EVALUATION OF A CONCENTRATE OF CANOLA MEAL AND MAIZE EARS FOR DAIRY COWS GRAZING NATIVE GRASSLAND IN THE HIGHLAND VALLEYS OF MEXICO

Abstract

Background. Native grasslands are a resource utilized for livestock feeding due to their low cost and mainly during the rainy season. However, native grasslands do not meet the nutritional requirements of dairy cows. Consequently, commercial supplementation with a high cost is used. Objective. The objective of this study was to evaluate the effect of a supplement mixture of canola and ground corn ears compared to a commercial concentrate during the rainy season. Methodology. Ten cows on continuous grazing for 9 h/d were used following the management of the participating farm in a double cross-over experimental design for animal variables, and a split plot design for the grassland evaluation. Results. There were no significant differences (P>0.05) for animal variables, with mean milk yields of 13.5 kg/cow/day, 35.7 g/kg for milk fat, and 32.0 g/kg for protein content. There were also no differences (P>0.05) for grassland height and herbage mass, nor for chemical composition, with crude protein content of 100.4 g/kg DM, and 526 g/kg DM of in vitro digestibility. Chemical composition of concentrates was similar, but the experimental concentrate had lower cost. Implications. Given the scenario of rising prices of concentrates, an alternative to the producer is preparing its own concentrate, with corn harvested in the production units and some ingredient that is high in crude protein.  Conclusions. It is concluded that the experimental concentrate made on farm resulted in the same performance as a commercial concentrate, which may reduce feeding costs.