Estimated Breeding Value of Kazakh White-Headed Cattle Breed

: The purpose of the study is to establish the estimated breeding value index of Kazakh white-headed cattle by productive indicators. The Estimated Breeding Value (EBV) of the productive indicators of animals of the Kazakh white-headed breed was determined for 2018-2021. The index values were further interpreted as an assessment of the own genetic productivity of each evaluated animal relative to the corresponding average values. For the Kazakh white-headed breed, the estimated breeding values in terms of live weight at birth in 2018 ranged from -8.00 to +12.91, in 2019 from -8.02 to +19.42, in 2020 from -9.96 to -0.96, in 2021 -9.87 to +19.91. The values by the indicator of live weight at weaning in 2018 ranged from -8.63 to +57.39, in 2019 from -23.27 to +57.31, in 2020 from 23.97 to - +57.29, in 2021 -24.37 to +57.26. The estimated breeding value in terms of live weight at one year of age in 2018 varied in the range from -51.37 to +58.26, in 2019 -58.53 to +72.10, in 2020 -57.77 to +71.43, in 2021 -52.73 to +72.00. The breeding value in terms of live weight for adult animals in 2018 ranged from -50.60 to +43.19, in 2019 -135.95 to +118.86, in 2020 from -138.04 to +121.82, in 2021 from -140.56 to +112.43. The breeding value by the milking capacity of mothers of the Kazakh white-headed breed in 2018 ranged from -35.55 to +33.79, in 2019 -8.85 to +46.67, in 2020 from -27.41 to +46.68, in 2021 from -30.26 to +46.65. The accuracy for the EBV of productive indicators of Kazakh white-headed breed animals was 0.004-0.999 by live weight at birth, 0.001-0.998 at weaning, 0.002-0.998 at 12 months, and 0.001-0.965 for adult animals. The estimated breeding value of dairy cows is 0.018-0.990. The features of the distribution of the indices of breeding value of the average daily increase of animals of the Kazakh white-headed breed in 2021 have been clarified. For the Kazakh white-headed cattle breed, the estimated breeding values in terms of the average daily gain from birth to 12 months of age are in the range from -183.56 to +813.34.


Introduction
The Kazakh white-headed breed of cattle is common in many livestock farms in Kazakhstan. Therefore, the study of the productive indicators of this breed is of particular scientific interest. In cattle breeding of meat productivity, the BLUP method is widely used (Forni et al., 2011;VanRaden and Sullivan, 2010).
When evaluating servicing bulls, statistical approaches and methods are mainly used: Assessment of the genetic breeding value of an animal according to a mixed biometric model Animal Model/Mixed Model Equation (AM/MME) using the classical method of the Best Linear Unbiased Prediction (BLUP). The advantage of this method is the determination of a linear predictive animal biometric model (animal model), in which it is possible to take into account and evaluate the degree of influence of many constant, periodic, and random factors and effects on the estimated useful, productive traits, namely: Environmental effects; seasonal effects; conditions of keeping and feeding; additive genetic effects; the 82 effects of the influence of selection groups; other random recorded effects; random unaccounted effects.
All factors included in the model are evaluated simultaneously. This approach makes it possible to compare the scores of animals from different generations, even if there was a genetic trend in the population. Based on this mathematical method, many popular index estimates are implemented, such as EPD, EBV, etc., (Strandén and Mäntysaari, 2010).
Live weight is a hereditary trait in the selection of each type of farm animal and one of the main indicators in the selection and technology of the productive traits of farm animals (Bozymov et al., 2019).
The experience of both domestic and foreign cattle breeding convinces us that the effective development of beef cattle breeding is determined by a set of measures to organize a sustainable forage base, the introduction of innovative technologies, and selection work. Continuous, purposeful work to improve breeds, breed groups, types, lines, and individual herds of meat animals through the use of the most valuable animals to improve large arrays of livestock is the main area of activity of breeding work on farms (Khakimov et al., 2021).
The age dynamics of live weight are interconnected with changes in the exterior (Nikonova et al., 2021;Kayumov et al., 2021).
The use of different methods for determining the live weight of farm animals by measurements is based on a high correlation between measurements and live weight: Height at the withers (0.51); chest depth (0.11); width in the head of the femur (0.80); oblique body length (0.56); chest girth (0.89); straight body length (0.76); girth of the belly (0.88).
Therefore, the assessment of bulls by their own productivity in the conditions of the assessment station will contribute to the selection of the most valuable genotypes for use in reproduction.
Further work should be directed to the creation of animals more adapted to the conditions of modern technology, namely, to obtaining livestock that combines high productivity, as well as good reproductive properties and health.
The recommendations of the international nongovernmental non-profit organization FAO regarding the assessment of the breeding value of livestock have been studied (Henderson, 1975).

The Aim of the Research
To set the estimated breeding value of the Kazakh white-headed cattle breed by productive indicators.

