Assessing lameness prevalence and associated risk factors in crossbred dairy cows across diverse management environments.

BACKGROUND: A thorough understanding of lameness prevalence is essential for evaluating the impact of this condition on the dairy industry and assessing the effectiveness of preventive strategies designed to minimize its occurrence. Therefore, this cross-sectional study aimed to ascertain the prevalence of lameness and identify potential risk factors associated with lameness in Holstein Friesian crossbred cows across both commercial and smallholder dairy production systems in Bengaluru Rural District of Karnataka, India. METHODS: The research encompassed six commercial dairy farms and 139 smallholder dairy farms, involving a total of 617 Holstein Friesian crossbred cattle. On-site surveys were conducted at the farms, employing a meticulously designed questionnaire. Lameness in dairy cattle was assessed subjectively using a locomotion scoring system. Both bivariate and binary logistic regression models were employed for risk assessment, while principal components analysis (PCA) was conducted to address the high dimensionality of the data and capture the underlying structure of the explanatory variables. RESULTS: The overall lameness prevalence of 21.9% in commercial dairy farms and 4.6% in smallholder dairy farms. Various factors such as age, body weight, parity, body condition score (BCS), floor type, hock and knee injuries, animal hygiene, provision of hoof trimming, and the presence of hoof lesions were found to be significantly associated with lameness. Binary logistic regression analysis indicated that the odds of lameness in crossbred cows increased with higher parity, decreased BCS, presence of hard flooring, poor animal hygiene, and the existence of hoof lesions. These factors were identified as potential risk factors for lameness in dairy cows. Principal component analysis unveiled five components explaining 71.32% of the total variance in commercial farms and 61.21% in smallholder dairy farms. The extracted components demonstrated higher loadings of housing and management factors (such as hoof trimming and provision of footbath) and animal-level factors (including parity, age, and BCS) in relation to lameness in dairy cows. CONCLUSIONS: The findings suggest that principal component analysis effectively reduces the dimensionality of risk factors. Addressing these identified risk factors for lameness is crucial for the strategic management of lameness in dairy cows. Future research in India should investigate the effectiveness of management interventions targeted at the identified risk factors in preventing lameness in dairy cattle across diverse environments.

Seasonal, physiological and bacteriological risk factors for subclinical mastitis in dairy cows maintained under different farming conditions.

Subclinical mastitis (SCM) is a major health problem of dairy animals in India and across the globe. An identification of potential risk factors of SCM can help for efficient udder health management in dairy animals. In this study, apparently healthy cows (HF crossbred: n = 45; Deoni: n = 43) were screened for SCM during different seasons through milk somatic cell count (SCC: reference test using 200 × 103 cells/ml as cut off value), California mastitis test (CMT) and differential electrical conductivity (DEC) test at an organized research farm. SCM positive milk samples (n = 34) were inoculated in selective media for Coliform sp., Streptococcus sp. and Staphylococcus sp. and DNA was isolated (n = 10) for species confirmation by 16s rRNA method. Both bivariate and multivariate models were used for risk assessment. We found the cumulative prevalence of 31 and 65% SCM in Deoni and crossbred cows, respectively. Screening of 328 crossbred cows under field conditions revealed point prevalence of 55% SCM. Multivariate analysis revealed stage of lactation (SOL), milk yield in previous lactation and test day milk yield in Deoni cows, as well as parity and mastitis treatment history in current lactation in HF crossbred cows as risk factors. SOL was a significant factor under field conditions. Receiver operated characteristic curve analysis revealed better accuracy of CMT than DEC. We found more mixed infections due to Staphylococcus sp. and Streptococcus sp. in culture, while 16s rRNA based molecular method revealed lesser-known pathogens associated with SCM. It is concluded that SCM prevalence rate is higher in crossbred than indigenous cows and these breeds have different risk factors for SCM. HF crossbred cows had similar SCM prevalence rate under different farming conditions, where CMT can be used for SCM diagnosis with excellent accuracy. The 16s rRNA method is useful for specific identification of lesser known and emerging mastitis pathogens.

