SPERM PRODUCTIVITY AND FERTILIZATION CAPACITY OF SPERMATOZOA OF HOLSTEIN STUD BULLS IN CONDITIONS OF LLC “UKRAINIAN GENETIC COMPANY”
Authors: Zakharchuk D. 
Published: January 2022

Effective selection and breeding in dairy farming is impossible without artificial insemination, results of artificial insemination largely depend on the quality of semen of bulls-improvers. Objective. To ascertain parameters of sperm productivity and fertilization capacity of spermatozoa of Holstein stud bulls of foreign selection in conditions of LLC “Ukrainian Genetic Company”. Methods. We have analyzed ejaculates of 20 mature Holstein stud bulls elite-record class brought to animal breeding enterprise from Germany and the Netherlands. The duration of use of bulls at the breeding enterprise is on average 4–5 years.Quantitative indicators of sperm were taken per year to avoid the influence of seasonal factors. Semen was collected twice a week by artificial vagina on the false stud. Ejaculates obtained were analyzed according to the DSTU 35.35-97 incertified production laboratory of LLC “Ukrainian Genetic Company”, equipped with up-to-date equipment for sperm quality assessment, packing, freezing and storage. Quantity and quality characteristics of sperm were analyzed on computer sperm analyzer IVOS (HamiltonThorneResearch, USA). Sperm fit for cryopreservation is diluted at a temperature of +35°С in the environment AndroMed (Germany) at rate no less than 20 million spermatozoids for one sperm dose and packed into 0.25 ml straws. Frozen sperm doses after check are kept in the special bio-storage in liquid nitrogen at a temperature of -196°С.

Results. Fertilization capacity ofthe spermatozoaof experimental stud bulls was measured by the percentage of quantity of cows and female calves that were impregnated after the first insemination in Zhytomyr (PAF “Ierchyky”, SPDG “Nova Peremoga”, ALLC “Ptakhoplemzavod “Korobivskyi”) and Kyiv (LLC “Agrofirm “Kyivska”) regions. On the whole results of insemination of 12525 cows and 1230 female calves of puberty age were analyzed.

Sperm productivity index and average fertilization capacity of spermatozoa of stud bulls was assessed by the method of M. M. Maiboroda, S. H. Hermanchuk, Yu. P. Polupan, and D. M. Basovsʼkyy.

It was revealedsignificant variability of sperm productivity indicators of experimental stud bulls, which vary within: number of obtained high-quality ejaculates within one year –32–173 pcs., total volume of native sperm – 201–1016 ml, average value of spermatozoa concentration in 1 ml – 1.51–3.52 milliard, average sperm motility in ejaculate – 7.2–83 points. Bull studs of LLC “Ukrainian Genetic Company” are characterized by a rather high index of sperm productivity which equals from 5.19 to 15.29 billion of motile spermatozoids in ejaculate.

Average fertilization capacity of spermatozoa of experimental Holstein bulls in conditions of 4 farms of Zhytomyr and Kyiv region ranges from 37.1 to 61.4%, average figure for examined livestock is 50.9%. During the research we found that stud bulls whose sperm fertilization capacity was above 50% in most cases (6 out of 8) had index of sperm productivity above average – 9.86–15.25billion of motile spermatozoids in ejaculate.

We have detected positive and statistically significant correlation between fertilization capacity of spermatozoa and the average value of concentration, motility of spermatozoids in ejaculate (+0.474 and+0.417 respectively) and sperm productivity index (+0.639). Conclusion. Our research proves dependence of fertilization capacity of sperm on its quality parameters. The results we obtained suggest that it is expedient to use index of sperm productivity to assess quality of sperm and prove its importance for breedingbulls selection.