Genetic parameters of production and reproduction traits of Egyptian buffaloes under subtropical conditions

Currently, in modern cattle breeding special importance is attached to improving the methods of using the world’s genetic resources and increasing the potential of domestic breeds. This is due to the wide spread of crossbreds with diff erent portions of blood and the lack of ways to determine the optimal genotype for further breeding. So the question of the relationship between the genotype and the productive traits of animals is always relevant. The purpose of the research was to study the growth and development of heifers of Black-and-White breed of diff erent origin under the conditions of the natural and climatic zone of the Central Caucasus in the Republic of North Ossetia-Alania. In order to carry out the experiment, 3 groups of newborn calves were formed. The 1st control group included purebred heifers of Black-and-White breed, the 2nd experimental group included heifers of Black-and-White breed with a blood ratio of 1/2 of Holstein breed, and the 3rd experimental group included heifers of Black-and-White breed with a blood ratio of 3/4 of Holstein breed. Experimental animals were fed taking into account the planned gains in live weight. The features of growth and development were studied by individual weighing and taking measurements at diff erent age periods. On the basis of weighing the live weight gains were calculated, and according to the measurements the body conformation indices were calculated. Studies have shown that the superiority of heifers of the 3rd experimental group over herdmates of the 1st control group in the fi rst months of life was 6,2 %, and animals of the 2nd experimental group were 2,7 % better than purebred analogues in this indicator. In the future, this diff erence increased and by the age of 18 months the diff erences between the groups were 7,4 and 9,6 %, respectively. In general, it has been established that the use of Holstein breed gene pool contributes to the increase in the growth and development of young animals. Heifers with 3/4 blood portion of Holstein breed were distinguished by the best live weight gains and body conformation indices.

Features of growth and development of young cattle depending on origin

Nogaeva¹,

Kokoeva²

2023

Productive and reproductive traits of cows of Kholmogorskaya breed depending on their origin from sire

Костомахин¹,

Gabedava²,

Voronkova³

2023

Among domestic dairy cattle breeds, Kholmogorskaya breed is very famous. The relevance of the work carried out lies in the evaluation of cows of one of the oldest genealogical lines of Kholmogorskaya breed – the line Khlopchatnic CX 1097, which today is of gene pool interest for this breed. The purpose of the research was to study the productive and reproductive traits of cows of Kholmogorskaya breed depending on their origin from sire. The research was carried out in breeding farms of the Kaluga region breeding cattle of Kholmogorskaya breed. During the research the indicators of milk productivity were studied such as milk yield, fat mass fraction, milk fat yield and reproductive traits such as period of open days, dry period, interval between calving, multiplicity of insemination, coeffi cient of reproductive ability, and duration of pregnancy. The study of the above indicators was carried out on mature cows-daughters of Kholmogorskaya sires: Gonets 85, Zador 313, Douplet 184 and Zemlemer 1901 belonging to the genealogical line Khlopchatnic CX 1097. The daughters of the sire Gonets 85 surpassed the daughters of sires of other producers in milk yield by an average of 838,7 kg. Thus, in cows-daughters of the sire Gonets 85 milk yield for 305 days of mature lactation exceeded the same indicator of the daughters of sire Zador 313 by 1123,3 kg (p < 0,001), and the daughters of sires Douplet 184 and Zemlemer 1901 by 79,6 and 1313,3 kg (p < 0,001), respectively. The duration of the period of open days, the multiplicity of insemination were lower in the daughters of sire Gonets 85, Zador 313 and Douplet 184, compared with the indicators of herdmates from the line Khlopchatnic CX 1097 and Kholmogorskaya breed. At the same time, a slight increase in the duration of pregnancy of the daughters of the sires Gonets 85, Zador 313 and Zemlemer 1901 was established. The results obtained indicate the possibility of line breeding and pure breeding for further improvement of the domestic line Khlopchatnic CX 1097 and the whole Kholmogorskaya breed.

Economically useful traits of cows received from different sires

Горелик¹,

Горелик²,

Safronov³

2023

When breeding Black-and-White holstinized cattle, the sperm of highly productive sires with high productivity potential of maternal ancestors, including Holstein breed, is used. Evaluation of sires by the quality of off spring is the most accurate method of determining the actual breeding value. The purpose of the work was to evaluate the economically useful traits of cows obtained from diff erent sires. The research was carried out in one of the breeding farms typical for the Sverdlovsk region for the breeding of Black-and-White cattle with a high proportion of blood in Holstein breed. The evaluation of three Holstein sires Zhadon 60044914, Onward 4512 and Plateau 62297905 on the quality of off spring was carried out by comparing the productivity of cows-daughters with their herdmates. It is established that when selecting sires for work in the herd, group selection of sires of the same type in terms of productive traits of maternal ancestors is used. This leads to almost equal milk yields for their daughters. There was also no signifi cant diff erence in milk quality indicators. When comparing the productivity of the cows-daughters of sires for the fi rst lactation with their herdmates, a certain diff erence was established, both in milk yield for 305 days of lactation, and in the mass fraction of fat and protein in milk. The cows-daughters of sire Onward 4512 turned out to be the best relative to herdmates in milk yield and mass fraction of fat in milk. The daughters of the sires Zhadon 60044914 and Plateau 62297905 had productivity lower than their herdmates by 315 and 127 kg, respectively. The daughters of the sire Plateau 62297905 surpassed their herdmates in terms of the mass fraction of fat and protein in milk. The level of profi tability of milk production for the highest lactation was 58,9–66,6 % and was higher in the group of cows–daughters of the sire Zhadon 60044914.