Reproduction on the Ranch Clay Lents 1, Kraig Peel 2, George Seidel Jr. 1,and Gordon Niswender 1 Colorado State University 1 Animal Reproduction and Biotechnology Laboratory 2 Western Center for Integrated Resource Management Clay Lents 1, Kraig Peel 2, George Seidel Jr. 1,and Gordon Niswender 1 Colorado State University 1 Animal Reproduction and Biotechnology Laboratory 2 Western Center for Integrated Resource Management Reproduction on the Ranch

Reproduction is the most important trait Heifer Development and Management Reproduction in Mature Cows Management of Bulls The Future

Example If we increase calf crop by 5% 300 Cows would yield 15 additional calves 15 calves average 450 pounds at weaning and sold at $.90 would equal $6075 additional income OR Cull the 15 open cows 15 cows off the ranch which cost $300/year= $4500 annual savings Sale of 15 cows at $400=$6000 $10,500/year Receipts from cull cows only pay for at best, 60% of the cost of replacements

Reproduction on the Ranch In General: –Reproductive traits have low heritability –But, reproductive traits do respond well to changes in management and environment

Heifer Management Heifers should conceive by 14 months of age Heifers should be in a BCS of 6.5 at calving (genetics, nutrition, environment) Strategies to increase pregnancy rates for first calf heifers –Provide extra feed –Match heifers to their environment –Remove calves for 48 hours or early wean calves (6-8 weeks)

Typical Natural Service Cost Per Calf (ABS) Bull Purchase Price $ 1,800$ 2,000$ 2,500$ 3, cows/year for 3 years $ 54.60$ 59.30$ 71.05$ cows/year for 3 years $ 43.68$ 47.44$ 56.84$ cows/year for 3 years $ 36.40$ 39.53$ 47.34$ * Typical natural service costs assume $800 salvage value, $500 annual feed & veterinarian, 95% final conception rate, 10% risk and 8% interest rate. $ 47.44

AI Cost Analysis with Varying Estrus Response and Pregnancy Rates (ABS) Estrus Response Rate Pregnancy Rate of those Responding 60%70%80%90%100% 70% % AI Preg Cost/Synch AI Preg 42% $ % $ % $ % $ % $ % % AI Preg Cost/Synch AI Preg 48% $ % $ % $ % $ % $ % % AI Preg Cost/Synch AI Preg 54% $ % $ % $ % $ % $34.44

AI Cost Analysis with Varying Estrus Response and Pregnancy Rates (ABS) Estrus Response Rate Pregnancy Rate of those Responding 60%70%80%90%100% 70% % AI Preg Cost/Synch AI Preg 42% $ % $ % $ % $ % $ % % AI Preg Cost/Synch AI Preg 48% $ % $ % $ % $ % $ % % AI Preg Cost/Synch AI Preg 54% $ % $ % $ % $ % $34.44

Reproduction on the Ranch Average Cost of Natural Service per Calf –$2000 bull/25 cows per year/3 years $47.44 Average Cost of Estrus Synchronization and AI –90% in estrus, 70% pregnancy rate $49.21

Reproduction in Mature Cows Genetics are important (Seedstock) Genetics are important (Commercial) Match time of calving and peak lactation to available forage Body condition score influences post partum anestrus

Reproduction in Mature Cows

Reproduction on the Ranch

Breeding Soundness Exam Structural soundness, scrotal circumference, semen quality Pregnancy rates increase 6-10% More cows pregnant at first service Increase bull to cow ratios (1:40 or higher) Every $1 invested yields $17 (Chenoweth 2000)

The Future Cloning will not be routine in near future Synchronized ovulation – timed insemination Use of sexed semen Cloning will not be routine in near future Synchronized ovulation – timed insemination Use of sexed semen

Heifers producing Heifers More rapid genetic improvement Heifer calves weigh approximately 6 pounds less at birth Match cows to environment – use terminal sires

Summary Before using any procedure to modify reproductive performance, be certain that use of the procedure will advance your goals and fit with available resources. A well designed crossbreeding program results in increased conception rates, calf survival, weaning weight, reproductive performance and longevity, which result in increased lifetime productivity and profits.

Summary In general, beef heifers should be bred before the cow herd to maximize their chances of rebreeding as first-calf heifers and remaining in the herd. The calving/breeding season should be limited and, in most cases, matched to the available forage.

Summary In special cases, treatments for synchronization of estrus can induce puberty and/or post-partum estrous cycles and enhance reproductive performance. Breeding Soundness Exams for bulls are a key strategy to increase reproductive performance and reduce costs in nearly all cow herds.

Returns on Tested Angus Bulls (ABS) Data from central bull test Test ATest BTest CTest DTotals # Bulls All angus % A.I. Sired 77%71%38%81%71% % non A.I. Sired 23%29%62%19%29% Avg. $$ A.I. Sired $2,073.73$1,661.85$1,763.46$1,591.81$1, Avg. $$ Non A.I. Sired $1,733.50$1,540.26$1,748.81$1,491.67$1, A.I. Premium $340.23$121.58$14.65$100.15$178.30

Reproduction in Mature Cows

(R=3-breed rotation, RT=2-breed rotational terminal sire, and T=static terminal sire)

Reproduction on the Ranch

Relative Economic Value