Serum and urine analyte comparison between llamas and alpacas fed three forages.

Serum and urine analytes were measured in 4 healthy adult llama and alpaca geldings housed in metabolism crates and fed three diets consisting of alfalfa (AH), barley (BH) or grass (GH) hay and water ad libitum. This comparative study was conducted to determine if differences exist in serum metabolites and urinary indices in llamas and alpacas consuming the same forages of differing protein and carbohydrate quality.  Daily feed intake was determined and concurrent serum and urine samples were obtained at 4-hr intervals on d13 and d14 for analysis of electrolytes, urea N, and creatinine.  AH was consumed more than BH or GH by both species, but llamas consumed more forage on both a body weight (BW) and metabolic BW (MBW, kg .75 ) basis. Serum electrolytes were similarly affected by diet between species, indicating that renal homeostatic mechanisms were functional and analogous in llamas and alpacas.  Serum and urine urea N were affected by forage (P<0.05).  Urine volume was highest for both camelid species when consuming AH (P<0.05).  Mean urine electrolyte excretion only differed by diet.  Dissimilarities between these species was evidenced by differences in renal excretion of urea N and differences in urine volume on a MBW (kg .75 ) basis.