Title: Tenure and turnover of dairy bulls in artificial service
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Permanent Link: http://ufdc.ufl.edu/UF00091665/00001
 Material Information
Title: Tenure and turnover of dairy bulls in artificial service
Physical Description: Book
Creator: Becker, R. B.
Publisher: Florida Agricultural Experiment Station,
Copyright Date: 1957
 Record Information
Bibliographic ID: UF00091665
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: 316568485 - OCLC

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Gainesville, Florida

Dairy Science Memo 57-1
April 1, 1957

Tenure and Turnover of
Dairy Bulls in Artificial Service

R. B. Becker and P. T. Dix Arnold

The study of useful lifespan of dairy bulls in artificial service, and of the
causes of turnover is continuing, with the cooperation of a large majority of the
artificial breeding organizations in the United States and Canada. The National
Association of Artificial Breeders has given a supporting grant which permits
assistance by a student helper in tabulation of the records and maintenance of the
card files of individual animals. The volume of completed records is accumulating
each year. The purebred dairy cattle associations have assisted with problem
records. Thankful acknowledgment is given with this progress report to each of
these cooperators whose contributions are making this study possible.

One of the major goals of this study is to assemble average life expectancy
tables for bulls in artificial service. Another goal is to ascertain and tabulate
the major causes of losses, which information may aid managers and herdsmen to
reduce losses, and perhaps to prolong the average useful life of bulls in artificial
service. A third goal is to provide some basis for estimating probable anticipated
turnover, which may assist in plans for average expected replacements each year. A
smaller but important phase deals with valuable bulls that have returned to lighter
natural use when no longer practical to be retained in artificial use. Many of
these bulls have rendered valuable service for selected matings in purebred herds,
or even in some commercial dairies.

Turnover of Desirable Bulls in Natural Service

Some 5,731 desirable daiky 'bulls were used full natural lifetime, average-
age of the grotip at last effective service being past. ten year. Three bulls
were effective to past 19 years old. The reasons for termination of these bulls
in natural use are given in Table 1. Failures in reproductive ability accounted
for nearly 38 percent of these animals. "Hardware disease" accounted for 5.08 per-
cent, with an additional 0.69 percent for various tumors, abscesses and liver
troubles part of which may have resulted from foreign bodies.

The total turnover for physical reasons amounted to 31.8 percent of animals
removed. Lump jaw (actinimycosis) removed 3.39 percent of these bulls from natural
service. This disease is communicable to man, and should be eliminated.
Tenure in Artificial Use

There were 691 bulls born before 1940 that completed their period of useful-
ness in artificial service. Only one or two bulls of this age group still are in
use, so exclusion of these two animals would involve only very slight age dis-
-tortion to the tabulation. It then would be slightly on the conservative side.

Table 1. Reasons for termination of usefulness of desirable bulls in
natural service. (To February 1, 1957.)

Reasons Number of Percentage
bulls of total
Sterility and defects of reproductive organs 1,604
Low breeding efficiency, inability to breed 502
Reproductive organs infected 54
Sub-total.............................. ...........2,160 37.7

Physical Reasons
Accidents and injuries 558
Old age 523
Feet and legs, crippled, lameness, arthritis,
rheumatism, infected feet 297
Foreign bodies 291
Paralysis, spinal troubles 81
Rupture, crampy, slow, poor physical condition 22
Miscellaneous 22
Poisons 16
Hereditary defects (recessive red color, etc.) 13
Sub-total. .............................. .. ....... 1,823 31.8

Diseases Generally
Brucellosis, Johnets disease, tuberculosis 225
Digestive diseases, bloat, intestinal twist 221
Lump jaw 194
Tumors, abscesses, liver infections 97
Trichomoniasis, vibriosis 81
Pus infections 76
Kidney and urinary conditions 58
Pneumonia, pleurisy, lung adhesions 94
Heart trouble 31
Miscellaneous infections and diseases 20
Blood vessel rupture 16
Cancer, leukemia 4
Died, but cause not diagnosed 631
Sub-total........................................ .1,748 30,5

TOTAL BULLS FROM NATURAL SERVICE...........................5,731


These 691 bulls began artificial service at an average age of 7.67 years.
They were used in the studs for an average of 2,84 years. The distribution of
these individuals is shown in Table 2. The larger proportion of these early bulls
came into the studs when between 4 and 10 years old. Nearly one-fourth of them
were usable less than one year, and another one-fifth went out when used less than
two years. Such a high early turnover was caused largely by factors other than
age. This high early loss suggests the desirability of a lease, with option of
purchase if the bull proves to be adapted for artificial use. Some organizations
have felt justified in carrying insurance on their bulls for the first year.

