Silagem de dieta total com coprodutos do milho e do ácido cítrico para vacas em lactação

Abstract

The co-products generated in agro-industries are foods with potential for use in feeding ruminants. However, due to the their different characteristics (i.e., texture, moisture) it is necessary to evaluate the best way to add them to animal feeding. Ensiling a complete diet (TMR – Total mixed ration), for example, is a strategy to facilitate the management and efficiency of the animal feeding system. However, there are gaps in knowledge regarding the best strategy for supplying corn and citric acid co-products in diets for lactating cows. Thus, the objective was to evaluate strategies for supply the co-products, mycelium, raffinate, corn straw and Goldenmil in the diets of crossbred cows in lactation on the consumption and digestibility of nutrients, blood parameters, ingestive behavior, production and composition of milk. Fifteen ¾ Holstein x ¼ Gir cows with an average initial weight of 594 kg and 80 ± 5 days of lactation were used. Three experimental diets were evaluated: control diet, without inclusion of corn and citric acid co-products; in natura complete diet, containing corn and citric acid co-products; ensiled complete diet containing corn and citric acid co-products. A triple Latin square design was used, with three treatments, three sampling periods and data collection. The experiment lasted 63 days, with 14 days for adapting the animals to management and to diets, and 7 days for data collection and sampling. The forage:concentrate ratio in the three experimental diets was approximately 36:64 on a dry matter (DM) basis. Cows fed the control diet consumed more 11.47 kg of DM than the ones fed the ensiled complete diet (average of 14.83 kg/day). The lowest consumption of crude protein (P0.05) between the diets on the digestibility of DM, crude protein, ether extract, NFC, NDFap and TDN, average of 615.8; 666.6; 996.0; 943.3; 465.9 and 619.2 g/kg DM, respectively. Cows fed control diets and in natura diets produced more 23.20% of milk compared to animals that received TMR ensiled with corn and citric acid co-products. The feed efficiency of cows that received the ensiled TMR was 22.83% higher than the other ones (average of 1.25 kg of milk/kg of DM). There was no difference between the diets regarding fat content (P=0.84), lactose (P=0.12), total solids (P=0.17) and somatic cell count (P=0.89). Considering aspects related to management, consumption of dry matter and nutrients, blood parameters, production and composition of milk, the in natura diet with corn and citric acid co-products stands out.