Polymorphism of growth hormone (GH) gene and its association with performance and body conformation of Harnali sheep

The present study was carried out to study the polymorphism in the GH gene and its association with various performance and body conformation traits, viz., birth weight (B-WT), weaning weight (W-WT), six-month body weight (6 M-WT), one-year body weight (Y-WT), annual greasy fleece weight (AGFW), body length (BL), body height (BH), heart girth (HG) and paunch girth (PG) in 138 Harnali sheep. PCR-RFLP was performed to identify polymorphism in the targeted region of the GH gene. The PCR product of 422 bp size of the GH gene was amplified encompassing partial exon 2 and inton 3 in Harnali sheep. The PCR product was digested with HaeIII restriction enzyme for the detection of Single nucleotide polymorphism (SNP). The digested products revealed the presence of two genotypes, i.e. AA and AB in the studied population. A > G mutation (A781G) was observed in our resource population. The AA genotype was found to be the predominant genotype (0.62). Chi square value revealed that resource population was not under Hardy-Weinberg equilibrium with respect to target locus. Period of birth was found to have significant effect on W-WT, Y-WT, BL, BH and PG. Sex of animal was found to have significant (P < 0.05) effect on W-WT and highly significant (P < 0.01) effect on 6 M-WT, Y-WT and AGFW in Harnali sheep. The effect of genotype was found to be significant (P < 0.05) on annual greasy fleece weight. AB genotype was found to be associated with higher annual greasy fleece weight and can be used as a potential candidate marker in selection criteria for improving greasy fleece weight in Harnali sheep.

Semen sexing and its impact on fertility and genetic gain in cattle

Semen sexing is among one of the most remarkable inventions of the past few decades in the field of reproductive biotechnology. The urge to produce offspring of a desired sex has remained since traditional times. Researchers have tried many methods for accurate semen sexing, but only the flow cytometry method has proved to be effective for commercial utilization. However, there were always concerns about the effects of sexed semen, especially on fertility and the rate of genetic gain. Some concerns were genuine because of factors such as low semen dosage in sexed semen straws and damage to sperm during the sorting process. Various researchers have conducted numerous studies to find out the effect of sexed semen on fertility and, in this article, we reflect on their findings. Initially, there were comparatively much lower conception rates (∼70% of conventional semen) but, with refinement in technology, this gap is bridging and the use of sexed semen will increase over time. Concerning genetic gain with use of sexed semen, a positive effect on rate of genetic progress with the use of sexed semen has been observed based on various simulation studies, although there has been a mild increase in inbreeding.

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.

Exploring MicroRNA biogenesis, applications and bioinformatics analysis in livestock: A comprehensive review

Small non-coding RNAs called microRNAs (miRNAs) control the expression of genes post-transcriptionally. Their correlation with commercial economic traits including milk, meat and egg production, as well as their effective role in animal productivity, fertility, embryo survival and disease resistance, make them significant in livestock research. The miRNAs exhibit distinct spatial and temporal expression patterns, offering insights into their functional roles within cells and tissues. Aberrant miRNA production can disrupt vital cellular processes and genetic networks, contributing to conditions like metabolic disorders and viral diseases. These short RNA molecules are present in extracellular fluids, displaying remarkable stability against RNA degradation enzymes and extreme environmental conditions. miRNAs preservation is facilitated through packaging in lipid vesicles or complex formation with RNA-binding proteins. Numerous studies have illuminated the roles of miRNAs in diverse physiological processes, including embryonic stem cell differentiation, haematopoietic stem cell proliferation and differentiation and the coordinated development of organ systems. The integration of miRNA profiling, next-generation sequencing and bioinformatics analysis paves the way for transformative advancements in livestock research and industry. The present review underscores the applications of miRNAs in livestock, showcasing their potential to improve breeding strategies, diagnose diseases and enhance our understanding of fundamental biological processes.

Population-wide genetic analysis of Ovar-DQA1 and DQA2 loci across sheep breeds in India revealed their evolutionary importance and fitness of sheep in a tropical climate

Genetic variability at the major histocompatibility complex (MHC) is important in any species due to significant role played by MHC for antigen presentation. DQA locus has not been studied for its genetic variability across sheep population in India. In the present study, MHC of sheep at DQA1 and DQA2 loci were evaluated across 17 Indian sheep breeds. Results revealed high degree of heterozygosity (10.34% to 100% for DQA1 and 37.39 to 100% for DQA2). 18 DQA1 alleles and 22 DQA2 alleles were isolated in different breeds. Nucleotide content for DQA region revealed richness of AT content (54.85% for DQA1 and 53.89% for DQA2). DQA1 and DQA2 sequences clustered independently. We could see evidence of divergence of DQA as DQA1 and DQA2 across sheep breeds. Wu-Kabat variability index revealed vast genetic variation across DQA1 and DQA2, specifically at peptide binding sites (PBS) that consisted 21 residues for DQA1 and 17 residues for DQA2. Evolutionary analysis revealed the presence of positive and balancing selection for DQA1 locus, however DQA2 was under purifying selection across sheep breeds. Higher heterozygosity and large diversity at both loci especially at PBS indicated the fitness of the sheep population for evading pathogens and adapt to the harsh tropical climate.