To February, 1957, some 2,859 completed records were obtained of bulls that
were in artificial service until ultimate disposal. These included animals from
yearlings to one individual past 18 years old. Including all of these records in
the analysis brings some age distortion toward such causes of losses as occur early
in life.

About one-half of the turnover was attributable to unsatisfactory reproductive
function. Low-breeding efficiency took the toll of about one-half of the animals,
more specific explanations having been given for some of them. Contrary to popular
opinion, a larger percentage of bulls placed in artificial service under 5 years
old were eliminated for low breeding efficiency than of animals obtained when 5 to
10 years old. Four percent of the losses were due to injury from foreign bodies
(hardware disease); over 3 percent due to conditions of the feet and legs, and 2.4
percent from lump jaw (actinimycosis). These losses were lower than those observed
with bulls in natural service, but perhaps could be reduced even further. Reasons
for losses of desirable bulls from artificial service are summarized in Table 3.

Death losses amounted to 15.2 percent of the animals, while full or partial
salvage values were received for 84.8 percent of these 2,859 bulls.

Bulls Discarded

There were 1,073 bulls sold for beef while yet fertile. The largest portion
was discarded for low production of daughters. Some developed into poor type
individuals, or were not popular. Some bulls were removed because of lack of early
proof, to avoid inbreeding, or to reduce the number of breeds. Daughters of a few
bulls were too small; had poor udders, rumps, or low butterfat tests. Bad dis-
position or difficult collection caused elimination of 3.4 percent of the bulls.

Reasons for discarding these 1,073 fertile bulls are given in Table 4.

Some 112 bulls of various ages were purchased but never used artificially.
Thirty-nine of them refused to serve an artificial vagina; 45 had poor semen, and
proofs of six were too low. Reasons for discarding the other 22 were distributed
variously among 16 other categories.

Bulls Returned From Artificial Service

The 254 bulls returned to natural service have not been involved previously
in these tabulations. A large proportion of these bulls had been appreciated, but
it was impractical to retain them longer. Yet they justified a higher financial
return to the stud than the salvage value for beef, and the majority were
appreciated for natural use. Reasons for their withdrawal from the studs are
listed in Table 5.

Tenure of dairy bulls placed in
born before 1940.

artificial service at various ages. All 691 of them were desirable bulls

Age at
first artifi-
cial use 0-1
1.0 1.99 1

2.0 2.99 1

"3.0 3.99

4.0 4.99 11

5.0 5.99 10

6.0 6.99 25
7.0 7.99 33
8.0 8.99 20

9.0 9.99 33

10.0 -10.99 18

11.0 -11.99 15
12.0 -12.99 4

13.0 -13.99 1

14.0 -14.99

15.0 -15.99

TOTALS ......172


1 2

in Artificial Service
5e- 6-7 7-8 -89
Number of Bulls
1 1 1

2 1 1


-910. 10-11 11-12



1 1


6 1

1 2

3 1

















'6 64

4 5


PERCENTAGE...... 24.5 20.7 16.9 11.0

.7 .7

Table 2.

9.3 8.1 3.8 2.2 1.1 .6


'1-2 2-g_2 --33 -4-::














I I [ l





STable 3, Reasons for elimination of desirable bulls in artificial
service, irrespective (f age. (To February 1, 1957.)

Reasons Number of Percentage
bulls of total
Low breeding efficiency 1,146
Refusal to work 130
Semen poor 116
Sterility and defects of reproductive organs 105
Semen would not stand shipment 30
Reproductive organs infected, trichomoniasis,
vibriosis 35
Inability to breed 24
Semen volume low 13
Sub-total................ ... .... .. ... ....... ......1,599 55.9

Physical Reasons
Old age 214
Accidents and injuries 159
Foreign bodies 125
Feet and legs, crippled, lameness 99
Arthritis, rheumatism, infected feet 76
Poor physical condition, rupture, crampy, slow 59
Paralysis, spinal troubles 48
Reason for disposal not stated 43
Hereditary defects (recessive red color, etc.) 38
Hard to collect semen 12
Miscellaneous 9
Sub-total.............................................. 882 30.9

Diseases Generally
Lump jaw 70
Died, but cause not diagnosed 51
Tumors, abscesses, liver infection 43
Brucellosis, Johne's disease, Tuberculosis 38
Digestive diseases, bloat, intestinal twist 37
Kidney and urinary diseases 35
Pneumonia, pleurisy, lung adhesions 32
Miscellaneous infections and causes 26
Heart trouble 16
BXood vessel rupture 13
Cancer, leukemia 12
Poisons 5
Sub-total.............................................. 378 13.2

TOTAL NUMBER OF BULLS........................ .......... ..2,859


Table 4. Bulls discarded from artificial use while fertile.

