Bovine and Ovine Gastrointestinal Flashcards
What is some important history questions to ask for bovine diarrhoea?
- Herd or single animal
- Previous occurrence?
- Age group
- Duration of diarrhoea
- Nutrition?
- Water source? Is this contaminated?
- Production effects – understanding if this is affecting growth rate or welfare
Why might calves have diarrhoea if put onto lush pasture?
Calves being on lush pasture with diarrhoea as a normal physiological response to nutrition, need gut microflora to adapt in order for diarrhoea to settle down. Knowing when to do nothing.
What should be looked for when examining a group or individual cow?
- Drooling saliva
- Abdominal pain
- Tenesmus
- Clinical examination, especially assessing level of dehydration
What is examined from the faeces when assessing bovine diarrhoea?
Consistency
Colour
Smell
Mucoid
Blood
Sample
What is assessed upon examination of an cow with diarrhoea?
- Oral cavity for lesions
- Perineal region
- Any abdominal pain?
- TPR
- Body condition?
- Any lameness?
- Any nervous signs?
What are the plant and chemical poisoning differential diagnoses for bovine diarrhoea?
- May become confined to area with little food
- May be exposed to dumping of potentially harmful material
- May be exposed to excessive lush pasture or acorns blowing into field (tannins are toxic and cause kidney damage and diarrhoea)
What are the dietary induced differential diagnoses for bovine diarrhoea?
- History of husbandry changes important
- Ruminal overload, frosted foods, grass scour, excess fodder beet
What is the epidemiology of coccidiosis causing bovine diarrhoea?
- Increasing incidence due to indoor intensification - in housed confined calves, often insufficient bedding
- Oocysts survive months in faeces but only a few hours in sunlight. Parasites are ubiquitous but disease due to build up of predisposing factors
What is the pathogenesis of coccidiosis causing bovine diarrhoea?
- Acute to chronic diarrhoea, smelly, often greenish, can get mucoid/blood
- Poor weight gain or actual weight loss
- Self-limiting, diagnose by examining group
How is coccidiosis treated in cows?
- Diclazuril orally or perhaps sulphonamides
- Decoquinate in feed preventive medication
What are 2 examples of helminths causing bovine diarrhoea?
Ostertagiasis type I and II
Fasciola hepatica
What does salmonellosis cause in cows?
Enteritis
Abortion
Septicaemia
How is salmonella transmitted in cows?
- Faecal-oral
- In feed, on vet, in slurry, rodents and birds
- Conjunctival
- Respiratory
What is the infective dose of salmonella in cows?
10^10 in adults, 10^8 in calves
Clinical cases excrete 10^8/g faeces
What is the incubation period of salmonella in cows?
1-4 days
What is the epidemiology of salmonella typhimurium?
- October-December
- Not host specific
- Causes enteritis or septicaemia
- Resolved after 3-16 weeks
- Epidemic
What is the epidemiology of salmonella dublin?
- Endemic in wetter areas
- Host-adapted
- Active carriers shed for up to a year
- Passive carriers shed while exposed
- Latent carriers shed when stressed
- May even get congenital infection as it can be spread from the reproductive tract in calf from cow that aborted
- Association with Fasciola hepatica
What are the sites of carriage of salmonella in cows?
- Caecal contents
- Terminal ileum
- Ileal/caecocolic lymph nodes
- Gall bladder
- Shed in faeces
Distinguish carriage in cows of salmonella typhimurium and dublin.
Carriage for around 4 weeks with Typhimurium but carriage for years with Dublin
How is salmonellosis diagnosed in a laboratory?
- Faecal culture
- Environmental samples
- Pathology especially gut lesions
- Histopathology
- Culture of lesions
- Culture at abattoir
- Serology – this will only tell you that the animal has antibodies, not if came from active or previous infection or vaccination
Why is salmonella difficult to treat and control in cows?
- Antimicrobial sensitivity testing aids selection of therapy
- S. Dublin largely sensitive
- Vaccines containing killed culture
- Organisms sensitive to disinfectants, but resistant to drying
What are the clinical signs of salmonella in cows?
- Adult cattle enteric syndrome
- Lethargy, pyrexia, milk drop
- Diarrhoea, possibly preceded by firm, bloody faeces
- Sometimes profuse and watery
- Often blood, mucus and casts
- Abdominal pain
- Recumbency
- Death
- Adult cattle abortion – abortion, with or without diarrhoea. More common with S. Dublin infection
What are the clinical signs of salmonella in calves?
