The Role of Injectable Mineral Treatment in Dairy Cow Health: Impact on Metritis, Milk Production, and Composition

Objectives: Mineral supplementation plays a crucial role in dairy farming, significantly impacting the health, reproductive efficiency, and milk production of dairy cows. Essential trace minerals, such as zinc, copper, manganese, and selenium, are vital for enzymatic functions, immune response, and overall metabolic balance. Deficiencies in these minerals can lead to compromised immune function, increased disease susceptibility, impaired reproductive performance, and reduced milk yield and quality. Reproductive challenges, including retained placenta, metritis, and poor conception rates, have been linked to mineral imbalances, emphasizing the necessity of adequate supplementation. This study investigates the impact of MULTIMIN injectable trace mineral supplementation on dairy cow health, reproductive performance, and milk production and composition, aiming to determine its efficacy in improving overall herd productivity. Methods: According to breed and production, all cows (from 30 days before the calving and finish 30 days after calving) were split into two groups: the treatment group (TG), which was receiving Multimin (n=78), and the control group (CG), which did not receive Multimin (n=74). Cows were grouped based on analogies. All cows in the study were vaccinated against bovine rotavirus, coronavirus, and Escherichia coli at the same time (30 days before expected calving). The supplementation protocol for the TG group involved administering Multimin at a dose of 1 mL/100 kg subcutaneously once 30 days before the expected calving date. The investigation divided these two groups of cows into first lactation cows and second plus lactation cows. Daily data were collected using Lely Astronaut® A3 milking robots, recording parameters such as rumination time (minutes/day), body weight (kg), milk yield (kg/day), milk protein content ( %), milk fat content ( %), milk lactose concentration ( %), and somatic cell count (SCC, thousand/mL). Results: The study revealed statistically significant differences between the test group (TG) and control group (CG) across several parameters. Milk production was significantly improved in the TG, with an 8.5 % higher milk yield (37.57 kg vs. 34.63 kg, p < 0.001) and 2.7 % greater milk protein content (3.75 % vs. 3.65 %, p < 0.001). A slight but significant reduction in the milk fat­ to­ protein ratio was observed in the TG (1.26 vs. 1.29, p = 0.04), alongside a 0.43 % lower lactose concentration (4.62 % vs. 4.64 %, p < 0.001). Feeding behaviour also differed, with the TG exhibiting 7.3 % less total eating time (161.43 min vs. 174.17 min, p < 0.001) but consuming 6.8 % more concentrated feed (5.33 kg vs. 4.99 kg, p < 0.001). Additionally, the incidence of retained placentas was twice as high in the CG, and metritis was seven times more frequent in the CG, suggesting a strong protective effect of MULTIMIN on reproductive health. Conclusions: The findings of this study demonstrate that injectable mineral supplementation (MULTIMIN) positively influences dairy cow productivity, reproductive health, and milk composition. Cows receiving MULTIMIN had higher milk yield (+8.5 %) and milk protein content (+2.7 %), along with improved feed efficiency and a reduction in retained placentas (50 %) and metritis cases (7-fold decrease). These results suggest that the strategic use of injectable mineral supplementation can enhance herd health, optimize milk production, and improve overall farm efficiency.