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Studies on Aureomycin and Vitamin B₁₂ Supplementations for Dairy Cows. II. Effect on Production, Composition, and Vitamin B₁₂ Content of the Milk¹

Dairy Department, Louisiana State University, Baton Rouge

ABSTRACT

Although it has been established that aureomycin (chlortetracycline) is beneficial to young calves, its value for mature ruminants has not been determined. Two reports (6, 7) in 1950 indicated adverse effects of feeding antibiotics to lambs and steers, but Rusoff (17, 18) in the same year reported beneficial effects of feeding aureomycin to ruminating calves 14 to 34 weeks of age. Subsequently, investigations with growing and fattening lambs (11), fattening beef cattle (16), mature dairy bulls (20), and lactating dairy cows (4, 10, 15, 20) have indicated neither detrimental nor beneficial effect of feeding aureomycin to these species.

It has been reported by Rusoff and Haq (19) and by Williams and Knodt (24) that a vitamin B₁₂ supplement did not produce any growth stimulation in young calves. Thus, the animals probably were obtaining their vitamin B₁₂ from cow's milk, since several investigators (2, 8, 9, 23) have reported the vitamin B₁₂ content of cow's milk to range from 2.6 to 7.6 per liter.

¹ Data for this publication are taken from a dissertation submitted by M. O. Haq to the Graduate School of Louisiana State University in 1952 in partial fulfillment of the requirements for the degree of Doctor of Philosophy.

² Present address: E. Dacca, Pakistan.