Polymorphism in DNA repair gene BRCA1 associated with clinical mastitis and production traits in indigenous dairy cattle

Estimation of maternal and additive effect on reproduction and productive traits in Hardhenu cattle

The study aimed to assess performance traits in Hardhenu cattle by analysing data from 445 animals born to 59 sires and 227 dams. The investigation focused on estimating (co)variance components and genetic parameters for reproduction and production traits in dairy cattle. Results from least-squares analysis indicated a significant effect (p < .01) of the period of calving (POC) on key production traits, including first lactation milk yield (FLMY), 300-day milk yield (FLMY300), first peak yield (FPY) and total lactation milk yield (TLMY) in studied population. The least squares means for these traits were reported as follows: FLMY (2665.68 ± 45.66 kg), FLMY300 (2425.52 ± 34.41 kg), FLL (312.95 ± 3.83 days), FPY (11.52 ± 0.15 kg) and TLMY (9282.44 ± 167.03 kg) in Hardhenu cattle. In the studied population, only additive genetic variability was found to be present and there was absence of any significant maternal effect with respect to targeted traits in the resource population. Direct heritability estimates (h2) for FLMY, FLMY300, FLL, FPY, TLMY and other traits ranged from 0.03 to 0.41 in Hardhenu cattle. These findings offer valuable insights into the genetic factors influencing performance traits, contributing to the enhancement of breeding and management practices in Hardhenu cattle.

Bayesian estimates of genetic effects on calf survival in Hardhenu (Bos taurus × Bos indicus) cattle

The aim of the present study is to carry out a risk analysis and Bayesian estimates of genetic effects on calf survival in Hardhenu cattle using data records of 2593 calves born to 102 sires and 790 dams over 25 years. The Bayesian analysis using Gibbs sampling was employed towards threshold animal models to estimate direct and maternal effects on animal survival of studied population. The results showed that mortality from birth to 3 months of age (S1), birth to 6 months of age (S2) and birth to 12 months of age (S3) was 10.22, 12.88 and 14.65%, respectively. It was revealed from the results of logistic regression analysis that the male animals had greater risk (1.41-1.61 times) of mortality during S1, S2 and S3 as compared to female animals. However, calves born during rainy season had higher risk (1.36 to 1.44 times) of mortality than calves born during winter season. Among died animals, the simultaneous infection of respiratory and digestive diseases had leading contribution (26.84%-30.19%) to deaths while alone of them contributed to 18%-20% only. On evaluation of six threshold animal models, model 1 was found to be most appropriate model and the Bayesian estimates (95% highest posterior density confidence intervals) of direct additive heritability for S1, S2 and S3 under model 1 were 0.15 ± 0.07 (0.04-0.23), 0.23 ± 0.12, (0.02-0.44) and 0.26 ± 0.06 (0.08-0.41), respectively. It was concluded that the inclusion of survival traits in existing selection criteria may be helpful to increase calf survival and ultimately economic gain in the dairy herd.

Impact of temporal variations and risk factors associated with udder inflammation in Hardhenu cattle (Bos taurus × Bos indicus)

This study aimed to explore the occurrence and risk factors associated with clinical mastitis within the Hardhenu cattle herd over a span of 14 years (2008-2021). A comprehensive analysis of 1515 lactation records was conducted to ascertain the incidence of clinical mastitis. The investigation determined an overall incidence rate of 26.80% in the studied population. A significant relationship between the year and clinical mastitis incidence was established through Chi-square analysis (p < .05). Temporal variations in clinical mastitis odds were apparent, with the highest odds (ranging from 0.91 to 1.00) observed during the initial years of 2008-2009 and 2009-2010. Logistic regression revealed that odds values for clinical mastitis incidence were highest in 2008-2009 (1.00), succeeded by 2009-2010 (0.91), 2012-2013 (0.88), 2018-2019 (0.67) and reaching the lowest in 2021-2022 (0.35). Subsequent rankings included 2010-2011 (0.39), 2014-2015 (0.43) and 2019-2020 (0.45). Parity was found to be significantly associated with clinical mastitis occurrence. When compared to Parity 3, both Parity 1 (odds ratio: 1.516, 95% confidence interval: 0.881-2.612) and Parity 2 (odds ratio: 2.626, 95% confidence interval: 1.568-4.398) exhibited higher odds values for clinical mastitis incidence. While the period of calving did not exert a significant influence on clinical mastitis incidence, a heightened occurrence was observed during the rainy season within the targeted population. These findings offer valuable insights into the patterns of incidence, temporal fluctuations, and non-genetic determinants impacting clinical mastitis within the Hardhenu cattle. The implications of this study can facilitate the development of targeted strategies and management protocols aimed at enhancing udder health and overall productivity in dairy cattle.

