Effect of TMR Briquettes on Milk Production, Nutrient Digestibility, and Manure Excretions of Dairy Cows in the Dry Zone of Sri Lanka

SIMPLE SUMMARY: Compact total mixed ration (CTMR) is a feeding concept to promote nutrition and productivity in cattle. We compared the milk production and nutrient digestibility of cows fed a form of CTMR, TMR briquettes made of dried forages vs. a conventional diet including fresh-cut Guinea grass in the dry zone of Sri Lanka. Our findings showed that feeding TMR briquettes tended to increase dry matter intake (DMI) and milk yield by about 0.5 and 1.0 kg/d, respectively. The TMR briquettes were related to higher fibre digestibility and lower milk urea nitrogen (MUN) and urinary nitrogen excretions compared to the conventional diet. ABSTRACT: We showed previously that TMR briquettes made with a variety of forages and industrial by-products had higher crude protein and energy concentrations than the conventional diet including fresh-cut Guinea grass and commercial cattle pellet (CTL). The study objective was to determine to what extent the nutritional advantages of TMR briquettes would be translated into the milk production of dairy cows in the dry zone of Sri Lanka. Nine Jersey × Sahiwal cows were assigned to CTL or two TMR briquettes in a 3 × 3 Latin square design with three periods each including 14 d for production measurement and 7 d for total faeces and urine collection. The TMR briquettes tended to increase milk yield (5.55 to 6.59 kg/d, p = 0.092), milk protein yield (0.170 vs. 0.203 kg/d, p = 0.091) and DMI (6.50 to 7.16 kg/d, p = 0.070), and decreased milk urea nitrogen (13.0 to 10.5 mg/dL, p < 0.006). The TMR briquettes had a higher organic matter and neutral detergent fibre digestibility (p < 0.001), and lower urinary N excretions as a % of N intake (p = 0.149). In conclusion, the TMR briquettes can improve forage digestibility, milk production and environmental sustainability of dairy cows in the dry zone of Sri Lanka.