Reason for disposal Number Percentage

Low production of daughters 442 41.2
Surplus, found better bull 187 17.4
Plor type individual 105 9,8
Poor pedigree, unpopular 62 5,8
Avoid inbreeding 44 4.1
Not proved early 37 3.4
Transmitted poor type 114 10,6
Disposition, size, lacked libido 29 2.7
Hard to collect 7 ,7
Stud discontinued 19 1,8
Reducing breeds 12 1.1
Lease expired 12 1.1
Association rule (Milking Shorthorn) 3 .3

TOTAL................................. ........ ... 1,073 100.0

Table 5. Bulls returned to natural service.

Reason Number

Low fertility, poor semen 111
Inability, refusal, or hard to collect 19
Lease expired, or not recalled 50
Not stated 21
Inbreeding, or age 8
Unproved, or low production 11
Type of progeny, or red factor 6
Accidents or injuries 5
Replaced by better bull, surplus 14
Disposition 3
Lump jaw, or illness 3
Stud consolidation 3

TOTAL ...................................... .................. 254

Table 6. Tenure of bulls in natural service after release from artificial use.

Tenure in
natural use 1-_

.0 0.99 1

1.0 1.99 2

2.0 2.99 3

3.0 3.99 2

4.C 4.99

5.0 5.99

6.0 6.99

7.0 7.99


PT .3ENTAGE...2.5

2 2-3 3-4 4-5 5-6 6-7

1hen Returned to Natural Service
7-8 8-9 9-10 10-11 11-12 12-13
Number of Animals

13 11 19 6 8 7

12 7 14 5 3 4

3 4 7 2 3 4

4 5 1 .

2 4 1








1 1

1 2 1


40 40 31














6.9 6.6 12.6 12.6 10.0 11.4 10.1 12.9 4.4 4.4


Additional bulls were found in natural service that had been used artificially,
but the reasons for change were not obtained.

Tenure in Subseauent Natural Use

Tenure of 317 bulls that have completed their usefulness in subsequent natural
service is shown in Table 6. They ranged in age from eight yearlings to three bulls
past 13 years old when removed from the studs. The average age at removal was
6.94 years. The average subsequent use was 1.76 years. Data on the majority of
these bulls were provided by the later owners or herd managers.

Reasons for final disposal from subsequent natural service are summarized in
Table 7.

Table 7. Disposals of 287 bulls from subsequent natural service.

Reasons for disposal Number Percentage

Sterility, or low efficiency 89 31.0
Inability or slow 27 9.4
Accidents, feet and legs 26 9.1
Age 17 5.9
Foreign body 10 3.5
Died, cause undiagnosed 6 2.1
Inbreeding, or surplus bulls 40 13.9
Poor transmitter 13 4.5
Disposition 10 3.5
Reason not stated 11 3.8
Herd sold 9 3.1
Pneumonia 6 2.1
Lump jaw 6 2.1
Vibriosis or leptospirosis 3 1.1
Miscellaneous diseases 8 2.8
Other reasons 6 2.1

Total............................ 287 100.0

Discussion and Summary

This progress report deals with completed records of 2,859 bulls whose use-
fulness terminated in artificial service (691 of which were born before 1940);
1,073 bulls discarded while yet fertile; 112 that were obtained but never used in
artificial service, and 317 whose service terminated in subsequent natural service.
The final turnover records of 5,731 desirable bulls in natural service are in-
cluded for comparison.

Time yet is required for sufficient records from which to commute dependable
average life expectancy tables of bulls in artificial service. However, data point
strongly to certain trends which may be useful to management.

A slight relationship was observed between age of bulls when secured for
artificial service, and their elimination because of low breeding efficiency.

Low efficiency accounted for the discard of 46 to 51 percent obtained under
5 years of age; 39 to 44 percent obtained when 5 to 10 years of age, and 47 percent
for the 53 bulls past 11 years old when purchased.

Suggestions and criticisms are solicited which may aid either in obtaining,
handling, or analysing the records. Appreciation is expressed to the stud managers,
staff and herdsmen as well as to the breed registry associations cooperating.
Thanks are given also to student assistants George Brown, George Milicevic, Jr.,
and to James Thornhill who helped in succession with the card files of bulls in
artificial service. A research grant by the National Association of Artificial
Breeders provided the office assistance.

1BB ~300 copies

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