Effect of lucerne (Medicago sativa) fodder supplementation on nutrient utilization and enteric methane emission in male buffalo calves fed on wheat straw based total mixed ration

Saponin content of lucerne (Medicago sativa) fodder was estimated at 3, viz. I, II and III cuts. Saponin content at II cut (flowering stage) was highest which decreased in the subsequent cut almost to the level of first cut. Male Murrah buffalo calves (6) were initially fed on wheat straw based total mixed ration (TMR_1) consisting R: C as 60:40 and data were recorded thereafter, these animals were shifted on isonitrogenous TMR_2 having 30 incorporation of lucerne fodder (II cut) as source of saponins (2 on DM basis) in TMR_2 replaced wheat straw partially maintained the R: C ratio similar to TMR_1 (60:40). DM intake, nutrient utilization and enteric methane emission were studied on both feeding regimes. DM intake (kg/d) in buffalo calves was higher on TMR_2 than on TMR_1, similarly on uniform basis (kg/100 kg bw) it was also higher on feeding TMR_2. Nutrient digestibility and nitrogen intake on feeding TMR_2 was higher than that on feeding TMR_1, which resulted in higher nitrogen excretion through faeces and urine. Methane emission on feeding TMR_1 and TMR_2 was 18.11 and 12.45 g/kg DMI, respectively, showed a reduction of 32 due to the addition of 30 lucerne fodder (II cut) in TMR_2. Thus, the saponins supplied through lucerne fodder (total intake 29.58 g/d) decreased methane emission in buffalo calves. GE loss in the form of methane was more on feeding TMR_1 (5.73) than that on TMR_2 (3.93). The lower loss of GE in form of methane on feeding TMR_2 showed that incorporation of lucerne fodder to straw based ration can increase DMI, nutrient utilization in one hand and mitigate methane emission on another. As production of lucerne fodder is a common and a traditional practice in India, therefore, incorporation of lucerne fodder as a source of protein in total mixed ration seems more practical and promising for the mitigation of methane than the other strategies. Thus, there is urgent need to explore natural feeds and herbs having saponins and safe level of their incorporation in the ration.