Voluntary intake and digestibility of forages with different nutritional quality in alpacas ( Lama pacos)

Abstract

There is an increasing interest in the introduction of domestic South American Camelids (SAC) to semi-arid and non-plateau arid lands located at the Central South (35-42°S/71-74°W) and Magallanic (49-55°S/69-75°W) regions of Chile. The climatic conditions of these zones differ from the ones at the Andean plateau (17-21°S/68-70°W), though they have in common, a low availability of poor quality forage, greatest in dry seasons. The objective of this study was to determine the apparent digestibility coefficients and voluntary intake of four forages from a location at the V Region of Chile (33°20 S/71°30 W), with eight adult alpacas in a replicated 4 X 4 Latin Square experiment. The forages (commercial hays, stage of maturity not established) were the following: (1) Clover (mostly Red clover plus Italian ryegrass and Fescue); (2) Ryegrass (mostly Italian ryegrass plus Fescue and weeds); (3) Wheat straw (mostly Wheat straw plus other herbs and weeds) and (4) Fescue (only Fescue). The voluntary intake of dry matter and organic matter per kg0.75 BW was greater (P < 0.05) in ryegrass and fescue than in clover and wheat straw, ranging from 39.9 to 63.1 g/kg0.75 for dry matter and 36.5 to 57.1 g/kg0.75 for organic matter. The results indicate that the intake of dry matter and organic matter was dependent on forage quality. The digestibility of dry matter ranged between 48.4 and 55.9% (P < 0.05). There were no significant differences (P > 0.05) between feeds in respect to organic matter digestibility (55.0 to 59.7%) in spite of differences in the nutrient composition. The digestibility of crude protein was higher (P < 0.05) in clover (63.0%) and ryegrass (55.5%) than in fescue (34.6%). The wheat straw had a negative protein digestibility coefficient (-42.0%). The digestibility of neutral detergent fiber and hemicellulose was greater (P < 0.05) for wheat straw and fescue than for clover which had the highest lignin content. The digestibility of acid detergent fiber (43.2 to 49.2%) and cellulose (57.9 to 64.8%) was not different (P > 0.05) between forages. The digestibility of cell wall was high considering the quality of the forages used in this trial and is in agreement with other studies where SAC showed also a great ability to digest low quality forages