Comparative forage selectivity and nutrition of South American camelids and sheep
San Martin Howard, Felipe A
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Forage selectivity, diet nutritional quality, voluntary intake, digestibility, and passage rates were studied in South American Camelids (SAC) and sheep. Investigations focused on (1) contrasting the seasonal dietary botanical composition and nutrient content, and intake of llamas, alpacas, and sheep grazing two native ranges and an improved pasture located in the highlands of Southern Peru; and (2) contrasting digestibility and passage rates of different rations fed to llamas and sheep under penned conditions. On the improved pasture, sheep consumed 2.6 times more legumes than SAC. On the range sites, llamas ate more (P < 0.05) tall grasses than alpacas or sheep. Alpacas and sheep showed greater (P < 0.05) selection for short grasses and forbs than llamas. Sheep always selected more (P < 0.05) leaf material than llamas and alpacas, while alpacas selected more (P < 0.05) leaves than llamas. Llama diets were most similar to the forage available; sheep diets were least similar. When ranked from most selective to least selective, the order was sheep, alpacas, and llamas. Alpacas were the most opportunistic. Diet similarity between species on improved pasture was highest between llamas and alpacas. In the dry season on a Festuca dolicophylla range site, alpacas and sheep diets were most similar, but on Festuca rigida range site, llama and alpaca diets were most similar. Llamas showed the lowest dietary quality, sheep the greatest, whereas alpacas were intermediate. Dry matter intake (g per kg BW' 75 ) on the improved pasture and on the range sites was 36 and 26% lower (P < 0.05) in SAC than sheep, respectively. Comparing llamas to sheep under penned conditions, particulate passage rate in the forestoraach was slower in llamas (3.5 vÂ£. 4.6%/h); total mean retention time was longer in llamas (63 vs_. 41h) . Liquid passage rate in the first two compartments of the forestomach was faster in llamas (10.3%/h) than sheep (7.7%/h). Llama digestibility of organic matter, neutral and acid detergent fiber, and protein was greater (P < 0.05) than sheep. Only when animals ate high quality rations were the digestibility values compared (P > 0.05) between both species.