The major alteration in the milk composition due to mastitis includes presence of somatic cells (neutrophills, monocytes, macrophages and mammary epithelial cells), bactericidal and bacteriostatic compounds and certain enzymes. Antibiotic residue violation and presence of foodborn pathogens with/without their toxins is another threat of immense importance. These changes in the milk account for the deterioration of the milk quality, risk of health hazards and also its acceptance in the international market. Of all these components, milk somatic cells are the single most widely used indicator of the udder health and mastitis. Somatic cell count (SCC) is used as a system for measurement of milk quality internationally. Strict legislation for monitoring the minimum SCC level is followed to ensure healthy milk in most of the developed countries. This paper introduces the concept of 'Clean White Revolution' and reviews the importance of SCC as a measure to ensure hygienic milk production in India. It also emphasizes upon a need to strengthen the existing legislations concerned.

The study was aimed to construct a discriminate model to differentiate health status of the udder in dairy lactating Holstein cows. Though SCC is a single most reliable indicator of mastitis, a fine demarcation line to differentiate the healthy and subclinical animals based on SCC, rarely exist. The model included contributory factors such as log_SCC, stage of lactation, rainy season, stall hygiene score, udder hygiene score and milking method constructed and was found to demonstrate 89.2 per cent accuracy with p< 0.001 and the Holstein functions at group centroids are -0.982 and 1.209 respectively for normal and mastitis infected animals. The model will facilitate 92.3 per cent of the cases to correctly classify for non-mastitis normal animals and 85.3 per cent to predict correctly as mastitis.

The expression profiles of inflammatory cytokines viz. interleukins (IL)-6, IL-8, IL-12, granulocyte macrophage-colony stimulating factor, interferon-γ and tumor necrosis factor-α in response to subclinical mastitis in indigenous cattle breed Kankrej (n = 6), Gir (Bos indicus) (n = 12) and crossbred (Bos taurus × Bos indicus) (n = 7) were investigated using quantitative real time PCR. Significant correlation (p < 0.05) was observed between total bacterial load and somatic cell count (SCC) in all three breeds of cattle. All the cytokines were observed to be up-regulated compared to cows with healthy quarters, however, level of their expression varied among three breeds of cattle. In Kankrej most cytokines were found to be transcribed to higher levels than in other two breeds; the milk had higher load of bacteria but not so high SCC, implying that Kankrej has a higher inherent resistance against mastitis. The results of present study indicated that mammary glands of crossbred cattle are more sensitive to bacterial infection than indigenous breed of cattle as they elicit immune response at lower bacterial load and result into higher SCC. Research on identification of factors responsible for differentially expressed cytokines profiles and use of cytokines as immunomodulatory tools can pave way for formulating control strategies against bovine mastitis.

TLRs are cell-surface receptors which recognize a broad class of pathogen-associated molecular patterns (PAMPs) that activates innate and adaptive immune responses. Thorough perusal of literature suggests a possible role of TLR2 gene in resistance to infection due to gram positive bacteria. Bovine TLR2 assigns to Bos taurus (BTA) chromosome 17 it spans over 13.2 kb of genomic DNA which includes 2 exons. The first exon is spread over 179bp while the second one is 3333bp. Molecular characterization of TLR2 gene, carried out by PCR- SSCP analysis, revealed presence of six SNPs viz., A827G (exon 2.2), C1088G (exon 2.3), C2155A (exon 2.5), G2281C (exon 2.5), G2410A (exon 2.6) and C2600T (exon 2.6). Gene and genotypic frequencies were determined by values for allele frequencies and hetrozygosity. The degree of heterozygosities, c2 (Chi-square) test for Hardy Weinberg (HW) equilibrium and F statistics were performed for the HF crossbred population. Population genetic analysis demonstrated high degree of genetic differentiation in the population. The studied population displayed a deviation from the HW equilibrium.