Ukrainian Red- and Black-and-White dairy breeds, which are the most common in the region, as well as each biological system, are in constant variability and need constant scientifically-based support and improvement not only in general milk productivity, but also in such specific features as duration of economic use and reproducibility. A systematic approach in the optimization of breeding programs and the search for optimal crossbreeding options in populations of domestic dairy breeds is a little-studied and relevant area of research.
The aim of the research is to study the peculiarities of the formation of the exterior of the first-born cows obtained from bulls of the Montbeliard, Norwegian Red and Holstein breeds.
Materials and methods of research. The research was conducted in 2019–2020 on the basis of 4 breeding farms of Cherkasy region. 120 heads of first-born cows of Ukrainian Black-and-White dairy breeds, 201 heads of Ukrainian Red-and-White dairy breeds, 80 heads of first-generation Ukrainian Red-and-White dairy breeds and Montbeliards, 96 heads of first-generation Ukrainian Black-and-White dairy breeds and Norwegian Black-and-White cows were taken into account. Comparative evaluation of animals on productive traits, exterior type was carried out within breeding herds, taking into account the structure of the genotype of animals. The study of morphological and physiological features of the udder of cows was carried out by determining the shape and size by taking measurements at 2–3 months of lactation for 1 hour. 30 min before milking.
The functional properties of the udder were studied by the intensity of milk production (kg/min.) during the control milking. The milk yield was determined by the formula proposed by N. P. Pogribna and others. The growth intensity of repair heifers and the index of decline in growth energy were determined by the methods of Yu. K. Svechin, L. I. Dunaev, V. P. Kovalenko. Biometric processing of experimental data – statistical, correlation and analysis of variance were performed according to the methods of N. A. Plokhinsky and E. K. Mercury on a computer type IBM PC/AT.
Research results. At the age of six months among local heifers obtained from breeders of the Montbeliard Breed received a live weight of more than 200 kg (when using Holstein Breeders for reproduction, the weight of heifers at 6 months was 174.4–182.1 kg), at the age of over 380 kg (383.5–384.8 kg), in 15 months over 440 kg (442.9–449.9 kg). From birth to 6 months of age, heifers of the Ukrainian Black-and-White dairy breed obtained from Holstein Breeders had a higher live weight compared to crossbreeds obtained from bulls of the Norwegian Breed. After 6 months of age, local heifers outnumbered their peers in terms of live weight with an unlikely difference.
The first-born cows of the Ukrainian Red-and-White dairy breed had high growth rates with well-developed breasts in depth, width and girth: height at withers and buttocks, respectively 133.7 ± 0.96 cm and 136.1 ± 1.05 cm with well-developed chest depth (72.9 ± 1.17 cm), width 42.6 ± 2.18 cm) and girth 193.0 ± 1.54 cm), with a wide back in the macula 51.6 ± 3.77 sm and in the buttocks 35.2 ± 1.09 sm.
Body measurements of local first-borns of genotype 1/2URW1/2M – only 80 heads: height at withers 124.7 ± 3.71 cm (below first-borns obtained from Holstein bulls by 9.0 sm (P > 0.95) URW); in the buttocks 127.9 ± 2.19 sm (8.2 sm below the firstborn URW breed) (P > 0.99), oblique body length 158.3 ± 13.82 cm (4.6 cm below the firstborn URW breed)). However, they outnumbered the first-borns obtained from Holstein bulls by measuring the depth of the breast 75.3 ± 3.11 cm (2.4 cm), breast width from 47.7 ± 2.40 cm (5.1 sm), chest circumference 205.0 ± 4 10 sm (12 sm (P > 0.99)), width of the buttocks in the macula and buttocks (6.1–3.1 sm (P > 0.95)).
The first-born cows of the Ukrainian Black- and-White dairy breed obtained from Holstein breeders had a height at the withers and buttocks of 130.9 ± 1.22 cm and 137.2 ± 0.86 cm, respectively, with well-developed breasts in depth and girth. Local first-borns obtained from the selection of Ukrainian Black-and-White dairy cows of Norwegian Black-and-White breeders had no significant difference in basic body measurements with those of the same age as those obtained from Holstein breeders.
Regardless of genotype and breed, the udder of first-born cows is large in volume (in girth – 128.6 ± 3.14 and 148.7 ± 2.66 sm, length – 35.1 ± 1.23 and 40.3 ± 1.55 sm and a width of 29.5 ± 3.26 and 33.8 ± 4.36 sm.) With proportionally developed parts of the udder, bath- or cup-shaped, firmly attached to the abdominal wall with cylindrical teats. Duration of milking 10.1 ± 0.167 – 12.2 ± 0.157 minutes, milk production rate 1.90 ± 0.01 – 2.50 ± 0.07 kg/min. It was found that with increasing daily milk yield, the intensity of milk production also increased: correlation coefficients (r = 0.439–0.577) have a high reliability (td = 3.97–7.58). The value of the udder index among the studied breeds and genotypes was different and ranged from 43.4 ± 0.06% to 45.2 ± 0.02%.
Conclusions. The crossing of Ukrainian Black-and-White dairy cows with Norwegian Black-and-White breeders did not have a significant effect on the exterior type of repair heifers under 12 months of age. Crossbreeding with the Montbeliard breed made it possible to obtain heifers that were inferior in growth, but had a developed, three-dimensional body, chest and pelvis. The use of genetic material of the Montbeliard and Norwegian Black-and-White breeds has contributed to the formation of cows of the desired exterior type with good udder characteristics that meet modern requirements of machine mil.
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