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Crossbreeding with Katahdins

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This presentation was given at the KHSI Expo in Cookeville, TN (August 2016).

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Crossbreeding with Katahdins

  1. 1. Crossbreeding with Katahdins SUSAN SCHOENIAN Sheep & Goat Specialist University of Maryland Extension sschoen@umd.edu - www.sheepandgoat.com www.slideshare.net/schoenian/ or go to www.sheepandgoat.com and choose SlideShare from the Social media drop down menu
  2. 2. The “Holy Grail” of sheep production (Dr. Charles Parker) Pounds of quality lamb marketed per ewe per year How do we increase it!
  3. 3. How do we increase pounds of quality lamb weaned per ewe exposed? Management Genetics • Management at lambing • Disease control • Parasite control • Predator control • Nutrition • Selection • Crossbreeding****
  4. 4. What is crossbreeding? • Mating individuals of different breeds or types. x Texel x Hampshire/Suffolk x Lacaunex White Dorper
  5. 5. What does crossbreeding actually do? • Creates new combinations of genes in crossbred animals. • Crossbred animals have increased heterozygosity (having dissimilar pairs of genes for a hereditary characteristic). • Heterozygosity is the basis for hybrid vigor (or heterosis).
  6. 6. Why crossbreed? • Hybrid vigor • Breed complementarity • Upgrading • Make composite breed
  7. 7. Hybrid vigor • Superiority of crossbred offspring compared to the average performance of its purebred parents.
  8. 8. Breed A Breed B First cross (F1) Purebred average SUPERIOR HETEROSIS
  9. 9. Estimates of lamb and ewe heterosis effects Trait Lamb Ewe Birth weight 3.2 5.1 Weaning weight 5.0 6.3 Pre-weaning ADG 5.3 -- Post-weaning ADG 6.6 -- Yearling weight 5.2 5.0 Conception rate 2.6 8.7 Lambing rate 2.8 3.2 Pre-weaning survival 9.8 2.7 Lambs born/ewe exposed 5.3 11.5 Lambs reared/ewe exposed 15.2 14.7 Litter weaning weight/ewe exposed 17.8 18.0 Effects expressed as percentage of purebred average (Nitter, G. 1978)
  10. 10. Lamb heterosis for weaning weight Purebred lambs Crossbred lambs A B BA AB Weight 53 63 62 60 Average 58 61 Heterosis 3 lbs. (61-58) 5.2% (3/58) Ewe heterosis for lambing rate Purebred ewes Crossbred ewes A B BA AB Weight 1.70 1.90 1.84 1.88 Average 1.80 1.86 Heterosis 0.06 lambs (1.80-1.86) 3.3% (0.06/1.80)
  11. 11. Heterosis in the crossbred ram • Less is known about the effects of heterosis in the crossbred male. • It is likely that heterosis influences traits such as libido, conception rate, hardiness, and longevity. • Increased fertility of crossbred rams used in spring mating has been reported. • Another use of crossbred rams is to optimize breed composition of crossbred ewes. • Usefulness and value of crossbred rams has not been fully recognized by US sheep industry.
  12. 12. Benefits of heterosis • Effects of heterosis on one trait may seem minor, but when total productivity is considered, heterotic effects accumulate to provide a substantial improvement over straightbred sheep. • Combined effects of lamb heterosis ewe heterosis, and complementarity can increase production by 40 to 50% relative to the average of purebred flocks of different breeds.
  13. 13. A crossbreeding system using terminal sires in a meat sheep operation SCENARIO 1 • Maternal ewes mated to maternal rams of the same breed. SCENARIO 3 • Maternal ewes mated to maternal rams of same breed (to produce replacements). • Maternal ewes mated to terminal sire breed (to produce market lambs. • Assume no hybrid vigor from production of crossbred lambs. SCENARIO 3 • Maternal ewes mated to maternal rams of same breed (to produce replacements). • Maternal ewes mated to terminal sire breed (to produce market lambs. • Hybrid vigor is included.
  14. 14. SCENARIO 1 SCENARIO 2 SCENARIO 3 100 ewes x maternal ram 35 ewes x maternal ram 65 ewes x maternal ram 35 ewes x maternal ram 65 ewes x maternal ram Ewe lambs mated Ewe lambs mated Ewe lambs mated 90% of ewes lamb 90% of ewes lamb 90% ewes x maternal lamb 92% ewes x terminal lamb (+2.6%) 1.5 lambs raised per ewe 1.5 lambs raised per ewe 1.5 lambs per ewe x maternal 1.7 lambs per ewe x terminal (+13%) 20 ewe lambs kept for replacement 20 maternal sired lambs kept for replacement 20 maternal sired lambs kept for replacement Rams purchased Rams purchased Rams purchased 115 market lambs sold at 114 lbs. @ $1.50/lb 27 maternal-sired lambs sold at 114 lbs @ $1.50 88 terminal-sired lambs sold at 128 lbs. @ $1.50 27 maternal-sired lambs sold at 114 lbs @ $1.50 102 terminal-sired lambs sold at 128 lbs. @ $1.50 $19,665 $4617 $16,896 $21,513 (+9.4%) $4,617 $19,584 $24,201 (+23.1%) Source: Strategic use of terminal sire meat breeds to improve flock production, David L. Thomas & Thomas W. Murphy, University of Wisconsin Assumptions and Results
