Renneting properties of dairy cows milk : influence of nutritional level

Abstract

This study was carried out between January and July 1989, in 6 dairy farms making cheese (Reblochon), located in the Th6nes area (Haute-Savoie). Coagulation properties (coagulation time, curd firming rate and curd firmness) were described and related to the feeding characteristics of the cows (energy, nitrogen and mineral balances) and with the chemical characteristics of the milk (fat and protein content, pH, etc). In all the farms the nutritional balances were positive, more so in those where milk characteristics were the more variable throughout the year. Using herd values (n = 6) or individual values (n = 160), it was not possible to relate the variations in coagulation properties with those of nutritional balances of the cows. The variations in coagulation properties were well related with those of milk pH or with the physiological stage of the cows. Other feeding factors (feed type etc) or non-feeding factors (milking, health, genetic factors) may be responsible for these variations.