Diarrhoea - Age-Specific Testing

Neonatal diarrhoea is often a multifactorial problem involving adequacy of colostral transfer, nutrition, husbandry, climate and infectious agents. The age of the animal is diagnostically important. In many instances, specifc infectious agents can be ruled out based on age.

Adult diarrhoea may be due to a wide range of causes, and may be secondary to non-gastrointestinal disease. A wider range of tests is often needed to diagnose specific causes of diarrhoea in adults.

Sample collection - general:

We suggest you consider the following range of samples, depending on the age of the animals affected.

1) Faeces or colonic content

2) Fixed small and large intestine from fresh intestine (freshly dead animal). Many of the causative infectious agents are transiently present, or produce villous atrophy that is obscured by autolysis; therefore, it is important to consider that intestinal mucosa shows histological signs of autolysis within 15 minutes of death, hindering diagnosis. For histology, take multiple 1 cm long segments and immerse in abundant formalin. Minimal handling of the fresh tissue is advised as the mucosa is fragile and susceptible to sloughing with manipulation.  Alternately, cut the wall of the intestine; at least 1 centimetre along its length, to allow proper fixation.

3) Serum (plain or gel tube)


Calf faecal panels:

Gribbles Veterinary Pathology offers a variety of calf faecal panels specific to age.

Faecal Panel 1 (1-2 day old): E. coli K99, Salmonella

Faecal Panel 2  (2 day - 2/3 weeks old): E. coli K99, Salmonella, Coronavirus, Rotavirus, Cryptosporiduium

Faecal Panel 3 (2/3 weeks - pasture age):  Salmonella, Coronavirus, Rotavirus, Cryptosporiduium, Coccidia

Faecal Panel 4 (Pastured calf): Salmonella, Coronavirus, Rotavirus, Cryptosporidum, Coccidia, Yersinia, Faecal Egg Count

Faecal Panel 5 (Pastured adult): Salmonella, Yersinia

Scours panels:

Our scours panels (combined faecal and serum testing) offer a wider range of testing dependent on broader age class definitions.

Scours panel (Neonate): Specimen: Faeces & Serum

Faecal - E.Coli K99, Salmonella, Coronavirus, Rotavirus, Cryptosporidium

Serum - GGT

Scours panel (Juvenile): Specimen: Faeces

Faecal - Salmonella, Yersinia, Faecal Egg Count, Coccidia

Scours panel (Adult): Specimen: Faeces, Serum, EDTA

Faecal - Panel 5, Faecal Egg Count

Serum - Johne’s Disease ELISA, Bovine Viral Diarrhoea (BVD) Pestivirus Ag Capture ELISA, Pepsinogen

K99 Escherichia coliApart from histology and culture, Enterotoxigenic E. coli in calves can be diagnosed by K99 antigen detection with ELISA. This antigen can also cause diarrhoea in piglets and lambs. K88 antigen detection is also available and this antigen is specific for piglets. 

Gribbles Veterinary Pathology offers culture for the confirmation of E.coli infection and a faecal immunoassay for the diagnosis of K99 or K88 infection. Cases negative for K88 and K99 are not necessarily negative for E.coli infection. Strain typing is available as a referred test if desired. 

Besides fresh intestine for culture and formalin fixed intestine for histopathology, formalin-fixed tissues of liver and lung may help in diagnosing enteropathogenic E.coli cases.

Please be advised that even with both culture and histopathology, a small percentage of E.coli cases can still be missed.

Serum GGT – Levels of serum GGT in calves are directly proportional to the quantity of colostrum absorbed. We recommend taking 5-10 sera samples from affected and in-contact calves. The half-life of GGT in serum is relatively short and so this test can only be interpreted in calves less than 5-7 days of age.





Escherichia coli, Coronavirus (Transmissible gastroenteritis), Rotavirus, Isospora suis

˂ 3 weeks of age

E. coli: No gross lesions

Isospora: ˃5-6 days

Clostridium perfringens Type C and Clostridium difficile

˂ 3 weeks of age


 Note: Bacteroides fragilis, Salmonella and Klebsiella sp. have rarely been implicated as a cause of diarrhoea in neonatal pigs. Strongyloides ransomi may infect young piglets causing diarrhoea. 


1. Lambs: Causes identified in neonatal lambs include E.coli, Rotavirus and Cryptosporidium, overfeeding and very occasionally milk replacer contaminated with bacteria at manufacture. Outbreaks of diarrhoea in colostrum-deprived orphan lambs held in sheds and fed milk supplements are not unknown.

Salmonellosis may occur rarely in young lambs. Bacteroides fragilis, producing enterotoxin, has been implicated as a cause of diarrhoea in neonatal lambs.

2. Goats: Causes of undifferentiated diarrhoea are poorly defined, but appears to be minor under usual conditions of husbandry. A similar spectrum of agents that affects lambs may be expected and sought.

Clostridium perfringens Type B in lambs and kids under 8-10 days can be recognized as severe haemorrhagic enteritis, occasionally with necrotic ulcers.

Coccidiosis due to Eimeria spp. in lambs and kids may occur in animals as young as 3 weeks of age.

Strongyloides may also be associated with diarrhoea in ruminants only a few weeks old.


The most common causes are foal heat diarrhoea, Strongyloides westeri, Salmonella, E. coli, Rhodococcus equi (1-4 months), Cryptosporidium and Rotavirus. Enterotoxigenic E coli and Coronavirus are not proven to cause diarrhoea in foals. Actinobacillus equuli may cause severe diarrhoea and haemorrhagic enteritis, with lesions of bacteraemia in other organs. Fibrinonecrotic enteritis in foals less than 1 week of age may be due to Clostridium perfringens Type B or C, or Clostridium difficile. Rhodococcus equi may cause chronic diarrhoea and wasting in foals. Clostridium piliforme (Tyzzer’s disease) which is restricted to foals under 6 weeks of age may be associated with diarrhoea; however, the liver lesions predominate.


Outbreaks of diarrhoea and death in unweaned fawns ˂ 2 years of age on pasture have been caused by Cryptosporidium. Diarrhoea outbreaks have also been recorded in slightly older fawns exposed to wallows heavily contaminated with faecal bacteria.

Reference: Jubb, Kennedy and Palmer’s Pathology of Domestic Animals. Grant Maxie, 2007. Volume 2. P129-131.