Comparison of long-term selection responses of breeding policy in dairy herds
Safus, P.(Vyzkumny Ustav Zivocisne Vyroby, Prague (Czech Republic))E-mail:[email protected] | Pribyl, J.
Genetic and economic responses to genetic gain were evaluated for the breeding arrangements as follows: single use of bulls under testing; single and repeated use of proved bulls for two or three years; negative selection of cows in the herd; negative selection of first-calvers in the herd; discarding of heifers and purchase of animals with high breeding value, and embryo transfer. Simulations for single use of breeding arrangements and their consequences over a fifty-year period were carried out using the gene flow method. The highest gain was attained with proved bulls selected from 1% of the best bulls, the cumulative genetic gain averaged 41.558 kg of milk proteins per cow for the whole observed period. Single use of bulls under testing in the herd resulted in the second highest cumulative genetic gain. High genetic and economic gain was recorded for replacement of all heifers by animals with higher breeding values from other populations.
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