A comparison of milk clotting characteristics and quality traits of Rendena and Holstein-Friesian cows

Milk coagulation properties (MCP) and composition, as predicted by mid-infrared spectroscopy (MIRS), were compared between Rendena (RE) local breed and Holstein-Friesian (HF) cows using 4614 individual milk samples from 28 single-breed herds. Records of rennet coagulation time (RCT, min), curd firmness (a30, mm), daily milk yield and quality traits were analysed using a linear mixed model which included fixed effects of breed, herd-test-date nested within breed, lactation stage, parity, and two-way interactions between the main effects. Random effects were cow nested within breed and residual. Milk from RE coagulated 2.1 min earlier and showed a firmer curd by 4.8 mm than that of HF cows (P<0.05). Milk yield (+9.7 kg/d) and fat content (+0.22 g/100 g) were greater for HF than RE (P<0.05), while protein (+0.05 g/100 g) and casein (+0.06 g/100 g) contents were greater in milk from RE cows (P<0.05). Rennet coagulation time was shortest at the beginning of lactation, and a30 was firmest at the beginning and end of lactation. Results from this study suggest that milk of RE is more suitable for cheese processing than that of HF cows. Milk clotting characteristics of the local breed should be taken into account when developing strategies useful for its valorisation.