Grass tetany: With a dip in nighttime temperatures forecast to continue, the risk of grass tetany is likely to intensify. The greatest risk is with cows grazing lush swards, especially where exposed to any stress factors. An increased rate of lush grass passing through an animal’s system reduces the opportunity for absorption of magnesium, which in turn is a trigger for grass tetany. Secondary factors that can also act as a trigger include a dip in temperatures as already mentioned, a significant change in diet, sharp changes to normal management (weaning, for example) and nutritional pressure (cows suckling strong early spring-born calves). Prevention is based on getting a daily allocation of magnesium into animals. This can be achieved by offering cows access to magnesium supplementation through lick buckets, meal feeding, inclusion in water troughs or by administering slow-release boluses. Increasing the opportunity for magnesium absorption from the diet through buffer feeding with hay, haylage or silage when grazing lush pastures and avoiding grazing high-risk cows on swards that received very high nitrogen or potassium fertiliser will also help. It takes a few days for cows to build magnesium levels. Therefore, supplementation should be introduced in advance of risk periods.

Management of purchased weanlings: Management post-sale is central to avoiding problems. The optimum situation is to get weanlings home from the mart and settled in a straw-bedded shed as soon as possible.

At this week’s beef information meetings organised by Aurivo, Progressive Genetics and the Irish Farmers Journal, MSD’s Fergal Morris said one of the most important factors is to ensure they can readily access a fresh supply of water. Housing, and in particular ventilation, is paramount to reducing the spread of disease. Fergal said that in sheds with optimum ventilation, viruses will persist for about 30 seconds on average in the environment. This increases to up to 10 minutes in poorly ventilated sheds, with damp bedding and poor airflow greatly increasing the risk of an outbreak. Avoid stress factors such as dosing and castration until animals have settled. While management will differ between farms, Fergal advises under normal conditions to allow animals settle for 24 hours before administering any vaccination programme. Try to retain animals in the groups they were purchased and avoid differences in size and weight. Where weaned animals are going straight to grass, it is advisable to first graze animals in a sheltered paddock where they can be quickly monitored and herded should they exhibit any signs of illness.

Dates for diary: The Teagasc National Beef Conference takes place on Tuesday 13 October in the Hudson Bay Hotel, Athlone, at 3pm. Session one focuses on improving breeding performance in suckler herds, while session two focuses on improving performance in beef finishing units.