With a wet and mild winter I think we are in for a summer of flies and midges, not to mention ticks!
With most farmers concentrating on finally getting their silage done, slurry spread and maize planted, flies are taking advantage of this sudden warm spell with moist ground to get a kick start in their breeding.
Flies are the culprits for many aliments in cattle – New Forest eye, Summer mastitis, decreased feed intakes, increased kicking in the parlour and the spread of some diseases. We certainly have seen the effects of midges last autumn with this spring having a much higher prevalence of Schmallenberg in cattle. Blue tongue will also be a concern this summer.
So how do we control or reduce flies? We need to act now!
There are many ways to help reduce flies and midges on farm. Reducing their breeding ground can really help so make sure dung heaps and muck is pushed away from the milking herd or from youngstock pens. This can really make a difference. For calves this can be more difficult, especially when they are in hutches but good drainage and ventilation can make a difference. Flies like long grass so cutting the grass around calf pens and hutches can help as well. Flies around a calf’s feeding bucket can reduce their intake dramatically so cleaning the buckets out after they have fed and moving the milk trolley or vessels used for suppling the milk away from the calves pens will also help. Parasitic wasps are particularly good for helping to reduce flies around calf pens. They need to be applied to areas once every 2 weeks and can make a huge difference not only for the calves themselves but for those that work with the calves.
Flies can increase summer mastitis and although a teat sealant is ideal for reducing any mastitis during the dry period, don’t forget the heifers. Stockholm tar, although old fashioned, works so well on heifers. You may need to reapply it every month but it is worth it if you save 1 quarter or 1 cow. Water sprays and misters can really lower the number of flies coming into the parlour with the cows. These can also help reduce heat stress as discussed in Graeme’s article last month. It may even reduce kicking in the parlour. Misters around robots could also be beneficial as well as fans.
If none of the above can be done for this year don’t forget to use chemical spot ons early to make it more effective. Some products can at times appear not to work but it is because the level of flies in the environment have become so high the product struggles to show an impact.
Last year we saw a high level of new forest eye and I predict that this year will be much the same. Any cows or heifers with infected eyes must be removed from the rest of the herd to prevent it spreading via flies feet or by direct contact, via shared troughs, amongst the group. Fly control is really important for these animals, not only to stop the spread but to stop the irritation around the damaged eye, as the flies are attracted to the tears running down the cheek. Treating affected eyes with antibiotics and pain relief is vital, as the damage to the cow’s cornea is very painful. Spraying the face where the tears have run can help reduce the spread of the bacteria that causes the infected eye but you must shield the eye before spraying to prevent any spray going directly into the eye. Most antibiotics will treat the bacteria Moxella bovis which is the usual pathogen involved in these infections but if you find that it doesn’t resolve then speak to your vet for other treatments or controls.
Written By Jenny Clayton, Veterinary Surgeon
