The Substitution Effect of Subabul (Leucaena leucocephala) with Alfalfa on Digestibility, Ruminal Fermentability, Chewing Behavior and Blood Metabolites of Najdi Goat

Introduction Subabul (leucaena leucocephala) is a multipurpose leguminous tree in the tropics and high-quality feed resource for ruminants especially during the dry season in most tropical and subtropical areas. Its leaf has high content of N (16 - 23 % crude protein) and Ca, a low content of tannins and phenolic compounds. The researchers reported dietary supplementation with leucaena silage could enhance feed intake, digestibility, and rumen fermentation in dairy steers. Therefore, this experiment was conducted to investigate the effect of subabul as a replacement for alfalfa on rumen fermentation and digestion, rumination and blood metabolites of Najdi goat.Materials and Methods The eight Najdi goats with average body weight average of 35 kg that were fed with the control diet and diet containing subabul (50 percent of alfalfa) for 40 days. Animals were randomly treated with four replications. Forage to concentrate ratio was 50 to 50. The leave of subabul were collected from Mollasani and milled. Diets fed twice per day for 40 days. Daily feed intake, nutrient digestibility, rumen and blood parameters and rumination activity was recorded. Rumen fluid was collected from animals before the morning feeding. About 200 mg sample (1.0 mm screen) incubated with 35 ml buffered rumen fluid under continuous CO2 reflux in 100 ml vials for 2, 4, 6, 8, 10, 12, 16, 24, 48, 72 and 96 h, in a water bath maintained at 39°C. Cumulative gas production data were fitted to the exponential equation Y=B (1−e−Ct). Partitioning factor, microbial biomass, actually degradable organic matter was calculated by Makkar. Digestibility of dry matter and NDF of the samples were determined. Data were subjected to analysis as a completely randomized design using the General Linear Model (GLM) procedure of SAS.Results and Discussion The results showed that the dry matter intake in goats fed with control treatment was more than treatment containing subabul (P