Temporal variation and risk factors associated with reproductive disorders in Hardhenu (Bos taurus × Bos indicus) dairy cattle

This study aimed to investigate the incidence and effect of non-genetic factors on reproductive disorders in the Hardhenu cattle population over a period of 11 years (2010-2021). The study included a total of 1340 cattle for calculating the incidence of reproductive disorders and analysed the occurrence of different reproductive disorders. In the present study, retention of placenta had highest frequency, accounting for approximately 18.36% of the incidence, followed by repeater cows (11.19%), metritis (6.27%), dystocia (0.60%), anestrus (0.45%) and prolapse (0.37%). Chi-square analysis revealed a significant relationship between the year and the incidence of reproductive disorders (p < .05). Logistic regression analysis of temporal variability of reproductive disorders was also analysed, with an increase in the odds from 2014 to 2020, peaking in 2017-2018 and 2018-2019. Logistic regression analysis showed that season and parity did not significantly influence the incidence of reproductive disorders. However, period of calving had a significant impact. Cows calving between 2008 and 2014 had a significantly lower odds ratio (0.13, 95% CI: 0.06-0.30), indicating a decreased risk, while those calving between 2014 and 2017 had a higher odds ratio (0.59, 95% CI: 0.38-0.90), suggesting an increased risk of reproductive disorders. Compared to parity 3, parity 1 (1.344, 95% CI: 0.869-2.08) and parity 2 (1.193, 95% CI: 0.768-1.851) showed highest odds ratio. Similarly, the odds ratio for winter (1.64, 95% CI: 0.93-2.89), summer (1.71, 95% CI: 0.89-3.26) and rainy season (1.64, 95% CI: 0.92-2.91) was higher as compared to autumn. The present results provided valuable insights into the incidence of various reproductive disorders and associated risk factors in Hardhenu cattle. These results can be utilized for targeted interventions to enhance reproductive health and overall productivity in dairy cattle.

Association of CXCR1 gene polymorphism with clinical mastitis, reproductive disorders and performance traits in Hardhenu (Bos taurus × Bos indicus) cattle

The present study investigated the presence of CXCR1 gene polymorphisms and their association with clinical mastitis, reproductive disorders and performance traits in Hardhenu cattle. Genotyping of the targeted SNP rs211042414 (C>T) at the g.106216468 loci of the CXCR1 gene was performed through PCR amplification and Bsa1 restriction enzyme digestion. The genotypic frequencies revealed three genotypes: CC, CT and TT, with the C allele being the most prevalent. Significant associations were found between the targeted SNP and clinical mastitis occurrence using chi-square and logistic regression analyses. The CC genotype showed higher susceptibility to clinical mastitis with a higher odds ratio of 3.47 compared to TT (1.00) and CT (2.90) genotypes (p < .05). Furthermore, least squares analysis revealed significant associations between genotypes and performance traits such as total milk yield, 305-day milk yield and peak yield (p < .05). The CC genotype exhibited higher milk yields than CT and TT genotypes, indicating a positive association between the C allele and increased milk production. These findings have practical implications for the genetic improvement of Hardhenu cattle. Incorporating the identified CXCR1 gene polymorphisms into existing selection criteria can help enhance disease resistance and milk production traits. However, further validation with a larger sample size is necessary to strengthen the observed associations and ensure their practical applicability.

Kompetitive Allele Specific PCR Genotyping of 89 SNPs in Romanian Spotted and Romanian Brown Cattle Breeds and Their Association with Clinical Mastitis

Mastitis is the most common production disease in the dairy sector worldwide, its incidence being associated with both cows' exposure to bacteria and the cows' genetic make-up for resistance to pathogens. The objective of our study was to analyse 89 missense SNPs belonging to six genes (CXCR2, CXCL8, TLR4, BRCA1, LTF, BOLA-DRB3), which were found to be associated with genetic resistance or susceptibility to mastitis. A total of 298 cattle (250 Romanian Spotted and 48 Romanian Brown) were genotyped by Kompetitive Allele Specific PCR (KASP) and a chi-squared test was used for genetic association studies with clinical mastitis. A total of 35 SNPs (39.3%) among the selected 89 SNPs were successfully genotyped, of which 31 markers were monomorphic. The polymorphic markers were found in two genes: TLR4 (rs460053411) and BOLA-DRB3 (rs42309897, rs208816121, rs110124025). The polymorphic SNPs with MAF > 5% and call rates > 95% were used for the association study. The results showed that rs110124025 in the BOLA-DRB3 gene was significantly associated with mastitis prevalence (p ≤ 0.05) in both investigated breeds. Current results show that the SNP rs110124025 in the BOLA-DRB3 gene can be used as a candidate genetic marker in selection for mastitis resistance in Romanian dairy cattle.

