and Implications Investigating different planes of nutrition on appetiterelated hormones could provide knowledge into the role of these hormones on growth performance in neonatal calves. The objective of the current study was to investigate the effects of feeding rates on ghrelin in plasma from preruminant calves. Treatments (n = 8 per treatment) were designed to achieve three targeted daily rates of gain (No Growth = 0.0 kg, Low Growth = 0.55 kg, or High Growth = 1.2 kg) in live weight over a

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... -wk period. All calves were fed a 30% crude protein, 20% fat, all-milk protein milk replacer reconstituted to 14% dry matter. Daily growth rates for No, Low, and High Growth calves were different (P< 0.001) throughout the experimental period and averaged 0.11 ± 0.02 kg, 0.58 ± 0.02 and 1.16 ± 0.04 kg, respectively. Fasting ghrelin active concentration was higher (P < 0.0001) in the No Growth calves over the 7-wk period in comparison to the Low and High growth calves. Circulating concentrations of ghrelin in neonates fed different planes are similar to responses of adult humans to feed intake. These results indicate an inverse relationship of ghrelin active concentration with respect to plane of nutrition and growth rate in neonates.