Season and plant species influence foraging efficiency of Nguni goats in pens

Abstract

This study investigated the seasonal and plant species patterns of short-term intake rate (STIR) by Nguni goats fed six common browse species in subhumid subtropical savannas. Six 2-year-old castrated Nguni goats weighing an average of 26 kg each were penned individually and maintained on a basal diet of ram, lamb and ewe pellets and grass hay. The STIR was influenced by season, with the highest mean STIR recorded during the dry season (mean ± SEM: 0.18 ± 0.012 g DM s^-1) and least during the late wet season (0.15 ± 0.009 g DM s^-1). Broadleaf species had higher STIR than fine-leaf species (0.18 ± 0.052 g DM s^-1 vs 0.14 ± 0.055 g DM s^-1). Species that produce new leaves on new long shoots were consumed at higher rates than those that produce new leaves on short shoots (0.19 ± 0.054 g DM s^-1 vs 0.15 ± 0.056 g DM s^-1). STIR showed no clear patterns in relation to leaf chemistry. These results can be used to improve estimates of intake rates from free-foraging animals using direct observation methods based on time spent at a feeding station depending on the plant species and the season in which it is consumed.

African Journal of Range & Forage Science 2011, 28(1): 29–34