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Using science to improve fertility in Bos Indicus cattle

Using science to improve fertility in Bos Indicus cattle. F.W.C. Neser. Efficiency of production. Source -National beef Cattle Sector Strategy and Implementation Framework – February 2006. Stud vs. Commercial vs. Communal. Fitness. Fitness = NATURAL SELECTION: Survival Fertility.

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Using science to improve fertility in Bos Indicus cattle

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  1. Using science to improve fertility in BosIndicus cattle F.W.C. Neser

  2. Efficiency of production Source -National beef Cattle Sector Strategy and Implementation Framework – February 2006

  3. Stud vs. Commercial vs. Communal

  4. Fitness • Fitness = NATURAL SELECTION: • Survival • Fertility

  5. The heritability of fitness traits are usually low and will be severly influence by inbreeding depression and heterosis (Bourdon, 1997)

  6. Unlike the dairy farmer, the beef farmer derives his entire income from calves born into the herd, making fertility unquestionably the most important trait. Results of a study placed the economic importance of fertility, growth rate and carcass quality in the ratio 10:2:1. This means that fertility is 5x more important than growth and 10x more than carcass quality (Dr G Coulter-Kanada)

  7. Differences in Gross margins using a medium frame cow and different fertility levels

  8. Perceptions on Fertility • All animals are equally fertile • It is impossible to improve fertility by selection • Feed your animals fertile

  9. Model P = μ + G + E Genotype Environment Phenotype

  10. Environment Nutrition & management that affect the animals in the herd now! • Cows: • manage heifers to attain mating weights (65% of adult weight) • manage 1st calf cows (e.g. early weaning & mate separately) • restrict joining & cull empties • control reproductive diseases • cull females having difficult births

  11. Bulls: • breeding soundness test (adequate scrotal size) • good physical structure (and sheath) • adequate pre-breeding nutrition (body condition) • control reproductive diseases • multi-sire groups, mating ratios, serving capacity

  12. Fertility • Female fertility is a complex trait with many components. • Each component use resources. • Nature select for intermediate optimum. • Holistic approach. • To much selection emphasis on production could decrease reproduction

  13. Genetics Less fertile Above average fertile Did not calf

  14. Traditional fertility traits in females • Age at first calving (Optimum) • ICP: First and second calf (Min) • Average lifetime ICP (Min) • Days to calving • whole herd recording (female inventory) • bull in date and service sire(s) • subsequent calving date • record culls, especially non-calvers /culled empty

  15. Traits Males • Scrotal circumference • measure scrotal circumference all young bull at around 400d - Scrotal circumference also contributes to DC EBV - Early indicator of DC EBV for young bulls • Mating ability • Fertility • Performance of ancesters and daughters

  16. Heritability of Fitness traits in females • Age at puberty 0.16 - 0.57 • Age at first calving 0.06 - 0.19 • Days to calving 0.08 - 0.11 • Calving interval 0.01 - 0.06 • Calving ease 0.09 - 0.13 • Days open 0.09 - 0.20 • Gestation length 0.15 • Longevity 0.06 - 0.08 • Stayability 0.03 - 0.11 • Scortal circumference 0.40 - 0.46

  17. Heritabilities (h2) of reproductive traits of heifers (Johnston 2013)

  18. Genetic correlations between early- and lifetime reproduction traits rate

  19. Correlations show selection for reduced age at puberty will result in increased reproductive performance at both the early and lifetime stages.

  20. Novelty traits for fertility • Male: • Sperm quality • Hormonal levels

  21. Novelty traits: Males LH – Luteinising hormone • Testosterone production • Influences onset of puberty Inhibin • Regulation of sperm production IGF-I – Insulin-Like Growth Factor-I • Growth stimulus • Bull SC and sperm motility and heifer puberty

  22. Novelty traits: Males Burns and Corbet 2012 .

  23. Genetic correlations between bull traits and heifer reproduction

  24. Genetic correlations between bull traits and 1st calf heifer reproduction

  25. Novelty Traits: Males • No genetic antagonisms between semen quality and production traits • Scrotal and semen traits are genetically related to female age of puberty • Scrotal traits but especially semen traits related to reproductive output in cows

  26. Requirements to implement novelty traits to improve beef production • Recognition of novel phenotypes associated with economically important traits • Determination if phenotype can be measured accurately • Assessment of variation associated with phenotype • Proportion of variation attributable to genetics • Programs to implement change

  27. Selection for early sexual maturity in Rancho daMatinha, ANCP Associate (Lôbo et al. 2012)

  28. Fertility and not growth is the most important trait in selection • Heifers should conceive first time and calf not later than 33 months • Each cow should calf each year (Herefords currently 384 days) • 95% • Strive to use Days to Calving – Mating seasons compulsory • DNA technology – Fertility markers

  29. Change in BIF accuracy from the incorporation of Pfizer molecular values into BLUP evaluation of young sires with no phenotypic information (Lôbo et al. 2012)

  30. Thanks

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