Effect roughage and physically effective neutral detergent fiber inclusion on eating behavior and particle sorting of Nellore cattle

Abstract

The objective of this study will be to evaluate the effect of roughage and physically effective neutral detergent fiber (peNDF) inclusion on eating behavior and particle sorting in finishing cattle. Eight cannulated Nellore yearling steers (450 kg), will be housed in individual pens (15 m2). The study will be conducted as a 4 × 4 Latin squares balanced for carry-over effects with 2 × 2 factorial arrangement of treatments, with the following factors: roughage inclusion (10% vs. 15% of dry matter of the diet) and peNDF inclusion (low vs. high peNDF). Corn will be harvested to whole-plant silage, from a single field, chopped to a theoretical chop length of 2.0 mm (low peNDF) or 9.0 mm (high peNDF). Each period of the Latin square will consist of 21 days including 14 days without sampling and 7 days of sampling, lasting 84 days. Eating behavior will be analyzed using a video camera monitoring system from day 17 to 21 of each experimental period, one camera will be used for two pens (n = 4). The animals' activities will be recorded every five minutes for 96 hours (starting at 04:00 on the day of recording and ending at 03:55). Samples of food and refusals will be collected from day 15 to day 21 of each experimental period to determine particle size distribution and particle sorting using the Penn State Particle Separator, with opening sizes of 19 mm, 8 mm, 4 mm and a tray.