Ruminal Fermentation Kinetics in Ewes Offered a Maize Stover Basal Diet Supplemented with Cowpea Hay, Groundnut Hay, Cotton Seed Meal or Maize Meal

摘要

The effect on ruminal digestive kinetics of supplementing maize stover (MS) with cowpea hay (CW), groundnut hay (GN), cotton seed meal (CSM) or maize meal (MM) was evaluated in a 5×5 Latin square using five Merino ewes with ruminal cannulae. CW and GN were offered at 30% w/w to MS, while CSM and MM were given at 15 g/kg0.75 per day. There were significant time (p<0.001) and time×diet (p<0.05) effects on pH but the effect of diet alone was not significant (p>0.05). There was a significant (p<0.05) increase in the concentration of ammonia with time on the supplemented diets. There were no significant (p>0.05) differences in the concentrations of total volatile fatty acids (VFAs). Butyrate increased with supplementation (p<0.05). Supplementation increased the concentrations of branched-chain and total VFAs with time (p<0.05). The non-glucogenic ratio was not significantly (p>0.05) lower on supplemented diets owing to the higher butyrate concentration. The degradation curve constants were not significantly different (p>0.05), the average effective dry matter degradation being 27.80%±0.618% at 0.05 h–1 flow rate. The chemical and physical characteristics of the cell wall of MS may have presented few sites for microbial colonization, so limiting degradation. These results showed that small quantities of forage supplements can improve the ruminal environment in animals subsisting on low-quality forages and form a basis for comparison with bought-in protein and energy sources.