- Lethargy, pyrexia, inappetence
- Diarrhoea
- Dehydration
- Death
- Sudden death
- Sloughed extremities in some recovered cases esp. S. Dublin
- Polyarthritis, pneumonia and meningitis are less common
How are individual cases of bovine salmonellosis diagnosed?
- Clinical signs and PM findings suggestive
- Faecal bacterial count
- Faecal/gut content culture – repeat cultures?
- Tissues to culture
- Haematology
How are cases of bovine salmonellosis on a herd level diagnosed?
- Herd culture – representative faecal samples, slurry samples
- Herd ELISA – many high titres indicate recent/active infection
How is salmonellosis in cows treated?
- Systemic antibiotics
- Supportive care – fluids (IV/PO), nursing, diet
How is bovine salmonellosis prevented and controlled?
- Biosecurity
- Vaccinate – active and passive
What are the consequences of salmonellosis causing peripheral gangrene in cows?
- Jelly looking lesion and clear demarcation of healthy skin
- Extremities would be very cold and are not lamb as they cannot feel it, so end up damaging it more
- Stink because they are gangrenous and necrotic
- Eventually toes will fall off
- Often the scruff end of tails and ears too, as infection has gotten into peripheral tissues and has affected the blood supply and has caused the peripheral tissue to die off
What are the risk factors for enteric disease in neonatal lambs?
- Pathogen/disease build up under intensive conditions in lambing sheds
- Overcrowding
- Overworked staff
- Contact between neonates and older lambs
What is the cause of watery mouth in noenatal lambs?
E.coli
What are the risk factors of watery mouth?
- Usually very young lambs (12-48hrs old)
- Often twins/triplets
- Poor colostrum intake
- Flocks housed at lambing
- Thin ewes
- Low birth rate
- Contaminated environment
What are the clinical signs of watery mouth in lambs?
- Dull, weak, unwilling to suck
- Drooling saliva
- May be acidotic (suppresses suck reflex)
- Hypothermia follows
- Abdomen becomes distended with gas
- Gut stasis (as opposed to diarrhoea)
- Retained meconium
- Die within 12-24 hours
How is watery mouth treated in lambs?
- Treat clinical signs
- Prevent starvation – intraperitoneal glucose as for hypothermic lambs
- Pain relief – NSAIDS via cascade
- No antibiotics – these will not work and will only cause resistance
- Prevention is better than cure
How are ewes managed to prevent watery mouth in lambs?
- Monitor body condition score
- Nutritional management
How are lambs managed to prevent watery mouth in lambs?
- Consider lambing outdoors
- Sufficient space
- Maintain hygiene
- Dry clean bedding – completely cleaned out regularly
- Clean utensils
- Isolation pen for sick lambs
- Avoid mixing of ages
- Lamb management – colostrum intake (50ml/kg within 4-6 hours of birth)
What is colisepticaemia?
- Lambs up to 7 days old
- May be in conjunction with watery mouth
- Systemic E.Coli infection
How does diarrhoea in neonatal lambs cause death?
Neonatal scour > dehydration > high mortality
How is diarrhoea in neonatal lambs diagnosed?
10 faecal samples from scouring lambs and/or PME
What is the pathogenesis of enteric colibacillosis?
- Non K99 E.coli strains
- Invasive strains enter via gut or navel
- Colonise and proliferate in upper SI
- Toxins cause secretion of fluid into intestinal lumen
What are the clinical signs of enteric colibacillosis?
Diarrhoea
Dehydration
Recumbency
Stop nursing
Death
How is enteric colibacillosis treated?
- Supportive fluid therapy
- NSAIDS
- Antibiotics? Can interfere with normal gut flora. IM amoxicillin may be beneficial
What causes lamb dysentery/cherry gut?
Clostridial perfringes type B
What are the clinical signs of lamb dysentery in lambs 1-3 days old?
- Haemorrhagic enteritis
- Abdominal pain
- Sudden death
- Mortality 100% in affected
What are the clinical signs of lamb dysentery at post mortem examination?
- Haemorrhagic enteritis, mainly with ileum
- Ulceration of mucosa
- Serosanguinous peritoneal fluid
- Toxins in intestinal content
What causes yellow lamb disease?
Clostridial perfringes type A/haemorrhagic enteritis
What are the clinical signs of yellow lamb disease in lambs?
Diarrhoea
Sudden death
Can sometimes appear as if they have icterus
What are the clinical signs of yellow lamb disease at post mortem examination?
