Combination of Feed Additives in the Diet of Jersey Cows and Their Impacts on Production, Milk Quality and Rumen Environment

The combination of additives in ruminant diets is a growing strategy focused on cow health and productivity; therefore, the additives need to have synergistic effects when combined. Because of this, the objective of this study was to evaluate the effects of combining functional additives (biocholine, live yeasts, Yucca schidigera extract, and exogenous enzymes) on the productive performance, milk quality, rumen environment, oxidative status, and metabolic parameters of lactating Jersey cows maintained in an intensive system as well as verifying whether the effects on metabolism and the rumen environment (volatile fatty acids and microbiota) directly or indirectly influence productive efficiency. Eighteen Jersey cows in their second lactation were used, distributed in a completely randomized design into two groups: control, receiving a basal diet, and treatment, receiving the same diet plus the additive mixture. The experiment lasted 56 days. Dry matter intake, milk production and composition, feed efficiency, apparent digestibility, volatile fatty acid profile, rumen microbiota, hematological and biochemical parameters, and oxidative stress markers were evaluated. The combination of additives was able to increase milk production and production corrected for fat, protein, and energy, without altering dry matter intake, resulting in greater feed efficiency. There was an increase in milk protein content from day 28 onwards. In the rumen, a reduction in the protozoan population and an increase in the proportion of propionic acid were observed, without altering the ruminal pH or the total production of volatile fatty acids. The apparent digestibility of crude protein was higher in the treated group. The consumption of additives also promoted specific changes in the ruminal microbiota, with a greater abundance of microorganisms associated with carbohydrate degradation and less activity of pathways related to denitrification. From a systemic point of view, the treatment reduced markers of oxidative stress (reactive oxygen species—ROS and thiobarbituric acid reactive substances—TBARS), decreased creatine kinase and cholinesterase activity, and increased serum fructosamine concentration, indicating antioxidant, anti-inflammatory effects and improved energy status, respectively. It is concluded that the combination of plant biocholine, yeasts, Yucca schidigera extract, and exogenous enzymes improves productive efficiency, promotes ruminal fermentation, and contributes to greater metabolic and oxidative stability in lactating Jersey cows.