Heritability of type traits in first calving Black and White cows

Abstract

Abstract. Group of secondary traits such as health, longevity, type and milkability represents some of very important factors for successful milk production. These traits have been given great importance in recent years. In order to realize productive life of dairy cows as long and successful as possible, special attention should be directed to traits of type and body constitution. Objective of the research was to establish heritability coefficients for 14 type traits of first calving Black and White cows, effect of genetic and paragenetic factors (bull sires, farm, year and season of calving, age at scoring and share of Holstein-Friesian [HF] genes) on type traits, so that these scores could be included in calculation of breeding value of the animal. Also, average values of milk traits have been established: milk yield and yield of 4 % fat corrected milk (FCM), content and quantity of milk fat. Evaluation was performed on a sample of 2 976 first calving Black and White cows. Evaluated cows were reared on 7 farms of the Agricultural Corporation Belgrade in Serbia. Analysis of discontinuous and continuous influences was done using the method of least squares. Investigation indicated that the value of linear type evaluation should be included in the total evaluation of the breeding value and in this way complete insight into genetic supremacy, especially of breeding bulls, would be obtained. Use of bull semen of proven supremacy in transmission of genes desirable from the aspect of body constitution, in the process of artificial insemination, would lead faster to production herds with animals which are uniform in type, of good conformation and longevity, which is of special significance in conditions of intensive rearing of dairy cattle.