Published online by Cambridge University Press: 27 March 2009
1. Three experiments are described on the feeding of supplements of calcined magnesite, linseed cake and vitamin D to dairy cows for the control of hypomagnesaemia and the prevention of hypomagnesaemic tetany on spring pastures.
2. A daily supplement of 2 oz. calcined magnesite either contained in 2 lb. of dredge corn cubes or 4 lb. dredge corn mix, or as a drench, gave adequate protection against the development of hypomagnesaemia in the fifty-six cows to which it was given.
3. The supplements of 3½–4 lb. linseed cake and 12,500 i.u. vitamin D gave only partial protection.
4. The economics of providing dairy herds with magnesite during the early grazing period is discussed.