1656
The effect of supplementation with a blend of capsicum, carvacrol, and cinnamaldehyde on performance of milk-fed calves
Plant extracts have antimicrobial properties that may reduce the risk of disease and improve the health and performance of young animals. The objective of this experiment was to study the effect of an essential oil feed additive (EO; XT-6930; Pancosma, Switzerland) on the performance of milk-fed calves. Eight male Holstein calves were randomly assigned to one of two treatments (n = 4 per treatment): control (no additive) or EO (115 mg/calf/d of XT-6930 added to milk replacer). Calves were housed in individual hutches and received 2 feeding/d of 2 L of milk replacer (22.4% CP, 20.6% fat) plus ad libitum access to commercial concentrate (16.9% CP; 5.3% crude fiber) until weaning (50 days of age). Calves were weighed at the start and the end of the experiment and concentrate intake was measured individually once a week. Feed efficiency was calculated for each calf as the ratio of body weight gain to average concentrate intake during the experimental period (weeks 2 to 5). Blood samples were collected from the jugular vein on the last day of the experiment before feeding to analyze insulin and glucose concentrations. Average daily weight gain was higher (P = 0.02) in EO calves (0.83 kg/d) compared with control (0.63 kg/d) and feed intake was also higher (P = 0.01) in EO compared to control calves (7.23 vs. 5.71 kg/wk, respectively). The efficiency of feed conversion was not affected by treatment (gain/feed = 4.11 vs. 4.09 for EO and control calves, respectively; P = 0.95). There was no effect of treatment on serum concentrations of insulin (0.80 vs 1.69 µg/L for control and EO, respectively; P = 0.31) or glucose (91.6 vs. 106.2 mg/dL for control and EO, respectively; P = 0.29). We conclude that supplementation of milk replacer with EO increased concentrate intake of milk-fed calves. Although there was no effect on feed efficiency, the increase in average daily weight gain has implications for decreasing costs associated with animal rearing. In addition, the increase in the intake of starter grain may enhance development of the rumen and subsequent animal performance.
Keywords: plant extracts, performance, calves