelmintic
capable of eliminating those arrested larval forms
can prevent Type II ostertagiasis.
Trichostrongylus axei and Haemonchus spp. in-
duce a clinical syndrome similar to that of Oster-
tagia with a few minor exceptions. In sufficient
numbers, Trichostrongylus axei is a serious parasite
that causes diarrhea, weight loss, mild anemia, and
rough hair coats. Heavy infections with haemon-
chus, in both larval and adult stages, can result in
profound anemia as both larval and adult stages are
blood suckers. Haemonchus, unlike ostertagia, causes
infection during warm, wet weather and may be
troublesome during the summer months in Florida.

Intestinal Worms: Worms found in the intestinal
tract include: Cooperia spp., Strongyloides papil-
losus, Trichostrongylus colubriformis, Nematodirus
helvetianus, Bunoostomum phlebotomum, Oesophagos-
tomum radiatum and Trichuris discolor. Heavy
infections with these worms result in poor diges-
tion, weight loss, diarrhea, stunted growth and
occasionally, coughing and dermatitis. Some of
these worms penetrate the skin and migrate to the
lungs and other tissues. Others are blood suckers
and all damage the intestinal tract to varying
degrees. These worms, however, are not generally
as damaging as the stomach worms described pre-
viously.


Lungworms: Dictyocaulus viviparous is the lungworm
of cattle. It is a major cause of respiratory disease
in cattle in the southeast as well as in the more
temperate climates. Infections typically occur in
young stock (less than one year old) grazing on
pasture. Climatic factors have a major influence on
the incidence of this disease with most outbreaks
occurring during the warm, wet spring and summer
months. Affected animals show only a slight cough
in the early course of the disease. Later on the
coughing becomes severe and breathing becomes
difficult. Animals may be seen stretching their


14









heads and necks to facilitate breathing. When the
disease reaches this stage (usually 3-6 weeks fol-
lowing from onset), death loss may be high. Animals
that survive the acute infection will develop a
variable degree of immunity, however, many will not
be productive due to permanent lung damage.
The life cycle of lungworms is different from that
described earlier for stomach and intestinal worms.
In the lungworm cycle (Figure 10), cattle ingest
infective L3 while grazing. These larvae penetrate
the gut wall and enter the blood stream where they
are carried to the lungs. They undergo further
development in the bronchi and bronchioles of the
lung to the adult stage. Here they lay eggs which
are coughed up and swallowed. The eggs hatch
larvae in the intestinal tract to L, larvae which are
passed in the feces. They develop to the L3 larval
stage in manure pat and soil. The L3 larvae can
remain infective for months in the manure pat or
on vegetation where the larvae migrate following
rainfall.




Adult worms in lungs.






Larvae penetrate the
intestinal wall and migrate
to lungs where they
undergo further develop-
ment to the adult stage.






Larvae
manure
Calves ingest the infective s
L3 larvae.


There are several products available for treatment
of lungworms. Other important considerations for
control should include efforts to reduce exposure of
young cattle to infective larvae. Young,
susceptible animals should not be grazed on pastures
contaminated by older animals especially during the
spring and summer months. Deworming of yearlings
should be accomplished so that pasture contamina-
tion can be avoided.

Trematode and Cestode Parasites of Cattle
Liver flukes (Trematodes) and tapeworms (Ces-
todes), unlike the nematode parasites described
above, depend on an intermediate host for comple-
tion of their life cycle.
Liver Fluke Infection (Fascioliasis): Liver flukes
are common in the southeast, particularly along the
Gulf Coast and central and south Florida. They are
often responsible for significant economic losses in
beef cattle from reduced production efficiency and


passed in the
develop into a 3rd
"infective" larvae.


Adults lay eggs in the
bronchi which are coughed
up, then swallowed.
These eggs hatch,
releasing L1 larvae into
the digestive tract.














Larvae in manure.


Figure 10. Life cycle of Dictyocaulus viviparous, the lungworm of cattle.


15









liver condemnation at slaughter. In dairy replace-
ments, primary losses result from occasional deaths,
depressed growth, poor feed conversion, and im-
paired reproduction. While liver fluke infection may
cause acute disease in cattle, it is often chronic
and asymptomatic (showing no symptoms).

