Effect of concentrate quantity and administration pattern on milk parameters and grazing time in a rationed dairy sheep grazing system

Abstract

Dairy sheep production systems in the Basque country are based on pasture utilisation in partial time grazing during spring. The aim of this study was to evaluate the effect of concentrate quantity and its administration pattern on standardized dairy milk yield (DMYs) and quality (% fat and crude protein), and on grazing time (GT) and live weight (LW). The experiment was conducted over 4 weeks. Sheep were blocked and randomly assigned to 4 different treatments: (A) 500 g, offered half at each milking time, (B) 750 g, offered half at each milking time, (C) 1000 g half at each milking time and (D) 750 g, offered 250 g at morning milking and 500 g at evening milking. Ewes grazed during 4 hours continuously. Moreover, each ewe received 275 g DM of lucerne hay after evening milking. Data were analyzed as a factorial design. As for concentrate quantity, group B and C showed significantly higher DMYs and quality, while group A and B showed significantly longer GT and lower LW. As for concentrate administration pattern, group B and D showed similar DMYs, milk quality and LW, but B had significantly higher grazing time. In conclusion, in this rationed grazing system no productive advantage is achieved when offering more than 750 g/d of concentrate or by altering the concentrate administration pattern.