Lactational response of dairy cows to oral administration of a synthetic glucocorticoid.

Effects of oral administration of 0, 5, 10, or 20 mug of 6 alpha, 9 alpha-difluoro-16alpha-methyl-prednisolone (Flumethasone) daily on milk and milk component yields, udder health reproductive performance, and body weight change were measured. With 24 Holstein cows in a randomized block design, daily Flumethasone administration was initiated 4 days postpartum and continued until milk secretion ceased or the completion of 305 days on treatment. Mature equivalent yields (adjusted for days open) of milk, solids-not-fat, and milk fat were higher for cows receiving 5 or 10 mug Flumethasone than for cows receiving 0 or 20 mug Flumethasone daily. Lactations for cows receiving 20 mug Flumethasone were 37 to 48 days shorter than lactations for cows in other treatment groups. There were no differences between treatment groups for measures of udder health, reproductive efficiency, and body weight changes. A second experiment of 45 Holstein cows in their second or third lactations included treatments 0, 5, or 10 mug Flumethasone daily for 25 days followed by a 5 day withdrawal. Treatments were begun between day 210 and day 270 of lactation. During the 30 days, Flumethasone failed to alter milk production. These experiments indicate that Flumethasone given continuously increased milk components and milk yield but had no significant effect on milk yield when given only during the latter stage of lactation.