Partial Results Regarding the Genetic Determinism of Growth Process in a Native Horse Breed using Wither’s Height

Study of variability in domestic animal populations is the foundation of quantitative genetics. Based on statistical methods, the weights of the total phenotype variation that belong to its different fractions (causal components) are quantified: variation due to gene additive effect, variation due to allelic and non-allelic interactions, variation due to environment (general and special), variation due to genotype-environment interaction and possibly variation due to the association between genotype and environment. In this study, during 2017-2020, we used the method of analysis of variance with two sources of variation. The material was represented by 538 individuals from Hucul horse breed analyzed at 18, 30 and 42 months old). The heritability of character was 0.3402±0.1546 (18 months), 0.5549±0.2225 (30 months), 0.4506±0.1895 (42 months), suggest that this is a hereditary condition that follows a quantitative model of inheritance, where the influence of additive genetic factors is moderate to intense. We can conclude that, in this native breed and for this character, a significant share of the phenotypic value is due to the additive effect of genes.

Influence of the type of higher nervous activity on milk yield and the productive longevity of mares

The presented work is the result of studies of the influence of the type of higher nervous activity on the dairy productivity of mares of the Russian heavy draft horse breed on stationary koumiss farms. To determine the types of higher nervous activity, a motor-food technique developed by the All-Russian Research Institute of Horse Breeding was used. The milk yield was counted at animals for the first lactation, for the highest lactation, on average for one lactation and a lifelong milk yield of mares. The milk yield on average for lactation is almost the same in mares with a strong balanced mobile type and with a strong unbalanced type of higher nervous activity. Animals of a weak type and a strong balanced inert type of higher nervous activity lag behind them in this indicator by 11-13%. Horses with a strong balanced mobile type, a strong unbalanced type and a weak type of higher nervous activity are most suitable for the duration of economic use and lifelong milk production. The mares with a strong balanced inert type of higher nervous activity are the least productive in terms of duration of economic use and lifelong milk yield on koumiss farms.

Variability of mitochondrial DNA D-loop sequences in Zabaikalskaya horse breed

The Zabaikalskaya horse is an indigenous breed of horses from Siberia with diverse use. It is characterized by e durance and good adaptability to year-round herd maintenance in the harsh conditions of the Baikal steppes. To determine the genetic characteristics of the maternal lineage of the Zabaikalskaya horse breed based on mitochondrial DNA polymorphisms, we collected hair samples from 31 horses belonging to breeding farms in the Trans-Baikal Territory. Analysis of the 530 bp sequence of the mtDNA D-loop was performed using the maximum composite likelihood (MCL) model in combination with bootstrap analysis. When studying the polymorphism of the hypervariable region of the mtDNA D-loop in Zabaikalskaya horses, we identified 31 haplotypes representing 8 haplogroups: B, C, G, H, L, M, Q and R according to modern classification. The sequenced fragment of the D-loop from nucleotide position 15471 to 16000 contained 17 polymorphic sites, mainly represented by the A→G, G→A and T→C transitions. The haplogroups Q (25.81 %), B (19.35 %), G (16.13 %) and H (12.90 %) were prevailing in the mtDNA structure of this breed. Genetic analysis of the mitochondrial genome of the Zabaikalskaya horse revealed a high level of diversity of haplotypes and haplogroups, which are typical for the horse populations of Eurasia.

Influence of the degree of homozygosity of STR-loci on the fertility of thoroughbred horses

