Performance and health of Holstein calves fed different levels of milk fortified with symbiotic complex containing pre- and probiotics.

The objective of this study was to evaluate the performance and health of Holstein calves fed low or high milk supply (MSP) with or without symbiotic complex (SYM) supplementation, consisting of prebiotics, probiotics, and fibrolytic enzymes. Thirty-two Holstein calves with body weight (BW) of 34 ± 7 kg were distributed in a randomized block design in a 2 × 2 factorial arrangement. Treatments consisted of low and high MSP: 10 % of BW from 1st to 8th weeks after birth (low) and 20 % BW from 1st and 2nd weeks after birth, 15 % BW for the 3rd and 4th weeks after birth, and 10 % BW from 5th and 8th weeks after birth (high). Solid ration was supplied in addition to milk. Intake, ADG, diet digestibility, and fecal consistency index were evaluated. Low and high MSP groups tended (P < 0.10) to differ in calf growth, final BW (69 vs. 73 kg), post-weaning average weight gain (548 vs. 788 g/day), and final average weight gain (549 vs. 646 g/day) in low and high MSP calves, respectively. There was an interaction between MSP level and SYM on the digestibilities of dry matter (DM) and neutral detergent fiber (NDF) (P < 0.10). In the low MSP group, inclusion of SYM increased digestibility of DM (0.720 to 0.736 g/kg) and NDF (0.758 to 0.783 g/kg). The inclusion of SYM improved calf health (P < 0.10) with a fecal score of 0.31 compared to 0.42 without SYM. Milk-feeding level was an important factor in calf performance, while SYM supplementation improved diet digestibility and animal health.