25-Hydroxycholecalciferol (25-OH-D3). III. Effect of Dosage on Soft Tissue Integrity and Vitamin D Activity of Tissue and Milk from Dairy Cows

Abstract

In Trial I, eight cows, two per treatment, were given the following doses of 25-hydroxycholecalciferol: (1) 1.0 mg orally daily for 14 days, (2) 4.0 mg, (3) 8.0 mg, or (4) 16.0 mg intramuscularly in 5 ml sesame oil. No clinical or pathologic evidence of hypervitaminosis D was found. Tissue from animals slaughtered 14 to 35 days after treatment revealed no evidence of tissue irritation and less than a twofold increase in vitamin D content. Tissue from control animals contained 18 to 26 IU of vitamin D per 100 g compared to 20 to 48 IU per 100 g from treated animals. In Trial II, the mean vitamin D content of milk taken on Day 4 postpartum from seven orally-treated cows was not greatly different than that of seven control cows, 35 compared to 31 IU per liter. Similar values for seven intramuscularly injected cows were 75 IU vitamin D per liter compared to 38 for five control cows. Thus, short-term administration of 25-hydroxycholecalciferol at dosages that effectively reduce the incidence of parturient paresis appear safe for the animal, and the products produced by these animals safe for human consumption. © 1974, American Dairy Science Association. All rights reserved.