Feeding behavior of sheep and goats in a deciduous tropical forest during the dry season: The same menu consumed differently

The sustainable use of the tropical deciduous forest (TDF) during co-grazing of sheep and goats is a complex paradigm. To unveil the latter, an important step is to identify which plants of the TDF are consumed by different ruminant species. Such information must consider the rainy and dry seasons because of the deciduous nature of the TDF, which imply great changes in biomass availability and species dominance. This study aimed at (a) describing the feeding behavior of sheep and goats in the TDF during the dry season, and (b) calculating the quantity of macronutrients harvested in the vegetation by sheep and goats. An observational study was implemented during dry season in the TDF of Yucatan, Mexico. The direct observation method was applied on 3 sheep and 3 goats (adult, non-pregnant females) to record the species of plants consumed, bite categories (BC) and the nutritional quality of different BC. Grazing circuits lasted 4h daily. Twelve days of observations were performed for each ruminant species according to a Latin-square design implemented to equally distribute variability due to routes of grazing, environmental conditions and shepherds between days. Feeding behavior of sheep and goats was similar in terms of plant species consumed (29 of 33 species). However, sheep obtained most of their DM from Acacia pennatula pods, whereas goats consumed mainly foliage from shrubs. Sheep performed fewer bites per day than goats (median of 2854 vs. 3634; P<0.05) and bites were smaller and lighter (P<0.05). Consequently, sheep harvested less DM/day than goats (median of 358.5 vs. 514.7g respectively; P<0.05). Furthermore, goats performed several BC that were exclusive of their behavior. Irrespective of differences between ruminant species, both covered approximately 50% of the DM and the metabolizable energy maintenance requirements after 4h of browsing. Meanwhile, crude protein maintenance requirements were covered by 76% and 141% in sheep and goats, respectively. Thus, the TDF is an important source of protein rich fodder during dry season, while dietary energy is a limiting factor for small ruminant’s performance.