FLORIDA A.1:LICULTlUR L r :'7 JiT :iT.-.TICN
Department of Dairy Science
Dairy Science Mimeo 60-1
October 5, 1959
Better Breeding Techniques Pay
J, M. Wing
Repeat breeders cost their owners at least an extra dollar a day.
Hence, careful planning of the breeding program is one of the most im-
portant jobs at the dairy or ranch, otherr breeding is accomplished
through artificial insemination or natural service the following physio-
logical fundamentals should be considered.
1. Most cows stay in heat about 14 hours, but individuals vary from
6 to 36 hours.
2. The egg is shed from the ovaries of the cow 7 to 15 hours after
the heat period has ended,
3. Fertilization must take place right after ovulation for best
4. Spermatazoa are propelled through the genital tract mainly by
muscular contractions. These movements occur properly only if the cow
is comfortable, healthy, is not excited, and is in or very close to the
5. About six hours are required for the spermatozoa to reach
the distal end of the genital tract whether breeding is done by natural
or artificial service, and they should be there before ovulation occurs. ,
Thus breeding should be done during the last part of the heat perio/~~
6. The sperms may be shocked, thereby losing part or all of their
effectiveness by (a) direct sunlight, (b) cooling too rapidly, or (c)
contact with chemicals including soap or the residual sulfur in rubber
7. The cells are delicate, and it's easy to break the tails off
spermatazoa by rough handling. This includes pulling them into the
inseminating tube too quickly and driving over rough roads too fast.
8. About 60 days are required for the genital tract to recover
9. About 10 percent of all cattle are likely to be unable to
conceive without treatment.
10. Most spontaneous abortions occur at 4 months and most pre-
mature births are at about 71 months of pregnancy.
11. Retained placentas may be caused by very mild to very severe
abnormalities of the uterus,
Based on these fundamentals, the responsibility for the breeding
may be apportioned approximately as follows:
A. The herd manager should:
1. Keep records of heat periods, breeding and calving dates,
difficult births, retained placentas, abortions or other
health data, and decide when each cow should be bred.
2. Call the technician in time for him to arrange the
proper time for breeding.
3. Provide catch pens for heifers and a shady, clean place
for for breeding.
4. Isolate cows to be bred and keep them as calm and com-
fortable as possible.
5. Wash the external portion of the reproductive organs.
6. Handle animals carefully at all times but especially at
4 and 71 months after breeding.
B. The inseminator should:
1. Examine the semen at frequent intervals using a good
2. Keep the semen at the proper temperatures (400 F. for
liquid and -1100 or -3200 F. for frozen semen).
3. Keep equipment clean. Wash all instruments with a deter-
gent (not soap). Rinse well in tap water then in double
distilled water. Dry in a dust free place.
4. Rubber parts are scrubbed than boiled in soda water to
neutralize any sulfur which may be present.
5. Use mineral oil or other nontoxic lubricant (not soap).
6. Handle semen carefully to prevent physical shock.
7. Keep semen out of direct sunlight.
8. Breed all animals quietly and quickly.
9. Use deep cervical deposition rather than entering the
uterus with the inseminating tube.
10. Use fresh semen as soon as it is removed from storage
and frozen semen as soon as it thaws.
11. Keep finger nails very short and never wear rings or
other possible injurious jewelry,
12. Disinfect his boots before leaving each farm.
Number twelve applies also to the veterinarian who in addition
should be reminded to:
1. Examine unbred heifers four to six weeks before the
breeding season to detect and treat potential causes of
2. Examine all bred cows just before the second expected
heat since some cows which are with c olf will c ome into
heat and these must not be bred again.
3. Examine all bred cows for pregnancy before 60 days have
elapsed after breeding.
4. All cows should be examined shortly after calving, es-
pecially if difficult calving or retained placentas are
When these precautions are observed, at least nine out of ten cows will
conceive to one of the first three services. The remaining ten percent
should be examined and treated if advisable. Any cow which still is
open after five breeding should be culled except in rare, special
cases where further therapy is promising.