1. Systems of Crossbreeding – Experiences in Research & Do’s and Don’ts R. Mark Enns Colorado State University

2. Overview Crossbreeding systems Research experience and recommendations

3. Factors to consider when selecting a system Amount of hybrid vigor –Two types Individual –For weaning weight – 5% –For weaning rate – 0% Maternal –For weaning weight – 6% –For weaning rate – 8% –Total Weaning wt per cow exposed – 18% Kress and MacNeil, 1999

4. Factors to consider when selecting a system Amount of hybrid vigor –Two types Individual Maternal Breed complementarity Consistency of product Replacement generation – males and females Simplicity of the system –Dr. Gosey calls “management ease” test Accuracy of evaluation –In the future? Assumption: Have appropriately selected the breeds to go into the system Bourdon, 2000

5. The Key Find a system that is beneficial for the specific production situation and whose downside is relatively minor.

6. Examples

7. 3 breed spatial rotation A higher proportion Breed B A higher proportion Breed C X Breed A X A higher proportion Breed A Breed B X Replacement

8. Attributes Hybrid vigorIncreased hybrid vigor Breed Complementaritypotential Consistencyinversely related to complementarity

9. Attributes Replacementsyes Genetic evaluationlikely Simplicitylow

10. 3-Breed Rotation in Time Most females a higher proportion Breeds B and C X Breed A Most females a higher proportion Breeds C and A X Breed B Most females a higher proportion Breeds A and B X Breed C Most females a higher proportion Breeds B and C X Breed A Time Replacement and remaining older females

11. Attributes of Rotations in Time Hybrid Vigor--somewhat reduced Breed complementarity, consistency of performance, replacement considerations, and accuracy of genetic prediction Simplicity – greatly increased

12. Rotations in time designed for small producers Weakness:Consistency of decisions over time

13. Terminal Sire Systems Maternal-breed females are mated to paternal-breed sires Goal: to efficiently produce progeny that are especially marketable

14. Static Terminal System Purchased F 1 AxB maternal females Breed C terminal X F 1 C x (A x B) market offspring

15. Key Consider the factors that are most important to the producer –Give the program the greatest probability of success

16. Comparison of systems Crossbreeding SystemHVCompConstEaseACC Spatial Rotation+ - Varies + Rotation in Time+ - varies+++ Terminal system (purchase replacement ♀)++ + + Composite system (already formed)++++++ Assumption: All of the above produce their own replacement females except the terminal system Bourdon, 2000

17. Numerous other systems Only limited by the breeder’s creativity

18. Rotation/Terminal Systems X A higher proportion Breed B A higher proportion Breed A X Breed B Replacement Excess (often older) females Male offspring sold Male offspring sold F 1 C x (A/B) market offspring

19. Composite/Terminal System Younger maternal composite females X Maternal composite Older maternal composite females X Terminal Breed F1 market offspring Male offspring sold

20. More systems than can be outlined in a hour

21. Research – Do’s and Don’ts

22. Heterosis will not overcome poor breed choice –Advantage of Zebu cross dams in Florida for pregnancy rate was 5.8% units over that in Nebraska (1.8% units) Olson et al., 1991 –Holstein Hereford cross had a 23% advantage over HA for calf weaned/cow-exposed, and Brahman cross a 13% advantage (Setshwaelo et al., 1990) Cross must be appropriate for its production environment –Drs. Kress and Franke will discuss next week.

23. Continous use of the same breed will result in loss of heterosis –Dr. Gosey 3 generations of using Angus bulls on F1 cows resulted in a loss of 87% of hybrid vigor

24. Crossbreeding works Increases in lifetime production due to maternal heterosis have been estimated at up to 1.44 calves when calving first as 2 year olds (Cundiff et al., 1992) defined as cumulative 200 day weight Nunez et al., (1991) crossbred cows had lower probabilities of being culled than straightbreds (Angus, Hereford, Shorthorns) Davis et al. (1994) reported F1 cows averaged 1.2 year longer lifespan than straightbred cows –Net profit per cow exposed increased ~$75

25. Do not be tempted to retain replacement females from terminal sire mating systems in restrictive environments Energy consumed to produce calf weight varies between breeds –Jenkins et al. (1991) In most environments –At low to moderate resource availability the British breeds tend to be most efficient at converting intake into calf weight –At higher levels of availability (intake) the continental breed tend be the most efficient Jenkins et al. (1994)

26. Develop a plan and stick to it, otherwise … Using Dr. Gosey’s example –15/16 Angus Realized that have lost heterosis, so go back to Hereford bulls –Use bulls for 3 years and 15% female replacement rate, 1 year after last crop born 38% of females are now F1 62% of females are still Angus

27. 38% are now F1 and 62% are still Angus –So switch to a 3 rd breed for 3 years A year after the last crop is born –24 % are HxA –38% are Angus –39% are new cross Point: –Without a plan and some determination to maintain focus can get quite the collection of different breeds Influences marketability

28. Choose not only breeds but appropriate animals within breeds Colorado State University experience –Generalization: Black baldy cows are adapted to the eastern Colorado shortgrass prairies –Can we identify another genotype that might be adapted to that environment but bring more performance in the feedlot and on the rail?

29. Approach Given: Hereford x Angus cross works well –Choose a breed from which we could find animals with similar milk production levels –Continental breed

30. Approach Given Hereford Angus cross works well –Choose a breed from which we could find animals with similar milk production levels –Continental breed Limousin –HxA and LxA females

31. EPD Guidelines BWYWMilk Hereford≤ 2.060 to 708 to 15 Percentiles20%55% to 30%80% to 45% On NALF Scale≤ 1.677 to 877.6 to 14.6

32. 2003 CalvesNo.WWCalf Age Adj WW Hereford x Angus 23498195521 Lim-Flex27510195531

33. 2003 CalvesNo.WWCalf Age Adj WW Hereford x Angus 23498195521 Lim-Flex27510195531 2004 CalvesNo.WWCalf AgeAdj WW Hereford x Angus 67409156520 LimFlex14456188502

34. No.Weight Frame Score Hereford x Angus287044.7 Lim-Flex336855.2 Difference19-.5 Yearling performance –Weight and Frame Score

35. WeightFS Pelvic Area Hereford x Angus7044.7168 Lim-Flex6855.2169 Difference19-.5 Yearling performance

36. % Bred 1 st 21days Total % Bred% Open Hereford x Angus 71937 Lim-Flex617921 Difference1014-14 Breeding performance –60 Day breeding season

37. After 1 st calf, all rebred except 1 Although preliminary, we believe we may have another adapted F1 cross appropriate to the eastern Colorado environment

38. Breed Averages LimFlex CW – 793 REA – 12.44 YG – 3.27(2.6) YG4 – 0% CAB – 40% $/cwt - $146.11 Last 83 days Avg Daily Intake – 30.0 ADG – 3.06 $/hd – $1159.20 Angus CW – 762 REA – 12.14 YG – 3.45(3.4) YG4 – 40% CAB – 20% $/cwt - $137.90 Avg Daily Intake – 31.7 ADG – 3.79 $/hd – $1050.57

39. Do’s and Don’ts Choose a system that has a high probability of success –simplicity Make appropriate breed choice Make appropriate choice from within breed Stick to the plan to avoid “mongrelization” Commercial producers should crossbreed

40. R. Mark Enns Dept. of Animal Sciences Colorado State University Fort Collins, CO 80523 Phone: 970-491-2722 Email: mark.enns@colostate.edu