Bovine lymphocyte antigen (BoLA) DRB3 locus in healthy and mastitis affected cattle has been genotyped by a polymerase chain reaction and restriction fragment length polymorphisms (PCR-RLFP) using RsaI restriction enzyme, followed by sequencing. In 130 farm animals, 25 BoLA DRB3 alleles have been detected by PCR-RFLP. Three distinct allelic patterns significantly associated with mastitis in Karan Fries crossbred and Sahiwal indicus cattle have been identified, whereas, four other allelic patterns were significantly high in frequency among healthy animals. Sequencing of RFLP genotypes revealed 25 and 47 alleles among healthy Sahiwal and Karan Fries, respectively, while 17 and 38 patterns observed in mastitis affected Sahiwal and Karan Fries animals, respectively. From Tajima’s D-test of neutrality, it was concluded that alleles associated with mastitis were expanding in the population, whereas those of healthy were under contraction. Phylogenetic analysis carried out to delineate the evolutionary relationship of the farm and field animals at DRB3 locus, differentiating allelic patterns into six different clusters. Among the phylogenetic lineages, five patterns DRB3*028:01, DRB3*011:03, DRB3*031:01, DRB3*001:01 and DRB3*043:01, were previously reported, whereas one novel allelic variant was observed in indicus and crossbred cattle. This information will help in further exploring the association between BoLA-DRB3 genetic diversity and disease resistance in distinct cattle breeds, important in designing breeding strategies for increasing the distribution of favorable alleles.

Among different cattle types, Bos indicus are known for their ability to better resist the tropical microbial infections comparatively, wherein MHC molecules play a significant role. In this study allelic diversity at MHC locus, DQA of Bos indicus, Bos taurus and crossbred of taurine-indicus has been explored to understand the possible role of MHC region in differential immune response. Thirty nine different DQA alleles were identified, out of which 14 were novel, along with documentation of duplication of DQA alleles. Indicus cattle population presented diverse types of DQA alleles compared to crossbred and exotic. Translated amino acid sequence analysis indicated, codon 64 and 50 of peptide binding sites being highly polymorphic and most of the indicus cattle presented alanine and arginine amino acid at position 64 and 50. Within breed genetic variation found to be higher than between breeds. Because of their ability to bind and subsequently respond to a wide array of antigens, the newly identified DQA alleles with high diversity present in the form of duplicated haplotypes in different combinations in cattle populations provided significant insights into probable role of this MHC locus in better tropical disease combating ability and genetic fitness of indicus cattle.

The growing demand for robust food authentication methods has driven the establishment of fast, sensitive, and field-based detection systems for identifying meat species. This study presents a colorimetric-based PSR approach for identifying yak (Bos grunniens) meat within fresh, thermally processed, and blended meat samples. Targeting the mitochondrial D-loop locus, the assay incorporates a simple alkaline lysis (AL) procedure for efficient DNA extraction, eliminating the requirement for specialized instrumentation. The PSR assay demonstrated high specificity, showing no evidence of cross-reactivity with closely associated food animals such as buffalo, cattle, goat, sheep, mithun, and pig. Sensitivity assessment revealed the assay’s capability to detect 1 pg of yak DNA, with reliable performance in samples exposed to thermal conditions up to 121 °C. Additionally, the technique detected yak meat down to a concentration of 0.1% in binary beef mixtures. This method provides a significant improvement in sensitivity over end-point PCR and is particularly well-suited for field applications due to its practical simplicity, affordability, as well as no reliance on sophisticated instrument. This is, to the best of our understanding, the first reported PSR-based approach developed for the identification of yak meat, offering a robust tool for food origin verification, regulatory enforcement, and product integrity monitoring.

In the current study, genetic diversity analysis of MHC class II (DRB3) locus has been documented among indicus cattle breeds. Genotyping of 192 zebu cattle belonging to eight different breeds, was carried out to identify different allelic patterns by PCR-RFLP of BoLA DRB3 exon 2, revealing 43 different restriction patterns. Highest genetic diversity of BoLA-DRB3 gene was observed in Malnad Gidda and Gir and least in Mewati, Tharparkar and Sahiwal cattle. Allelic pattern, BM was the most frequently observed heterozygous pattern and with highest frequency among Mewati and Ladakhi cattle breeds. Few breed specific alleles also identified, which were found specifically in Tharparkar, Gir and Ongole breeds. This genetic information may be important for exploring the correlation between BoLA-DRB3 genetic diversity and disease susceptibility and overall allelic diversity status of the Indian cattle populations.

Expression analysis of immune response genes in the mammary gland tissues of both healthy and infected animals help to explain the genetic basis of differential immune response. This study was conducted to analyze the differential expression of MHC class II DRB3 gene, in mastitis-affected and healthy animals of indicus (Sahiwal) and crossbred (Karan Fries) cattle. Real-time PCR was performed on the cDNA synthesized from the RNA isolated from PBMCs of the mastitis and healthy animals. However, no significant difference was observed in the expression of DRB3 in the two populations. The results point towards polymorphism supposed to be playing major role in differential immune response, rather than the expression of DRB3 gene as far as state of udder health is concerned.