Summer Scour Syndrome
In recent weeks we have had reports of and received samples from cases which would certainly fit the case description of summer scour syndrome.
This condition has been recognised and reported on in recent years (see below) and is a syndrome of unresponsive diarrhoea and wasting in weaned dairy calves at grass. Oral and oesophageal ulceration and necrosis have been a feature of some of these cases (see picture below). It is not uncommon to see cases in the second half of the summer as younger calves are turned out.
The cases have typically tested negative for parasitic gastroenteritis, coccidiosis, salmonellosis, yersiniosis, BVD, MCF and IBR. Bovine popular stomatitis virus or pseudocowpox virus has been isolated from some of the oral and oesophageal lesions, however these might be secondary opportunist infections.
Morbidity has been variable, but often high, with morbidity and mortality rates of up to 40% in some groups. Typically younger calves are affected (3-6 months of age), but the syndrome has been reported in calves up to 12 months of age. Some recover slowly upon housing and return to their previous diet, but others continue to waste. Diet may be part of the story, as cases often occur soon after turnout in calves which have moved from a straw and concentrate diet to a grass based diet, particularly where the grass has been heavily fertilised or is a silage aftermath.
Along with surveillance colleagues across the UK we are interested in investigating this further, and would be grateful if you could notify us of any farms which have had similar clinical presentations. Post mortem of unresponsive cases is the best way to investigate this presentation. A fresh carcass will allow gastrointestinal histopathology to be carried out, which is likely to yield the most useful information.
A link to further information on the follow up investigations that are available can be found here.
The best general advice for investigating and managing suspect cases is:
- Review control measures and test for the common causes of scour such as PGE, coccidiosis and concurrent bacterial infections. The Young Ruminant Enteritis package is suitable for this. As an example we did see potential cases on farms shortly after turn out this spring where Eimeria alabamensis was the diagnosed cause
- Review the diet available pre-turn out and grazing available. More mature grass pastures with more stemmy grass might be more suitable from a dietary perspective although may also carry a greater parasite risk
- Are the calves grazing properly particularly in the early days after turn out? Grazing is actually a learned activity and young cattle need to learn how to do it. This would be easy for a suckled calf, but perhaps less so in a batch of similar aged animals that have not seen grass before
- Consider transitioning from the housed diet to the grazing ration by making the housed ration available at grass as well for a period of time. The challenge of course will be getting young cattle to continue to eat straw
- Management of affected calves may often involve housing again and transitioning on to the original ration
If you wish to discuss further cases, or wish to submit a carcass for PM, please get in touch.
Posted by Veterinary Services on 10/08/2020