Association of polymorphisms in the GHRL, GAST, and SCTR genes with feed conversion and productivity indicators of meat chickens bred at the Smena Breeding Centre

ASSOCIATION OF FABP T3499A GENOTYPE WITH BODY MEASUREMENTS, TEMPERATURE, AND MILK PRODUCTION PARAMETERS IN IRAQI BUFFALOES

The study aimed to detect the genotype of the FABP gene T>A: 3499 in a sample of 41 buffaloes to investigate the relation between this genotype and several productive traits. The study was conducted from October 1st, 2024, to January 30th, 2025, at the Ruminant Research Station in Abu Ghraib. By detecting the genotype of the FABP gene at the T>A: 3499 site, two genotypes, TT and TA, were identified. Their distribution ratios were 80.49% and 19.51%, respectively (P≤0.01). The allelic frequencies for the T and A alleles were 0.90 and 0.10, respectively. Significant differences (P≤0.01) were found in body length, Heart girth, and body temperature during the 2nd month of the study. Regarding milk production and composition, the first month was represented by milk density, the 2nd month by the daily milk yield (DMY), and the 3rd by DMY and density. The TA genotype showed superiority over the TT genotype for heart girth, milk density in the first month, DMY in the 3rd month. In conclusion, the study of genetic structures in the FABP gene: T>A: 3499, the resulting changes can be used in the process of genetic improvement of Iraqi buffaloes performance.

RESULTS OF GENOTYPING OF HOLSTEIN COWS BY THE TLR4/ALUI GENE LOCUS AND STUDYING THE INFLUENCE OF TLR4 GENE ALLELES ON REPRODUCTIVE FUNCTION

The relevance of this study is determined by the need to improve the efficiency of dairy cattle reproduction using molecular genetic markers that can predict animal fertility. The aim of the study was to genotype Holstein cows for the TLR4/AluI gene locus and establish the relationship between its alleles and reproductive function indicators. The objectives included isolating genomic DNA, amplifying a 382-bp TLR4 gene region, and performing restriction analysis with the AluI enzyme. The study included 190 clinically healthy Holstein cows maintained under identical feeding and microclimate conditions at Baiserke-Agro LLP. TLR4/AluI genotyping was performed using PCR-RFLP; the genotype distribution was tested for compliance with Hardy-Weinberg equilibrium. Association analysis was performed taking into account the period of fruitful insemination of cows after calving (45–60; 61–90; 91–120; ≥121 days) and the non-return rate on day 58 (NRI-58). Three genotypes were identified: TT - 39.5%, TC - 43.7%, CC - 16.8%; allele frequencies: T = 0.61, C = 0.39; the distribution corresponds to HWE (χ² = 1.97; p > 0.05). In the 45–60-day group, the TT/TC/CC shares were 42/48/10%, with an increase in the open period (61–90; 91–120 days) an increase in the CC share to 16–22% was noted. According to NRI, 58 animals were registered: TT - 19 heads, TC - 24 heads, CC - 0 (a total of 43 out of 190). The data indicate a favorable role for the T allele and an unfavorable role for the C allele in determining fertility. The TLR4/AluI locus is informative for assessing reproductive function in Holsteins; the T allele is associated with earlier fruitful insemination and better fertility indicators, supporting its use as a selection DNA marker.

Uncovering genetic markers for growth and fat-tail traits in Kurdi sheep: associations with DGAT1 and PPARGC1B variants

Complex combination of polymorphic variants of the OPN and IGF-1 genes in a cattle population