Expression profiling of immune genes associated with black pepper (Piper nigrum) powder supplementation in the diets of broiler chickens

The present study was conducted on three hundred commercial broiler chicks with the aim to evaluate the effect of black pepper supplementation on expression of TLR gene where the negative control (T1) group was given basal diet without antibiotic and in the control group (T2) basal diet with antibiotic was fed, third (T3), fourth (T4), fifth (T5) and sixth (T6) groups were supplemented with black pepper powder (BPP) at levels 0.25, 0.5, 0.75 and 1%, respectively in diet. After 42 days, a significant reduction (p < 0.05) in ileal E. coli count and a higher value of Lactobacilli was recorded in the various black pepper powder supplemented groups, and they differed significantly (p < 0.05) from negative control. The mRNA expression levels of Toll-like receptors (TLR 2 and TLR 4) had shown significant (p < 0.05) changes in experimental groups. The TLR 2 and TLR 4 genes revealed differential expression in all black pepper supplemented groups in comparison to negative control and control group, while TLR 7 did not show any significant change. Thus, supplementation of black pepper powder can be exploited as an immunomodulator to enhance adaptive immune response of broiler chicks after validation on large number of samples.

Cross-population genetic analysis revealed genetic variation and selection in the Ovar-DRB1 gene of Indian sheep breeds

In sheep, MHC variability is studied widely to explore disease association. The aim of the current study was to explore the genetic diversity of Ovar-DRB diversity across sheep breeds of India. Here, Ovar-DRB1 locus was studied across 20 sheep breeds. DRB1 was amplified (301 bp) and sequenced using a PCR-sequence-based typing approach. Results revealed a high degree of heterozygosity across breeds (mean: 73.99%). Overall mean distance for DRB1 was highest in Sangamneri (0.18) and lowest in Madgyal sheep (0.10). There was a higher rate of transition, across breeds. Further, 39 alleles were isolated in different breeds, out of which 10 were new. To allow easy access and use of the immune-polymorphic database, an online database management system was launched (http://www.mhcdbms.in/). Nucleotide content across breeds for the DRB1 region revealed the richness of GC content (59.26%). Wu-Kabat index revealed vast genetic variation across peptide binding sites (PBS) of DRB1. Residues 6, 66, 69, 52, and 81, were polymorphic showing utility for antigen presentation. All breeds were under positive selection for DRB1 locus (dN > dS). Study revealed the importance of DRB locus diversity for beta chain specifically at PBS across sheep breeds of the Indian subcontinent and presented evidence of positive selection for DRB owing to its evolutionary significance.

Candidate K232A mutation of DGAT1 gene associated with production and reproduction traits in Indian Dairy cattle

The present study was conducted on Hardhenu and Sahiwal cows to evaluate the genetic diversity and the effect of candidate K232A mutation of diacylglycerol O-acyltransferase (DGAT1) gene on performance traits. PCR product of 413 bp size targeting K232A mutation of DGAT 1 gene was genotyped by Eae1 restriction enzyme and further confirmed by sequencing. The PCR-RFLP analysis for K232A showed that the frequencies of alleles K and A were 0.80 and 0.20 in Hardhenu and 0.98 and 0.02 in Sahiwal cattle, respectively. The frequencies of genotypes for KK and KA genotype were estimated as 0.60 and 0.40 in Hardhenu and 0.96 and 0.04 in Sahiwal cattle, respectively. Chi-square test showed that K232A SNP did not meet with the Hardy-Weinberg equilibrium (p < .01) in Hardhenu cattle. Association analysis revealed that KA genotype was significantly associated with total milk yield (p < .01) and 305 days milk yield (p < .01)in Hardhenu cattle. Hardhenu cows having KA genotype comparatively revealed favorable mean values for AFS (880.31 ± 26.65), AFC (1166.36 ± 19.94), SP (157.46 ± 22.80), CI (441.41 ± 44.28) and AI/Conception (1.80 ± 0.17), indicating that KA genotype can be used as a candidate marker for simultaneous improvement of both production and reproduction traits.

Silver nanoparticle as an alternate to antibiotics in cattle semen during cryopreservation

The proposed study was to determine if the silver nanoparticles can be used as potential antimicrobial agents and can replace the use of conventional antibiotics in semen without affecting the motility and fertility of semen. The silver nanoparticles prepared by chemical reduction method were confirmed by determination of the wavelength of surface plasmon resonance peak and further characterized using Zetasizer by determining their size, polydispersity index, and zeta potential. The nanoparticles were assessed for antibacterial activity and their concentration was optimized for use in semen extender for cryopreservation. Cryopreserved semen was further evaluated for seminal parameters, antioxidant parameter, and microbial load. Prepared silver NPs showed a plasmon resonance peak at 417 nm wavelength. NPs were found to possess antibacterial activity and were supplemented in semen extender @ 125 and 250 µg/ml for semen cryopreservation. There was a significant increase in pre and post-freezing motility and other seminal parameters. The microbial load of frozen-thawed semen of control and supplemented groups were well within the permissible limits. Lipid peroxidation levels were reduced in NPs supplemented groups, and reactive oxygen species (ROS) levels were significantly reduced in semen supplemented with 125 µg/ml NPs. Thus it can be conclude that silver NPs can be successfully used as a substitute for antibiotics in cattle bull semen cryopreservation with good antimicrobial activity and no adverse effects on sperm characteristics.

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.

Investigating the impact of linseed supplementation, rich in omega-3 fatty acids, on the expression of immune genes in Beetal Goats

The present study investigated the effect of linseed supplementation on serum profiling and differential expression levels of IL-2 and TLR 2 genes involved in the immune system of lactating goats. The study was conducted on 15 lactating Beetal goats for 3 months, which were divided into three groups. Treatment group T1 was kept as a control group with no linseed supplementation, whereas treatment group T2 received ground linseed at the rate 10% of concentrate per day per animal, and treatment group T3 received 20% ground linseed. The concentration of triglycerides, cholesterol and LDL concentration were found to be significantly lower (P < 0.05) in both 10% and 20% linseed supplemented group than the control group. Whereas, HDL concentration in T2 and T3 group were found to be significantly higher than the control group. The differential expression of targeted genes comparatively revealed highest relative expression in the group that received 20% linseed supplementation. Although the study did not show a significant effect of linseed supplementation on the expression of TLR-2 and IL-2 genes in goats, it highlights the potential benefits of omega-3 PUFA supplementation on immune system modulation in animals.

