Investigation of Calf Diarrhoea

In any disease investigation the first step is to take a full history. In the case of a calf scour outbreak key informat

ion will include :

·        Age of affected calves.

·        Severity-Number affected and any deaths.

·        System type- Beef/Dairy. Outdoors/Housed. Home reared/Purchased

·        Policy for ensuring early adequate/ quality colostrum provision. This may also involve looking at dry cow feeding.

·        Feed system-Milk/Milk powder;-Bucket fed/Wyedale/Ad lib; Once a day/Twice daily  feeding; Temperature? How is concentration and temperature monitored? Cleanliness of utensils. Type and level of concentrate offered; Water available? Fibre provided- Hay/Straw? How is powder stored and is it in date? Mins/vits levels may be affected

·        Environment- Type of calf housing-hutches/ individual pens/groups; particularly focussing on Stocking rate, Ventilation, Hygiene, Lighting.

·        Cleanliness and frequency of cleaning out. Cleanliness of calving environment. Do navels get treated promptly?

·        Experience and ability of stock person.

·        Any recent management changes?

The next step will be to examine the calves in their environment and assess for general condition and behaviour, colour and consistency of faeces, presence of blood and degree of soiling of hind quarters. Take temperatures, assess for level of dehydration, and  always take faecal samples to identify which if any pathogen(s) are responsible.

It will be important to differentiate between nutritional and infectious causes of a calf scour problem. The main distinguishing factors can be just the general demeanour and appetite. Faecal colour can give a clue but is not guaranteed diagnostic.  Bright yellowy scour can be “milk” scour but can also be associated with rotavirus. Brown scour may point to a “cake” scour but a similar dark faeces is common with coccidiosis. Presence of blood may suggest Coccidiosis or Salmonella., although it will also be worth ruling out the likelihood of presence of mycotoxins from mouldy feedstuffs. One possible nutritional cause that may also need ruling out is copper toxicity from inadvertent feeding of high copper level concentrates e.g.  supplemented cow cake fed to calves.

Many different pathogens can cause scours but Rotavirus is by far the most common, responsible for about 42% of cases.  Second is Cryptosporidia with 23% of incidents, followed by Coronavirus (14%), Salmonella (12%) and E coli K99 (3%). Coccidiosis also causes scours typically in older calves.

With so many possibilities, getting a definitive diagnosis is vital to determine appropriate treatment. Submitting 4 or more fresh faeces samples at the beginning of any scour problem can provide a rapid result and allow correct treatment and control measures. It is dangerous to assume that a one-off diagnosis will determine treatment in a protracted outbreak as the organisms involved may change and  regular monitoring is  recommended.

In house laboratory tests or even calf-side kits are now available which allow rapid results to be generated for rota, corona, K99 and crypto. Salmonella culture will take  48-72 hours. Coccidial oocyst counts can also be carried out quickly in the  practice lab. However to verify that the coccidia detected are pathogenic species- e.g. Eimeria zurnii, E.bovis, they need to be sent to a specialist lab for identification.

It is also advisable to assess the colostral antibody status by blood testing a number of calves 1-2 days old. This will be an important determinant of cause and control.

Accurate diagnosis of calf diarrhoea needs consideration of all the available information including  laboratory results.