International Journal of Animal Breeding and Genetics Vol. 6 (2), pp. 001-005, February, 2017. © International Scholars Journals
Full Length Research Paper
Phenotypic and genetic trend lines of milk yield and the breeding values of the cows
*Pervez Benazir, Nusrat Ali Zardari and Malala Afridi
Department of Livestock Production, University of Veterinary and Animal Sciences, Lahore, Pakistan.
*Corresponding author. E-mail: email@example.com
Accepted 20 October, 2016
A total of 937 pedigree, breeding and performance records of 567 Friesian cows at the Livestock Experiment Station Bhunikey Dist. Kasur (Pakistan) spanning the years 1982-2001 were analyzed using Best Linear Unbiased Predictions procedure. Individual animal models were fitted to total milk yield from all lactations to estimate breeding values by Restricted Maximum Likelihood methodology. Milk yield and lactation length averaged 3391.66 ± 137.97 kg and 278.40 ± 90.17 days, respectively. The estimated breeding values for milk yield ranged from –354 to 503 kg. The corresponding values for the standing herd ranged from –209 to 294 kg. The genetic trend for milk yield was slightly positive indicating that the sires used during the last 20 years were of better breeding values. Phenotypic reduction in milk yield over time was observed, a probable reflection of the inability of the cows to adapt to the local environment and other environmental inadequacies.
Key words: Friesian, pedigree, genetic, phenotypic, trend lines, Estimated Breeding Value (EBV), animal model.