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.

Modelling the growth curve and estimation of associated genetic parameters in Munjal sheep

The study of growth curves in sheep is an effective approach to monitor the animal development for predicting the growth rate and improving overall flock performance. The purpose of the present work was to study the growth curve traits of Munjal sheep using different non-linear models and to estimate the genetic parameters of those traits for the possibility of inclusion of them under selection strategy. Total 2285 weight records at birth, 3, 6 and 12 months of age of 706 lambs born to 48 sires and 149 dams were collected from the registers maintained from 2004 to 2019. Various non-linear growth models viz., Brody, Gompertz, logistic, Bertalanffy and negative exponential were fitted to targeted growth curve traits and then evaluated using goodness of fit criteria such as adjusted R², root means square error (RMSE), Akaike's information criterion (AIC) and Bayesian information criterion (BIC). The genetic parameters of growth curve traits were estimated using animal model. The results suggested that Brody model was best fitted to the data than other models. The growth curve estimates for mature weight (A), inflexion point (B) and rate of maturation (k) under Brody model were 25.82 ± 1.72, 0.84 ± 0.04, and 0.21 ± 0.04, respectively for female lambs, and 29.55 ± 2.04, 0.86 ± 0.03 and 0.19 ± 0.04, respectively for male lambs. The males showed superiority for mature weights whereas female lambs had higher maturation rates. The estimates of direct heritability for A, B and k were 0.33, 0.41 and 0.10, respectively. The moderate estimate of direct heritability of A and its negative genetic correlation with k indicated the scope of genetic improvement through selection based on mature weights. Therefore, it was concluded from the present findings that Brody model was the one that best describes the growth curve in the Munjal sheep and the selection based on mature weights can be employed for genetic improvement of Munjal flock.

Estimation of inbreeding and its effects on growth traits in Beetal goat

The purpose of the present study was to estimate the inbreeding coefficient and its effects on various growth traits in Beetal goat using pedigree records of 963 kids born to 38 sires and 287 dams over the period of 2004 to 2019. The inbreeding coefficients for each individual were obtained under animal model. The effects of inbreeding along with other fixed effects such as year of birth, sex of kid, type of birth, and dam's weight at kidding on growth traits viz., weight at birth (BWT), 3 (WT3), 6 (WT6), 9 (WT9), and 12 (WT12) months of age were studied using least-squares analysis. Additionally, average daily gain and Kleiber ratio up to weaning age (90 days) were studied under the same model. The overall inbreeding coefficient was low in magnitude (1.42%) and ranged from 0 to 25% over the study period. The significant (P < 0.05) increase in average inbreeding coefficient (%) over the years was observed among the studied population. Although, the effects of various factors had significant (P < 0.05) influence on growth traits under least-squares model, the regression of targeted traits on inbreeding were non-significant (P > 0.05) and the same ranged from - 0.06 to 0.04. The present findings indicated that there was no inbreeding depression among the growth traits of Beetal goat. However, as inbreeding (%) raised in recent years only, the scientific efforts must be taken to avoid inbreeding at resourced population by introducing new germplasms at earliest.

Neural network and Bayesian-based prediction of breeding values in Beetal goat

The estimation of breeding values is prime concern for animal breeders in order to achieve desired genetic progress of farm animals. However, current methods for estimating BV involve simultaneous selection of animal model which are computationally intensive and time-consuming. The present attempt was made to predict breeding values of weaning trait under artificial neural networks (ANN), Bayesian technique (BT), and multiple regression (MR) methods. The data records comprising year of birth, sex, type of birth, dam's weight at kidding, birth weight, weaning weight, and estimated breeding values (BV) for weaning weight (under animal model) pertaining to 849 kids born to 37 sires and 237 dams between 2004 and 2019 were used in this study. All three methods, viz., ANN under multilayer perceptron (2 hidden layers), BT under Markov chain Monte Carlo (MCMC) approach, and MR under full model, were used for 75% training dataset initially and prediction model developed was applied on 25% test dataset. The initial analysis showed positive and significant (P < 0.01) relationship of BV with other variables which hinted that BV may be predicted with accuracy. Then, it was revealed from the results indicated that ANN, BT, and MR methods have similar accuracy (r = 0.86 to 0.87) for prediction of BV. However, ANN showed slightly higher but negligible model adequacy than BT and MR method. The prediction error under three methods was almost equal. The results indicated that these methods could be used as potential alternative for recurrent prediction of BV based on phenotypic data in order to optimize selection plans at young age in resourced population of Beetal goat.

Investigation of cause-specific pre-weaning mortality in Harnali sheep

Lamb mortality is an important aspect in sheep production system which affects farm profitability worldwide. The aim of the present study was to investigate the causes of pre-weaning mortality (PWM) in Harnali lambs with respect to various associated factors. The data records of 173 lambs which died before 90 days of age (weaning age) out of 2057 lambs born during 2001-2020 year were collected from various registers, and the respective causes of mortality were taken from the post-mortem reports. The association of various factors such as age, sex, period of birth, birth weight of lamb and causes of death with PWM was assessed using chi-square test and log-linear modelling. The results showed that respiratory and digestive diseases were major causes of PWM. The log-linear modelling showed significant (P < 0.05) association of age, sex and period of birth with PWM. In the first month of age, digestive disease was the predominant cause of death; however, with age of lamb advances, respiratory disease was more prevalent. It was also revealed that male lambs (odds ratio (OR) = 0.48, 95% confidence interval (CI) = 0.24, 0.97) had lesser deaths due to respiratory diseases as compared to digestive disease. The reverse scenario was observed in female lambs. The findings of the present study might be helpful for understanding the risks and common causes of PWM in lambs to implement appropriate management practices in order to reduce economic losses to sheep farmers.

