Hypomagnesaemia in cattle

Extract The clinical condition of “Kopziekte” or “grass tetany” in cows was recognized in the Netherlands for many years before Sjollema (1928 Sjollema, B. 1928. Translation published as Sjollema, B. (1930) On the nature and therapy of grass staggers. Vet. Rec, 10: 425–431. 450–4 [Google Scholar], 1932 Sjollema, B. 1932. Nutritional and metabolic disorders in cattle. Nutr. Abstr. Rev., 1: 621–632. [Google Scholar]) and his colleague (Sjollema and Seekles, 1929 Sjollema, B. and Seekles, L. 1929. Translation published as Sjollema, B. (1930) On the nature and therapy of grass staggers. Vet. Rec., 10: 425–431. 450–4 [Google Scholar]) first reported its association with low serum magnesium values in distinction to the low calcium of “milk fever”. The first parallel British observations were made by Dryerre (1932 Dryerre, H. 1932. Lactation tetany. Vet. Rec., 12: 1163–1168. [Google Scholar]) who established pronounced hypomagnesaemia in cases of so-called “lactation tetany” in grazing cows. This term was introduced by Lothian (1931 Lothian, W. 1931. Lactation tetany in the cow. Vet. Rec., 11: 585–585. [Google Scholar]) who described the clinical effects without correlation of the blood findings. In cows recently turned out from stall to grass, Blakemore and Stewart (1933 Blakemore, F. and Stewart, J. 1933. Some observations on several outbreaks of so-called lactation tetany in cattle. 3rd Rep. Inst. Anim. Path. Univ. Camb., 1932–1933: 159–168. [Google Scholar]) found hypomagnesaemia not only in cases of clinical tetany but also in a proportion of the apparently normal cows of the same herd at the same time. Concurrently Hopkirk et al. (1933 Hopkirk, C. S. M., Marshall, D. and Blake, T. A. 1933. Grass tetany of dairy cows. Vet. Rec., 13: 355–361. [Google Scholar]) reported a similar observation in cows at grass throughout the year in New Zealand.