Antimicrobials use and their indications in dairy farm and individual farmer production conditions in southern India.

Antimicrobials use (AMU) is the key driver for development of antimicrobials resistant (AMR) pathogen in human and veterinary medicines. Therefore, understanding AMU pattern is prerequisite for focused intervention on AMR. The aim of this study was to understand the AMU pattern and their indications in dairy farm and individual farmer production conditions in southern India. Treatment registers of 6 years (2012 to 2017) containing 3178 cases from dairy farm and 12,057 cases during 2017-2019 under individual farmer production conditions were collected and analyzed by log-linear model. Seasons were classified as rainy (Jul-Oct), winter (Nov-Feb), and summer (Mar-June) as per climatic conditions in the study area. It is observed that mastitis, lameness, and reproductive problems were major health disorders among treated animals in farm and individual farmer production conditions. Season had significant influence on proportional rates of various health disorders in crossbred cows under both the production conditions. AMU pattern was different between the breeds and production conditions. Antibiotics were the most commonly used group of drugs (23-28%) than non-steroidal anti-inflammatory drugs (20%), antihistamine (17%), and nutrient supplements (14-16%). Antibiotics were mostly used for mastitis (47-67%) than other conditions like fever (18%), reproductive problems (15%), and lameness (16%). For treating mastitis, cephalosporins and gentamicin were most commonly used under individual farmer production condition, while penicillin group was frequently used in farm. It is concluded that mastitis is the most common indication for AMU in dairy animals and thus developing appropriate guidelines for mastitis treatment and control is necessary to reduce overall AMU.

Sperm preparedness and adaptation to osmotic and pH stressors relate to functional competence of sperm in Bos taurus.

The adaptive ability of sperm in the female reproductive tract micromilieu signifies the successful fertilization process. The study aimed to analyze the preparedness of sperm to the prevailing osmotic and pH stressors in the female reproductive tract. Fresh bovine sperm were incubated in 290 (isosmotic-control), 355 (hyperosmotic-uterus and oviduct), and 420 (hyperosmotic-control) mOsm/kg and each with pH of 6.8 (uterus) and 7.4 (oviduct). During incubation, the changes in sperm functional attributes were studied. Sperm kinematics and head area decreased significantly (p < 0.05) immediately upon exposure to hyperosmotic stress at both pH. Proportion of sperm capacitated (%) in 355 mOsm/kg at 1 and 2 h of incubation were significantly (p < 0.05) higher than those in 290 mOsm media. The magnitude and duration of recovery of sperm progressive motility in 355 mOsm with pH 7.4 was correlated with the ejaculate rejection rate (R2 = 0.7). Using this information, the bulls were divided into good (n = 5) and poor (n = 5) osmo-adapters. The osmo-responsive genes such as NFAT5, HSP90AB1, SLC9C1, ADAM1B and GAPDH were upregulated (p < 0.05) in the sperm of good osmo-adapters. The study suggests that sperm are prepared for the osmotic and pH challenges in the female reproductive tract and the osmoadaptive ability is associated with ejaculate quality in bulls.

Orchestrating the expression levels of sperm mRNAs reveals CCDC174 as an important determinant of semen quality and bull fertility.