Meta-analysis of MspI derived variants of growth hormone gene associated with milk yield in dairy cattle

OBJECTIVE

The present work aimed to obtain common effect sizes for the gene frequency and association of MspI derived variants of growth hormone (GH) gene with milk yield in dairy cows.

METHODS

We performed a systematic review and meta-analysis of 35 published studies identified in literature search from 2000 to 2020 (n = 4164). These studies were specific to fragment size (329) for genotypes viz., CC (224, 105 bp), CD (329, 224, 105 bp) and DD (329 bp). Pooled standard mean differences (SMDs) as effect sizes between allele pairs were derived using different genetic models. The heterogeneity between effects sizes across studies was estimated using I² Index (%).

RESULTS

The common effect size for gene frequency of allele C (224, 105 bp) was significantly (P < 0.05) higher in 2881 Bos taurus/cross cows (0.82; 95% CI: 0.74, 0.89; I² = 97.81%) than 1283 Bos indicus cows (0.15; 95% CI: 0.12, 0.18; I² = 71.90%), with overall gene frequency was 0.33 (95% CI: 0.21, 0.46; I² = 99.29%). Additive (CC vs. DD) and dominant (CC + CD vs. DD) did not revealed significant (P > 0.05) association with milk yield. However, completely over dominant (CC + DD vs. CD) and recessive (CC vs. CD + DD) models showed significant (P < 0.05) and positive SMDs with milk yield specially at early lactations. There was no evidence of heterogeneity (I² = 0.00%) between SMDs across studies.

CONCLUSIONS

This meta-analysis suggested potential association of C allele for enhancing milk production of dairy cows.

Effect of biostimulation on growth rate and reproductive development of Bos indicus dairy heifers

The present study aimed to compare the growth rate, feeding behavior, reproductive development, and concentrations of GH and leptin in Sahiwal heifers exposed to direct bull contact, bull contact through a fenceline, or isolated from bulls. Overall, 24 heifers were allotted to three treatment groups (n = eight/group) based on birth weight, body weight, and age. Heifers from the non-exposed group (NBE) remained isolated from bulls; heifers stimulated by fenceline bull contact (FBE) remained continuously exposed to bulls through a fenceline, and heifers with direct bull contact (DBE+FBE) had direct contact with a bull during 6 h/day plus continuous fenceline bull exposure for the entire 24 h period. It was considered that heifers attained puberty when progesterone concentration was >1 ng/mL. Biostimulated heifers achieved puberty at both a lower age and body weight (P < 0.05) than NBE heifers. Overall, average daily gain (g/day) was greater in DBE+FBE (516.3 ± 4.5) and FBE (501.6 ± 4.3) than in NBE (441.8 ± 2.9, respectively; P < 0.01). Leptin and growth hormone concentrations were significantly greater in FBE and DBE+FBE than NBE heifers. Both groups of biostimulated heifers devoted more time eating than NBE heifers, P < 0.05). In conclusion, biostimulation of Sahiwal heifers, either by exposing them to bulls through a fenceline or by both fenceline exposure and direct contact, reduced the age of puberty and increased growth performance. Overall, fenceline bull exposure can be recommended as an easy handling management to stimulate reproductive precocity and growth rate in heifers.

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.

Evaluation of candidate point mutation of Kisspeptin 1 gene associated with litter size in Indian Goat breeds and its effect on transcription factor binding sites

Kisspeptin gene (Kiss1) has a significant role in reproductive processes in mammals. However, only little information is available about the association of Kiss1 gene with litter size in Indian goat breeds. Thus, blood samples from 285 randomly selected animals were collected for DNA isolation and SNP profiling. The PCR product of 242 bp size harboring g.2540C>T mutation of Kiss1 gene was digested with the restriction enzyme Sac1. Least squares analysis revealed that Barbari goats showed significantly higher average litter size (2.86±0.08) compared to Beetal, Sirohi and Sojat breeds (P < 0.01). SNP locus g.2540C>T of Kiss1 gene also showed significant effect on litter size (P < 0.01). Goats with Genotype CT (2.66 ± 0.07) and TT (2.67 ± 0.26) had significantly higher (P < 0.01) litter size than CC (1.50 ± 0.05). From the transcription factor binding site analysis, it was predicted that due to g.2540C>T SNP, both native and mutant variant forms coded for putative binding sites for different transcription Factor. Allele T had putative binding sites for the androgen receptor which plays a significant role in the signaling pathway involved in increase in ovulation rate; which consequently can have a tremendous effect on average litter size.

Influence of maternal and additive genetic effects on lamb survival in Harnali sheep

Lamb survival is a critical aspect in the sheep industry as it increases the chances of economic gain in the flock. The objective of the current study was to assess the incidence of lamb mortality in Harnali sheep and to estimate maternal and additive genetic effects of lamb survival using the data of 2057 lambs born to 134 sires and 623 dams for the period of 20 years (2001-2020). The genetic evaluation was carried out using threshold animal models comprising direct and maternal effects using THRGIBBS1F90 and POSTGIBBSF90 programs. Cumulative mortality (95% CI (confidence interval)) for the S1 (lambs which died up to weaning age), S2 (lambs which died from birth to 6 months of age) and S3 (lambs which died from birth to 12 months of birth) groups was 8.41 (7.21-9.61), 14.10 (12.59-15.60) and 17.70 (16.05-19.34) %, respectively. The logistic regression analysis revealed significant (p < 0.05) influences of non-genetic factors and indicated that the female lambs, heavier dam and higher birth weight of lamb were associated with better survival as compared to their counterparts. The estimates of direct additive heritability for S1, S2 and S3 were 0.04 ± 0.01, 0.07 ± 0.03 and 0.11 ± 0.04, respectively. In addition to this, significant influences of the maternal permanent environmental effects were observed for lamb survival up to weaning as well as six months of age. Thus, the present findings suggest that lamb survival could be improved through better management practices but consideration of maternal permanent environmental effects is important for initial survival of the lamb.