Completion of the life cycle of the liver fluke
(Figure 11) requires the presence of a lymnaeid
snail which serves as the intermediate host. In
Florida, only two species of snails, Lymnaea cuben-
sis and Pseudosuccinea columnella, are capable of
fluke transmission. These snails are not found in
or near large bodies of permanent water or on dry
land. They prefer soils with a neutral pH and thus
are not commonly found in cypress heads where
soils are too acid. Ideal habitat for these snails is
water-saturated soil in poorly drained pastures,
irrigation ditches, and around springs.


Grazing calves ingest
metacercariae.


Adult flukes living in the bile ducts of the liver
lay eggs that eventually enter the gastrointestinal
tract with the bile. These eggs are passed in the
manure and hatch, releasing free-living miracidia.
The miracidium infects a lymnaeid snail, develops
into a cercaria which leaves the snail to encyst on
vegetation as a metacercaria. This is the stage
infective for cattle, which ingest metacercariae
while grazing. Following ingestion, metacercariae
invade the wall of the gastrointestinal tract and
migrate to the liver. During migration, they
continue to develop into immature flukes. Upon
reaching the liver they invade and continue their
migration through the liver tissue and eventually
enter the bile ducts where they develop to adults,
feed on blood, and begin to lay eggs.
A two-pronged approach is necessary to control
liver flukes: snail population control, and the use


After metacercariae
develop into adult flukes,
they lay eggs which are
passed out in feces.


Eggs hatch into miracidia.


Cercariae leave snail and
encyst on vegetation as
metacercariae.


A miracidium infects
lymnaeid snail and
develops into a cercariae.


Figure 11. Life cycle of Fasciola hepatica, the liver fluke of cattle.
16


Fry-









of anthelmintics to reduce pasture contamination.
Controlling snail populations may not be practical
under certain conditions, but improving pasture
drainage, repairing leaky water pumps and irrigation
lines, and fencing off localized areas prone to heavy
contamination with metacercariae will help in redu-
cing potential exposure.
Strategic anthelmintic treatment regimes are
currently being studied in Florida. Present recom-
mendations suggest treatment in the fall (September
through December) and again in late spring, prior to
the summer rainy season (Table 10). Curatrem
(clorsulon) is the only treatment presently available
for liver flukes.
Tapeworms: Tapeworm infection is common in young
replacement heifers during their first grazing sea-
son. Tapeworms rarely cause serious disease, but in
extremely heavy infections may be responsible for
depressed growth rates.
Like the liver fluke, the tapeworm requires an
intermediate host to complete its life cycle. Free-
living mites feed on the egg-bearing segments of
the adult tapeworm that are passed in manure.
Tapeworm infection develops when infective mites
are eaten during grazing. Adult tapeworms attach
themselves to the mucosal wall of the small intes-
tine. Tapeworms grow in segments as they absorb
nutrients from ingesta in the small intestine.
Infections in older cattle are usually of minimal
consequence. There is no effective treatment.
External Parasites
Lice: Cattle in the United States are troubled by
four species of sucking lice and one species of


biting lice. Lice can cause death in heavily in-
fested calves, but often only slow weight gain and
reduce feed conversion efficiency. Heavy infesta-
tions of sucking lice often cause a blood loss
sufficient enough to result in serious anemia.
Anemic calves become weak, and are increasingly
susceptible to other diseases which may lead to
death. Biting lice feed on skin and cause the
animal to develop a scruffy appearance with hair
loss and raw, reddened skin Infected animals lose
hair when they rub, scratch, lick, and bite the
irritated skin.
In Florida, probably the most important louse is
the tail louse, (Haematopinus quadripertusis), a
sucking louse found only in the Gulf Coast states
and Puerto Rico. These lice inhabit the brush or
switch of the tail; immature forms may be found
near the eyes and eyelids and in the ears.
Cattle lice control methods include pour-on
insecticides, dust bags, sprays, and backrubbers.
Flies: Flies of major importance in livestock in
Florida are horn flies, house flies, and stable flies.
Nationwide losses to these pests are estimated to be
in excess of $400 million annually through decreased
weight gain, lower milk production and control
costs. Because of their rapid reproductive rate,
flies quickly develop resistance to insecticides,
making them one of the most difficult parasites to
control.
Grazing heifers are likely to suffer from horn
flies. The flies' mouthparts pierce skin and suck
blood from the animal's back and shoulders. In this
location they are less accessible to switching tails.