  15. 15. Composite breeds • A new breed formed by crossing two or more breeds, then selecting within new crossbred population. • Appeal of composite breeds: simple and practical breeding system to use breed and heterosis effects, an alternative to more complex crossbreeding systems.
  16. 16. Crossbreeding systems
  17. 17. Terminal crossbreeding systems
  18. 18. Do all traits respond to crossbreeding? • Traits that are lowly heritable respond the most to crossbreeding, i.e. have the most hybrid vigor. ▫ Reproduction ▫ Resistance ▫ Fitness ▫ Longevity • Crossbreeding (heterosis) has little to no effect on traits that highly heritable. Example: Carcass traits • As heritability increases, crossbreeding has little to no effect.
  19. 19. Breed complementarity • No one breed of sheep is best of all traits, not even Katahdins! • Crossbreeding takes advantage of breed complementarity. ▫ Breed complementarity is the combining of desirable traits from two or more breeds into one animal. ▫ Strengths of one breed will offset the weakness of another breed. ▫ To maximize the benefits of breed complementarity, breeds must be chosen wisely; they must complement each other.
  20. 20. Katahdin criticisms • They don’t grow fast enough • They lack muscling. • They finish too light • They have too much internal fat. • Their lambs are suitable for all markets. ▫ Hot house (30-50 lbs) ▫ Commodity (over 120)
  21. 21. Improvement of carcass merit while maintaining parasite resistance in crossbred Katahdin lambs Feedlot finished, artificial parasite challenge Katahdin Suffolk Texel Primary infection no differences Challenge infection 757 epg 226 epg 462 epg Worm burdens no differences ADG not statistically significant 0.71 lbs/d 0.88 lbs/d 0.77 lbs/d REA different no differences 2.13 in2 2.67 in2 3.04 in2 Leg score 11.0 12.0 12.8 ParasitesGrowthCarcass West Virginia University and Virginia Tech, 2016
  22. 22. Performance of crossbred Katahdin lambs, pasture-raised Trait Sire breed Katahdin Dorper Texel Suffolk Birth weight no difference Weight, d-30 Lighter Intermediate Heavier Weight, d-120, lbs. 88.0 ± .13 92.6 ± .13 90.4 ± .13 99.2 ± .13 ADG, d 0-240, lb/d 0.29 ± .004 0.31 ± .004 0.31 ± .004 0.35 ± .004 FEC, d-90, epg 1469 2380 1085 1990 FEC, d-120, epg 1159 ± 534 5069 ± 877 1159 ± 534 5069 ± 877 # lambs dewormed 55 ± 7% 67 ± 7% 43 ± 7% 70 ± 8% Frequency of Tx, # 0.7 ± .1 1.2 ± .2 0.6 ± .1 1.2 ± .2 Age at first Tx, d 173 ± 6 155 ± 7 180 ± 7 157 ± 7 University of Maryland Eastern Shore (2007)
  23. 23. Improvement of carcass merit while maintaining parasite resistance in crossbred Katahdin lambs 90-d summer grazing season Trait Sire breed Katahdin Suffolk Texel Birth weight, lbs. 9.3 10.1 na Lambing difficulty no differences observed Pre-weaning death loss 0.08 0.43 0.11 Adj. weaning weight, lbs. 52.5 56.4 58.0 End weight 64.4 67.9 77.4 ADG 0.132 na 0.198 Fecal egg counts no differences observed % lambs requiring deworming 63 90 na West Virginia University and Virginia Tech, 2016
  24. 24. What crossbreeding is not •Indiscriminate mixing (crossing) of breeds. X
  25. 25. What crossbreeding is • Crossbreeding is a systematic use of breed resources to create animals of specific type for specific goals. 1. Crossbred lamb (terminal cross) 2. Crossbred ewe 3. Crossbred ram • A good crossbreeding program combines breeds with complimentary traits.
  26. 26. About crossbreeding with Katahdins • If crossbred (with wooled breeds) are retained, they will probably require shearing. • The fleeces from hair x wool sheep should be discarded. They should be discarded. They should not be mixed with wool and/or taken to wool pools.
  27. 27. SUSAN SCHOENIAN Sheep & Goat Specialist University of Maryland Extension sschoen@umd.edu www.sheepandgoat.com Thank you for your attention. Questions? Comments?

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