15 selection of breeders


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15 selection of breeders

  1. 1. Selection and management of bulls, cows and calves intended for breeders
  2. 2. Setting goals for beef cattle breeding <ul><li>Some traits that commercial breeders consider for selection goals, include: </li></ul><ul><ul><li>Low birth weight for ease of calving. </li></ul></ul><ul><ul><li>Weaning weight or pre-weaning rate of gain. </li></ul></ul><ul><ul><li>Post-weaning rate of gain. </li></ul></ul><ul><ul><li>Efficiency of feed conversion. </li></ul></ul><ul><ul><li>Mature mass. </li></ul></ul><ul><ul><li>Mothering ability. </li></ul></ul><ul><ul><li>Carcass traits. </li></ul></ul><ul><ul><li>Conformation. </li></ul></ul>
  3. 4. The Selection and Management of Breeding Bulls <ul><li>The right genetics </li></ul><ul><li>Age of bulls </li></ul><ul><li>Management on the day of turnout </li></ul><ul><li>The start of the fourth week of the mating period </li></ul><ul><li>Rotating bulls </li></ul>
  4. 5. The right genetics <ul><li>Select top quality bulls to maximise the output </li></ul><ul><li>Assessing the genetic package a bull will pass onto his offspring is often more difficult than assessing structural aspects. </li></ul><ul><li>Some of the physical traits are of limited value as indicators of genetic merit. </li></ul><ul><li>Much more useful information is provided by recording differences in performance among animals run under the same conditions. </li></ul><ul><li>If differences are observed in situations where animals are given the same opportunity to perform then it is more likely that the differences are due to variation in genetic merit. </li></ul>
  5. 6. Age of bulls <ul><li>Experienced mature bulls can easily cope with around 40 cows </li></ul><ul><li>In comparison young bulls in their first mating season can only cope with around 15 cows and even then only for a short 3 – 4 week period. </li></ul>
  6. 7. Management on the Day of Turnout. <ul><li>When the bull is turned out there is a good chance that at least one of the cows will be in season. </li></ul><ul><li>It is therefore sensible to wait for half an hour and watch if the bull serves successfully ie successfully enters the cow and jumps. </li></ul><ul><li>This is particularly important for young bulls being used for the first time. </li></ul>
  7. 8. The Start of the Fourth Week of the Mating Period <ul><li>The most critical time to check how well the bull is performing. </li></ul><ul><li>A fit fertile bull should stop around 60% of the group in the first 3 weeks. </li></ul><ul><li>For a bull running with around 35 cows this would mean around 17 – 21 cows becoming pregnant in the first 3 weeks. </li></ul><ul><li>The remaining 15 cows would come back into season over the second 3 week cycle. </li></ul><ul><li>On average this would be less than one cow served per day </li></ul>
  8. 9. Rotating Bulls <ul><li>Traditionally move bulls between groups of cows every 3 weeks to minimise the impact of an infertile bull. </li></ul><ul><li>Unfortunately rotating bulls tends to have the reverse effect, making it difficult to identify problem bulls unless precise records are both kept and fully analysed each year. </li></ul><ul><li>The more effective and much safer way of more rapidly identifying an infertile bull is to closely observe cows at the start of the fourth week of the mating period as described above. </li></ul>
  9. 10. Selection of cows/heifer <ul><li>Select heifers at weaning based on these economically important factors: </li></ul><ul><ul><li>Early birth in the calving season — early born heifers will have a head start on development, reach puberty sooner and have higher conception rates earlier in the breeding season </li></ul></ul><ul><ul><li>Heavier weaning weights </li></ul></ul><ul><ul><li>Utilize adjusted weaning weights to account for age differences </li></ul></ul><ul><ul><li>Fertility of the dam </li></ul></ul><ul><ul><li>Calving ease </li></ul></ul><ul><ul><li>Milking ability </li></ul></ul><ul><ul><li>Structural soundness and frame size </li></ul></ul><ul><ul><li>Disposition </li></ul></ul>
  10. 11. Calf selection <ul><li>weaning weight, </li></ul><ul><li>yearling weight, </li></ul><ul><li>birth weight </li></ul><ul><li>feed efficiency </li></ul>