Table 10. Liver fluke control recommendations for Florida using Curatrema.
Yearly Weather Severity of Flukes on Dairy
Pattern Low Moderate Severe
Average rainfall autumn only autumn only autumn & spring
(reduced dose)a (full dose) (full dose)
Dry spring/dry autumn autumn only autumn only autumn & spring
(reduced dose or none) (reduced dose possible) (full dose)
Wet spring/dry autumn autumn only autumn and spring autumn & spring
(reduced dose possible) (full dose) (full dose)
Dry spring/wet autumn autumn only autumn only autumn & spring
(full dose) (full dose) (full dose)
Wet spring/wet autumn autumn & spring autumn & spring autumn & spring
(full dose) (full dose) (full dose)
a Curatrem Merck, Sharp and Dhome.
b Reduced dose: 1/4 oz. (7 1/2 ml) per 400 Ibs body weight.
c Full dose: 1/4 oz. (7 1/2 ml) per sOO lbs body weight.


17









Self-application devices, such as dust bags and
back-rubbers, provide daily fly control to pastured
cattle. Calves in isolated pens should be sprayed or
dusted individually.
Confined cattle are more vulnerable to stable flies
and house flies. Similar to the horn fly, the stable
fly is a voracious pest. They cause blood loss poor
feed conversion, annoyance and irritation. Swarms
of flies can cause pastured or drylot cattle to
bunch together. This, during the summer months,
increases heat stress.

The house fly is the vector of numerous animal
and human diseases. One of the more important of
these diseases in heifers is pinkeye. In
northeastern states, the face fly transmits pinkeye.
The face fly does not presently occur in Florida,
but its role in spreading pinkeye has been assumed
by the house fly. Both species feed on secretions
of the eyes, muzzle, and other mucus membranes.
As cattle bunch together, the disease spreads
rapidly throughout the herd. Pinkeye vaccination
continues to grow in popularity as a means to
reduce the incidence of pinkeye in herds.


Control methods for stable flies and house flies
consists primarily of insecticide self-application
devices or regular spraying or dusting. Problems
with fly populations resistant to the insecticides
used in eartags have made these of limited value in
fly control.

Summary
Many dairy farmers and skilled calf raisers have
been successful in raising replacement dairy heifers
through good management techniques such as those
described in this circular. The importance of good
management cannot be overemphasized since a
sizable investment is incurred in any good heifer
raising program. To protect this investment, start
with good breeding and follow through with solid
management and careful attention to details.
Remember that even the best facility is no better
than the manner in which it is managed and
average quality heifers tend to be average quality
cows. Well-planned facilities and programs allow
dairy farmers an opportunity to use their time and
labor more efficiently in raising healthy
replacements.


18







































































This publication was produced at a cost of $1,643, or 82 cents per copy, to provide information on raising
replacement heifers to Florida dairy operators and other interested persons. 8-2M-88


COOPERATIVE EXTENSION SERVICE, UNIVERSITY OF FLORIDA, INSTITUTE OF FOOD AND AGRICULTURAL SCIENCES, K.R. Tefertiller,
director, in cooperation with the United States Department of Agriculture, publishes this information to further the purpose of the May 8 and
June 30, 1914 Acts of Congress; and is authorized to provide research, educational information and other services only to individuals and institu-
tions that function without regard to race, color, sex, age, handicap or national origin. Single copies of Extension publications (excluding 4-H UNIVERSTY OF FLORIDA
and Youth publications) are available free to Florida residents from County Extension Offices. Information on bulk rates or copies for out-of-state . '
purchasers is available from C.M. Hinton, Publications Distribution Center, IFAS Building 664, University of Florida, Gainesville, Florida 32611. Before publicizing
this publication, editors should contact this address to determine availability.




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