Effect of green tea and oregano extracts fed to preweaned Jersey calves on behavior and health status

Abstract

The aim of this study was to evaluate the effects of green tea (Camellia sinensis) and oregano (Origanum vulgare) extracts on behavior, weight gain, and health indicators of dairy calves from birth to 60 days of age. Twenty-one Jersey calves were distributed into three treatments: without additives (CON); green tea extract (GT): supply of 30 mg/kg of body weight/day; and oregano extract (OR): supply of 60 mg/kg of body weight/day. Observers registered animal's behavior at 5-minute intervals from 8:00 to 16:00, three times a week, from day 1 to day 60 of life. The behavioral variables considered were time spent in standing, lying down, ruminating, frequency of visits to feeders, frequency of eating pasture and straw, as well as body weight gain, body temperature, heart and respiratory rates, and health conditions. GT and OR anticipated the occurrence of the first rumination and the ingestion of straw in approximately 7 days compared with CON but did not modify the body weight gain, incidence of diarrhea, health conditions, and other behavioral variables. Supply of GT and OR stimulated the onset of dry feed intake and rumination without changing performance and health status.