Abstracts Health Sciences

Lactational response of Holstein cows to oral administration of a synthetic glucocorticoid

by Ronald Egnard Lind

Two experiments involving 33 Holstein cows were conducted for the primary purpose of studying the effects of flumethasone (a synthetic glucocorticoid) on milk and milk constituent yields. The secondary purpose was to compare udder health, reproductive performance, and body weight changes of cows on flumethasone therapy. Nine Holstein cows were assigned randomly to three treatments in Experiment I and received .00, .01, and .05 mg. of flumethasone daily in treatment groups I, II, and III, respectively. All cows were fed 10 to 12 pounds of alfalfa hay daily, corn silage ad libitum, and one pound of concentrates for every three pounds of milk produced per day, throughout the 120 day experiment. Average daily milk yield,mature equivalent (ME) milk, 4% fat corrected milk (FCM), and ME, 4% FCM were significantly less (P < .05) for treatment III than treatment I. Cows on treatment II produced more milk than cows on treatment I. However, the differences were not statistically significant. Experiment II involved 24 Holstein cows initiating their second or third lactations which were allotted randomly to four treatments. Cows on treatments I, II, III, and IV received .00, .005, .01 and .02 mg. of flumethasone, respectively, each day. Flumethasone therapy was initiated four days post partum and continued until milk secretion ceased or the completion of a 305 day lactation. Cows in this experiment received the same ration as cows in Experiment I. Milk, butterfat, and solids-not-fat (SNF) were significantly lower (P < .05) for treatment IV than treatment II. Controls were intermediate. During the first 70 days of lactation cows on .005 mg. of flumethasone produced significantly more (P < .05) butterfat (23.9%) and SNF (18.39%) than controls and cows receiving .01 mg. of flumethasone produced significantly more (P < .05) butterfat (21. 04%) than controls. There were no significant differences between treatment means during the second 70 days of lactation. Cows receiving .01 mg. of flumethasone produced significantly more (P < .05) milk, butterfat, and SNF between 141 and 210 days of lactation than cows receiving .02 mg. of flumethasone. There were no differences between treatments for measures of udder health, reproductive performance, and body weight changes. However, there was a significant difference (P < .05) in length of lactation. Cows receiving .02 mg. of flumethasone had considerably shorter lactations (31 to 43 days). These results indicate that .05 mg. of flumethasone has an inhibitory effect on lactation. Although .02 mg. of flumethasone had an initial stimulatory effect, there was an inhibitory effect on milk secretion and synthesis of butterfat and SNF later in lactation. These data suggest that .005 and .01 mg. of flumethasone may stimulate lactation in dairy cattle.