Tropentag, September 20 - 22, 2017 in Bonn "Future Agriculture: Social-ecological transitions and bio-cultural shifts"

Diet Selection and Ingestive Behaviour of Lambs Fed Diets with Increasing Levels of Whey Permeate

Federal University of Paraná, Department of Animal Science, Brazil

Abstract

The selection of feed by ruminants may have an impact in their productivity due to the nutritional value of the different diets, changing the time spent in feeding and rumination, and the size of ingested particles. The aim of this study was to evaluate the diet selection and ingestive behaviour of lambs fed diets with levels of dry whey permeate (WP) during different times along the feedlot period. Twenty four crossbred ½ Dorper × ½ Santa Inês non-castrated male lambs with four months of age and 24 ± 3.2 kg body weight were used. A completely randomised design with six replicates was used. The WP replaced ground corn in the diet (0.0, 5.0, 12.5 and 25.0% of dry matter (DM)). Lambs were fed ad libitum for 90 days with diets composed of Cynodon dactylon hay (64% DM) and concentrate feed (36% DM). We measured the time of feeding, rumination and idling, and the average particle size (APS) of leftovers, at 9, 37, 71 and 86 days of feedlot. Data were analysed in a mixed model with the fixed effects of WP, feedlot time and their interactions (5% significance). There was no interaction between WP and feedlot time. Comparing days 9 and 86, there was an increase in large particles (37.11 vs. 55.87%) and decrease of small particles (16.32 vs. 4.90%) in the leftovers. It's likely that selection is related to higher energetic demand of finishing lambs compared with the ongoing rumen development of young lambs. Intake of large particles is usually a natural way to stimulate the rumen motility. Feeding was higher at day 9 (342 min) than at day 37 (289 min), reflecting the time demand for large particles. This is also supported by the higher rumination at day 9 (587 min) than at day 37 and day 86 (533 min on average), which is in line with the lower APS at day 9 (8.98 mm) compared to day 86 d (14.67 mm). The behaviour and the diet selection demonstrate how lambs change their feeding patterns, and that the substitution of corn by WP does not affect this process in feedlot conditions.

Keywords: Feeding, leftover, particle size, rumination

Contact Address: Américo Fróes Garcez Neto, Federal University of Paraná, Department of Animal Science, Rua Pioneiro 2153 Jd. Dallas, 85950000 Palotina, Brazil, e-mail: americo.garcezufpr.br