Dairy cows feeding with sorghum silage supplemented with concentrate

Abstract

Concentrated feed can be used to increase the milk yield in dairy farms. However, the feeding cost increases when concentrates are used and, sometimes, farmers lose competitiveness, if the cows do not produce what is expected with supplementation. Thus, this study aimed at evaluating the nutrients intake, milk yield and composition and live weight change of dairy cows fed with sorghum silage alone or supplemented with concentrates. Nine crossbred cows (Holstein-Gyr) were allocated in three balanced Latin squares and fed with sorghum silage supplemented with minerals (0.2 kg) or with 2.6 kg (38.5% of crude protein) or 5.0 kg (20% of crude protein) of concentrate per day, aiming at supplying the same amount of crude protein (1.0 kg day^-1). The dry matter intake and milk yield were higher for the cows fed with concentrate, independently of its protein level. The productive response (in kg of milk per kg of concentrate) was 1.67 and 0.83, respectively for the low and high supplemental levels. The cows that received only minerals lost weight, while those fed with concentrate gained weight. The cows which produced 13.0 kg of milk day^-1 showed a higher increase in milk yield when fed with supplements containing high protein and mineral contents. The response for milk production per kg of concentrate was higher when lower amounts of concentrate with high protein and mineral levels were used, allowing a reduction in the production costs.