Application of sexed semen of sires in breeding farms of Kaluga region

Relevance. The main direction in the improvement of dairy cattle breeds is search for ways and methods creating highly productive herds. However, successful solution these issues impossible without use modern technologies. Among them, sexed sperm a divided into Xand Y-containing spermatozoa. When using breeding, it possible to regulate receipt desired sex (heifers). effective semen will provide farms with complete set their own breeding stock allow sale heifers. Methods. object research was cows inseminated stud bulls different unit. fertilization stock, duration pregnancy, effect season on fertilization, analytic investigation calf crop percent were investigated. For analysis data used from database zootechnical pedigree registration «SELEKS». Results It found that heifers first insemination 38,8%, subsequently decreased amounted 27,7% at second insemination, 5,5% third. 28% remained infertile, 72% total pregnant. 85% live 15% obtained. During initial calving sperm, became pregnant, repeated — 27,7%. Fertilization decreased, 39,1% animals infertile. best results obtained during primary