Effect of BsaA I genotyped intronic SNP of leptin gene on production and reproduction traits in Indian dairy cattle

In the present study, candidate single nucleotide polymorphism (SNP) g.92450765 G > A of leptin gene was explored for Bos indicus cattle with an aim to explore its possible effect on production and reproduction traits. The genotypic and allelic frequencies of BsaA 1 genotyped SNP g.92450765 G > A indicated the predominance of AG (0.65) genotyped Sahiwal cows in our studied population. The least-squares analysis showed a significant association (p < 0.05) of identified genetic variants with total milk yield (TMY) and 305 days milk yield (MY) (p < 0.05). The GG genotyped cows were found to be associated with higher milk yields. However, for reproduction traits under study AA genotype was found to be more favorable with respect to service period and calving interval (p < 0.05). Computational analysis was also performed to predict changes if any in the transcription factor binding sites (TFBS) caused due to the identified SNP in the intronic region of the leptin gene. TFBS analysis predicted that the targeted SNP at g.92450765G > A may lead to the disappearance of TFBS such as Hypermethylated in cancer 2 protein (HIC2), Max-binding protein MNT (MNT), Cyclic AMP-dependent transcription factor -3 (ATF3), Myc-associated factor X (MAX) and Microphthalmia-associated transcription factor (MITF). It may lead to changes in transcriptional regulation.

Evaluating advanced computing techniques for predicting breeding values in Harnali sheep

Advanced computing techniques have been used by animal researchers to understand the intricate data structures for deriving the most reliable allusions of populations in order to conserve genetically superior animals. The present attempt was made to evaluate the potential of two advanced techniques, artificial neural networks (ANN) and Bayesian technique (BT), for predicting breeding values (BV) of weaning weight (WWT) using data of 498 lambs born to 41 sires and 173 dams in Harnali sheep for the period from 2014 to 2019. The estimated BV for WWT was initially obtained using univariate animal model under restricted maximum likelihood procedure. ANN using multilayer perceptron with two hidden layers was fitted to training set (75%) of estimated BV to predict BV for test set (25%). Similarly, BT using Markov chain Monte Carlo (MCMC) method was also fitted to similar datasets. The high accuracy of prediction, i.e., correlation between BV and predicted BV, was observed as 0.89 and 0.90 under ANN and BT, respectively. Further, similar ranges of goodness of fit criteria, viz., R², root mean square error (RMSE), mean absolute error (MAE), and bias, indicated that both ANN and BT had similar prediction ability, which was also confirmed by 10-fold cross-validation. The present study indicated high capability and analogous model adequacy for both techniques that can be exploited in selection programs.

Influence of maternal and additive genetic effects on offspring growth traits in Beetal goat

The purpose of the present study was to obtain estimates of variance components and genetic parameters for direct and maternal effects on various growth traits in Beetal goat by fitting four animal models, attempting to separate direct genetic, maternal genetic and maternal permanent environmental effects under restricted maximum likelihood procedure. The data of 3,308 growth trait records of Beetal kids born during the period from 2004 to 2019 were used in the present study. Based on best fitted models, the direct additive h² estimates were 0.06, 0.27, 0.37, 0.17 and 0.10 for birth weight (BWT), weight at 3 (WT3), 6 (WT6), 9 (WT9) and 12 (WT12) months of age, respectively. Maternal permanent environmental effects significantly contributed for 10% and 7% of total variance for BWT and WWT, respectively, which reduced direct heritability by 40 and 10% for respective traits from the models without these effects. For average daily gain (ADG1) and Kleiber ratios (KR1) up to weaning period (3 months) traits, maternal permanent environmental effects accounted for 7% and 8% of phenotypic variance, respectively, and resulted in a reduction of 6.6% and 5.4% in direct h² of respective traits. For post-weaning traits, the maternal effects were non-significant (p > .05) which indicates diminishing influence of mothering ability for these traits. High and positive genetic correlations were obtained among WT3-WT6, WT6-WT9 and WT9-WT12 with correlations of 0.96 ± 0.25, 0.84 ± 0.23 and 0.90 ± 0.13, respectively. Thus, early selection at weaning age can be practised taking into consideration maternal variation for effective response to selection in Beetal goat.

Meta-analysis of SNP in growth hormone gene associated with milk traits in dairy cows

Previous studies reported varied findings regarding growth hormone polymorphisms and their association with milk traits in dairy cattle. The objective of the present study was to combine the information of Alu1-derived gene polymorphisms of growth hormone in 6571 dairy cows using 51 published studies for obtaining pooled estimate of gene frequency of L allele in dairy cows and for deriving common effect size of association of gene variants with various milk traits (lactation milk yield, fat yield, fat%, protein yield, and protein%) using meta-analysis. The pooled estimate of gene frequency was obtained using proportion as effect size with 95% confidence interval under random effects model. For association analysis, standardized mean difference was employed as effect size under four genetic models comprising additive (LL vs. VV), dominant (LL + LV vs. VV), completely over dominant (LL + VV vs. LV), and recessive (LL vs. LV + VV). The heterogeneity between studies was estimated using Q test and I² statistic. The results showed that pooled estimate of gene frequency of L allele was 0.81 (95% CI: 0.77, 0.85; I² = 96.86%). Subgroup analysis revealed that it was significantly higher in Bos indicus cows (0.97, 95% CI 0.89, 1.00; I² = 95.15%) than Bos taurus/cross cows (0.78, 95% CI 0.73, 0.82; I² = 96.84%). An association analysis showed that the effects of GH variants on milk-related traits were not significant (P > 0.1) under all genetic models. Substantial range of heterogeneity indicated modest effects of SNP genotypes with milk traits. It was concluded that although allele L is predominant than V allele of GH in dairy cows over large geographical populations, they may not be particularly useful for selection programs for improving milk traits in dairy cows.

