The effect of four enzymes: collagenase, fibrinolysin, hyalurodinase, and trypsin were recorded on the viscosity, motility, percent live spermatozoa and acrosome integrity of Llama and Alpaca semen. Semen samples were collected using a modified artificial vagina for each of the five llamas and five alpacas. A 25% solution of the of enzyme at a concentration of 1 mg/ml was added to the ejaculate. Analysis of variance was used to determine differences in eliminating viscosity and alterations in motility, percent live spermatozoa and the acrosomal integrity at 0 (time of semen collection), 2 and 5 min. In Llama and Alpaca semen, collagenase eliminated viscosity in 100 and 99% of the samples, respectively. Correspondingly, fibrinolysin in 89 and 59%; hyalurodinase in 88 and 36%; and trypsin in 55 and 68% of the samples (p<0.05). In the Llama sperm, motility decreased (p<0.05) with the addition of fibrinolysin (28%), trypsin (13%), hyalurodinase (12%), and collagenase (4%). In Alpaca semen, the enzymes used had no effect on sperm motility. Percent live spermatozoa variably decreased after the addition of fibrinolysin, hyalurodinase and trypsin. There was no significant difference in the acrosome integrity in Llama and Alpaca makes following the addition of the enzymes. Overall, collagenase had little or no influence in decreasing motility, percent live spermatozoa and acrosome integrity, whereas, it was effective in eliminating semen viscosity. (C) 2000 Elsevier Science B.V.