Farm Animal Flashcards
What does tritrichomonas foetus cause in cows?
Abortion
Transferred to cats
What are the four factors involved with diarrhoea in farm animals?
Pathogens
Calf factors (immune system, stress)
Environment
Management
Why should we not always think of pathogens when judging diarrhoea in farm animals?
Lots of other causes - mainly dietary
What are some pathogens that cause calf diarrhoea?
E. coli
Rotavirus
Coronavirus
Cryptosporidium
Salmonella
Mixed infections
Coccidiosis
What bacteria is a normal inhabitant of the colon in all animals?
Escherichia coli
What three types of disease can E. coli cause?
Extraintestinal infection (colisepticaemia)
Enteric disease (special strains: ETEC)
Disease affecting public health (rare, special strains: STEC)
What can enterotoxigenic E. coli cause in calves?
Watery diarrhoea
Scours
When can E. coli cause disease in calves?
First 5 days
Coupled with management problems and loss of immunity
What can make ETEC infection in calves more common?
A younger calf
Less colostrum makes it more likely to be infected
How does ETEC get into the GIT?
Ingested
Colonises the lower small intestine
What can exacerbate ETEC infection?
Rotavirus
What two factors does ETEC require to cause disease?
Adhesive fimbriae
Enterotoxin
What are adhesive fimbriae?
Proteinaceous surface appendages that stick to epithelium
Why is ETEC not zoonotic?
Colonisation factors (fimbriae) won’t allow cross colonization into other species
What makes up the labile toxin in ETEC?
5 B subunits and 1 A subunit
What is the ETEC labile toxin similar to?
Cholera toxin
What does the labile toxin attach to?
Brush border of small intestine
How can labile toxin be used in a vaccine?
Included as the body can produce antibodies
What is released into the cytoplasm when the labile toxin binds to the cell border?
The A subunit
How does the labile toxin work with ETEC?
Causes conversion of Gs into Gs-ADP-R
Can’t control adenylate cyclase causing an increase in cAMP
Activates Cl- channel causing a loss of Na+ and H2O into lumen
Active secretion
What diseases are associated with the labile toxin on ETEC?
Metabolic acidosis
Dehydration
Electrolyte loss
What are the two forms of the stable toxin of ETEC?
STa - raises intracellular guanylate cyclase
STb - action unknown
Is the stable toxin immunogenic?
No
Why are faecal cultures for E. coli pointless?
Culture will always yield E. coli and can’t tell ETEC from normal
How can ETEC be demonstrated?
Show both the toxin and the fimbriae
What age calves does rotavirus cause disease in?
1-3 week olds
Describe how rotavirus causes disease
Shed by cows and older calves and persists in environment
Younger calves pick them up
Immune status not yet developed so can’t fight infection off
Which parts of the GIT does rotavirus affect?
Duodenum
Jejunum
What age calves can Coronavirus cause disease in?
7-28 days
What is usually coupled with rotavirus infections?
Coronavirus infections
What age calves does salmonella cause in infection in?
Any age
What should be done if salmonella culture is detected?
Report it to the local Veterinary Laboratories Agency laboratory
What does salmonella cause in cows and what is always indicated?
Systemic illness
Pyrexia
Antibiotics always indicated
When are clinical signs of cryptosporidium seen?
5-14 days old
If a cryptosporidium problem is present what does this indicate about the farm?
Management problem as pathogen exists in environment for a long time
What part of the GI tract does cryptosporidium infect?
Lower part of the small intestine
Colon
What does cryptosporidium cause in calves?
Villous atrophy causing malabsorption
Results in white pasty diarrhoea
What age does coccidiosis affect calves?
Slightly older weaned calves (>3 weeks)
What presents with coccidiosis?
Blood stained faeces
Tenesmus
What occurs with subclinical coccidiosis?
Poor growth rate
Other infections as immunocomprimised
What should be taken to diagnose cause of diarrhoea?
Faecal samples
Which animals should faecal samples be taken from?
Healthy and affected
Could be a herd problem
What should be consider first with farm animal diarrhoea before a pathogen?
Dietary problem
What should indicate the pathogen with diarrhoea in calves?
Age
History
Clinical signs
What are the four factors that affect infection in calves?
Colostrum access
Dystocia - difficulty birthing
Competition
Cow factors
How much more likely are calves to die with an inadequte colostral status?
Four times
What is needed for adequate rumen development?
Cake
What is the recommended feeding rate for calf milk replacer?
15-20% of body weight per day
What endoparasites cause disease in the growing animal?
Ostertagia
Coccidia
Fluke
What nutritional diseases affect growing calves?
Rumen acidosis
Copper deficiency
What are some infectious diseases in growing animals?
Salmonella
Mucosal disease
What are some infectious causes of disease adult cow diarrhoea?
Johne’s Disease
Salmonella
Coronavirus
What is a nutritional disease causing adult cow diarrhoea?
Sub-acute rumen acidosis
What are the parasitic causes of adult diarrhoea in adult cows?
Fluke
Ostertagiosis
What causes Johne’s disease in cattle?
Mycobacterium avium paratuberculosis
What presents with the initial stages of Johne’s disease?
Off milking
Depressed
What does Johne’s disease cause in clinical cases?
Severe diarrhoea
Weight loss
What needs to be done to cows with Johne’s disease?
Culled
What may Johne’s disease be involved in as a zoonosis?
Chron’s Disease - IBD in humans
When does Johne’s disease become clinical?
At least 2 years old
Do not really see it before 3
How is Johne’s disease spread and what percent of calves are infected within the first week of life?
Faecal-oral route
90% infected in first week
What does control of Johne’s disease largely rely on?
Preventing young animals becoming infected from:
- Faeces
- Colostrum
- In utero
What tests are done in a clinical farm animal to test for MAP?
ZN smear
ELISA
These are cheap
What tests are done for Johne’s when buying an animal?
PCR faecal
Faecal culture
More expensive