Evaluation of candidate genes related to litter traits in Indian pig breeds

Improvement in litter traits is the key to profitable pig farming that directly enhances the economic standing of the farmers in developing countries. The present study aimed to explore oestrogen receptor (ESR), epidermal growth factor (EGF), follicle-stimulating hormone beta subunit (FSHβ), prolactin receptor (PRLR) and retinol-binding protein 4 (RBP4) genes as possible candidate genetic markers for litter traits in indigenous pigs of India. The breeds included in the study were Ghungroo, Mali, Niang Megha and Tenyi Vo, and the reproductive traits considered were litter size at birth (LSB), number born alive (NBA), litter weight at birth (LWB), litter size at weaning (LSW) and litter weight at weaning (LWW) at their first parity. PCR-RFLP and primer-based mutation detection methods were used to identify polymorphism, and associations between the genotypes and the traits were analysed using a general linear model. The Ghungroo pigs recorded the best litter performances among the breeds (p < .05, LWB p < .01). Different alleles and genotypes of the genes under study were detected. Short interspersed nuclear element (SINE) -/- genotype of FSHβ revealed significantly higher litter traits (p < .05, LSB p < .01). The LWW was also found to be significantly influenced by ESR BB and AB, EGF AB and BB, and PRLR CC genotypes (p < .05). Although we did not find statistically significant and consistently superior litter traits with respect to different genotypes of other studied genes than genotype SINE -/- of the FSHβ, PRLR CC genotype demonstrated superior performances for all the litter traits. Our study revealed the FSHβ as a potential candidate genetic marker for litter traits in indigenous pig breeds of India.

Meta-analysis of Genetic Structure and Association of Prolactin Gene with Performance Traits in Dairy Cattle in India

The present meta-analysis was carried to provide the more reliable estimates of gene frequency and association of Rsa 1 generated candidate genotype of prolactin gene within exon-3 with performance traits in 1198 Indian dairy cows using data from 15 published studies. Six genetic models viz., codominant (AA vs. AB, AA vs. BB and AB vs. BB), dominant (AA+AB vs. BB), completely over dominant (AA+BB vs. AB) and recessive (AA vs. AB+BB) were used to obtain standardized mean difference (SMD) between genotypes. Meta-analysis showed that the gene frequency of A allele (156 bp) was 0.60 (95% confidence interval (CI) 0.54, 0.65). In association analysis, cows with AB genotype [SMD = 0.65, 95% CI 0.00, 1.30] had significantly (P < 0.05) higher lactation milk yield (LMY) as compared to BB genotype, whereas AA and AB genotypes had similar trend. Likewise, AA + AB also had larger effect [SMD = 2.31, 95% CI 0.21, 4.10] on LMY as compared to BB. Cows with AB genotype had significantly lower age at first calving (AFC) with small effect [SMD (AA vs. AB) = 1.38, 95% CI 0.06, 2.70] and medium effect [SMD (AB vs. BB) =  - 3.83, 95% CI - 6.41, - 1.24] as compared to cows with AA and BB genotypes, respectively. This finding was confirmed under dominant and completely over dominant models. In case of fat%, AA genotype showed negative effect (SMD =  - 0.51, 95% CI - 0.84, - 0.17) under recessive model. It was concluded that the propagation of allele A is promising to help dairy farmers to improve the genetic quality of their dairy cows.

Evaluation of candidate genotype of leptin gene associated with fertility and production traits in Hardhenu (Bos taurus × Bos indicus) cattle

The present study was conducted on Hardhenu cattle to screen genomic region of leptin gene with an objective to find the association of genotypes with fertility and production traits. The association analysis with traits under study was analysed by least squares analysis of variance by taking SNPs genotype as fixed effects in the statistical model. The genotypic frequencies with respect to targeted loci g.92450765 G > A indicated that AG (0.54) genotype was highest in Hardhenu cattle. Chi-squared tests showed that g.92450765G > A SNP meet with the Hardy-Weinberg equilibrium (p > .05).The association analysis revealed significant association of genotypes with total milk yield (TMY) and 305 days milk yield (MY) (p < .05). Service period (SP) and calving interval (CI) were also found significantly associated with genotypes (p < .05). Whereas, lactation length (LL), dry days (DD) and age at first calving (AFC) did not divulge any significant association with genotype. The AG and GG genotypes were associated with higher milk yields as compared to AA genotype, indicating that allele G was associated with superior milk performance. However, AA genotyped cattle found to be favourable with SP, CI and artificial insemination (AI) per conception compared to AG and GG genotyped cows. Chi-square analysis revealed that genetic variants of g.92450765 G > A SNP of leptin gene differ significantly with regard to reproductive disorders incidence (p < .05). The frequency of GG genotype (88.89%) in the affected animal group was very high followed by AG. The animals with GG genotype were found to be more susceptible to reproductive disorders as suggested by the higher odd ratio value (16.00) in logistic model. These observations and their differential association with the fertility and production traits can be utilized as an aid to selection for genetic improvement of antagonistic traits in dairy cows.

