Replacement Heifer Management: A coordinated management concept

1. Replacement Heifer Management:A coordinated management concept Richard F. Randle, DVM, MS Beef Extension Veterinarian University of Nebraska-Lincoln

2. Economic and GeneticImportance of Various Traits Adapted from (A)Willham, 1973; (B)Melton, 1995

3. Heritability of Reproductive Traits From Dearborn et al., 1973; Laster et al., 1979

4. Reproductive Losses (%) Adapted from Bellows and Short, 1990; Wiltbank, 1990

5. Bred Replacements Adapted from Bellows and Short, 1990; Wiltbank, 1990

6. Replacement Heifers • Calve by 24 months of age with minimum problems • Give birth to and raise a vigorous, healthy calf • Successfully re-breed

7. Importance of Replacement Heifers • Dictates future performance of herd • Where will the herd be in 5 years? • Substantial investment before any return • 30 months minimum before sale of 1st calf • Highest potential for reproductive problems • Dystocia, calf survival, rebreeding

8. Courtesy of Dr. Jeff Ondrak GPVEC Dr. Jeff Ondrak - GPVEC

9. Breeding: Conception Puberty Gestation Rebreeding Weaning Parturition Postpartum period; lactation

10. Process…. • Selection • Development • Procedures • Monitor

11. Heifer Selection • Replacement rate - 10% to 20% • Select 10% to 20% more • Age, Size • Conformation • Dam performance

12. Heifer Selection Scenarios • Retain all heifers and breed • Retain all heifers born in 1st half of calving • Remove top and bottom 10% by size or weight • Retain all heifers born in 1st 30 days • Remove top and bottom 10% by size or weight • Calf performance data • Dam performance data

13. Heifer Development • Grow • Attain puberty • Determine breeding strategy • Bull selection

14. Puberty • Function of… • Age • 10 to 12 months • Breed influence • Weight • 55% to 65% of mature weight

15. Pregnancy Rates of Heifers Bred at Pubertal or Third Estrus % Pregnant Pubertal 57 Third 78 from Byerley et al., 1987

16. Heifers Optimum Growth Rate for Breeding Herd Replacement Heifers Adapted from Fox et al., 1988

17. Target Weight • Determine breeding date based on when you want them to calve • Determine the target weight for breeding • Determine the number of days from weaning to breeding • Determine ADG

18. Target Weight = ADG Breeding Weight - Weaning Weight Breeding Date - Weaning Date

19. Breeding Strategy • In order for heifer to calve by 24 months of age she must conceive by 15 months of age

20. Breeding Strategy • In order for a cow to calve every 365 days she must conceive by 80 days post calving • Uterine involution • Return to cycling • Cows average 40 to 60 days • Heifers average 60 to 80 days

21. Breeding Strategy • Breed heifers to calve 2 to 3 weeks before the cow herd • Calve the second time in line with the cow herd

22. Breeding Strategy • Natural Service • Synchronization • Artificial Insemination

23. Procedures • Health • Pre-breeding • Pregnancy Examination • Pre-calving

24. Health and Vaccination Program • Advice and guidance of veterinarian • Proper product use • Timing • Starts at or before weaning • Prebreeding, Pregnancy Exam, Pre-calving • Focus on diseases that cause reproductive losses and reduced reproductive performance • IBR, BVD, Lepto, Brucella, Campylobacter, Trichomoniasis, Neonatal diarrhea, Parasites….

25. Pre-breeding Evaluation • Evaluate weaning to pre-breeding development • Average age of the group should be 12.5 to 13.5 months (375 - 410 days) • Performed 30 to 60 days prior to scheduled breeding program

26. Pre-breeding Examination • Weight and body condition • 80 % at 55% of mature body weight • Pelvic measurement • 150 cm2 or greater • Reproductive tract score • 50% or greater cycling (RTS 4, 5) • Conformation and structural soundness • Health

27. 65% 55%

28. Reproductive Tract Scores From Anderson et al., 1991

29. Identify abnormally small or shaped pelvis

30. Neonatal Exposure to Progesterone & Estradiol on Reproductive Tract in Beef Heifers aData were collected from cyclic adult beef heifers on Day 12 of induced estrous cycle. Group means (n = 5) and SEM are presented. bTreated heifers received a single Synovex-C implant sc on designated day of life. Controls were untreated. cWet weight. d,e,f(P<0.01), g,,h(P<0.02), i,j(P<0.09): Means within a row with different superscripts differ. Adapted from Fox et al., 1988

31. Pre-breedingIndividual and Summary Data • Used to evaluate success, identify potential problems and institute management changes • Pre-breeding analysis • % cycling, nutritional status, structural soundness • Review breeding management

32. Pregnancy Examination • Perform prior to 120 days gestation • determine fetal age • Weight and body condition • Distinguish AI pregnancies from natural service pregnancies • withhold clean-up bulls 2 weeks • Health

33. PregnancyIndividual and Summary Data • Used to evaluate success and identify management changes for improvement • Pregnancy rates, pregnancy histograms, synchronization response, AI conception rates, synchronized pregnancy rates

34. Pre-calving Examination • Perform 30 to 45 days before calving • Weight and body condition • 85% of mature weight • BCS of 6 • Health

35. Reproductive Summary Adapted from Patterson and Bullock, 1995

36. Reproductive Performanceby Reproductive Tract Score Randle RF, Patterson DJ, 2005

37. Reproductive Performanceby Reproductive Tract Score Randle RF, Patterson DJ, 2005

38. Comparison of pre-breeding weights by RTS in yearling replacement heifers Randle RF, Patterson DJ, 2005

39. CHAPA 799 operations 18 top beef states 70% of U.S. beef cow/calf operations Alabama, Arkansas, California, Colorado, Florida, Georgia, Iowa, Kansas, Kentucky, Mississippi, Missouri, Nebraska, New Mexico, Oklahoma, Tennessee, Texas, Virginia, Wyoming Use of Reproductive Management Technology in Beef Heifers NAHMS Survey, 1994

40. Selected Management PracticesUsed on Replacement Beef Heifers NAHMS Survey, May 1994