The article presents the results of a study on the combined genotypes of OPN (c.8514C/T) and IGF-1 (512T/C) genes in a population of Holstein heifers (n=202). The experiment was conducted at the Lenin Breeding Farm (Atninsky District, Republic of Tatarstan), and laboratory analyses were carried out at the Tatar Research Institute of Agriculture, Kazan Scientific Center of the Russian Academy of Sciences. The relevance of the study is driven by the need to identify genetic markers associated with reproductive traits in cattle, as fertility indicators alongside milk productivity determine the economic efficiency of dairy farming. The OPN and IGF-1 genes are involved in the regulation of embryogenesis, implantation, folliculogenesis, and early embryonic development; however, their combined interaction remains insufficiently studied. Genotyping was performed using PCR-RFLP with restriction endonucleases BseI (for OPN ) and BstSNI (for IGF-1 ). The analysis revealed the presence of all nine possible combined genotype combinations, confirming the genetic heterogeneity of the studied population. The highest frequency was observed for the combined genotype CT/AB (29.7%), while the lowest frequencies were found for CC/BB (2.0%) and CC/AA (3.0%) by OPN / IGF-1 . A pattern of decreasing frequency of combined genotypes was established with an increasing number of homozygous loci. Comparison of the observed and theoretically expected distributions showed no statistically significant deviations (χ² = 4.67; p > 0.05), indicating independent allele combination of the studied genes and the absence of factors disrupting genetic equilibrium in the sample. The obtained data can be applied in breeding programs for marker-assisted selection of parental pairs, genetic passportization, and monitoring of the genetic structure of cattle populations.

Complex SNPs of leptin and somatotropin and their association with economic traits in cattle

The aim of the study was to evaluate the effect of 12 complex GN and LEP genotypes on cow productivity in order to identify consistently effective allele combinations that account for genotype-environment interactions, and to develop personalized strategies for herd breeding and management. The conducted study revealed a significant association between complex genotypes of the somatotropin (GH, LV polymorphism) and leptin (LEP, R25C and A80V polymorphisms) genes and milk productivity in Holstein cows. A study of 120 animals (60 animals each from two agricultural organizations) showed a marked uneven distribution of the 12 analyzed genotypes in both herds, due to the farm breeding priorities. A key result was the identification of the GHLVR25CRRA80VAA genotype as the most promising for breeding for high lifetime milk productivity. Animals with this genotype consistently demonstrated maximum milk yields in the first and third lactations and lifetime productivity, demonstrating stability and high genetic potential. In parallel, genotypes associated with milk quality traits were identified. For example, in animals carrying the GHLVR25CCCA80VVV genotype at Organization "K," the lifetime fat and protein content was 3.92 and 3.27 %, respectively. Animals with the GHLVR25CCRA80VAA genotype in Organization "P" had a maximum fat content of 4.13 % while maintaining high milk yield. The study confirmed the critical influence of environmental factors (feeding, management) on the realization of genetic potential. The significantly higher milk yields in Organization "P" compared to Organization "K" highlight the need for a systematic approach combining genetic selection with improved livestock production technologies. The obtained data demonstrate that the complex GH and LEP genotypes serve as informative markers for predicting milk productivity and the adaptive potential of cows.

Predicting Predisposition to Subclinical Ketosis in Holstein Cattle Based on Polymorphism Analysis of the DGAT1, GHR and GH_2141 Genes

This article presents the results of a study investigating the genetic factors influencing the predisposition of first-lactation Holstein cows to subclinical ketosis, based on an analysis of polymorphisms in the DGAT1, GHR, and GH_2141 genes. The study involved 940 first-lactation cows housed at the "Krasnodarskoe" training and experimental farm of Kuban State Agrarian University. We analyzed the associations between the genotypes of these genes and the physicochemical milk parameters, including acetone, ß-hydroxybutyrate, fat, urea, and casein content. The polymorphism of the DGAT1 gene was found to primarily affect lipid metabolism. A moderate positive correlation was identified with fat content, along with a pronounced negative correlation with acetone levels. For the GH_2141 gene, no significant association with protein or nitrogen metabolism parameters was established; however, a moderate negative correlation with ketone body concentration was observed. Analysis of the GHR gene demonstrated a weak effect on the studied traits, although a tendency for altered acetone and ß-hydroxybutyrate levels depending on the genotype was noted. The findings indicate the complex influence of genetic factors on the metabolic status of animals and confirm that individual genetic markers do not provide high predictive accuracy without considering environmental factors. It is demonstrated that using polymorphisms of the DGAT1, GHR, and GH_2141 genes in conjunction with biochemical milk parameters improves the effectiveness of early diagnosis of subclinical ketosis. The research materials can be applied in the development of breeding programs aimed at reducing the risk of metabolic disorders and increasing the resilience of high-producing dairy herds.