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

The present study was conducted on Karan Fries cows to identify SNPs in breast cancer 1 (BRCA1) gene and their association with inflammation of mammary gland and production traits. Chi square analysis showed significant association of both SNPs i.e. G43737229T (P < 0.01) and G43761121A (P < 0.05) with incidence of clinical mastitis. Logistic modeling showed that GG genotype cows of G43737229T SNP was less susceptible to mastitis in comparison to TT genotype cows as the odds ratio of TT against GG for the non-incidence of mastitis was less i.e. 0.23. Whereas, cows with genotype AA of G43761121A SNP were less prone to clinical mastitis in comparison to GG genotype cows. G-T haplotype and GGTT combined genotype exhibited maximum mastitis incidences. Least squares analysis revealed significant association of G43737229T SNP with total milk yield (P < 0.01), 305 days milk yield (P < 0.01) and lactation length (P < 0.05). The TT and GT genotyped Karan Fries cows were associated with higher milk yields during first and second lactation, as well as with first lactation length. These observations on SNPs, genotypes and combined genotypes of BRCA1 gene and their differential association with the incidence of mastitis and production traits can be utilized as an aid to selection for simultaneous improvement of both antagonistic traits.

Genotype of MTNR1A gene regulates the conception rate following melatonin treatment in water buffalo

Buffaloes have tendency to show seasonal reproduction and remain in anestrus due to limited ovarian activity during summer. The seasonal reproductive behavior is ascribed the effect of melatonin related to photoperiod. Treating animals with melatonin could be a possible strategy to overcome the problem. The role of MTNR1A gene has not been fully explained in the buffalo. Therefore, we conducted a study on 114 buffalo heifers to detect the polymorphic site in MTNR1A gene and further treated them with melatonin implants to investigate the role of most frequent genotype following melatonin treatment on pregnancy. The present investigation is the first to investigate the association between melatonin treated different MTNR1A genotype buffalo and pregnancy. We confirmed SNP at position 72 in 812 bp fragment exon II of MTNR1A gene. RFLP of PCR products with Hpa I enzyme resulted in three genotypes: TT (812bp), CT (812, 743, 69bp) and CC (743, 69bp). Next, buffaloes of each genotype (TT, CC, CT; n = 28 for each) were treated with melatonin implants to compare the conception rate with their corresponding untreated control (n = 10 for each genotype). Melatonin concentrations were higher (P < 0.05) for the treatment groups of all genotypes compared to their respective untreated control from day 1-28. The pregnancy rate was significantly associated with the MTNR1A genotype. The conception rate was higher (P < 0.05) for TT genotype than for the other genotypes of buffaloes treated with melatonin. Furthermore, buffaloes of TT genotype treated with melatonin started exhibiting estrus activity soon from second week of melatonin treatment (14.1 ± 2.1; range: 10-17 days) and were found to be 7.8 times more likely to become pregnant compared to other genotypes following melatonin treatment. In conclusion, TT genotype of MTNR1A gene is more sensitive to melatonin treatment that favours pregnancy in buffaloes during summer.

Candidate SNP of CACNA2D1 Gene Associated with Clinical Mastitis and Production Traits in Sahiwal (Bos taurus indicus) and Karan Fries (Bos taurus taurus × Bos taurus indicus)

The present study was conducted to identify polymorphisms in CACNA2D1 gene and their association with clinical mastitis and production traits. Exon 18 and its flanking regions were screened for the presence of SNPs. Statistical analysis was performed to identify association of period of birth, breed, and genotype with mastitis incidence on randomly selected 103 Sahiwal and 102 Karan Fries cattle. PCR-RFLP analysis revealed that g.38819398G > A mutation in exon 18 (269 bp amplicon) of CACNA2D1 gene resolved into AA, AG, and GG genotypes in Sahiwal and Karan Fries cattle. Wald chi-square analysis revealed that the period of birth, breed, and genotype were significantly associated with mastitis incidence. GG genotyped cattle were found to be less susceptible to mastitis. Least square analysis revealed that GG and AG genotype animals of G38819398A SNP of CACNA2D1 gene in Sahiwal as well as in Karan Fries cattle were associated with higher average milk yields during 1st, 2nd, and 3rd lactations (P < 0.01). These observations and their differential association with the incidence of mastitis and production traits can be utilized as an aid to selection for simultaneous improvement of both antagonistic traits; however, validation of results on large number of animals is warranted.

Molecular characterization and combined genotype association study of bovine cluster of differentiation 14 gene with clinical mastitis in crossbred dairy cattle

Aim:

The present study was undertaken with the objectives to characterize and to analyze combined genotypes of cluster of differentiation 14 (CD14) gene to explore its association with clinical mastitis in Karan Fries (KF) cows maintained in the National Dairy Research Institute herd, Karnal.

Materials and Methods:

Genomic DNA was extracted using blood of randomly selected 94 KF lactating cattle by phenol-chloroform method. After checking its quality and quantity, polymerase chain reaction (PCR) was carried out using six sets of reported gene-specific primers to amplify complete KF CD14 gene. The forward and reverse sequences for each PCR fragments were assembled to form complete sequence for the respective region of KF CD14 gene. The multiple sequence alignments of the edited sequence with the corresponding reference with reported Bos taurus sequence (EU148610.1) were performed with ClustalW software to identify single nucleotide polymorphisms (SNPs). Basic Local Alignment Search Tool analysis was performed to compare the sequence identity of KF CD14 gene with other species. The restriction fragment length polymorphism (RFLP) analysis was carried out in all KF cows using Helicobacter pylori 188I (Hpy188I) (contig 2) and Haemophilus influenzae I (HinfI) (contig 4) restriction enzyme (RE). Cows were assigned genotypes obtained by PCR-RFLP analysis, and association study was done using Chi-square (χ²) test. The genotypes of both contigs (loci) number 2 and 4 were combined with respect to each animal to construct combined genotype patterns.