Genetic polymorphisms in immune- and inflammation-associated genes and their association with bovine mastitis resistance/susceptibility

Bovine mastitis, the inflammation of the mammary gland, is a contagious disease characterized by chemical and physical changes in milk and pathological changes in udder tissues. Depressed immunity and higher expression of inflammatory cytokines with an elevated milk somatic cell count can be observed during mastitis in dairy cattle. The use of somatic cell count (SCC) and somatic cell score (SCS) as correlated traits in the indirect selection of animals against mastitis resistance is in progress globally. Traditional breeding for mastitis resistance seems difficult because of the low heritability (0.10-0.16) of SCC/SCS and clinical mastitis. Thus, genetic-marker-selective breeding to improve host genetics has attracted considerable attention worldwide. Moreover, genomic selection has been found to be an effective and fast method of screening for dairy cattle that are genetically resistant and susceptible to mastitis at a very early age. The current review discusses and summarizes the candidate gene approach using polymorphisms in immune- and inflammation-linked genes (CD4, CD14, CD46, TRAPPC9, JAK2, Tf, Lf, TLRs, CXCL8, CXCR1, CXCR2, C4A, C5, MASP2, MBL1, MBL2, LBP, NCF1, NCF4, MASP2, A2M, and CLU, etc.) and their related signaling pathways (Staphylococcus aureus infection signaling, Toll-like receptor signaling, NF-kappa B signaling pathway, Cytokine-cytokine receptor, and Complement and coagulation cascades, etc.) associated with mastitis resistance and susceptibility phenotypic traits (IL-6, interferon-gamma (IFN-γ), IL17, IL8, SCS, and SCC) in dairy cattle.

Evaluation of candidate genotype of GH gene associated with growth, production and reproduction traits in Dairy Cows

Growth hormone (GH) is a major regulator of postnatal growth and metabolism in mammals and plays a critical role in growth, production and fertility in cattle. The present study was conducted in dairy cattle to find the association of g.48769565 C>T mutation with growth, production and reproduction traits in Sahiwal and Hardhenu cattle. PCR-RFLP was performed to genotype g.48769565 C>T mutation using the MspI restriction enzyme in our resource cattle population. In Hardhenu cattle, the frequencies of C and T alleles were 0.59 and 0.41 respectively while genotypic frequencies were 0.06, 0.36 and 0.58 for CC,CT and TT respectively. The frequencies of the C and T allele were 0.24 and 0.76 respectively in Sahiwal cattle and it was observed that highest frequency was forTT genotype (0.58) and lowest for CC genotype (0.06). Chi-square analysis showed that g.48769565C>T SNP loci did not meet with the Hardy-Weinberg equilibrium (p< 0.01) in Sahiwal cattle. From the least-squares analysis, it was observed that CC genotype was significantly associated with total Milk Yield (TMY), 300 days milk yield (300D MY), lactation length (LL), Dry period (DP) and Artificial insemination (AI)/conception (p<0.05). We also observed a significant association (p<0.05) of genotype CT with 3-month calves body weight. Cows with TT genotype revealed comparatively revealed favourable service period (SP) and calving interval (CI) in both Hardhenu and Sahiwal. These observed differences in their allelic and genotypic frequencies in association with the traitsunderlying production and fertility can be utilized for genetic improvement in dairy cattle.

Polymorphisms of SORBS1 Gene and Their Correlation with Milk Fat Traits of Cattleyak

Simple Summary

Increasing milk fat rate has a good effect on the milk quality of cattleyak. SNPs can help us find potential molecular markers for the milk fat traits of cattleyak, and they can be screened according to molecular markers when they are young. It provides a reference for cultivating high milk fat cattle population in the future. The results of this study suggest that the SORBS1 gene polymorphism is closely related to the milk fat traits of cattleyak, which could be used as a candidate genetic marker for milk fat trait selection in cattleyak. This study provides a new molecular marker and theoretical basis for screening the milk fat traits of cattleyak. It has a certain reference value for the research and improvement of milk quality.

