At times spore counts will exceed 500,000, and even over a million in many areas, usually only in the North Island which is considered as “high risk”. That risk may continue into June in some areas.
Prevention may require more than one approach. e.g. Time capsules and pasture spraying.
Zinc can be used in a number of forms, but at high spore count, there will still be some affected animals. For lactating cows at least, ensure they also get limeflour and organic copper.
- Zinc oxide for drenching or mixed with feed. 2.5grm/100kgs lwt/day minimum
- Zinc sulphate (mono or heptahydrate; know which you have because they have different dose rates. Mono approx 5 grm/100kgs, Hepta 7.5gms/100kgs) can be used in water or feed. Make sure you have the correct dose. Make sure you check what sort of zinc is in meal and at what concentration!
- Zinmol is a molasses zinc product, useful in shed or in feed.
- Time capsule zinc boluses give good coverage for 4 – 6 weeks. Ensure you are using the correct sizes, and they must be repeated, up to 3 times.
Mycosorb added to drench or feed appears to help – use in addition to zinc – there is no research to prove any effectiveness against F.E, but it seems to help at high risk.
Some further points to consider...
- Spraying pastures with fungicide needs to be done early enough and is also not foolproof.
- Preventing access to all ryegrass based pasture works but is almost impossible in most situations.
- Higher levels of zinc, at crisis levels, can be used for short periods.
- Remember zinc itself can be toxic, causing pancreatic failure and haemolysis, even death.
- Affected animals need easily available high energy feeds and bland fibre such as good quality hay. Limit ryegrass where possible. Plenty of shade or summer covers. Good quality water without competition. Zinc ointment or other sunscreen for affected skin or teats. Starter drench and monopropylene glycol drenches are useful. High doses of vitamin B12injections to aid appetite, liver function and healing. Oils and fats help – good energy source for the animal not dependant on liver function. Many animals will require additional calcium, either in feed or as CBG under skin. May need dextrose/glucose I/V. Can be more susceptible to other infections.
- Lactating cows – milking will depend on severity but should be only OAD or less.
- High performing well fed cows have an exponentially higher liver blood flow so are often at higher risk, and will show more clinical signs but also tend to recover much better. Supplementary feeding does not reduce risk – “dilution” is irrelevant as animals still tend to be eating the same amount of grass and spores, just get extra on top!
- Apparent severity of clinical signs is not always a good indicator of degree of liver damage or likelihood of recovery. Some of the most severely affected may show no obvious signs at this stage.
Grass Samples for Testing:
We need 60 gm (bread bag full) of grass from a height at which the cow is eating to. Do not get soil in the sample. (you will need to cut close to the ground) . Collect multiply samples from different locations where you anticipate moving your cattle.
Have them delivered to The Vet centre, and we should have your results the same day.
