Effect of walking on roughage intake and milk yield and composition of Montbéliarde and Tarentaise dairy cows

Abstract

Twenty-eight multiparous cows (14 Tarentaises and 14 Montbeliardes) in mid-lactation were used in a changeover design with 2 periods. Throughout the trial, cows received second-cut cocksfoot hay ad libitum, complemented with a fixed amount of concentrate adapted to the milk yield of each cow. On day 1 of each of the two 8-day periods, one of the 2 groups (7 cows of each breed) was subjected to a single walk of 12.8 km. During the following 24 h, walking produced a drop in quantities of forage ingested (-1.1 kg DM/day, P<0.01) and in milk yield, which was greater (P<0.05) in Montbeliarde (-3.3 kg/day) than Tarentaise (-1.7 kg/day) cows. At the same time, fat content increased similarly in both breeds (+6 g/kg, P<0.01). Protein content increased only in the Montbeliarde cows (+1.1 g/kg, P<0.1). In both breeds, milk cell counts rose significantly after walking (+600 000 cells/ml, P<0.01), but no occurrence of clinical mastitis was observed. Walking provoked a rise in body temperature (+0.5 deg C, P<0.01) and in non-esterified fatty acid (+1.18 mmol/litre, P<0.01) and glucose (+0.08 g/litre, P<0.01) plasma contents