The effect of animal species (cattle or sheep) and level of intake by cattle on in vivo digestibility of concentrate ingredients

The effect of animal species (cattle or sheep) and level of feeding (mainte nance and 2 x maintenance) on the digestibility of concentrate ingredients were examined. Twelve Friesian steers, bodyweight (BW) 351 kg (sd 18.9) wer e assigned to blocks of two on a descending BW basis. Each block was assign ed to an incomplete (four periods), six (animals) by six (periods) Latin Sq uare. Animals in one of the squares were offered feed at maintenance and an imals in the second square were offered feed at 2 x maintenance. Twenty fou r wether sheep, BW 40.2 kg (sd 3.77) were used simultaneously and offered f eed at maintenance with four sheep being randomly allocated to each treatme nt. The treatments were copra meal, sunflower meal, dry corn gluten feed (A rcher Daniels Midland Company (ADM)), dry corn gluten feed (Cargill), soya hulls and palm kernel meal. The digestibilities of dry matter (DM), organic matter (OM), crude protein (CP), gross energy (GE), neutral detergent fibr e (NDF) and acid detergent fibre (ADF) were measured in both species, and i n addition, the digestibility of Oil B (OBD) was measured in cattle fed at maintenance and 2 x maintenance. Species had a significant effect on the di gestibilities of CP (P < 0.05) and NDF (P < 0.001) only, in that sheep had a significantly greater ability to digest CP than cattle, and the opposite being true for NDE Increasing the level of feeding decreased the digestibil ities of DM, OM, DOM, CP, GE, NDF and ADF (P < 0.001), but had no significa nt effect on the digestibility of OB. It is concluded that the digestibilit y values of concentrate ingredients derived in maintenance-fed sheep are ap plicable to maintenance-fed cattle for DM, OM, DOM, GE and ADE In addition, the digestibility of concentrate ingredients was significantly depressed w ith an increase in level of feeding (P < 0.001) for all digestibility compo nents except OB, where no significant effect was observed. Therefore, it is concluded that feed is not utilised as efficiently when the level of feedi ng is increased from maintenance to 2 x maintenance. (C) 1999 Elsevier Scie nce B.V. All rights reserved.