Economic and Biological Values for Pasture-Based Dairy Cattle Production Systems and their Application in Genetic Improvement in the Tropics

Abstract

Economic and biological values for milk yield (MY), milk butter fat (FY), daily gain (DG), weaning weight (WWT), mature live weight (MLW), calving interval (CI), pre-weaning survival rate (PreSR), post-weaning survival rate (PostSR), age at first calving (AFC), and productive life time (PLT) were estimated under fixed herd (FH) and pasture (FP) production circumstances assuming milk marketing based on volume, and volume and butter fat. Further, economic values were estimated involving risk using the Arrow Pratt coefficients at two levels. For the former economic values for the traits ranged from KSh. -17.246 to 100.536 while the biological values ranged between -1.29 to 0.791. Economic values with higher Arrow-Prat coefficient of absolute risk aversion (λ=0.02) were lower than those reported under λ=0.0001 indicating that the uncertainty of the future market is important and should be considered during the estimation of economic values. Genetic improvements targeting MY and growth traits would be recommended to production system with unlimited feed supply for profit maximization. However, since dairy production systems in the tropics are characterised by feed scarcity, fixing the herd and concentrating on genetically improved animals would result to more profitability than increasing animal populations.