Effect of feeding Bacillus coagulans and Bacillus subtilis probiotics on growth performance, health and blood parameters in suckling Holstein calves

Gastrointestinal tract infections and subsequent diarrhea are the main reason of mortality of newborn calves. Diarrhea is the most common disease that occurs in cattle farms and causes death and serious economic losses to the livestock industry. Due to negative effects of antibiotics, including Bacterial resistance to antibiotics, many countries in the world have banned the use of these antibiotics in the animal industry since 1996. The use of probiotics is mostly seen as an alternative to antibiotics in animals, and many scientific works show the beneficial effects of supplements with probiotic strains in the diets of different farm animals. Probiotics have been shown to have positive effects on the whole body, including weight gain and immune function, and reducing the presence of pathogens. This study aimed to evaluate the probiotics Bacillus coagulans and Bacillus subtilis and their effect on the growth performance, health, and prevalence of diarrhea in suckling Holstein calves. . . . . . .

The present study was conducted in the form of a completely randomized design with 32 replications in two treatments. Calves were monitored for 28 days. Body weight was measured every week, and dry matter intake and health status were checked and measured every day. Blood samples were taken from the calves on the first, seventh, 14th, 21st, and 28th days, and the blood was kept at 4°C until reaching the laboratory, and then blood parameters were measured. fecal samples were taken for microbial culture on the 7th, 14th, and 28th days and were cultured in the laboratory.

The results showed that probiotic supplementation does not affect weight, daily weight gain, skeletal growth, Feed Efficiency, and hematological parameters. However, feed intake and the number of Lactobacillus in feces increased significantly (P < 0.05). Additionally, probiotic supplementation reduced fecal score, diarrhea duration, and body temperature significantly (P<0.05).

Probiotic oral supplement improved the symptoms of diarrhea and the negative effects of diarrhea, and it also improved the performance of feed consumption and increased the beneficial bacteria of the gastrointestinal tract system in suckling calves. By preventing diarrhea, probiotic supplements can reduce the losses caused by calves dying and, as a result, make dairy farms more profitable.