Influence of replacing concentrate mixture with AFEX pellets on rumen fermentation, blood profile and acetamide content in the rumen of crossbred (Alpine × Beetle) female goats

Abstract

This study evaluated ammonia fiber expansion (AFEX) treated wheat straw on health, growth and rumen fermentation of goats relative to concentrate. Twenty growing crossbred (Alpine × Beetle) female goats were blocked into either a control or treatment group (n = 10). The control group was maintained on a diet containing concentrate and green fodder (50:50 on DM basis), whereas the treatment group was fed AFEX-treated wheat straw and green fodder (50:50). Goats fed the treatment diet exhibited lower dry matter intake (DMI), average daily gain and feed conversion ratio (FCR) than control animals (P < 0.05), although these differences diminished over time (P < 0.05). Rumen acetamide and acetamidase enzyme activity were measured to determine if non-protein nitrogen in the AFEX feed was being metabolized. Rumen acetamide and acetamidase activity were higher (P < 0.05) in treatment group. Goats receiving AFEX pellets showed a decrease (P < 0.05) in rumen ammonia-N, total volatile fatty acids and propionic acid whereas acetic acid increased (P < 0.05). Rumen pH and butyric acid concentration were not different between two groups. Blood metabolites were similar between two groups. Feeding of AFEX-treated wheat straw in growing goats did not affect the blood metabolites and rumen fermentation. Given the similarity in blood metabolites and evidence of acetamide metabolism, AFEX-treated wheat straw has potential as a feedstock for goats, although long-term experiments are required to optimize feed inputs.