[Hormonal profile and formation of the sexual function of heifers of Belarusian Black-and-White breed of various intrabreed types]
2006
Tanana, L.A.(Grodno State Agrarian Univ. (Belarus)) | Doroshko, A.A.(Volkovysk State Agrarian College (Belarus))
Research results of studies of the hormonal status of heifers of Belarusian Black-and-White breed of various intrabreed types in the period of pubescence determined according to the functional state of the endocrine glands, in the period of completion of organism formation and after the attainment of the physiological maturity of animals were presented. Investigation results showed that the pubescence and the value of the sexual cycles of the observed beef and dairy heifers were revealed at the age of 8,6 months (258,8 days) and the same parameters for the dairy type heifers were stated at the age of 7,9 months (237,3 days). The physiological maturity of beef and dairy type heifers was attained at the age of 17,1 months (512 days) and physiological maturity of milk type heifers was stated at the age of 16,2 months (487 days). The age of the first insemination of the milk type animals was on 27 days earlier in comparison with the beef and dairy type animals. Research studies did not reveal the considerable differences between the groups of studied heifers according to conception rate. Conception rate after the first insemination was 62-65%, after the second – 38-35%. Pregnancy of all studied animals was without any complications
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