USE OF TOP GREEN AND SWEET CANE SORGHUM SILAGE FOR MILK PRODUCTION IN SMALL-SCALE SYSTEMS

Abstract

Background. Sorghum is a crop that stands out as an alternative to maize due to its higher drought tolerance and lower soil fertility demand. Objective. To evaluate the productive response of lactating cows fed maize silage (Zea mays) in substitution with sorghum silage (Sorghum bicolor L.). Methodology. The research was carried out in the central highlands of Mexico, in the farmer of a small-scale dairy family. Nine cows were used, distributed in three 3X3 Latin squares with test periods of 14 days, of which 12 were for adaptation of the animals to diets and 2 d to the collection of samples. The treatments were: 1) Top Green = 5 kg DM sorghum silage cv Top Green + 5 kg DM maize silage; 2) Caña Dulce = 5 kg DM sorghum silage cv Caña Dulce + 5 kg DM maize silage; 3) Maize silage = 10 kg DM maize silage (testigo). The study included the productive behaviour of the cows, feed composition and feeding costs. Treatment data were analysed with a split-plot arrangement. Results. Inclusion of sorghum silage in the diet reduced dry matter intake (P<0.05), but did not affect average production (22.9 kg/day) and milk composition of cows (P>0.05). There were no differences (P>0.05) for variables related to the nutritional value of the silages. Although there were no significant differences in animal response variables, economic analysis showed that the inclusion of sorghum silage increased feed costs by 15% due to lower dry matter yields. Implications. Sorghum has been proposed as a resilient alternative to maize especially in drought stress scenarios, when the availability of quality forages decreases and grain and forage prices increase. Conclusions. Although feeding costs were higher, sorghum silage can be a substitute for maize silage.