A survey on protein content in milk from the dairy cow

Abstract

A detailed survey was conducted on 42 dairy farms located in Puy-de-Dôme to determine some of the factors in herd management that influence milk protein content. Farm structures, herd structures and feeding practices (during winter and summer) were related to milk protein content. Though these farms had similar breed (friesian) and used similar roughage (grass silage), large variations were noted among farms (3.2 g/kg between annual mean protein content). High protein content was associated with good feeding practices (roughage quality, pasture management), high genetic levels, and calving dates grouped in early winter. The analysis of individual results measured monthly in a total of 1600 cows showed the specific effects of the stage of lactation and of the season on milk production and composition. At the same lactation stage, the months from february to july months showed the lowest protein content but the highest milk production. The differences between extreme months were higher in cows in late lactation than in cows in early lactation. August seemed to be very unfavourable for milk production of cows in early lactation.