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

Abstract

The effect of animal species (cattle or sheep) and level of feeding (maintenance and 2 × maintenance) on the digestibility of concentrate ingredients were examined. Twelve Friesian steers, bodyweight (BW) 351 kg (sd 18.9) were assigned to blocks of two on a descending BW basis. Each block was assigned to an incomplete (four periods), six (animals) by six (periods) Latin Square. Animals in one of the squares were offered feed at maintenance and animals in the second square were offered feed at 2 × maintenance. Twenty four wether sheep, BW 40.2 kg (sd 3.77) were used simultaneously and offered feed at maintenance with four sheep being randomly allocated to each treatment. The treatments were copra meal, sunflower meal, dry corn gluten feed (Archer 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 fibre (NDF) and acid detergent fibre (ADF) were measured in both species, and in addition, the digestibility of Oil B (OBD) was measured in cattle fed at maintenance and 2 × maintenance. Species had a significant effect on the digestibilities 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 NDF. Increasing the level of feeding decreased the digestibilities of DM, OM, DOM, CP, GE, NDF and ADF ( P < 0.001), but had no significant effect on the digestibility of OB. It is concluded that the digestibility values of concentrate ingredients derived in maintenance-fed sheep are applicable to maintenance-fed cattle for DM, OM, DOM, GE and ADF. In addition, the digestibility of concentrate ingredients was significantly depressed with an increase in level of feeding ( P < 0.001) for all digestibility components except OB, where no significant effect was observed. Therefore, it is concluded that feed is not utilised as efficiently when the level of feeding is increased from maintenance to 2 × maintenance.