Agrawal, RajeshKour, Simrandeep2024-05-012024-05-012024-04-22APAhttps://krishikosh.egranth.ac.in/handle/1/5810208520Milk somatic cells (SCs) are a mixture of milk producing cells and immune cells that are secreted in milk during normal course of milking and are used as an index to estimate mammary health and milk quality of dairy animals worldwide. The present study was conducted in Jammu to determine the effect of herd and cow level factors on somatic cell count (SCC) and to assess the effect of organic zinc supplementation on SCC and milk quality in crossbred dairy cow. The study revealed that the management practices that were associated with higher milk SCC included bigger herd size, dirty barn hygiene, poor drainage facilities in the barn, using rubber mats as bedding material, cleaning udder/ teats with inappropriate method without proper disinfection, machine milking and following loose housing system of rearing cows. Significantly (p<0.05) higher SCC was found to be associated with dirty udder and teats of cows. Among physiological parameters studied, cows in higher parity group (≥5) and with higher CMT scores (+++) were having significantly (p<0.05) higher milk SCC. Significantly (p<0.05) higher milk SCC was found to be associated with low body condition score, weak and loose fore udder attachment and higher teat score. In correlation analysis of udder and teat morphometry with milk SCC the fore udder depth, rear udder depth, udder length, fore udder width, udder circumference, teat length, teat diameter, distance between right fore-right hind teat and left hind-right hind teat were found to be significantly(p<0.05) positively correlated whereas rear udder width, udder height from from ground, distance between left fore- left hind teat, right fore-left fore teat and teat height from ground were found to be significantly (p<0.01) negatively correlated. Significantly (p<0.01, p<0.05) positive correlation was found between udder circumference, teat length, teat diameter and milk Fat%, SNF%. Milk Malondialdehyde concentration (MDA) was significantly(p<0.01) positively correlated with milk SCC. It also, increases significantly(p<0.05) with advancement of lactation. No relation was found between milk quality parameters and SCC. Lame cows were found to have significantly (p<0.05) higher milk SCC. Supplementation of organic zinc to animals with higher SCC resulted in significant (p<0.05) decrease in milk SCC and increase in milk SNF%, protein% from day 14 onwards of supplementation whereas milk Fat% significantly(p<0.05) increased from day 7 onwards of supplementation hence, proved to be very effective in decreasing the milk SCC and improving quality of milk of the crossbred dairy cowsEnglishThesis