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Dr BE Mostert Geneticist SA Stud Book

The Genetics of Longevity… A Quantitative Perspective. Dr BE Mostert Geneticist SA Stud Book. Are there really genetic differences between cows ???. Production increased tremendously since 1930. Nutrition Management Genetic Potential. Genetic Potential.

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Dr BE Mostert Geneticist SA Stud Book

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  1. The Genetics of Longevity… A Quantitative Perspective Dr BE Mostert Geneticist SA Stud Book

  2. Are there really genetic differences between cows ???

  3. Production increased tremendously since 1930 • Nutrition • Management • Genetic Potential

  4. Genetic Potential • Successful freezing of semen – AI industry • Technology : Computers + Genomics • Genetic Evaluations • Breeding Values • Accurate Selection

  5. Milk : 62 kg / year Butterfat : 1.82 kg / year Protein : 1.99 kg / year

  6. Selection for Milk Production had a negative effect on : • Solid percentages • Reproduction • Health • Feed Efficiency • Intake Capacity • Longevity

  7. Average Number of Lactations of SA Dairy Breeds Holstein : 2.92 Guernsey : 3.05 Ayrshire : 3.13 Jersey : 3.27 Countries start to include secondary traits in TMIs

  8. Canada – Lifetime Profit Index

  9. Germany-Austria-Luxembourg – RelativZuchtwertGesamt

  10. The Netherlands

  11. New Zealand – Breeding Worth

  12. Economic Importance of Longevity • Increased longevity - associated with decreased costs for raising or purchasing replacement females • Proportion of mature cows increase as longevity increases - increase in the average production level in herds • Economic importance of Herd Life is second to Production and therefore higher than that of other Functional or Non-productive traits

  13. Longevity is a measure of the success of a cow to survive either voluntary or involuntary culling Voluntary- Productive Longevity / Herd Life - Breeder decides – production, likability Involuntary- Functional Longevity / Herd Life - Longevity adjusted for production - Cow determines moment of culling – - Diseases, poor reproduction, functional problems, death

  14. Genetic Evaluation for Longevity • Statistically difficult to handle : • Binary Trait : Dead / Alive • Takes a long time to measure • Record complete only when cow died • Heritability is low (Literature : 0.01 – 0.13) • Countries differ in definition and methodology

  15. Linear type traits are easy to measure, measured early in life, are moderate to highly heritable and known to be used as predictors for cow survival. • Other traits, for example Somatic Cell Score and Fertility also play a key role in the survival of cows. • These traits are often included in the genetic evaluation of Longevity, to increase the accuracy of prediction of Longevity EBVs. Direct – Survival Measurements Indirect – Indicator Traits

  16. Genetic Evaluation for FHL in SA Lactation records up to 4th parity, since 1975 Trait definition : HL1 :Survival up to 120 dim 1st Lactation HL2 :Survival up to 240 dim 1st Lactation HL3 :Survival up to 2nd Lactation HL4 :Survival up to 3rd Lactation HL5 :Survival up to 4th Lactation Indicator traits included :SCS, FA & UD

  17. Genetic Parameters : Jerseys

  18. Genetic Parameters : Jerseys

  19. Genetic Parameters : Jerseys

  20. Genetic Parameters : Jerseys

  21. Genetic Parameters : Jerseys

  22. Functional Herd Life for SA Dairy Breeds

  23. Functional Herd Life for SA Dairy Breeds

  24. Functional Herd Life for SA Dairy Breeds

  25. Functional Herd Life for SA Dairy Breeds Holsteins : 0.41 / year

  26. Functional Herd Life for SA Dairy Breeds Jerseys : 0.46 / year

  27. International Participation • Logix Milk GE system – Validated by INTERBULL • Participation in Direct Longevity Interbull Evaluations : • 6 Dairy Breeds • 21 Countries

  28. International Participation Genetic Correlations and common sires for the Jersey breed amongst cnts

  29. International Participation Genetic Correlations and common sires for the Jersey breed amongst cnts

  30. International Participation Genetic Correlations and common sires for the Jersey breed amongst cnts

  31. International Participation Genetic Correlations and common sires for the Jersey breed amongst cnts

  32. Variation in Functional Herd Life EBVs

  33. To Conclude … Longevity do have a genetic component Progress slow Included in SA TMIs : Jersey SAINET : 10 % Holstein LMI : 20% Ayrshire LMI : 21% Guernsey LMI : 20%

  34. THANK YOU !!!!!

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