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Reproductive Efficiency Begins with the Heifers

Reproductive Efficiency Begins with the Heifers. Lee Jones MS, DVM UGA College of Veterinary Medicine Tifton VDIL, Tifton, GA. Heifer Selection. Moderate frame Efficient, easy keeper Fertile Reach puberty by 12 months Conceive early in breeding season Rebreed every 12 months.

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Reproductive Efficiency Begins with the Heifers

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  1. Reproductive Efficiency Begins with the Heifers Lee Jones MS, DVM UGA College of Veterinary Medicine Tifton VDIL, Tifton, GA

  2. Heifer Selection • Moderate frame • Efficient, easy keeper • Fertile • Reach puberty by 12 months • Conceive early in breeding season • Rebreed every 12 months

  3. Buy or Raise? Home Raised purchased • Select replacements from proven females • Known genetics • Fit my program • Requires additional mngt • Heifer bulls or AI • Separate pastures/pens • Delayed income- 2 yr • Opens, culls • Death loss • Biosecurity • Unknown genetics • Easier • Doesn’t require committed resources • Genetic improvement • Know your source • Opportunities • Synchronized • Calving ease bulls

  4. Age at Calving • 2 yr old has more calves over lifetime • Higher inputs to get her ready • May require some assistance at calving • Earlier return on investment • 3 yr old is bigger at breeding and calving • Less intensive development • More developed at calving • Cost more to calve later

  5. Puberty • Need to be cycling by target age • 2-3 cycles prior to breeding • Function of age and weight • Genetics • Daughters of bulls with high SC • Breed • Pedigree • Crossbred • Environment • Nutrition • Growth rate prior to weaning • Growth rate weaning to breeding

  6. Fertility • AI • Estrus synchronization • Proper timing and technique • High quality semen • Natural service • Fertile bulls passed BSE • Confirmation and body condition • Ratio • Young bull- 15-20 heifers • Experienced bull- 30-40 heifers • Caution: size • Calving ease bulls

  7. Vaccinations • 2 doses of MLV prebreeding • BVD and IBR (BHV) • Vibrio- C. fetus; transmitted by bulls • Leptospirosis • Fertilization failure • Embryonic mortality and abortion

  8. Calving • Heifers have higher calf loss than cows • Require more supervision • Heifers are not experienced mothers • Assist if >2 hr with no progress • Depends on observation frequency • Labor in heifers is naturally longer

  9. Heifer Development • Nutritional restriction • Light prebreeding BW • Fewer heifers at puberty prebreeding • Lower pregnancy rates • Late breeding dates • Leading to • Late calving • Lower lifetime production • Exit herd at younger age • Weaning lighter calves

  10. Heifer Development • 65% target weight • Increased percentage cycling • Increase percentage bred AI and first 21 days • Calve ahead of cow herd • Relied on process feeds • Risk of over condition-lower life fertility and increased risk of calving problems • Increase over all development costs

  11. Heifer Development • 55% target weight • Restrict ADG in post-weaning period • Protein supplementation (ADG<1.5lb/day) • Pre-breeding increase in nutrition • No differences in AI CR or season PR • AI; 69 vs 58%; PR 94 vs 92% • 22% less development costs • Fewer restricted growth heifers at puberty • Synchronization may have induced puberty

  12. Heifer Development 65% TW 55% • More heifers reach puberty • More heifers conceive AI • Calve earlier • Higher input costs • Risk of too fleshy • Fewer heifers reach puberty by breeding • Lower AI conception • Usually calve later • May have higher cull rate • Lower input costs • Selection tool

  13. Raising Heifers Opportunity to save $ in development Adequate supplement Good nutrition program prior to breeding Estrus synchronization Vaccinations Preg check early and sell opens

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