VARIABILITY OF MILK TRAITS IN PROGENY TESTING OF THE SIMMENTAL BULLS

Abstract

The data of the Institute for Animal Husbandry, Belgrade-Zemun have been used to investigate the variability of the properties that are observed in the progeny testing of Simmental bulls. The analysis is based on a sample of 7,845 first-calving heifers in the period 2007-2010. The tests included the following milk properties in the standard first lactation (305 days): milk yield (kg), milk fat content (%) and milk fat yield (kg). An analysis of the production traits of the first-calving heifers under control showed that their average milk yield was 4346.49 kg milk with 3.93% milk fat and yield of 171.11 kg of milk fat. Sires, years and calving season exhibited a highly significant impact (p<0.01) on all the milk properties observed in the progeny testing. Based on the BLUP solution, the rank of bulls for each trait was formed, and then the correlation coefficients of the rank, ranging from 0.402 (relationship between the yield of milk and milk fat content) to 0.989 (the relationship between the yield of milk and the yield of milk fat) were established.