Nutritional evaluation of dairy goat rations containing indigofera zollingeriana by using in vitro rumen fermentation technique (RUSITEC)

Abstract

This study aimed to evaluate nutritional quality of total mixed rations containing Indigofera zollingeriana for dairy goats by using in vitro rumen fermentation technique (RUSITEC). Four rations with different levels of I. zollingeriana were tested, i.e., 20% of dry matter (R1), 40% (R2), 60% (R3) and 80% (R4). Each ration was repeated three times by following a randomized complete block design in which different batch of rumen fluid served as the block. Variables observed included chemical composition, In Vitro Dry Matter Digestibility (IVDMD) and In Vitro Organic Matter Digestibility (IVOMD), methane emission, Volatile Fatty Acid (VFA) profiles and protozoa population. Results revealed that R4 contained significantly higher crude protein content than that of R1-R3 (p<0.05). Rations containing higher proportions of I. zollingeriana (60 and 80% dry matter) had significantly higher IVDMD and IVOMD as compared to their lower proportions (20 and 40% dry matter, p<0.05). Methane concentration was lowest in ration containing the highest proportion of I. zollingeriana and it was accompanied with the lowest protozoa population. It can be concluded that higher inclusion levels of I. zollingeriana in rations improved their nutritional values while decreasing methane emission as a main greenhouse gas.