- Generalised haemorrhagic enteritis
- Bloody diarrhoea
- Toxins ins intestinal content
How is yellow lamb disease treated and prevented?
No treatment
Prevention – ewe vaccination (as this affects new borns so ewes can pass on antibiotics in colostrum), colostrum, hygiene at lambing
What are the clinical signs of cryptosporidium parvum in lambs and kids?
- Diarrhoea – liquid and yellow
- Lambs often remain alert, active and nursing
What is the epidemiology of cryptosporidium parvum in lambs and kids?
- Often associated with E.coli and rotavirus as they are immunosuppressed from the cryptosporidium
- Predisposed by poor hygiene, bad weather, inadequate energy intake
How is diarrhoea treated in lambs?
- Oral fluids and allow to suck dam - prevents villous atrophy
- If severe – fluid therapy. Hartman’s solution and sodium bicarbonate to combat acidosis until stops scouring
- NSAIDs under cascade: flunixin, ketoprofen
- Antibiotics rarely indicated – avoid using
- Suitable disinfectant (check will work against causative agents)
Distinguish diarrhoea in neonatal lambs and older lambs?
Neonatal scour > high mortality due to dehydration
Diarrhoea in older lambs – ill thrift
How is diarrhoea in older lambs investigated with history?
- Age
- Grazing history
- Clinical signs
- Treatment history (anthelmintics)
- Environment – hygiene, overcrowding?
- Diet – check for overfeeding with concentrates (acidosis), check for low dry matter forage intake (very lush pasture) or fertiliser application without rainfall
How is diarrhoea in older lambs investigated with diagnostic testing?
- Post mortem examination of dead animals
- Faecal samples for worm egg count, oocyst count, salmonella culture
What are the clinical signs of coccidiosis eimeria in sheep?
- Dehydration
- Dull coat
- Diarrhoea which is often bloody and mucoid
- Depression and lethargy
- Tenesmus (straining)
- May get rectal prolapse due to severe tenesmus
How is coccidiosis eimeria in sheep treated?
- Diclazuril
- Toltrazuril
- In-feed coccidiostats but prevents immunity developing
How is coccidiosis eimeria in sheep controlled?
- Oocysts survive better in wet environments
- Hygiene
What are the clinical signs of salmonellosis in sheep?
- Pyrexia
- Diarrhoea
- Putrid smell, with mucous and flecks of blood
- Tucked up’ abdomen
- Rapid dehydration
- Peracute – found dead
How is salmonellosis in sheep treated?
- Isolate
- Oral rehydration
- Antibiotics
- Move remaining animals from contaminated area
- Disinfect area
- Biosecurity
What is the epidemiology of Johne’s disease in sheeo?
- Very common in goats, sporadic in sheep
- 18 month+ incubation period
What does Johne’s disease cause in sheep?
- Chronic granulomatous enteritis but doesn’t really cause diarrhoea in sheep
- Johnes in sheep is not associated with diarrhoea, it is associated with chronic weight loss (wasting)
When might Johne’s in sheep be associated with diarrhoea?
Animals with Johnes may have concurrent parasitism which produces diarrhoea
Where is mycobacterium avium subsp paratuberculosis located?
Bacteria localise and multiply in mucosa of intestines and their associated lymph nodes (also tonsils)
Why is Johne’s hard to eliminate?
Survive on pasture for up to a year and rabbits implicated as reservoirs of infection, so very difficult to eliminate
How is Johne’s in sheep controlled?
- Cull thin animals
- Do not keep offspring
- Alternate lambing areas each year (reduce spread)
- Vaccinate breeding animals within one month - they will become infected but will not develop clinical signs
What are the clinical signs of scour in claves?
- Fever
- Change in abdominal contour
- Diarrhoea – colour, consistency, blood
- Weight loss
- Inflammation in another body system (umbilicus)
Name 4 endemic pathogens causing calf scour.
Rotavirus
Coronavirus
Cryptosporidia
Enterotoxigenic E. coli
Name 2 exotic pathogens causing calf scour.
E.coli K99/F41
Salmonella
Name 2 pathogens of unknown prevalence causing calf scour.
E.coli AEEC (adherent)
Calicivirus
How does a calf’s age suggest the scouring agent?
0 – 6 days = enterotoxigenic E. coli (ETEC)
6 – 21 days = rotavirus, coronavirus, cryptosporidium
> 21 days = coccidiosis
What is the epidemiology of rotavirus in calves?
