GROWTH, REPRODUCTIVE CAPACITY AND PRODUCTIVITY OF COWS OF DIFFERENT BREEDS, METHODS OF SELECTION AND PATERNAL ORIGIN

Abstract

The aim of the research. To conduct a comparative analysis of growth characteristics, productive qualities and reproductive capacity of dairy cows using purebred breeding and interbreeding in the herd. Маterials and methods of reserch. The study was conducted in the herd of the State Enterprise “Niva” on cows of Ukrainian Red- and Black-and-White dairy and Holstein breeds. The analysis included information on the growth intensity, reproductive capacity and milk productivity of 978 cows with the first calving during 2015-2021. Among the breeding herds of the Ukrainian Red-and-White and Black-and-White dairy breeds, a comparative analysis of selection groups from breeding "in-house", selective crossing with Holstein and crossbreeds of the first generation with Montbeliard breeds was carried out. The degree of influence of genetic and paratypic factors on the phenotypic variability of the considered traits was assessed by means of univariate analysis of variance with the calculation of Fisher's test and the indicator of the strength of influence based on the ratio (%) of factorial and total variances (sum of squared deviations). Calculations were carried out using the methods of mathematical statistics using the "STATISTICA-12.0" software package on a PC. Research results. A comparison of the growth of live weight of controlled heifers of different breeds shows a certain (0.3–5.6%) advantage of Ukrainian Black-and-White dairy animals over peers of Ukrainian Red-and-White dairy and Holstein animals of red-and-white color over same-breed Black-and-White heifers. The effectiveness of three selection options was compared in the breeding breeder for the breeding of Ukrainian Red-and-White dairy cattle. The advantage of purebred breeding ("in-house") compared to the further use of purebred Holstein breeders has been established. The intergroup difference was insignificant in terms of the reproductive capacity of first-borns. According to the quantitative indicators of milk productivity, there was a reliable advantage in cows for breeding "in-house". The most intensive increase in live weight of heifers, higher milk productivity and reproductive capacity of cows differed from the analyzed interbreed crossing with the Montbeliard breed.The highest intensity of growth of crossbreeds with the Montbeliard breed of animals provided the youngest age of first calving (by 49 ± 19.7 days (P ˂ 0.02) compared to counterparts from inbred crosses and by 75 ± 21.3 g (P ˂ 0.001) – from breeding "in yourself"). In terms of milk yield, the first-born offspring of the Montbeliard breed were superior to their peers from the inbred crossing by 577 ± 73.0 kg (P ˂ 0.001), in terms of milk fat output – by 20.5 ± 2.63 kg (P ˂ 0.001), protein – by 23.2 ± 2.75 kg (P ˂ 0.001). More intensive growth of heifers ensured a significantly younger age of first calving of Montbeliard crossbreds compared to counterparts from self-breeding by 75 ± 21.3 days (P ˂ 0.001), from inbreeding – by 49 ± 19.6 days (P ˂ 0.02). At the younger age of calving, the firstborns of the place were superior to their peers from breeding "in-house" in terms of milk yield in 305 days of lactation by 225 ± 216.1 kg (P ˃ 0.1), from absorptive crosses – by 391 ± 216.1 kg (P ˂ 0.1), according to the output of milk fat – by 11.1 ± 7.47 kg (P ˃ 0.1) and 17.2 ± 7.50 kg (P ˂ 0.05), respectively, protein – by 9.7 ± 6.55 kg (P ˃ 0.1) and 15.6 ± 6.58 kg (P ˂ 0.02). The higher milk productivity of the Montbeliard crossbreds was combined with the better reproductive capacity of the first-borns. According to the coefficient of reproducibility, they exceeded the analogues from breeding "in themselves" by 0.131 ± 0.072 (P ˂ 0.1), from selective crossing – by 0.086 ± 0.073 (P ˃ 0.1) for a shorter service period (corresponding to 75 ± 29.4 days, P ˂ 0.02 and at 60 ± 31.0 days, P ˂ 0.05) and the period between the first and second calving (respectively at 75 ± 29.4 days, P ˂ 0.02 and at 60 ± 31.0 days, P ˂ 0.05). Such an advantage of crossbred cows with the Montbeliard breed may indicate the manifestation of the heterosis effect. Conclusions. 1. The difference between the animals of the Ukrainian Red-and-White and Black-and-White dairy breeds and the Holstein breeds according to the economically useful traits taken into account was mainly insignificant and multidirectional, which reveals almost the same efficiency of their use. 2. With a successful selection of improvers, purebred breeding ("in-house") in herds of Ukrainian Red-and-White and Black-and-White dairy breeds shows higher efficiency compared to the further use of purebred Holstein breeders (receptive crossing). However, at present, this method becomes practically unavailable due to the lack of progeny-rated bulls of the specified domestic breeds with high breeding value. Therefore, for the future, the only possible selection direction remains is further cross-breeding of newly created domestic breeds with improvers of the Holstein breed according to the scheme of selective crossing and formation of an array of breeding cattle of the Holstein breed of Ukrainian selection due to the immediate need to restore the domestic bull breeding system and the mandatory re-evaluation of imported breeders in the conditions of Ukraine. 3. According to most of the considered characteristics, the superiority of crossbred cows with the Montbeliard breed was established. This indicates the manifestation of the effect of heterosis, which, according to theoretical expectations, cannot be preserved in subsequent generations. Therefore, the selection strategy is to create a purebred breeding breeder of the Montbeliard breed by selective crossing. 4. It was established that the degree of intergroup differentiation for most of the considered characteristics increases from the interbreeding difference to the difference according to the selection method and the highest difference between groups of half-sisters by father. The analysis of variance established that the pedigree determines 0.03–3.9% of the total phenotypic variability of growth intensity, reproductive capacity and milk productivity of cows, the selection method – 0.02–18.1%, and the highest influence (4.2–55.8%) gives descent according to the father. 5. The correlation analysis established the superiority of the additive component (50.2–60.4%) in the genotypic variance, which will ensure high efficiency of mass selection based on the productivity of cows for higher lactation to the breeding core. The relative variability of the sire's breeding value with the milk productivity of the daughters at the level of 10.1–13.5% confirms the selective feasibility of progeny assessment and the selection of identified improver bulls.