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Why is Bull Selection Important? - PowerPoint PPT Presentation

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Why is Bull Selection Important?

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  1. Why is Bull Selection Important? • The bull contributes 1/2 of the genetic makeup of his offspring • He’s the most important individual in herd • Use a bull to improve the quality and performance of your herd

  2. It can be estimated that 87% of the genetics in your cow herd are a result of the last 3 bulls in your cow’s pedigree. Name these three breeds

  3. Selection Criteria: Sires • Varies depending on the use of the calf and the age of the cow being bred • Low BW bulls are an advantage for heifers, but not necessary or desirable for larger, mature cows • Look for more growth and size when breeding larger framed, mature cows

  4. Genetic Tools - Selection • Use EPD’s and other estimates of genetic potential to make permanent improvement in the genetic level of the herd • Effective when heritability is moderate to high • ex: growth- high heritability • ex: reproduction- low heritability

  5. Why Is Heritibility Important • Commercial: sell cattle by weight ^ Weight at various ages is heritable • WW is estimated to be: ~ 30% heritable • YW is estimated to be: ~ 45% heritable

  6. Genetic Tools - Crossbreeding • Breeds can be crossed to improve heratability traits that are low Ex: Reproductive Performance - Crossing Angus bulls on Brahman cows (Brahman cattle reach sexual maturity later than other breeds)

  7. What is an EPD • Expected Progeny Difference • The difference between EPD’s of two bulls is the expected difference in progeny averages when bulls are mated to similar cows in a herd • # expressed in pounds & can only be used as a comparison for animals in the same breed

  8. Which Bull Would You Selectto use on mature cows when growth is the most important trait to you?

  9. Use of EPD’s • Use only to compare two or more bulls • EPD’s allow valid comparisons of all bulls of the same breed, but they do not allow you to compare bulls from different breeds

  10. EPD Charts • Most breed associations provide EPD’s for : 1. Birth Weight (BW) 2. Weaning Weight (WW) 3. Yearling Weight (YW) 4. Maternal Milk 5. Carcass

  11. Birth Weights • High Birth Weight EPD’s 1. Calving Difficulty when bred to first calf heifers 2. Increased Cost and death loss

  12. The American Angus Association suggests that sires with a birth weight EPD in excess of 3.0 pounds should not be used on first calf heifers in most cases

  13. Weaning & Yearling Weights

  14. What is the difference between a sire with a 45 pound EPD for yearling weight versus one that has an EPD of 5 pounds? • A. Progeny with 20 lbs. difference in YW • B. Progeny with 30 lbs. difference in YW • C. Progeny with 40 lbs. difference in YW • D. Progeny with 50 lbs. difference in YW

  15. Scrotal Circumference • Yearling bulls with large scrotal circumference sire daughters that show estrus at an earlier age • Be sure to select a bull with a SC of at least 30 cm at one year of age

  16. Milk • Measured in terms of how it affects weaning weight of a calf • Milk EPD on a bull is an estimate of lbs. of a calf at weaning produced by the bull’s daughter due to her milking ability

  17. Breeding Plan Replacement Heifers • Mate 1st calf heifers to bull with low BW, calving ease & large scrotal circumference • Expect to use as many heifers as possible from these matings as replacements

  18. Breeding PlanMain Cow Herd • Mate the remaining cows to bulls which have EPD’s that meet market criteria • Look for bulls with higher EPD’s for growth & carcass yield

  19. How Many Bulls Will I Need • Age: 1. Yearling (15 mos.) - 20-25 cows per 90 days 2. 2-5 year old- ~ 40 cows per 90 days • Condition: 1. Poor nutrition - influence semen quality 2. Fat bulls lack stamina to breed a large number of cows

  20. Factors Affecting A Bull’s Value • # of calves the bull may sire • Performance level of the herd on which bull is to be used • Type of breeding system you select • Bull’s Pedigree

  21. Summary • Look for traits that are economically important to you • Demand & buy bulls with total performance records that will improve your herd • Selecting and buying a herd bull is the quickest way to make genetic improvements in your herd besides using Artificial Insemination