Diagnosis is easy !

But knowing when it is a problem, and when treatment is necessary can often be challenging

Approximately 50% of all TB foals develop diarrhoea in the first few months of life

The annual direct cost to the industry is approximately $1 million, which doesn’t include costs eg decreased growth rate, increased susceptibility to other diseases etc

So it is a big problem, and while there is no realistic way to prevent the occurrence of diarrhoea, there are ways to decrease its incidence and severity

INFECTIOUS

Bacterial

Viral

Protozoal

Parasitic

NUTRITIONAL

"FOAL HEAT" DIARRHOEA

ANTIBIOTIC/DRUG ASSOCIATED

 

Important to recognise the early signs of sick foals

Foals can get sick very quickly, and early recognition can make all the difference

One of the earliest signs is that foals go off the suck - instead of going straight to the teat when they are woken up, they will play around with the teat, or just stand next to the mare

Milk on the face is a sign that the foal is not sucking properly - they nuzzle the teat, which makes the mare let down, but they do not drink

Normal foals do not sleep standing up. They spend the majority of time eating and sleeping lying down

An increased ( > 39 degrees ) or decreased ( < 37 degrees ) temperature

Common occurrence in foals 6-14 days of age

Gets its name due to timing - often occurs at about the time of foal heat

foals do not get sick. It is usually self-limiting and requires no treatment in most foals.

If diarrhoea lasts longer than three days, may need treatment

BUT if a foal does have diarrhoea at this age and is sick ( eg off the suck, increased temperature), then another cause of diarrhoea should be suspected

Previously thought to be due to changes in milk composition, hormonal changes associated with foal heat, coprophagy, ingestion of mare’s vaginal discharges, ingestion of irritants or forage, carbohydrate malabsorption, overeating or parasitic infection

however, orphan foals which are fed an artificial diet, and are parasite free also develop foal heat diarrhoea

Now generally accepted to be caused by adaptive changes in the foals gut ie the foals are adapting to increasing amounts of forage in the diet

 

 

The most common and serious cause of bacterial diarrhoea in foals

The majority of these foals are sick. They go off the suck, have an increased or decreased temperature, increased heart rate (HR) and respiratory rate ( RR), rapidly become dehydrated, and may be colicky

Rapid onset of clinical signs

The diarrhoea ranges from cowpat to severe profuse foul smelling

May have other diseases concurrently eg joint ill, pneumonia

Become infected by ingesting the bacteria in the faeces of an infected horse, which may be the mare

foals with diarrhoea caused by E.coli are generally septicaemic, and systemically unwell

usually have eg joint ill, pneumonia

Most often seen in foals less than three days old, although may also occur in older foals

Acute onset of abdominal pain, dehydration, recumbency and profuse watery diarrhoea. The faeces may also be bloody

Foals may die of shock before they develop diarrhoea - may be found dead .

several other bacteria capable of causing diarrhoea, but decreased incidence compared to above

eg R. equi ( "rattles bacteria" )

Most common cause of infectious diarrhoea in foals throughout the world

Seen in foals 2 days to 6 months

Younger foals tend to get more severe disease

Foals get sick - off the suck to start with, may have an increased temp

Break with diarrhoea after 1-2 days

The type of diarrhoea ranges from watery or pasty , and from bright yellow to grey in colour

Clinical signs generally lasts 6-7 days ( up to 13 days )

The loss of fluid and electrolytes in the diarrhoea, and the fact that the foals are not nursing means they can quickly become dehydrated and need treatment with fluids ( usually IV )

 

Rotavirus is transmitted by the faeco-oral route ie foals become infected by ingesting the virus which exists in the faeces

Most foals are exposed to the virus early in life. It can survive a long time ( 9 months ) in paddocks, stalls etc. They ingest the virus, and become infected.

But disease doesn’t necessarily develop because disease is dependent on the size of the infecting dose

Thus, foals which ingest small doses of the virus will not develop the disease, but instead will develop immunity to subsequent infections

However, these foals do shed virus in their faeces, thus further contaminating the environment

So as foal numbers increase during the season, viral contamination increases, and there is an increased likelihood of foals receiving a sufficiently large dose to cause disease

Overcrowded conditions increase the likelihood of disease developing

Foals with diarrhoea shed huge amounts of virus, and outbreaks can occur if steps to control further contamination are not taken

 

parasite burdens can cause diarrhoea in foals as young as 2 weeks old

Infection occurs by ingesting milk infected with larvae, or eggs / larvae in faeces

May also have fever, colic and depression

Routine worming of mare during pregnancy and lactation will help prevent this

 

This is relatively common, especially when foals are fed artificial diets

overfeeding / overeating can lead to bloat, gut stasis and diarrhoea

When a foal starts to eat artificial diets, may see diarrhoea

Eating sand or other indigestible feeds can cause bowel irritation and diarrhoea

A slow introduction of dietary changes will help decrease the prevalence of nutritional diarrhoea.

Foals with sand diarrhoea / colic may need treatment with metamucil orally

Milk intolerance , with signs of bloat, colic and gastric reflux can occur in sick foals with diarrhoea. May need to restrict milk intake and supplement with either oral or IV electrolytes, fluids and glucose

antibiotics eg trimethoprim –sulfa’s ( TMPS ), erythromycin, metronidazole and oxytetracyclines may play a role in the development of diarrhoea, primarily due to alteration of the gut microflora

Discontinue antibiotics if practical, supportive therapy, yoghurt

Overuse of anti-ulcer drugs eg cimetidine can change the pH of the stomach so that bacteria which are normally killed by the low pH of the stomach are now able to survive the higher pH , and thus reach the lower GIT, resulting in diarrhoea

 

Any foal with diarrhoea which is sick eg off the suck , should be seen by a vet. This will help to prevent severe illness and dehydration

Ensure all foals receive sufficient colostrums. Supplement with colostrum or plasma if necessary. Foals with low IgG levels are at increased risk of developing disease such as bacterial and viral diarrhoea

Foal down in clean, thoroughly disinfected boxes. Clean the mare up before foaling etc

Disinfectants- see table

avoid overcrowding in foaling paddocks, especially as the season progresses

isolate all new introductions to the farm for at least two weeks. This quarantine time will help identify any new mares / foals which are incubating disease, and prevent them from introducing it to other horses on the farm

any foal with diarrhoea should be isolated to prevent them from further contaminating the environment eg one ml or diarrhoea from a foal with rotavirus contains 10 ⁹ viral particles, and it takes as little as 90 viral particles to cause disease in a susceptible foal. Foals with rotavirus diarrhoea can shed virus in their faeces for up to 6 days after the diarrhoea has stopped, thus foals should be isolated for at least a week after the clinical signs have stopped

Mares and foals which have been in contact with a foal with diarrhoea should not be mixed with other horses, as they are potentially infected

Wash hands after handling foals with diarrhoea ( povidone iodone)

Vaccination eg Salmonella

G+ve = gram positive bacteria

G-ve = gram negative bacteria

QACS = Quaternary ammonium compounds

`Foals with diarrhoea can get sick quickly - catching them early and identifying those foals which need treatment is important to decrease the severity and mortality rates

Prevention of diarrhoea relies on ensuring sufficient IgG levels, preventing infection of the newborn by thorough disinfection, and preventing further spread by isolation and quarantine practices