I was recently called out to a large coastal sheep and beef property to check a mob of poor-doing steers. The affected group comprised of two and three-year old Angus and Hereford steers running on the flatter paddocks. The manager mentioned that he had this problem in previous years, but the steers seemed to recover in the spring. This year however, six cattle had already gotten sick and died.

When we brought them into the yards, they were very agitated. As the manager mentioned, they had poor gut-fill (were “slab-sided”). They also appeared a bit pale and jaundiced. Their faeces were a bit loose but they were not scouring.
The farm had previously had some liver fluke on the kill sheet, so we were suspicious of liver fluke. Blood and faecal samples were sent to the lab.

The results were surprising! Although there was evidence of some liver fluke, the real problem seemed to be low Magnesium! The Magnesium was so low in these animals that it was causing anaemia, poor gut function and nervous signs.
Low Magnesium is a common problem in early lactation for dairy cattle. As a result, Magnesium supplementation is standard for dairy cattle around calving time. This problem is almost unheard of in drystock. There are no stated cases in the New Zealand literature recording Magnesium deficiencies in drystock. In order to find out why this property is so unique, I have recommended running pasture samples this coming autumn/winter (when the problem first starts). Although this is a very unusual case, it was very satisfying, as there is an easy solution; Magnesium supplementation or grazing a different class of stock on the affected paddocks.