This study’s objective was to evaluate whether adding a combination of phytoactive (microencapsulated essential oils, minerals, turmeric extract, tannin, prebiotic, and probiotic) to the feed of lactating Jersey cows positively affects the production, composition, and quality of milk, rumen environment, and animal health. Fourteen Jersey cows were divided into two groups (control and phytogenic) for an experiment with two lactation phases of 45 days each (early lactation and mid-lactation). During the experiment, milk production was higher at various times in cows that consumed phytoactive, and these animals had the best feed efficiency. In mid-lactation, phytoactive intake increased nutrient digestibility. The number of lymphocytes in the blood is reduced when cows consume phytoactive substances. Globulin levels increased in these cows fed with the additive, which may be related to a higher concentration of immunoglobulins, especially IgA. Cows fed phytoactives had lower ceruloplasmin and haptoglobin concentrations. Lower serum lipid peroxidation, associated with greater glutathione S-transferase activity, is a good health indicator in cows that consume phytoactive substances. The higher concentration of volatile fatty acids was due to the higher proportion of acetic acid in the ruminal fluid combined with lower butyric acid. Somatic cell counts in milk were lower in cows that consumed phytoactives during mid-lactation, as well as the effect of the treatment on Streptococcus spp. (lower in cows that consumed the additive). We conclude that consuming the additive benefits cows’ health modulates rumen fermentation and nutrient digestibility, and positively affects milk production and quality.

The use of exogenous enzymes in the nutrition of dairy cows is an innovative and efficient strategy to maximize productivity and milk quality, with positive applications in the economic and environmental aspects of dairy farming. Therefore, the objective of this study was to evaluate whether the addition of a blend of exogenous enzymes to the diet of lactating Jersey cows has a positive effect on productive performance, milk quality, animal health, ruminal environment, and digestibility. Twenty-one primiparous Jersey cows, with 210 days in lactation (DL), were used. The exogenous enzymes used were blends containing mainly protease, in addition to cellulase, xylanase, and beta-glucanase. The animals were divided into three groups with seven replicates per group (each animal being the experimental unit), as follows: Control (T-0), basal diet without enzyme addition; Treatment (T-80), animals fed enzymes in the diet at a daily dose of 80 mg per kg of dry matter (DM); Treatment (T-160), animals fed enzymes in the diet at a daily dose of 160 mg per kg of DM. The study lasted 84 days, during which higher milk production was observed in the treated groups (T-80 and T-160) compared to the control group (p = 0.04). When calculating feed efficiency from days 1 to 84, greater efficiency was observed in both groups that received the blend compared to the control (p = 0.05). In the centesimal composition of the milk, it was observed that the percentage of protein in the milk of the T-160 group was higher compared to the control group (p = 0.03). The effect of the enzymes was verified for butyric (p = 0.05) and palmitic (p = 0.05) fatty acids. We also observed the effect of the enzyme blend on the amount of volatile fatty acids (VFAs), which were higher in the ruminal fluid of cows that received the enzymes (p = 0.01). Cows that consumed enzymes showed a higher apparent digestibility coefficient of crude protein (p = 0.01). In vitro, the main result is related to lower gas production in 24 and 48 h at T-160. We concluded that the use of a blend of exogenous enzymes in the diet of lactating Jersey cows was able to increase milk production in these animals, resulting in greater feed efficiency and also an increase in milk protein content, positively modulating the fatty acid profile in the rumen and improving the apparent digestibility of nutrients.

This study evaluated whether iron supplementation in the form of chelated minerals in cows in the final third of lactation has a positive effect on iron bioavailability, immunity, oxidative status, milk quality, and biochemical and hematological parameters, as well as production efficiency and fecal microbiota. Twenty-four multiparous Jersey cows, with 210 ± 18 days in milk (DIM), an average production of 25 kg, and 4 ± 0.6 months of gestation, were divided into two groups: Control (n = 12, without supplementation) and Iron (n = 12, supplemented with 30 mg of iron/kg of dry matter (600 mg/animal/day)). Blood and milk samples were collected on days 1, 16, 29, and 42 of the experiment. Supplemented animals had higher serum iron concentrations and a higher unsaturated iron-binding capacity, especially on day 42. Higher iron content in milk was also observed. A higher granulocyte count was observed in the iron group, as well as a lower number of lymphocytes compared to the control, which may indicate immunosuppression associated with iron supplementation. Fructosamine levels were significantly lower in the iron group animals on days 14 and 28, suggesting a possible alteration in glucose metabolism. In contrast, levels of the liver enzymes AST and ALT increased significantly in the group supplemented with iron on days 28 and 42, indicating potential liver overload or injury. Iron supplementation significantly increased levels of reactive oxygen species and thiobarbituric acid-reactive substances, as well as superoxide dismutase activity in the blood. Iron supplementation altered gut microbial diversity, promoting dysbiosis characterized by increased alpha diversity and enrichment of transient colonization by Nitratireductor, Brevundimonas, Flavobacterium and Sporosarcina. Lower milk production was observed in the iron-supplemented cows in the last 10 days of the experiment, which is related to the occurrence of disease in nine cows in this group: seven with mastitis and two with intestinal peristalsis paralysis. Based on these results, we conclude that chelated iron supplementation at a dose of 600 mg/animal/day should not be used because it harms cow health and productivity.