The aim of this study was to evaluate the effects of diphenyl diselenide (PhSe) supplementation during the transition period on the metabolism, immunity, oxidative status, and milk production of postpartum dairy cows. Twenty-seven Holstein females were divided into groups: (PhSe) (DDG), which received 3 μmol/kg of (PhSe)₂ in 4 mL of dimethyl sulfoxide (DMSO) subcutaneously, DMSO (DMSOG), and NaCl (NACLG) which received 4 mL of DMSO and 0.9% NaCl. Evaluation of body condition score (BCS), weighing and administrations were performed at 42, 28, and 14 days prepartum, and on the day of calving (0). On days 0, 7, 14, 21, and 35 postpartum, BCS was evaluated, and blood were collected. Colostrum was obtained from the first postpartum milking. Production was measured, and milk was collected on days 7, 14, 21, and 35 postpartum. DDG showed higher values of total protein (TP) and globulins (GLOB) 7 days postpartum and increase from day 0 to days 21 and 35. DDG immunoglobulin G (IgG) was higher on days 21 and 35, and increased between days 7 and 21. In postpartum TP, GLOB and IgG are physiologically reduced, therefore, the results indicate that supplementation of transition females with (PhSe) stimulated postpartum humoral immunity.

This study aimed to assess the impact of prepartum maternal diphenyl diselenide (PhSe)₂ supplementation on the development, biochemical, immune, and antioxidant parameters of calves. Eighteen Holstein breed calves were used, born to females who were or were not subjected to supplementation, at 42, 28, and 14 days prior to calving. The (PhSe)₂ group (DDG) was administered 3 μmol/kg of (PhSe)₂ in 4 mL of dimethyl sulfoxide (DMSO), while the DMSO and NaCl groups were administered 4 mL of DMSO and 0.9% NaCl, subcutaneously. The calves were evaluated based on their weight, withers height, body condition score 24 h post-birth (0), as well on days 14, 28, 42, 56, 70. Blood samples were also taken to determine serum variables. Calves on the DDG showed higher average levels of total protein, albumin, and globulins on day 0, and the immunoglobulin G level was significantly higher than the other groups on days 0, 14, 56, 70. Maternal supplementation showed immunomodulatory effect on calves, evidenced by the exceptional rates of passive immunity transfer, as well as the enhancement of humoral immunity. Our research offers fresh insights into the immunomodulatory potential of (PhSe)₂, making it a viable alternative in facing this challenging phase, rearing dairy calves.

The purpose of this study was to evaluate the effect of protected niacin and yeast rich in chromium on the productive and metabolic performance of dairy cows under thermal stress. 46 lactating Holstein cows were divided into four treatments: protected niacin (GN), yeast rich in chromium (GCr), niacin+chromium (GNCr) and control (GC). Were measured: milk production, SCC, MUN, NEFA, BHB, glucose, cholesterol, insulin, cortisol, T4 and T3. There was an 8% increase in milk production in the GNCr. The use of these elements is an alternative for producers who need to maintain production during periods of thermal stress.

Objective. This systematic review examines the effects of essential oils used as phytonutrients in the diet of dairy animals, considering parameters such as feed consumption, total apparent digestibility, methane emissions and milk production, based on studies published between 2018 and 2023. Material and methods. Bibliographic research electronic method resulted in a careful selection of articles, which were reviewed and tabulated for evaluation. Results. The results show that 51.35% of the articles did not report significant effects of phytonutrients on milk production. However, 66.67% of the studies observed an increase in feed efficiency and 50% reported the presence of effects on apparent digestibility. Furthermore, there was a reduction in methane emissions in animals treated with phytonutrients. Conclusions. Sharing these results with dairy farming professionals can promote more sustainable and effective practices, as well as support future research and innovations in animal nutrition, aiming for both productive efficiency and environmental sustainability.