Assessing Performance and Safety of Feeding a Standardized Macleaya cordata Extract to Calves.

This study examined the effects of Sangrovit^®, a Macleaya cordata plant extract (MCE) preparation on feed intake, growth, blood chemistry, and tissue-residue levels of calves. Twenty male and 20 female calves (~5 d of age) were assigned to one of four daily Sangrovit^® doses: 0.0 and 0.0 (CTL), 2.0 and 4.0 (D1), 5.0 and 10.0 (D2), and 10.0 and 20.0 (D3) g/calf in pre-weaning (5 to 49 d of age) and post-weaning (50 to 95 d of age) periods, respectively. Sangrovit^® doses were fed in milk replacer pre-weaning and top-dressed on calf starter post-weaning. Milk replacer and calf starter intake was recorded daily. Body weight, hematology, and serum chemistry were measured at 5, 49, and 95 d of age. Calves were slaughtered at 95 d of age for MCE tissue residue analysis. Compared to CTL, D1 increased milk-replacer intake (4.90 to 5.09 L/day), but decreased calf starter intake pre- (0.65 to 0.53 kg/d) and post-weaning (3.42 to 3.20 kg/d). No Sangrovit^® dose affected average daily gain. The hematology and blood chemistry of all treatment groups fell within the ranges of healthy calves. Results showed no adverse effects of MCE on health and growth performance of calves when fed up to 10.0 g/calf/day pre-weaning and up to 20.0 g/calf/day post-weaning.