Grass samples were collected across the country week commencing 21st September. On a whole, September has been quite a good month weather wise across the country. However, with ups and downs in temperatures we are experiencing colder nights and frosty mornings going forward into October. There was significantly more rainfall in the week leading up to the sample compared to the week of collection (See Figures 1 and 2 for rainfall, grass growth and soil moisture).
Spring and Autumn are usually the main high-risk periods for grass tetany in both cattle and sheep. However, it can appear at anytime during the year depending on magnesium availability. It is important to note that grass tetany can be a result of low magnesium in the forage or an interference between potassium/salt and magnesium.
A high potassium intake is a major dietary factor that inhibits Mg absorption which entails the risk on Mg deficiency. The inhibitory effect of K on the efficiency of magnesium absorption can be counteracted by supplemental magnesium.