INFLUENCE OF STUD BULL ON HEIFERS PRODUCTIVITY QUALITIES

Abstract

In this article the results of analysis of pedigree registration and personal investigations in dairy farms during 11 years concerning the productive longevity of Holstein cows are presented. Last years in many farms of the Russian Federation parallel with the with the increase of animals productivity a duration of cause use comes down to 2-3 lactations. In the region conditions this connection becomes apparent with lower indices of productivity. The researches of studying the factors causing the productive longevity determined a presence of a seasonal prevalence in the farms of Middle Priamurye, which leads to unjustified expenditures of work and means for the production. Two circumstances deserve a special attention.  They are: sharp cutting down of the productive period duration of cows, birth and first calving of which are in summer, the first-calf heifers of the autumn calving have higher viability independently of a season of their birth. These factors must be expediently taken into account when organizing and remounting the herd in dairy farms. The researches also determined that the seasonal factor becomes apparent independently of cows origin by father. The inter-seasonal differences by yield of milk taking into account the origin by father were 130.6 %, and with taking into account the origin by father, but without the season of first calving – 114.8 %. The superiority by yield of milk by daughters-first-calf heifers of the autumn calving was by posterity of Tarzan 128.0 %, Leman – 147.0 , Charodey – 134.0  and Plan – 116.0 %. For all this than the yield of milk is higher, the inter-seasonal difference is more (r_s=+0.36).