Somatic cell count and milk yield on physicochemical components of milk from free-stall housed cows

Measurement and evaluation of the factors that may influence milk composition has been shown to determine the actual gains in milk quality and quantity. The study was conducted to evaluate the influence of daily milk yield on the physicochemical composition of milk and analyze the correlations between milk yield and somatic cell count (SCC) on the fat, protein, lactose, total solids and nitrogen urea contents in Holstein cows' milk. A total of 3,544 data collected from 467 cows were evaluated. In the analysis, the animals were divided into groups - I (5-15 kg milk day(-1)), II (15-30 kg milk day(-1)) and III (above 30 kg milk day(-1)) - based on their daily production. Animals of Group I had higher SCC (P < 0.05) and fat and protein percentage when compared with Group III. However, the lactose content was lower (P < 0.05) than Group II and III. No correlation (P > 0.05) between SCC and fat, protein and total solids contents was observed. A lower milk yield is significantly associated with a higher SCC, which, besides hindering the quality of milk, compromises the cow's udder health.