Seasonal Effect on Milk Composition, Somatic Cell Content and Milk Coagulation Properties of Italian Holstein-Friesian Cows

This study investigated the seasonal effect on composition, somatic cell content and coagulation properties of bovine milk during two different periods of the year (summer and autumn). 592 samples of raw milk from Italian Holstein-Friesian cows from different locations in the Veneto region, Italy, were collected. The samples were submitted to the following analyses: fat, protein, casein and lactose percentages and pH by infrared spectroscopy; somatic cell counting by optical fluorescence and milk coagulation properties expressed in rennet coagulation time (RCT, min) and curd firmness or consistency 30 minutes after the addition of rennet (a30, mm) by lactodinamography. The index of the aptitude of milk to coagulate (IAC) was also determined from the lactodinamographic parameters that were obtained. To verify the environmental conditions, the temperature humidity index (THI) was calculated for each collection period. No significant difference (p