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Extreme Inbreeding at Beltsville 1912-1949

Extreme Inbreeding at Beltsville 1912-1949. Experimental Design. 8 consecutive generations of mating sires to their daughters, and dams to their sons Highest inbreeding coefficients ever obtained in cattle (maximum F = 75.1%)

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Extreme Inbreeding at Beltsville 1912-1949

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  1. Extreme Inbreeding at Beltsville 1912-1949

  2. Experimental Design • 8 consecutive generations of mating sires to their daughters, and dams to their sons • Highest inbreeding coefficients ever obtained in cattle (maximum F = 75.1%) • Foundation Guernsey sire (Prince Billy) imported from the Isle of Guernsey in 1910 • Foundation Holstein sire (Lad 11th) purchased from Minnesota in 1912

  3. Pictures From The Study • Early matings within the Guernsey and the Holstein lines • The 8 Holstein herd sires used. Sire 1 was the sire, maternal grandsire, and maternal great grandsire of sire 2. Further inbreeding led to sire 8 with coefficient F = 62.5% • Pedigree of an example cow with F = 64.6% • Pedigree of the highest cow with F = 75.1%

  4. Early Matings in the Guernsey Line USDA Tech. Bulletin No. 339

  5. Early Matings in the Holstein Line USDA Tech. Bulletin No. 339

  6. Eight Herd Sires Used USDA Tech. Bulletin No. 927

  7. Sire 1 Appears 50 Times (64.6% F)

  8. Most inbred cow ever (F = 75.1%) 6 2 1 1 6 3 2 1 A26 6 1 A26 1 A26

  9. Other Highly Inbred Lines • Prospector line of Herefords, max F = 66.3% in 1984 at Colorado State • Anxiety 4th line of Herefords, F > 50% in 1980 at North Dakota State • Duchess family of Shorthorns, mean F of 40% in 1800’s by Thomas Bates, England • Current maximum F in each dairy breed is 40–50% in USA

  10. Conclusions • Guernsey line died due to lethal recessive and Brucellosis epidemic • Holstein birth weights decreased from 37 kg to 29 kg • Milk yield decreased by 7% and fat yield by 17% with inbreeding levels near 50% • “Continued inbreeding of whole herds, however, is almost certain to be disastrous.”

  11. References • Woodward, T.E. and R.R. Graves. 1933. Some results of inbreeding grade Guernsey and grade Holstein-Friesian cattle. USDA Tech. Bulletin No. 339 • Woodward, T.E. and R.R. Graves. 1946. Results of inbreeding grade Holstein- Friesian cattle. USDA Tech. Bulletin No. 927 • Swett, W.W., C.A. Matthews, and M.H. Fohrman. 1949. Effects of inbreeding on body size, anatomy, and producing capacity of grade Holstein cows. USDA Tech. Bulletin No. 990

  12. Acknowledgements • Max Paape rediscovered the original records at the Beltsville research farm. • Batchimeg Tseveenjav, Mike Bishop, and Mike MacNeil supplied information on inbred beef lines. • Kim Fletcher-Carroll arranged the graphics.

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