PERFORMANCE OF CROSSBRED COWS AS A FUNCTION OF ENERGETIC AND PROTEIC SUPPLEMENTATION IN DIETS BASED ON SUGARCANE

Abstract

It was evaluated levels of energy and protein concentrates sources on six Holstein x Zebu cows with mean BW of 450 ± 10 kg, first lactation, 60 days post-partum and 10 kg/day of milk, in diets based on sugarcane (Saccharum spp) corrected with 0.3% urea ammonia sulfate: 9:1 in dry season. Six cows were distributed in a 6x6 Latin square, in six periods of 10 days, being distributed in 2x3 factorial treatments (0.8 and 1.6 kg of corn meal – CM/cow/day; and 0.0; 1.2 and 2.4 kg of soybean meal – SBM/cow/day). With the increased levels of CM it was observed increase in consumption of dry mass (DM), organic mass (OM), crude protein (CP), Ethereal extract (EE), non-fibrous carbohydrate corrected for ash and protein (NFCap) and total digestible nutrients (TDN), without effect on the consumption of forage and neutral detergent fiber (NDFap). The CM also increased digestibility coefficients of DM, OM, EE and TDN, did not change the production and milk composition and BW and BW variation. The increment in SBM increased consumption of DM and all constituents, most often of quadratic form, with the exception of consumption of forage, which remained unchanged. The SBM also increased digestibility coefficients of DM, OM, CP and NFCap, increased the daily production of milk and the daily production and content of its constituents, with the exception of fat, total dry extract and somatic cell count, and did not change BW and BW variation. There was interaction between CM and SBM in NFCap consumptions and TDN in kg/day and g/kg BW, in which there was no benefit of CM at the highest levels of SBM. The SBM stimulated the digestibility of NDFap only in the lowest level of CM and increased protein content in milk at the highest level of CM. In conclusion, the addition of CM and SBM in the used levels increase the consumption of nutritional fractions and digestibility of nutrients, 1.2 kg of SBM increase the production of milk and increases in CM and SBM decrease the efficiency in the use of concentrate.