Bulls with acceptable semen quality vary in actual field fertility and this can be elucidated by studying the expression levels of mRNAs in the sperm. The present study aimed at assessing the variations in the sperm gene expression levels of PRM1, CCDC174, RPL36A, TMCO2, SWI5 and OIT3 in bulls differing in fertility status. Frozen semen samples from Holstein-Friesian bulls were classified into high-fertile (n = 8, average field conception rate = 46.1 ± 0.51, p < 0.001) and sub-fertile (n = 7, average field conception rate = 39.4 ± 0.69) groups. In the post-thaw semen samples, sperm kinematics, structural and functional membrane integrities, mitochondrial membrane potential and chromatin distribution were analyzed. The sperm total RNA was subjected to gene expression studies by Real-Time PCR. Multivariate regression analysis was performed using gene expression levels and conception rates. The sperm functional attributes did not differ significantly between the groups. The relative mRNA levels (fold change) of CCDC174 (6.20), RPL36A (4.66), SWI5 (1.86) and OIT3 (1.53) were higher in high-fertile bulls. Further, the expression level of the CCDC174 gene was significantly (p = 0.02) up-regulated in high-fertile bulls. The fertility prediction multivariate model with genes, CCDC174, RPL36A, TMCO2 and OIT3 had the maximum coefficient of determination (R2 = 0.68) with the field conception rate. This model had 93.3% bull fertility prediction accuracy with 100% sensitivity and 87.5% specificity. The study suggests that the expression level of CCDC174 can be used as a potential marker for assessing bull fertility.

Protective role of epigallocatechin-3-gallate on arsenic induced testicular toxicity in Swiss albino mice.

Arsenic, often referred to as the king of poisons is carcinogenic in humans and animals. It affects multiorgan systems including reproduction. The present study was undertaken to explore the protective role of green tea compound, epigallocatechin-3-gallate (EGCG) on arsenic induced testicular toxicity in Swiss albino mice. Thirty two adult male mice were randomly assigned to four groups (n=8). Group I served as control without test chemical. The group II received arsenic (200ppm) through drinking water, group III received only EGCG (20mg/kgb.wt., intraperitoneally, alternate days) and group IV was administered arsenic+EGCG for 40days. Factorial experimental design was employed to assess the treatment effect. The EGCG restored arsenic induced decrements in epididymal sperm concentration, kinematic attributes (total motility, rapid, progressive motile, fast progressive, VSL, VAP, VCL, BCF, LIN, WOB, STR and Type A), structutal membrane integrity, functional membrane integrity and mitochondrial membrane potential. As evidenced by the histoarchitectural studies, the EGCG reversed the deleterious effects of arsenic on testicular malondialdehyde (p<0.05) levels, reduced glutathione, antioxidative enzymes and spermatogenesis. Overall, the results suggest that EGCG reduces the testicular oxidative stress induced by arsenic poisoning and thereby protect the reproductive system.

Spermatozoal transcripts expression levels are predictive of semen quality and conception rate in bulls (Bos taurus).

Spermatozoal transcripts expression levels could be used to assess fertility potential of a male. The objective of the present study was to elucidate the predictive ability of the expression levels of growth, apoptosis and homeostasis regulating transcripts on sperm functions and fertility. The expression levels of spermatozoal RNA isolated from the neat semen samples were related to the good (discarded ejaculate, <25%; n = 7) and poor (discarded ejaculate, >40%, n = 6) quality semen producer and bulls (n = 12) with known conception rate. The relative fold expression levels of BMP2 were significantly (p < 0.01) higher in good than the poor semen producers and positively associated with post-thaw sperm velocity parameters (LIN and VAP). The NGF expressions fold levels had significant (p < 0.05) positive relationship with mitochondrial membrane potential of neat semen samples. The genes involved in the apoptotic, UBE2D3 (r = -0.61, p = 0.02), CASP3 (r = -0.57, p = 0.03) and homeostatic, HSFY2 (r = -0.61, p < 0.02) regulators had significant negative correlation with the percentage of post-thaw fast progressive motile spermatozoa. The expression level of TRADD had significant negative influence on the mitochondrial membrane potential (r = -0.54, p = 0.05) of neat semen samples and conception rate (r = -0.57, p < 0.05). The expression levels of BMP2 had highly significant positive correlation with NGF (r = 0.99, p < 0.01) and CASP3 (r = 0.56, p = 0.05). The BMP2 expression level might be used to predict the quality of the semen and TRADD determine the conception rate of the bull. The study provides ample evidence that the sperm transcripts expression levels might be used to predict quality semen production and bull fertility.