Effects of Supplementing a Low Quality Diet with Desert Shrub (Kochia prostrata) on Alpaca (Vicugna pacos) Nutritional Status

This study determined the effects of supplementing a low quality (straw) diet with forage kochia (Kochia prostrata) on the nutritional status of alpacas (Lama pacos). Two experiments were conducted with this objective. The first experiment (Exp A), 20 adult male alpacas were randomly assigned to 1 of 5 treatment diets, including 100% straw, straw plus 20%, 40% and 60% forage kochia, or straw plus 15% alfalfa. Each alpaca received a 2-week all-straw diet before we placed each in a metabolism crate with the treatment diet for 2 weeks (1 week acclimation period). Feed, orts, feces, and urine were measured daily and samples taken for analysis. Blood was collected every 30 min for 6 h at the end of treatment period and analyzed. In the second experiment (Exp B), 25 adult, male alpacas were assigned to 5 treatment groups. All animals received 6 weeks of an all-straw diet before 15 days of the same 5 treatments previously described. Data were collected on weights, feed given and refused and blood drawn twice per day on days 1-7, 9, 11, 13, and 15. Blood serum was analyzed for electrolytes (Na, K, and Cl) and metabolites (glucose, urea-N, and creatinine). In Exp A, the dry matter digestibility significantly increased across the treatments indicating that forage kochia was more digestible than straw. The data showed a significant increase in N intake with an increasing amount of forage kochia as well as a significant increase in N digestibility, but not enough to compensate for the period of low quality feed intake. The high urine output and high BUN values indicate that N was still being mobilized from muscle catabolism in order to compensate for the lack of nutrition. In Exp B, there were no significant differences due to diet alone. Day showed significance with respect to creatinine. Creatinine showed a significant decrease over time particularly in the diets with greater supplementation suggesting that with a longer treatment period, differences among diets may have been significant.