Purpose: to study the effect of the level of homozygosity and inbreeding on the fecundity of thoroughbred mares.Materials and methods. A total of 3662 heads of breeding sows from leading stud farms of the Russian Federation were selected for the analysis. The influence of the homozygosity level on 17 microsatellite DNA loci on the main indices of reproduction of thoroughbred mares, such as the safe yield of foals and the number of fetal years, was analyzed in the article. All mares in the experimental sample had at least three years of breeding use. Individual fecundity rates and the number of homozygous loci in the STR profile were calculated for each horse.Results. The highest live foal yields (75.92%) had sows with homozygosity levels of 62.78-69.02%, and the lowest foal yields (45.73%) were recorded in mares with the highest homozygosity levels (75.28-76.92%). The maximum foal yield (65.85%) was determined in sows with an inbreeding rate of 4.1% or more, with a productive longevity of 6.26 fetal years on average. Analysis of the data showed that the level of inbreeding had almost no effect on the yield of live foals (R=0.010 at P>0.05), but had a negative correlation with the number of fruiting years (R=-0.092 at P<0.005).Conclusion. Estimation of homozygosity level of thoroughbred horses is especially relevant, as this breed has been perfected by purebred breeding method only for more than thirty years. In the thoroughbred horse breed, it is necessary to create a system of maintaining heterozygosity as well as the diversity of genotypes through the organization of breeding work.

Exploring the Origin and Relatedness of Maternal Lineages Through Analysis of Mitochondrial DNA in the Holstein Horse

Maternal lineages are important for the breeding decision in the Holstein horse breed. To investigate the genetic diversity of the maternal lineages and the relationships between founder mares, the maternal inherited mitochondrial genome (except the repetitive part of the non-coding region) of 271 mares representing 75 lineages was sequenced. The sequencing predominantly revealed complete homology in the nucleotide sequences between mares from one lineage with exceptions in 13 lineages, where differences in one to three positions are probably caused by de novo mutations or alternate fixation of heteroplasmy. We found 78 distinct haplotypes that have not yet been described in other breeds. Six of these occurred in two or three different lineages indicating a common ancestry. Haplotypes can be divided into eight clusters with all mares from one lineage belonging to the same cluster. Within a cluster, the average number of pairwise differences ranged from zero to 16.49 suggesting close maternal relationships between these mares. The results showed that the current breeding population originated from at least eight ancestral founder mares.

Welfare assessment of cattle submitted to equestrian sporting events

The concern with the animal’s welfare has become increasingly frequent and the use of cattle in sporting events has aroused discussions about the preservation and integrity of these animals. The objective of this work was to evaluate whether the cattle participating in the team roping modality receive all support regarding the animal welfare criteria. During the 41st National Championship of the Quarter Horse Breed of Work and Conformation, aspects of animal welfare of 410 cattle that participated in the team roping were evaluated. Behavioral aspects were observed before, during and after the end of the competition, in addition to quantifying the number of runs per animal, the presence of ectoparasites, thermal comfort, food and hydration. It was possible to conclude that the environment in which the tests were carried out, the feeding conditions, the space and the thermal comfort meet the criteria of animal welfare.

Milk productivity of Yakut horses

The article presents a brief review of scientific research on the milk productivity of mares of the Yakut breed. One of the most valuable products of horse breeding in Yakutia is the milk of Yakut mares, which is characterized by a high content of milk sugar, rich in vitamin C, which is especially important for the production of koumiss. Milk of mares of the Yakut horse breed is a valuable raw material for processing. A brief review of research has shown that the mares of Bashkir, Kazakh and Kirghiz breeds, which have been milking since ancient times, have a good milk content among the horse breeds of the herd. A Mare of the Yakut horse breed gives an average of 4 – 5 liters per day, and a maximum of 6 – 8 liters of milk. According To M. F. Gabyshev's research, the average daily milk productivity of a Mare reaches 10–12 liters. A thorough study of milk production of mares of the Yakut breed held the T. V. Amosova. She found that for 6 months of lactation, the daily milk yield of mares of the Yakut breed averaged 9.9 liters, during this time they produce from 1124 to 1942 liters, an average of 1750 liters of milk. In studies A. I. Pavlova found that the native type mares of the Yakut breed of horses milk yield is 8.8 l per day and 1592 L. 6 months of lactation and in enlarged type – 9.2 and 1666 l; from MagicScore and 13.3 2393 and l, respectively. It was found that winter milk is inferior to summer milk in terms of protein, ash, phosphorus, calcium, and vitamin C, but it is higher in sugar content and has a high acidity. As a result, we came to the conclusion that it is necessary: 1. conduct breeding work to increase the milk productivity of mares of the Yakut horse breed, 2.develop and test a recipe for starter feed for weanling foals that is similar in composition to their mothers' milk.