Impacts of mixed cactus pear-sorghum silages on nutrient intake, digestibility, and ruminal, ingestive, and productive parameters in lactating crossbred cows
Abstract
This study aimed to evaluate diets with different inclusion levels of cactus pear in BRS 716 sorghum biomass silage for feeding lactating crossbred cows (approximately 80 days in milk, with an average initial body weight of 471.5 ± 52.8 kg). Ten lactating cows were assigned to two simultaneous 5 × 5 Latin squares over a 90-day period (five periods of 18 days). Five diets with increasing levels of cactus pear (0%, 15%, 30%, 45%, and 60% on a fresh matter ((FM) basis) or (0%, 6%,13.4%, 19.9%, and 35.1% on a dry matter basis) in sorghum biomass silage were evaluated. The diets had a roughage-to-concentrate ratio of approximately 75:25, being isonitrogenous and supplied as TMR. Increasing cactus pear in the silage did not affect dry matter intake but decreased NDF intake by 12.03 g/day and increased NFC intake by 14.87 g/day for each 1% inclusion. NDF digestibility decreased by 2.14% points in all diets with the increased inclusion of cactus pear, whereas NFC digestibility increased. Nitrogen balance and microbial protein synthesis were not altered. Ingestive behavior changed ( P < 0.05), particularly water intake, which decreased by 0.26 L/day for each 1% cactus pear inclusion. Milk yield (mean of 13.6 kg/day) and composition were not affected by diets. However, body weight change showed a quadratic response ( P < 0.05) to cactus pear levels, with the maximum estimated at 31.4% cactus pear in the silage’s fresh matter. Including up to 60% cactus pear in sorghum biomass silage is feasible for crossbred cows without compromising productive or nutritional performance, representing an efficient option for semiarid regions.