Rehydrated corn ensiled with different concentrations of protease in the diet of dairy cows: impacts on intake, digestibility, ruminal and blood parameters, and milk yield and composition

ABSTRACT The objective of this work was to evaluate the protease levels in rehydrated corn silage and the impacts of its inclusion in the diet of dairy cows on intake, nutrient digestibility, ruminal and blood parameters, fatty acid profile, and animal performance. The study included eight cows with an initial body weight (BW) of 432.9 ± 15 kg and 45 ± 5 days of lactation at the beginning of the experiment. The experimental design was in two 4 × 4 Latin squares, simultaneous, each composed of four animals, four treatments, and four experimental periods. The experimental diets were as follows: Control – basal diet; SGR – rehydrated corn grain silage without added protease; SGR – 500, rehydrated corn grain silage with inclusion of 500 g t −1 of protease; SGR – 1000, rehydrated corn grain silage with inclusion of 1,000 g t −1 of protease. Protease activity was 600 IU g −1 . Cows fed the SGR diet with proteases showed a 9.64% higher milk yield compared to those fed the control diet (average 17.93 kg day −1 ). The use of protease at up to 1,000 g t −1 in rehydrated corn silage improved the ruminal and productive parameters of lactating Jersey cows.