Materials and Methods
The material of the study the genealogical structure of animals of the Kazakh white-headed breed is represented by intrabreed types, factory lines, and related groups, common in many herds of our country and CIS countries. As a result of solving linear equations of animal biometric models (AM/MME) using the BLUP method on the data of zootechnical registration of events in the IAS for the Kazakh white-headed cattle breed, genetic estimates of their productivity were obtained according to economical traits: Live weight at birth; live weight at weaning; milking capacity of cows; body weight at one year of age. Also, as trial calculations, genetic assessments were carried out on average daily gains in live weight: In the period from birth to weaning (SP 0-205); in the period from weaning to a year (SP 205-12); in the period from birth to one year (SP 0-12).
The BLUP method was carried out based on data on productivity and zootechnical events of breeding cattle of beef breeds from farms registered in the Database of the Information Analytical System (DB-IAS). Initial indicators of the productivity of cattle of the studied breed for evaluation by the BLUP method: Live weight at birth, live weight at weaning, and live weight at one year of age. Fixed effects of influence took into account: Differences in the content of individuals on farms; years and seasons of calving; sex and age group of calves; mother's age; type of birth (single, twin). The biometric model of the animal took into account additive genetic effects due to parental qualities in generations taken up to three ancestors, the sex of the animal, the effects of the herd, and the effects of the year and season of birth.
The Estimated Breeding Value (EBV) of the productive indicators of animals of the Kazakh white-headed breed was determined for 2018-2022. The index values were further interpreted as an assessment of the own genetic productivity of each evaluated animal relative to the corresponding average values.
Assessment of genetic qualities an index assessment of the genetic breeding value of cattle of the Kazakh white-headed breed was carried out by the method of the best linear unbiased prediction BLUP.
For this, Mixed Model Equations (AM/MME) were built for each estimated productive trait: Live weight at birth, live weight at weaning, the milking capacity of cows at weaning of the calf, and live weight at one year of age. These models took into account the contributions of many factors and effects to the estimated productive trait: Fixed and genetic effects, environmental factors, seasonal factors, and random and unaccounted effects.
The influence of all factors included in the model was taken into account simultaneously in the calculation process (Bozymov et al., 2019). The initial indicators of the live weight of young animals at birth, and at weaning 83 were adjusted in accordance with the age of the mothers, which affect the studied indicators.
Similarly, live weight at weaning was adjusted to 210 days of age and body weight per year by 365 days of age. Initial data adjustments were made according to formulas (1, 2, 3): where: СМр = Adjusted live weight at birth, kg Мр = Live weight at birth, kg ФМр = Adjusted live weight at birth, taking into account the age of the mother, kg Смо = Adjusted live weight at weaning, kg Мо = Live weight at weaning, kg Вм = Animal age when weighed at the time of weaning, days ФМо = Correction factor of live weight at weaning by mother's age, kg СМг = Adjusted live weight at one year of age, kg Мг = Live weight at one year of age, kg Вг = Animal age when weighed at one-year-old, days In 2018, 10,584 business entities were engaged in breeding Kazakh white-headed cattle, in 2019-8,739, in 2020-8,848, and in 2021-9,012.
The number of animals whose productive and hereditary data, with a depth of at least three generations, were downloaded from the IAS database for the subsequent calculation of the Estimated Breeding Value (EBV). To calculate the breeding values, data were taken on live and archival animals of the Kazakh white-headed breed for 2018-2022. There were 1,018,163 cattle of the Kazakh white-headed breed in 2018, of which the EBV was calculated for 258,403 animals; in 2019 of 1176070-358325 animals, 2020 of 1241069-386368 animals, in 2021 of 1317755-355084 animals.

Results and Discussion
It has been established that the largest (best) and smallest (worst) estimated breeding values for cattle of the Kazakh white-headed breed are in 10% marginal intervals relative to the entire set of calculated estimates.
For the Kazakh white-headed breed, the values of the estimated breeding value indices in terms of live weight at birth in 2018 varied in the range from -8.00 to +12.91, in 2019 -8.02 to +19.42, in 2020. -9.96 to -0.96, in 2021 -9.87 to +19.91, and in 2022 -9.57 и to +19.59 (Table 1).
The accuracy for the EBV of the productive indicators of animals of the Kazakh white-headed breed was 0.004-0.999 for live weight at birth, 0.001-0.998 at weaning, 0.002-0.998 at 12 months of age and 0.001-0.965 for an adult animal. The estimated breeding value of the milking capacity of cows is 0.018-0.990.
The features of the EBV distribution of the average daily gain in animals of the Kazakh white-headed breed in 2021 were clarified (Table 7).
For the Kazakh white-headed cattle breed, the EBV in terms of average daily gain from birth to 12 months of age range from -183.56 to +813.34.
The general increase in the proportion of non-zero EBV accuracy values indicates a more complete and highquality content in recent years of the database on live weight for the Kazakh white-headed cattle breed.
A methodology for calculating predicted EbV using the BLUP AM statistical method with the construction of an animal genetic model was developed and predicted EBV was calculated for 6 productive indicators: Live weight at birth, at weaning, at 12 months of age, an adult animal (5 years old), the milking capacity of cows, average daily gain (Table 8).
For the Kazakh white-headed cattle breed, the values of the calculated EBVs in terms of average daily gain from birth to 12 months of age lie in the range for the minimum indicator from 0.211-0.424, for the maximum indicator from 0.996-0.999 (Table 8).
It was established that the average live weight of bulls and heifers of the Kazakh white-headed breed corresponded to the elite class (Table 9).
It was found that the live weight at 5 years of age in bulls of the Kazakh white-headed breed corresponded to the elite class, cows to class 1 (Table 10).
The breeding value of Kazakh white-headed cattle is determined by certain quantitative indicators, the variability of which depends on genetic and paratypical factors (Abilov et al., 2014;Nasambaev et al., 2020;. The conducted studies are devoted to the evaluation of productivity by the BLUP method. The genealogical structure of Kazakh white-headed cattle has been clarified for the first time in Kazakhstan. The results of the research work carried out confirm the effectiveness of productivity assessment and selection by the BLUP method. The accuracy for the EBV of the productive indicators of animals of the Kazakh white-headed breed was 0.004-0.999 for live weight at birth, 0.001-0.998 at weaning, 0.002-0.998 at 12 months of age and 0.001-0.965 for an adult animal. The estimated breeding value of the milking capacity of cows is 0.018-0.990.