Effects of species-specific probiotic addition to milk replacer on calf health and performance during the first month of life

The aim of this study was to evaluate the effects of the administration of a species-specific probiotic (Lactobacillus animalis SB310, Lactobacillus paracasei subsp. paracasei SB137 and Bacillus coagulans SB117 in a 30:35:35 ratio, respectively; 1.8 × 1010 CFU/g of powder) on gut microbial balance, immune response and growth performance of Holstein female calves during the first month of life. Twenty-two calves were divided into two experimental groups from 2 to 28 days of life: control (C), fed with milk replacer and concentrate as a basal diet, and treatment (T), fed C diet plus 1 g/calf/day of probiotic powder for the first month of age. Faecal and blood samples were individually collected and analysed weekly. Individual faecal score was recorded daily and general health score was calculated at the end of the trial. Cell-mediated immune response was evaluated by skin test at 7 and 28 days of life. Milk replacer and concentrate intake were recorded daily, while body weight and biometrical parameters were recorded at 2, 8, 14, 21 and 28 days of life, thus average daily gain and feed conversion rate were calculated. During the first week of treatment, lower blood eosinophil percentage (0.05% vs. 0.22%; P≤0.01) was found in T group, while basophils were higher in T than C group at the end of the trial (0.21% vs. 0.16%; P≤0.05). Higher faecal lactic acid bacteria (LAB)/E. coli ratio on day 28 of life (3.73 log CFU/g vs. 2.02 log CFU/g; P≤0.05) and lower incidence of diarrhoea were found in the treated group (63.30% vs. 70.71%; P=0.05). Body weight (48.92 kg vs. 46.92 kg; P≤0.05), total concentrate intake (14.77 kg vs. 12.56 kg on dry matter basis; P≤0.05), and heart girth (81.16 cm vs. 78.49 cm; P≤0.05) were significantly higher in T group. The administration of the probiotic during the first month of life improved gut microbiota and increased the growth performance and some biometric parameters of calves.