Abstract

This study aimed to find the SNPs in the SORBS1 gene of cattleyak, analyze the relationship between its polymorphisms and the milk fat traits, and find potential molecular markers for the milk fat traits of cattleyak. The polymorphism of the SORBS1 gene in 350 cattleyak from Hongyuan County (Sichuan, China) were detected by PCR and DNA sequencing, and the correlation between these SNPs and the milk production traits of cattleyak was analyzed. The results showed that there were nine SNPs in the CDS and their adjacent non-coding regions of the SORBS1 gene, and all SNPs have three genotypes. The correlation analysis found that the genotypes with superior milk fat traits in the other eight alleles were homozygous genotypes with a high genotype frequency except the g.96284 G > A (c.3090 G > A) (p < 0.05). However, at locus g.96284 G > A, the milk fat percentage, monounsaturated fatty acids (MUFAs), polyunsaturated fatty acids (PUFAs) and saturated fatty acids (SFAs) of the GA genotype were significantly higher than that of GG and AA genotypes (p < 0.05). Among these SNPs, three SNPs (g.6256 C > T (c.298 C > T), g.24791 A > G (c.706 A > G) and g.29121 A > G (c.979 A > G)) caused the amino acids change. The genotypes of the three SNPs consist of three haplotypes and four diplotypes. The amino acid mutation degree of diplotype H1–H1 (CCAAAA) was the highest, and its milk fat percentage, MUFAs, PUFAs and SFAs were also the highest (p < 0.05). Taken together, we found nine SNPs in the SORBS1 gene that are closely related to the milk fat traits of cattleyak. Moreover, the mutation of amino acids caused by SNPs had positive effects on the milk fat traits of cattleyak. H1-H1 is the dominant diplotype which significantly related to the milk fat traits of cattleyak. This study provides a new molecular marker and theoretical basis for screening the milk fat traits of cattleyak.

Association of milk production and udder type traits with polymorphism of phosphorylase kinase regulatory subunit alpha-2 gene in Sahiwal cattle

The study was conducted in Sahiwal cattle in tropical region in the Indian sub-continent where the production of dairy animals is yet to be optimised. The present investigation was executed to identify SNPs in PHKA2 gene and to explore its effect on udder type and milk production traits. The study was based on the hypothesis that the PHKA2 gene has highly variable exons that could be related with udder traits and eventually milk production. PHKA2 gene regulates glycogen phosphorylase a, a catalyst in breakdown of glycogen. Milk production traits were recorded; 9 udder type, 5 teat type and 8 visual traits were measured for 100 animals. Five highly variable targeted regions of PHKA2 gene were amplified using PCR and sequenced. The association analysis was carried out using general linear model (SAS) to study the fixed effect of genotype on studied traits. The synonymous type SNP g.124556852C>T was found for the first time in Sahiwal cattle and possibly associated with udder type traits. The genotypic frequencies with respect to targeted loci g.124556852C>T indicated that homozygote CC (0.58) were highest in our resource population. The chi-square 2 test showed an agreement to Hardy–Weinberg equilibrium. The association analysis revealed significant association of genotypes with udder width, udder balance and 305 days milk yield. The attempt to find significant association with the visual udder traits was also done, however no significant alliance was observed. Homozygote CC animal were desirable as they favoured the selection of animal with superior udder width, udder balance and 305 day’s Milk Yield values.

Evaluation of candidate genotype of immune gene MBL1 associated with udder health and performance traits in dairy cattle and buffalo of India

An investigation was conducted to identify polymorphism in mannose-binding lectin 1 (MBL1) gene and its effect on udder health and performance traits in dairy cattle and buffalo of India. Candidate single-nucleotide polymorphism (SNP) c.2534G > A of MBL1 gene was genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). All the possible genotypes for SNP c.2534G > A (GG, AG, and AA) were observed in the studied population. However, Sahiwal cows revealed dimorphic pattern (AG and GG). The effect of targeted SNP on incidence of mastitis was evaluated and found to be significant. Animals with GG genotype were less susceptible to clinical mastitis and had comparatively lower somatic cell score (SCS) in Hardhenu cattle (P < 0.01) and Murrah buffalo (P < 0.05). Animals having GG genotype also exhibited significantly (P < 0.05) lower age at first calving (AFC). AG genotyped Murrah buffalo animals revealed significantly higher second lactation milk yield (P < 0.01). GG genotype with SCS and AFC could therefore be exploited as a promising candidate marker for the genetic improvement of udder health and AFC in dairy animals.