Genetic and Economic Evaluation of Nucleus Breeding Schemes for Commercial Artificial Insemination Firms

Abstract

Genetic and economic aspects of adoption of a multiple ovulation and embryo transfer nucleus breeding scheme by a commercial AI firm were investigated. Selection for a lactation trait in a large dairy cattle population with a competitive semen market served by five AI firms was simulated using a semi-stochastic model. Returns were from sale of semen from progeny-tested bulls, discounted to the time of adoption of the new scheme. Comparisons were to an effective conventional program using multiple ovulation and embryo transfer to produce young bulls. Sires of bulls and nucleus females were selected from progeny-tested bulls across AI firms. Therefore, rates of inbreeding within the nucleus were small. Closed adult nucleus schemes were competitive to the conventional scheme only for large nucleus sizes. Open adult schemes increased present values of returns from 20 yr of selection by 10 to 20%. Further cost analysis is needed to determine their economic profitability. Juvenile nucleus schemes increased present values of returns but also risks on returns. Relative gains in returns increased from 8 to 16% for the first 4 yr of selection to 46 to 63% for the first 20 yr. Additional returns from opening the nucleus were small due to high genetic superiority of the nucleus. Additional returns from repeated, instead of one-time, selection of females as donors were similar to returns from a 50% increase in nucleus size. Additional returns from eligibility of young bulls as bull sires were small due to the small number of young bulls selected. © 1990, American Dairy Science Association. All rights reserved.