1. Beef cow reproductive management
Benny Sharir DVM
Dr. Benny Sharir

2. The perfect beef cow Reproductive specifications regular cycle by 15mo
delivers first calf at 24mo
calves in first 3 weeks of calving season
is cyclic again by onset of breeding season
conceives at first breeding opportunity
produces a calf every 365 days
Dr. Benny Sharir

3. The perfect beef cow Maternal specifications calves unassisted
calf weights are close to breed average
gestation length close to breed average
provides excellent maternal care (colostrum etc.)
produces sufficient quality milk
has sound udder (teat size, no mastitis etc.)
Dr. Benny Sharir

4. The perfect beef cow Other specifications
temperament is such that she is not a danger to herself or humans
“easy keeper”
adapted to her environment
has good “disease resistance” (vaccinations)
has high salvage value
Dr. Benny Sharir

5. Characteristics of Beef cow reproductive cycle
Prolonged (variable length) PP anestrus (lactational anestrus)
FSH / follicular development continue during the anestrus period
low LH pulse frequency and therefore no LH surge possible in anestrus period
Dr. Benny Sharir

6. Beef cow reproductive physiology
“suckling effect” and “milk removal” do not solely explain PP anestrus (muzzled calves)
intact innervation of udder not essential to prolong PP anestrus provided suckle > 2 times per day
suckling induced hormone changes: prolactin, oxytocin, corticosteroids all increased
Dr. Benny Sharir

7. Lactational anestrus
Dr. Benny Sharir

8. Dr. Benny Sharir

9. Beef cow reproductive physiology
PP anestrus appears to be result of a complex interaction of several sensory inputs:
olfactory
visual
auditory
hormonal
metabolic cues (BCS at calving)
Alien calf
Dr. Benny Sharir

10. Factors affecting PP anestrus in beef cow
age: heifers versus cows
heifers have longer PP anestrus
pre-partum nutrition and BCS at calving
profound effect on PP anestrus
post calving nutrition
may affect CR but less effect on PP anestrus
Dr. Benny Sharir

11. Dr. Benny Sharir

12. Body condition scoring areas
1=back 2=tail 3=pins
4=hooks 5=ribs 6=brisket
Dr. Benny Sharir

13. Dr. Benny Sharir

14. Dr. Benny Sharir

15. Body condition scores
accurately reflect metabolic reserves as opposed to just body weight
varies over the year depending:
on feed availability,
feed quality
metabolic status of the cow
in general cows that calve thin remain thin
Dr. Benny Sharir

16. Body condition scores
accurate predictor of when cyclicity likely to return
1 BCS represents about 35Kg BW in medium frame cow
Equiv. to energy and protein in 125Kg corn
critical calving:
BCS 5 is min. for cows
BCS 6 is preferred for heifers
Dr. Benny Sharir

17. Body condition scores and return to cyclicity percent cycling
BCS (calving) # cows @
thin (1-4)
mod. (5-6)
good (7-9)
Dr. Benny Sharir

18. BCS @ pregnancy test. v mean pregnancy rates
within age group and for the entire cow herd
Parity body condition scores
all
1 40%
>
all
note: 1) poor performance of heifers at low BCS v cows
2) first calf heifers still 10% less than cows even at
higher BCS
Dr. Benny Sharir

19. Effect of BCS at calving on interval to
estrus return and BCS at breeding on PR
BCS post calving interval (days) PR ( %)
Dr. Benny Sharir

20. Heifer management calve in min. BCS 6
breed to calve 3wk prior to cow herd
allows 3 weeks longer to return to cycling
manage as a separate herd (avoid “social” stress)
post calving stresses of
growth
lactation
Dr. Benny Sharir

21. onset calv. end calv. weaning 6-8mo
end heifer
breed.
end cow breed.
onset cow breed.
onset heifer breed.
Dr. Benny Sharir

22. Efficient beef cow reproduction
calve at 2 yr
calve every 12mo
60% cows conceive first 21d of breeding
cow breeding season=63d
70% heifers conceive first 21d of breeding
heifer breeding season=42d
Dr. Benny Sharir

23. Pregnant in the first 21 days
Cows preg. in first 21 days is dependent on:
1) cows cycling first 21 days
2) first service conception rate
a) cow fertility
b) bull fertility
Dr. Benny Sharir

24. The calving pattern
measures frequency of calvings that occur in each successive 21d period
goal
95% of herd in 63d
60% first 21d
profound effect on Kgs beef weaned
Dr. Benny Sharir

25. Prolonged (>60d) breeding season
prolonged calving season
uneven line of weaner calves
inefficient forage use
retention of late cyclers / non-cyclers
increased late pregnancies
increased open cow
greatly reduces Kg beef sold
Dr. Benny Sharir

26. Critical steps in efficient beef production
Heifer management
raise to breed at 15mo and calve at 24mo
limit breed. season to 42d
begin breed. 3 wk before cow herd
use bulls with low BW EPD’s (Expected Progeny Difference)
monitor BCS and calve at min. 5 preferably 6
monitor calv. closely, don’t delay intervention
minimize post calving weight loss
separate first lactation cows from cow herd
Dr. Benny Sharir

27. Critical steps in efficient beef production
cow herd management
min. BCS 5 at calving
BCS herd 2-3mo before calving season
separate off thins and calculate economic ration to raise to BCS 5
minimize weight loss post calving
limit breeding season to max. 65d
>60% cows inseminated (bull / AI) in first 3wk
Dr. Benny Sharir

28. Critical steps in efficient beef production
cow herd management
bulls semen tested prior to breed. season
preg. check early after breed. season, cull opens
BCS at preg. check / plan for if, when and how adjustments will be made
check udders, teeth and eyes at preg. check
maintain adequate “clean” calving pastures
monitor vaccine and parasite programs
Dr. Benny Sharir