COMPARATIVE ANALYSIS OF DAIRY PRODUCTIVITY OF FIRSTBORNS OBTAINED FROM SEXED AND TRADITIONAL SPERM OF BULLS
Authors: Goncharenko I. V. , Pelykh Yu. S. 
Published: December 2019

Development, acquisition and practical use of sexed sperm of sire bulls is the greatest achievement of biological science in breeding, selection and reproduction of agricultural animals of the 21st century. Today, artificial insemination of cows and heifers with sexed sperm of bulls is a new biotechnological method gaining the widespread worldwide commercial use.
As early as in 1996 the company X&Y, USA, patented a method for sperm sortation using laser equipment. Cogent (Great Britain) is the world’s first company to use the method of distribution of sires’ sperm by sex under production conditions (1999). The world’s leader in manufacturing, distribution and quality of sexed semen is the American company CRI (Cooperative Resources International). The company’s products are distributed in 67 countries of the world.
The well-established method of sperm distribution by sex-determinant attribute makes it possible to use the best bulls making top five or ten world’s leaders of INTERBULL – International Bull Evaluation Service – in the selection process. If such heifer intended to become a herd replacement is obtained and properly raised, it is possible to obtain a cow with notably higher genetic potential.
In Ukraine, the sexed sperm of foreign selection has been used in dairy farming since 2005. It is distributed by the corresponding foreign companies to such farms as Agricultural Limited Liability Company (ALLC) Promin, ALLC AF Glushky, ALLC Agrofirma Kyivska, OJSC Poltavaplemservis, Private Agricultural Enterprise (PAE) Pleshkani etc.
The use of sexed semen calls for certain conditions and qualification of insemination operator. Improper storage and thawing of sexed sperm may negatively affect its fertilizing ability. It has been regularly mentioned by the originators of the development and practitioners. Unfortunately, some of Ukrainian farms have a negative experience of the use of sexed bull sperm. Therefore, we decided to share the results obtained from the experience of one of Ukraine’s leading dairy enterprises.
The objective of our study was to evaluate the efficiency of the use of sexed sperm of Holstein bulls in breeding farm and to compare the milk productivity of firstborns obtained from sexed and traditional sperm of bulls using various methods.
Methods. The study was conducted in a herd of purebred Holstein cows of State Agricultural Enterprise Chaika, Dydarkiv Branch, in Boryspilskii District, Kyiv region. During the selection of cows according to a set of features (reproductive ability, lactation performance, economic use duration), this herd suffered the lack of breeding stock for its replacement. For this reason, in 2012 the farm, with the help of an English nominee company in Ukraine, Right Frank LLC, bought from Cogent 75 sperm dosages of sexed sperm belonging to two Holstein bulls of American selection: Ri-Val-Re MOUNTAINEER-ET 60815578 (50 semen dosages) and Diamond-Oak FROSTY 31520543 (25 semen dosages). These bulls belong to the famous lines Chif 1427381.62 and Marshall 2290977.95 correspondingly. The sexed sperm of these bulls was used in mating age heifers.
A control group of animals – the “daughters” – was formed from the heifers born from the use of bulls’ sexed sperm. A group of mothers was singled out according to their origin and a group of age-mates – according to calving dates. The animals falling under the group of “mothers” and “mates” were obtained using a traditional non-sexed sperm of bulls.
The established feeding system in the farm and the technology of management provides the implementation of inherited genetic potential of cows’ performance in 2010–2018 at the level of 6900–8100 kg of milk. It became a basis of comparative analysis of lactation performance of the formed groups of animals that have already completed the first lactation using the generated database of Dairy Farming Management System (DFMS) Intesel Orsek.
Results. The data obtained from the use of sexed sperm of bulls Ri-Val-Re MOUNTAINEER-ET US 60815578 and Diamond-Oak FROSTY ET US 31520543 have shown, that the insemination of the heifers with the sperm of the both bulls is rather low. First of all, it is due to the low qualification of artificial insemination operators available in the farm, and the non-compliance with the terms of optimal insemination of heifers according to their oestrus. It resulted in obtaining of 27 and 11 calves from each bull with the sex correlation of ♀89 : ♂11 and ♀91 : ♀9.
In the process of raising of the daughters of Ri-Val-Re MOUNTAINEER, only 12 of 24 heifers lived to the mating age. The average age of the 1st insemination of all the heifers with the sexed sperm was 16.2 months (with the variation of 15.6 months in the daughters of Ri-Val-Re MOUNTAINEER and 16.8 months in the daughters of Diamond-Oak FROSTY). In total, the first lactation was completed by 10 firstborns of each bull.
In the contiguous generations “mothers-daughters” (n = 20 animal units) we observe the increase in lactation duration (from 356 to 408 days) and milk yield (from 7762 to 9953 kg of milk; d = +2191 kg; Р ≥ 0.99).
In the first 305 days of lactation the reliable difference in lactation performance is observed only in the daughters obtained from the use of sexed semen of the bull Diamond-Oak FROSTY. Thus, the level of milk yield in these cows increased to reach 8222 kg of milk in comparison to the milk yield of the mothers (+1592 kg; Р ≥ 0.999) and the mates (+450 kg) for the corresponding period. At the same time the fat level in the milk of the firstborn daughters decreased from 3.67% and 3.64% to 3.60%, with the persisting tendency to the decrease of protein level in the milk in comparison with the mothers and their mates.
No notable and statistically reliable difference in the milk performance parameters of the daughters of the bull Ri-Val-Re MOUNTAINEER was observed.
Besides, we revealed, whether there were any changes in the birth of heifers and bulls before the use of the bulls’ sexed sperm and after it in general for the herd of cows and heifers.
To that end, we analyzed the dynamics of obtaining the litter from the breeding stock over seven recent years (2012–2018). The daughters of the bull Ri-Val-Re MOUNTAINEER calved mainly during 2014, and the daughters of the bull FROSTY – at the end of 2015-early 2016. As a result of the birth of 34 heifers obtained from the sexed sperm of the bulls in 2014–2016, no notable shift in the correlation of the sex of the litter was observed.
The study conducted suggests the following conclusions.

The use of 75 sperm dosages of sexed sperm of the bulls Ri-Val-Re MOUNTAINEER-ET US 60815578 and Diamond-Oak FROSTY ET US 31520543 in the purebred Holstein heifers in State Agricultural Enterprise Chaika, Dydarkiv Branch provided the change of the sex rate in the litter and obtaining heifers in 89–91% of cases. However, the non-compliance with the requirements of the process of use of the sexed sperm caused rather low insemination of the heifers – 58–44%.
Of 34 heifers, obtained from the use of sexed sperm of the bulls, 22 firstborns were introduced into the herd, and 20 caws completed the first lactation, which accounts for almost 60% of potentially possible amount.
The milk yield level of the firstborns obtained from the use of sexed sperm of the bulls is rather high (7717 kg of milk in the first 305 days of lactation), it exceeds the yield level of the mothers (d= +862 kg) and slightly exceeds the yield of the mates (d = +276 kg). At the same time, the fat level of milk of such firstborns decreases (d = -0.02 … -0.05%).

The further use of sexed sperm of bulls in each of the farms must be substantiated and feasible.