Association study of genetic variants at single nucleotide polymorphism rs109231409 of mannose-binding lectins 1 gene with mastitis susceptibility in Vrindavani crossbred cattle

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.

Molecular markers for resistance against infectious diseases of economic importance

Huge livestock population of India is under threat by a large number of endemic infectious (bacterial, viral, and parasitic) diseases. These diseases are associated with high rates of morbidity and mortality, particularly in exotic and crossbred cattle. Beside morbidity and mortality, economic losses by these diseases occur through reduced fertility, production losses, etc. Some of the major infectious diseases which have great economic impact on Indian dairy industries are tuberculosis (TB), Johne's disease (JD), mastitis, tick and tick-borne diseases (TTBDs), foot and mouth disease, etc. The development of effective strategies for the assessment and control of infectious diseases requires a better understanding of pathogen biology, host immune response, and diseases pathogenesis as well as the identification of the associated biomarkers. Indigenous cattle (Bos indicus) are reported to be comparatively less affected than exotic and crossbred cattle. However, genetic basis of resistance in indigenous cattle is not well documented. The association studies of few of the genes associated with various diseases, namely, solute carrier family 11 member 1, Toll-like receptors 1, with TB; Caspase associated recruitment domain 15, SP110 with JD; CACNA2D1, CD14 with mastitis and interferon gamma, BoLA--DRB3.2 alleles with TTBDs, etc., are presented. Breeding for genetic resistance is one of the promising ways to control the infectious diseases. High host resistance is the most important method for controlling such diseases, but till today no breed is total immune. Therefore, work may be undertaken under the hypothesis that the different susceptibility to these diseases are exhibited by indigenous and crossbred cattle is due to breed-specific differences in the dealing of infected cells with other immune cells, which ultimately influence the immune response responded against infections. Achieving maximum resistance to these diseases is the ultimate goal, is technically possible to achieve, and is permanent. Progress could be enhanced through introgression of resistance genes to breeds with low resistance. The quest for knowledge of the genetic basis for infectious diseases in indigenous livestock is strongly warranted.