EFFECT OF AN ADAPTATION PERIOD TO BROILER LITTER INTAKE ON RUMINAL DEGRADABILITY OF DRY-MATTER AND NITROGENOUS COMPOUNDS IN SHEEP AND CATTLE

The effect of an adaptation period to the consumption of broiler litte r (BL) on the ruminal degradability (dgr) was evaluated. The dgr of dr y matter (DM), total N (TN), protein N (N x 6.25) and uric acid was de termined for 6 BL; 3 BL were obtained during the winter months from sh eds with earth floor and 3 during the summer months from sheds with co ncrete floor. The dgr was measured using the Mehrez & Orskov technique (1997) in 3 heifers and 3 male lambs. The BLs were incubated in 9 x 1 7 cm dracon nylon bags for 2, 4, 8, 12, 18 and 24 hours in sheep and h eifers, and also for 48 hours in heifers. The diet gradually changed f rom 100% alfalfa hay to a mixture of 60% alfalfa hay and 40% BL (DM ba se) during a period of 21 days. In the lambs, the dgr of DM, TN and N x 6.25 increased, from 59.9, 80.8 and 71.1 to 82.1, 86.1 and 79.2%, re spectively due to the adaptation period (P<0.05). Nevertheless, the dg r of uric acid was similar in both groups of lambs (96%). In heifers, the adaptation period was insufficient to increase the dgr of TN, N x 6.25 and uric acid, but it decreased the dgr of DM from 78.5 to 73.5%.