1. Reproductive Management of the Cow Herd

2. Basic Bovine Reproductive Facts
Puberty at 6 to 12 months of age
Estrous cycle is 21 days + 3 days
Standing heat or estrus is 12 to 18 hrs.
Ovulation occurs after estrus.
Gestation period is 285 days + 5 days

3. GOALS
To achieve a high conception rate in a relatively short breeding season.
60 to 90 day season is ideal.
Calves that are uniform in age are easier to manage and market.
To retain cows in the herd for a long time and thus reduce the number of replacements
Normal replacement rate is about 20%

4. Natural Service
In commercial beef herds, most of the mating is via natural service.
Bulls are with the cows 24 hours per day and do all heat detection.
With natural service, a relatively large volume of semen is placed in the vagina during standing heat.

5. Artificial Insemination
Used primarily in seedstock herds and well managed commercial herds.
Usually consists of 1 or 2 AI services followed by a “cleanup” natural service sire.
Heat detection is labor intensive.
A relatively small volume of semen is deposited in uterine horn at end of estrus.
Cows detected in heat in a.m. are bred in p.m. and vice versa.

6. Heat Detection Frequent observation.
“Gomer” bulls that have been vasectomized
Fitted with chin-ball marker
Penal deviation prevents disease transmission
Cull cows that have been injected with testosterone.
Pressure patches on rump.

7. Estrus Synchronization
One injection PGF with 10 day breeding
Two injection PGF programs
MGA/PGF
Synchro-Mate-B program
GnRH/PGF – “Select Synch”
Co-Synch

8. Embryo Transfer
Used primarily in seedstock herds to generate increased numbers of progeny from superior “donor” females.
Progeny must have superior economic value to make system cash flow.
Lesser value “recipient” females are synchronized to match estrous cycle of donor.

9. Embryo Transfer (continued)
Donor cow is super-ovulated and then mated at estrus.
Embryos are recovered (“flushed”) from the donor 7 days after estrus.
Embryos can be transferred to recipients or frozen for future transfer.
Approximately four pregnancies are generated per flush.

10. Calving Season Management
Heifers should be bred to begin calving about 3 weeks prior to the cow herd.
Allows for a longer postpartum interval before rebreeding.
Permits crew to check heifers early in season.
Be prepared to assist as needed.
Abnormal presentations
Heifers may require more assistance than cows

11. Processing Newborn Calves
Get colostrum into calf within a few hours after birth.
Iodine navel to prevent navel ill.
Inject with Bo-Se and Vitamin AD&E.
Intranasal vaccine for IBR, BVD & PI3
Scour vaccine (E. coli and Rota-Corona viruses).
Identify (tattoo and ear tag).