Productivity of the servicing bulls progeny with different index scores

Abstract

The problem of studying the degree of influence of the index "Period of productive life/productive longevity" of the servicing bulls on the duration of productive use of their progeny is not sufficiently covered in the scientific literature, which substantiates the relevance of the research. A comparative assessment of economically useful features of the daughters of servicing bulls with the index value from 103 to 117 has been carried out. Dynamics of the experimental animals' mortality is determined in the period from birth to the end of the second lactation, the level of milk productivity according to the data for the first and second lactations. It was found that mortality among the daughters of the servicing bulls with an index equal to 103 and 105 was the highest in all physiological periods and amounted to 80.0 and 78.1% at the end of the experiment, respectively. In the groups of the daughters of the servicing bulls with index values of 109 and 117, the proportion of animals that died out reached 62.9 and 65.6%. The lowest productivity for the first and second lactations was recorded in the daughters of the servicing bull with the index value of 103 6760.2 and 7100.7 kg of milk. The daughters of the servicing bull with the index equal to 117 were distinguished by the highest milk productivity 7475.9 and 8158.3 kg of milk in two lactations. Analysis of the obtained data shows that fixation of servicing bulls to the breeding herd taking into account the "Period of productive life/productive longevity" index will make it possible to obtain more robust progeny with good productive qualities.