Lecture 11 - Heifer Development and Management PDF

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AS 264 Lecture #11 in Summer 2019 with Cody Wright...

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Lecture 11 - Heifer Development and Management I.

Heifers that calve early… A. Continue to calve early B. ↑ likelihood of becoming pregnant as 2-yr-olds and to calve early as 3-yr-olds C. wean healthier calves D. Greater lifetime production

II.

Growth rate A. Pre-weaning growth rate has a greater impact on age at puberty than postweaning growth rate 1. Creep feeding is not recommended if additional energy will be used for fat deposition B. Large WW variation…split into smaller groups and feed appropriately C. Target weights 1. Historical: 65% of mature weight at breeding 2. Now: maybe as low as 55% D. Timing of gain 1.

III.

Does not need to be consistent

Ionophores A. Rumensin and Bovatec 1. ↓ age and weight at puberty 2. May ↑ birth weight and calving difficulty

IV.

Implants A. Suckling calves

1. ↑ growth rate and pelvic area 2. ↑ potential for ↓ pregnancy rates B. Post-weaning 1. Not advisable V.

Management at breeding A. Consider reproductive tract scores 1. Makes sure they are pubertal B. Breed heifers 20 to 30 days prior to breeding mature cows C. Use calving ease bull to breed to heifers 1. AI is the best option D. Have a limited breeding season – 45 to 60 days 1. Promotes retention of fertile heifers E. Avoid transporting heifers for at least 45 days following the breeding season 1. Transportation ↑ embryonic losses 2. If necessary, transport 2 to 5 days after AI

VI.

Post-breeding management A. Detect pregnancy as early as possible 1. Predict calving dates 2. Market open heifers B. Manage and feed heifers separately from mature cows 1. Heifers require additional nutrients 2. Additional attention at calving C. Target: BCS = 6 and 85% of MBW at calving 1. ↑ number of pregnant by 60 days in subsequent breeding season 2. Positively correlated with WW

VII.

Management at calving A. Maintain heifers in most assessable pasture 1. Easy access to barn or area to assist heifers having calving difficulties is needed B. Check on heifers often

C. Continue to feed heifers additional feedstuffs to prevent loss in weight and body condition following calving VIII.

Management at 2nd breeding A. 2-yr-old, first calf heifers are the most difficult female to get pregnant in the beef herd!!! 1. Anestrous at start of breeding season 2. Prolonged postpartum interval 3. ↑ nutrient demands

B. Target BCS = 6 C. Gaining weight, not losing weight, following calving and through the next breeding season D. UIP may be beneficial during lactation 1. ↑ weight gain 2. ↑ reproductive efficiency...