Results:

Two types of sequences of KF were obtained: One with 2630 bp having one insertion at 616 nucleotide (nt) position and one deletion at 1117 nt position, and the another sequence was of 2629 bp having only one deletion at 615 nt position. ClustalW, multiple alignments of KF CD14 gene sequence with B. taurus cattle sequence (EU148610.1), revealed 24 nt changes (SNPs). Cows were also screened using PCR-RFLP with Hpy188I (contig 2) and HinfI (contig 4) RE, which revealed three genotypes each that differed significantly regarding mastitis incidence. The maximum possible combination of these two loci shown nine combined genotype patterns and it was observed only eight combined genotypes out of nine: AACC, AACD, AADD, ABCD, ABDD, BBCC, BBCD, and BBDD. The combined genotype ABCC was not observed in the studied population of KF cows. Out of 94 animals, AACD combined genotype animals (10.63%) were found to be not affected with mastitis, and ABDD combined genotyped animals was observed having the highest mastitis incidence of 15.96%.

Conclusion:

AACD typed cows were found to be least susceptible to mastitis incidence as compared to other combined genotypes.

Novel SNP identification in exon 3 of HSP90AA1 gene and their association with heat tolerance traits in Karan Fries (Bos taurus × Bos indicus) cows under tropical climatic condition

Heat shock proteins (HSPs) act as molecular chaperones those are preferentially transcribed in respose to heat stress and the polymorphism in HSP genes associated with heat tolerance traits in cows. HSP90AA1 gene has been mapped on Bos taurus autosome 21 (BTA-21) and spans nearly 5368 bp comprising of 11 exons out of which the first exon does not translate. The present study was done on Karan Fries (5/8 HF × 3/8 Tharparkar) cows reared in tropical climate with the objectives of identifying single-nucleotide polymorphisms (SNPs) in targeted regions (exon 3) of HSP90AA1 gene and analyzing their association with heat tolerance traits in Karan Fries cows. Respiration rate (RR) and rectal temperature (RT) were recorded once daily for four consecutive days during probable extreme hours in different seasons or temperature humidity index (THI), viz., winter, spring, and summer. For detecting single-nucleotide polymorphisms, sequence data were analyzed using BioEdit software (version 7.2). Comparative sequence analysis of HSP90AA1 gene showed point mutation, viz., g.1209A>G (exon 3) as compared to Bos taurus (NCBI Ref Seq: AC_000178.1). Association analysis indicated that THI was influenced (P < 0.01) by RR, RT, and HTC. Similarly, SNPs at locus g.1209A>G were categorized into three genotypes, i.e., AA, AG, and GG, and the least squares means (LSMEANS) of RR, RT, and HTC for GG (homozygous) genotype were significantly lower (P < 0.01) than AA (homozygous) and AG (heterozygous) genotypes. These findings may partly suggest that cows with GG genotypes were favored for heat tolerance trait, which can be used as an aid to selection for thermo-tolerance Karan Fries cows for better adaptation in subtropical and tropical hot climate.

Characterization and validation of point mutation in exon 19 of CACNA2D1 gene in Karan Fries (Bos taurus x Bos indicus) cattle

The objective of this study was to characterize and validate the candidate point mutation in Calcium channel, voltage-dependent, alpha-2/ delta subunit 1 (CACNA2D1) gene in Karan Fries (Bos taurus x Bos indicus) cattle. The CACNA2D1 gene reported as one of the potential candidate gene influencing Somatic cell Score and Mastitis. A PCR product of 249 bp amplifying the exon 19 and partial 18 and 19 intronic region of CACNA2D1 gene was digested with Hae III restriction enzyme to screen the reported point mutation. A monomorphic banding pattern with genotype AA was found in Karan Fries cattle. Sequencing was also carried out to characterize and explore insilico screened mutation in the nucleotide sequence of a particular region. The result indicates highly conserved sequence in Karan Fries cattle. The Phylogenetic tree revealed that Karan Fries cattle were closer to Bos taurus cattle, Bos mutus (Yak), and Bison bison (American buffalo) compared to other species.

Genome-wide analysis of the heat stress response in Zebu (Sahiwal) cattle

Environmental-induced hyperthermia compromises animal production with drastic economic consequences to global animal agriculture and jeopardizes animal welfare. Heat stress is a major stressor that occurs as a result of an imbalance between heat production within the body and its dissipation and it affects animals at cellular, molecular and ecological levels. The molecular mechanism underlying the physiology of heat stress in the cattle remains undefined. The present study sought to evaluate mRNA expression profiles in the cattle blood in response to heat stress. In this study we report the genes that were differentially expressed in response to heat stress using global scale genome expression technology (Microarray). Four Sahiwal heifers were exposed to 42°C with 90% humidity for 4h followed by normothermia. Gene expression changes include activation of heat shock transcription factor 1 (HSF1), increased expression of heat shock proteins (HSP) and decreased expression and synthesis of other proteins, immune system activation via extracellular secretion of HSP. A cDNA microarray analysis found 140 transcripts to be up-regulated and 77 down-regulated in the cattle blood after heat treatment (P<0.05). But still a comprehensive explanation for the direction of fold change and the specific genes involved in response to acute heat stress still remains to be explored. These findings may provide insights into the underlying mechanism of physiology of heat stress in cattle. Understanding the biology and mechanisms of heat stress is critical to developing approaches to ameliorate current production issues for improving animal performance and agriculture economics.