Наукові горизонти (Nov 2020)
EVALUATION OF HOLSTEIN STUD BULLS BY PRODUCTIVITY AND QUALITY OF SPERM
Abstract
The sperm quality of stud bulls is an important indicator on which depends the result of cattle reproduction. The aim of the study was to evaluate the Holstein bulls in terms of productivity and quality of sperm in the conditions of LLC “Ukrainian Genetic Company”. The study was carried out on livestock of 20 stud bulls of the Holstein breed of foreign selection, which were in the same conditions of feeding, keeping and use. The sperm production parameters were determined using an IVOS sperm analyser and evaluated in accordance with respective DSTU standard. Freezing resistance of sperm was estimated as a percentage ratio of sperm doses rejected after cryopreservation to their total amount. The absolute sperm efficiency of stud bulls was evaluated by the method of the experts of the Institute of Animal Breeding and Genetics nd. a. M.V. Zubets of National Academy of Agrarian Science. It was found that that stud bulls of LLC “Ukrainian Genetic Company” are characterized by sufficient fertility. They have produced, on average, 156 ejaculates within a year, which included 106 high-quality ejaculates (67.9%). Characteristics of sperm efficiency of experimental stud bulls are rather variable (Сv from 23.1–79.7%), and vary within the following limits: the number of high-quality ejaculates throughout a year – 3–173 pcs., native sperm obtained – 201–1016 ml, percent of rejected sperm – 3.1–76.1, doses of sperm obtained – 5755–61920 pcs. It was revealed that probable difference in sperm production indicators of sperm providers is associated with their individual characteristics. Volume of ejaculate ranges from 3.77 to 7.30 ml (d=3.57; td=16.6; P<0.001), sperm motility ranges from 7.2 to 8.3 points (d=1.1; td=11.1; P<0.001), sperm concentration in ejaculate ranges from 1.51 to 3.52 bln/ml (d=2.01; td=24; P<0.001), freezing resistance of sperm ranges from 59.6 to 99.6%. Holstein stud bulls of LTD “Ukrainian Genetic Company” have rather high sperm productivity index that ranges from 5.19 to 15.29 bln of motile spermatozoids in ejaculate. A strong positive correlation was found between motility and sperm concentration (r = +0.825; P<0.001), motility and the quantity of sperm doses obtained per year (r = +0.766; P<0.001), concentration and quantity of sperm doses obtained per year (r = +0.595; P<0.001)
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