The regulatory effect of pine sawdust (Pinus pinaster) on the intake of wheat grain by sheep

Abstract

In two experiments, pelleted diets consisting of different proportions of wheat grain and Pinus pinaster sawdust were offered ad libitum to sheep. The ratios of wheat to sawdust fed in the first experiment were 100: 0, 85 : 15,70: 30, 60: 40 and 50: 50. Organic matter (OM) intakes (and digestible organic matter intakes (DOMI)) were 436(382), 520(423), 244(146), 293(117) and 165(88) g/day respectively. In the second experiment the ratios of wheat to sawdust were 100:0, 80:20 and 65: 35. These diets were fed with and without the addition of formaldehyde-treated casein (FTC). Intakes (OM (DOMI)) of the diet without FTC were 499(442), 611(431) and 239(134) g/day respectively, and of the diets with FTC 500(431), 406(320) and 320(199) g/day respectively. Addition of FTC had no significant effect on intake. Sawdust had a major regulating effect on the intake of wheat. The mean sawdust intake of the eight different diets was 94 g/day (range 73-122 g/day). Since sheep would eat only 94 g/day of sawdust the intake of wheat depended on the ratio of wheat to sawdust, i.e. the quantity of wheat that was associated with 94 g sawdust.