Reproductive Management for Beef Females Cliff Lamb Assistant Director and Professor

1. Reproductive Management for Beef Females Cliff Lamb Assistant Director and Professor

2. Semen Sales in USA and Brazil from 1995 to 2011 (NAAB and ASBIA, 2011)

3. Estrous Synchronization and AI in Beef Cattle

4. Definitions • Synchronization Rate: % of females detected in estrus compared to total number synchronized. • Conception Rate: % of females pregnant compared to number of females inseminated. • Pregnancy Rate: % of females pregnant compared to total number synchronized.

5. Effect of synchronization rate on pregnancy rates

6. Effect of synchronization rate on pregnancy rates

7. TAI in Bostauruscows

8. Cidirol

9. TAI in Bostaurus heifers

10. Cidirol

11. Can we resynchronize estrus in non-pregnant cows?

12. Protocol for Resynchronization after TAI - Cows TAI 7-d Co-Synch + CIDR protocol Heat detect and AI CIDR 0 13 20 23 Days relative to TAI

13. Protocol for Resynchronization after TAI - Heifers TAI 7-d Co-Synch + CIDR protocol Heat detect and AI CIDR 0 12 19 22 Days relative to TAI

14. Protocol for Resynchronization after TAI (Larson et al., 2009)

15. Does estrous synchronization affect subsequent fertility?

16. Answers to field results from commercial producers 438 suckled cows were estrous synchronized using the 7-day CO-Synch + CIDR Protocol. TAI & GnRH GnRH PGF CIDR

17. Pregnancy Rates n=275 90% Overall pregnancy rate ?? n=85 n=37 n=34

18. Estrus response of cows following the 7-day CO-Synch+CIDR protocol 97.5% return to estrus rate!! Average Interval to estrus = 20.9 days

19. Economics of implementing TAI program

20. Impact of Fixed-Time AI on Calving and Weaning Control Natural mating TAI + GnRH GnRH PGF TAI Natural mating CIDR (Rodgers et al., 2011)

21. Impact of Fixed-Time AI on Calving and Weaning (Rodgers et al., 2011)

22. Impact of Fixed-Time AI on Calving Distribution 44% vs. 25%

23. Impact Calving Distribution on Calf Value

24. Impact of Fixed-Time AI on Calving and Weaning 17 kg (Rodgers et al., 2011)

25. (Rodgers et al., 2011)

31. Can I use sexed semen in beef cattle operations?

32. Semen sorting overview Nozzle Forward Fluorescence Photodiode DNA Content Laser beam Drop Delay Side Fluorescence Orientation Objective Pulse of Charge Applied Last Attached Drop Charged Deflection Plates + - + Waste Catcher + - + - Sort Receptacle

33. Gender ratio after 20% of cows are inseminated to sexed semen (Hall et al., 2010)

34. Embryo Production of Superovulated Angus Cows 32.4% 49.5% ** ** Category ** Treatments differ (P < 0.05)

35. Heifer Development

36. Influence of calving period on reproductive longevity (Cushman et al., 2012)

37. Influence of calving period on weaning weights (Cushman et al., 2012)

38. Factors affecting attainment of puberty • Body weight • Age • Genetics • Nutrition • Reproductive management • Rate of gain • Plane of nutrition • Body composition • Animal handling

39. Factors affecting attainment of puberty • Body weight • Age • Genetics • Nutrition • Reproductive management • Rate of gain • Plane of nutrition • Body composition • Animal handling

40. Factors affecting attainment of puberty • Body weight • Age • Genetics • Nutrition • Reproductive management • Rate of gain • Plane of nutrition • Body composition • Animal handling

41. Effect of timing of gain on attainment of puberty and reproductive performance Lynch et al., 1997 JAS 75:1715-1722

42. Effect of Timing of Gain on Reproductive Performance ADG, kg/d d0-112 EVENGAIN - 0.45 LATEGAIN – 0.11 ADG, kg/d d112-168 EVENGAIN – 0.45 LATEGAIN – 0.91 ADG, lbs/d d0-168 EVENGAIN – 0.45 LATEGAIN – 0.45 EVENGAIN LATEGAIN (Lynch et al., 1997)

43. Effect of Timing of Gain on Reproductive Performance Year 1 ADG, kg/d d0-112 EVENGAIN - 0.45 LATEGAIN – 0.26 ADG, kg/d d112-168 EVENGAIN – 0.80 LATEGAIN – 0.95 ADG, lbs/d d0-168 EVENGAIN – 0.57 LATEGAIN – 0.49 EVENGAIN LATEGAIN (Lynch et al., 1997)

44. Effect of Timing of Gain on Reproductive Performance Year 2 ADG, kg/d d0-112 EVENGAIN - 0.39 LATEGAIN – 0.05 ADG, kg/d d112-168 EVENGAIN – 0.74 LATEGAIN – 1.30 ADG, lbs/d d0-168 EVENGAIN – 0.53 LATEGAIN – 0.50 EVENGAIN LATEGAIN (Lynch et al., 1997)

45. Effect of Timing of Gain on Reproductive Performance Item EVENGAIN LATEGAIN Age at puberty, d Year 1 388 384 Year 2 386a407b Weight at puberty, kg Year 1 330 315 Year 2 314314 abMeans within row differ (P < 0.01) (Lynch et al., 1997)

46. Effect of Timing of Gain on Reproductive Performance Item EVENGAIN LATEGAIN First service PR, % Year 1 55.3 55.5 Year 2 56.4 71.1 Overall PR, % Year 1 87.2 86.8 Year 2 87.5 87.5 (Lynch et al., 1997)

47. Estrous cyclicity responses of heifers of distinct body conditions to energy restriction and repletion. Cassadyet al., 2009, JAS 87:2255-2261 and JAS 2262-2273

48. BCS 3 BCS 5 BCS 7

49. Design Restriction Re-feeding (FAT) ?? BCS 7 BCS 5 Resumption of estrous cycles (MODERATE) Termination of estrous cycles Cassady et al., (2009)

50. Change in BW, BCS and days to anestrus during feed restriction Cassady et al., (2009)