This study evaluated the effects of dietary starch and calcium salts of fatty acids on lactation performance, metabolic profiles, and methane emissions in lactating Nili Ravi buffalos. Sixteen lactating multiparous Nili Ravi buffaloes at 7.53 ± 0.76 kg/d of milk yield and 125 ± 45 DIM were randomly assigned to one of four treatments in a 4 × 4 Latin square design: low starch low fat (LSLF), low starch high fat (LSHF), high starch low fat (HSLF), and high starch high fat (HSHF). Each period lasted 21 days, with data collected during the last week. Experimental diets were formulated using the Cornell Penn Miner Dairy software, and all buffaloes received a fixed allowance of 16 kg of dry matter (DM) per day. The high fat treatments included 300 grams of calcium salts of fatty acids (Ca-FA) per animal per day, while starch levels were adjusted using maize grains.

Dry matter intake (DMI), body weight (BW), and milk yield were recorded daily, and milk composition was analyzed for fat, protein, and lactose content. Rumen fluid samples were taken for pH measurement, and blood samples were analyzed for plasma urea nitrogen (PUN), triglycerides, and glucose. Methane emissions were measured and expressed in MJ, Mcal, g/d, and g/kg DMI. The interaction between dietary starch and fat did not significantly affect DMI, BW, rumen pH, milk yield, milk protein percentage, or nitrogen efficiency. However, milk fat percentage and milk lactose percentage were significantly influenced by fat, with no significant interaction. Metabolic parameters, including plasma pH, glucose, cholesterol, urea, PUN, and triglycerides, showed non-significant effects. A notable interaction effect was observed for methane emissions per unit of DMI, suggesting a complex relationship between dietary components and methane emissions efficiency. Overall, the results showed that, while starch and fat had significant individual effects on several parameters, their interaction was non-significant, except for methane emissions per unit of DMI. The findings suggest that dietary starch and fat can be independently adjusted to optimize Nili Ravi lactating buffalo performance and milk composition. This study provides valuable insights for formulating diets aimed at enhancing productivity while mitigating methane emissions.

Keywords: Buffalo, starch, rumen bypass fat, milk yield, methane emissions