Once sporidesmin pasture spore counts are above 20,000/g nutritional strategies are a vital tool to reduce the impact of facial eczema in a herd or flock. The use of zinc in the diet of grazing stock, as a drench, in water or in feed, has long been recognized as one of the most effective methods of minimizing the impact of facial eczema. The use of zinc as a means of prevention was first discovered in the early 1970’s by Mrs. Gladys Reid. It’s sometime thought of however, as the only tool available.
And the challenge with facial eczema is that when spores are in really high concentrations, zinc is often not enough to prevent damage. What’s more, like many strong medicines, zinc comes with some unfortunate side effects. For example, therapeutic doses of zinc are likely to be antagonistic to other minerals, especially calcium, increasing the likelihood of hypocalcaemia (milk fever).
With a bit of planning however these side effects can be minimized and other means of bolstering immunity and minimising exposure to spores can prove highly valuable additions to the tool kit.
Feeding non pasture feeds during summer allows for the amount of spore intake to be reduced, effectively diluting intake. Sollus customers will have already made a lot of silage this spring as they realized the benefit of feeding non-pasture feeds during peak grass production in spring.
There is another benefit of feeding meals/silages during this period. It enables zinc oxide to be used in feed instead of water dosing with the much more aggressive zinc sulphate (ZnSO4).
It has also been demonstrated that feeding the right proportion of micro minerals, vitamins and antioxidants, in particular vitamin E, can further contribute to the resistance of animals to facial eczema (Munday et. al.). Sollus incorporate antioxidants and key nutrients that aid in the repair of damaged organs caused during the inevitable oxidative stress produced by sporidesmin.
Sollus also incorporate Hy-D. Hy-D increases active absorption of both calcium and phosphorus, helping offset the antagonism of zinc, thereby reducing the risk of hypocalcaemia.
Also, remember to watch the level of copper intake while spore levels are high. Free copper is thought to be critical to the creation of the superoxide radicals.
- Zinc may inhibit the generation of the superoxide radical by sporidesmin.
- Copper is required to enable damage by sporidesmin.
- Zinc reduces the absorption of Copper which catalyses the reaction.
- The use of non-pasture feeds over supper will help limit spore exposure.
- Zinc may be antagonistic to calcium, thereby increasing the risk of hypocalcaemia. The use of Hy-D can improve calcium absorption.
- Vitamin E has been shown to have a separate mode of action to zinc in helping to prevent damage by free radicals involved with facial eczema .
Talk to your Sollus Account Manager about how you can deal with inevitable stress during this period as well as continue to build stronger cows – ready for next season.