Keeping cattle healthy when they're at grass

摘要

John Shaw, a vet with Somerset-based Wilkins and Partners, considers some of the problems that can be experienced as cattle go out to grass. Hypomagnesaemia or grass staggers is a common problem in the spring and, confusingly, does not only occur in cows that have been turned out. The basic problem is that cows only store 24 hours or so supply of magnesium in their blood, so if the supply falls short the cow's blood magnesium level drops rapidly. Any subsequent stress on the cow, such as bad weather, calving or coming into heat, can trigger the often fatal sequence of events that begins with tremors and a staggering gait, and ends with violent fits.