Are some cattle breeds more susceptible to tetany than others?
Many investigators have suggested the existence of a hereditary predisposition to grass tetany.3 ALTEN claims to have observed such a predisposition in several successive generations. The question of breed gives expression to a whole number of hereditary characteristics. It has been wondered whether certain dairy breeds are more frequently affected by tetany than others. The results available are far from uniform. BARTLETT thought that Friesian cows showed less tendency towards hypomagnesaemia than Shorthorns 4 and Guernseys. LEECH considers that Ayrshires are less attacked by grass tetany. ALLCROFT reports that grass tetany is fairly rare among Jersey cows in England and is practically unknown in the native island of the breed. On the other hand, PATERSON is of the opinion that the most susceptible cows are Jersey-Shorthorn crosses, 10% of which cows in his herds have been affected by tetany against only 4% in the case of Ayrshires and 2% in Friesians. Taken as a whole, therefore, the
