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Beef cow reproductive management
Benny Sharir DVM Dr. Benny Sharir
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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
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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
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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
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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
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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
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Lactational anestrus Dr. Benny Sharir
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Dr. Benny Sharir
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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
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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
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Dr. Benny Sharir
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Body condition scoring areas
1=back 2=tail 3=pins 4=hooks 5=ribs 6=brisket Dr. Benny Sharir
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Dr. Benny Sharir
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Dr. Benny Sharir
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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
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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
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Body condition scores and return to cyclicity percent cycling
BCS (calving) # cows @ thin (1-4) mod. (5-6) good (7-9) Dr. Benny Sharir
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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
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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
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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
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onset calv. end calv. weaning 6-8mo
end heifer breed. end cow breed. onset cow breed. onset heifer breed. Dr. Benny Sharir
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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
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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
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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
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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
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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
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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
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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
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