- Infection in almost 100% of calves
- Cows shed virus, colostrum contains specific antibodies
- Several strains, some avirulent
How does rotavirus cause scour in calves?
Destruction of microvilli in enterocytes
How is immunity affected by rotavirus in calves?
- Immunity requires local antibody
- Immunity overcome by heavy challenge
What are the clinical signs of rotavirus in calves?
Thin, yellow white diarrhoea, second week of life
How is rotavirus in calves prevented against?
Vaccine available (administered to the dam, immunity via colostrum)
Describe the normal intestinal function in calves.
Lactase cleaves lactose into glucose and galactose. Sodium glucose cotransporter 1 then transports glucose and galactose across the luminal (gut) side of enterocytes with sodium ions.
What is the pathogenesis of rotavirus in calves?
- The non-structural virus protein NSP4 can specifically inhibit this sodium glucose symporter, meaning water cannot be reabsorbed and is lost.
- Calcium ion movement from the ER to the cytoplasm and a loosening of intracellular junctions, which loses fluid from intracellular space to gut lumen
- It is further thought that this can lead to a release of amines and peptides from infected cells that stimulate the enteric neural system, elevating crypt cell sodium secretion and gut motility.
- This takes a while to get over which stunts their growth rates
What is the epidemiology of coronavirus in calves?
- Widespread infection, virus in faeces of 65% cows (winter dysentery)
- Commonly subclinical
- Virus causes diarrhoea that can be acute and severe leading to rapid death in calves or more commonly causes chronic debilitating diarrhoea in older calves
What is the pathogenesis of coronavirus in calves?
- Massive loss of intestinal epithelium and villus stunting
- Greatly reduced absorption of intestinal fluid
- Basal crypt cells less affected, recovery can be rapid
What is the epidemiology of cryptosporidium in calves?
- Extracellular protozoan, not host specific
- Zoonosis
- Infection widespread, favoured by dirty conditions
- Mixed infections common
- Earliest cases 5-7 days, age immunity at three weeks
What are the clinical signs of cryptosporidium in calves?
Profuse watery diarrhoea for about 7 days
Why is cryptosporidium hard to treat in calves?
- Poor response to anti-protozoals
- Oocysts resistant to disinfectant
What are the pathogenic E.coli serotypes?
- Enterotoxigenic E. coli (EETEC)
- Verotoxigenic E. coli (VTEC)
- Attaching and effacing E. coli (AEEC)
- Enteroinvasive E. coli (EIEC)
- Unclassified
What is the pathogenesis of enterotoxigenic E.coli in calves?
- Rare over 5 days old due to loss of receptors on the gut epithelium for E. coli adhesins/toxins
- Specific antibody blocks the adhesion
What are the clinical signs of enterotoxigenic E.coli in calves?
Sudden onset
Profuse watery diarrhoea
Severe dehydration leading to collapse of calf
Recovery takes a while
How does the normal calf gastrointestinal tract digest milk?
- Milk bypasses the rumen via oesophageal groove
- Acid (and rennin) causes paracasein to clot quickly
- Abomasum acts as reservoir, releasing small amounts of clot into SI by action of gastric enzymes
- The whey, containing lactose and globulins, moves quickly into SI
What are the causes of poor clotting of casein that can cause nutritional scour in calves?
- Failure of sufficient acid and enzyme secretion
- Poor quality milk product
- Farmer uses incorrect concentration of milk powder
- Farmer feeds at incorrect temperature
- Feeding times irregular
- Infection of the abomasum
- Overfeeding
What is the consequence of poor clotting of milk in calves?
Casein “spills” over into SI which results in poor digestion leading to poor growth rates as well as possibly nutritional scours
What is the pathogen responsible for calf diphtheria?
Opportunist Fusobacterium necrophorum infection
What is the epidemiology of calf diphtheria?
- Occurs in pre-weaned calves and those up to about 6-9 months age
- Usually single animal, poor hygiene
What causes calf diphtheria?
Need physical abrasion to allow bacteria in – such as feeding bedding hay instead of barley hay, rougher and causes abrasions in the mouth that allow bacteria in
What are the clinical signs of calf diphtheria?
Necrotic infection of oral cavity and often larynx
Extensive salivation
Some swelling
May be dull
How is calf diphtheria diagnosed?
Diagnose on examination of mouth, halitosis, enlarged draining lymph nodes and pain
How is calf diphtheria treated?
- Treat with Penicillin or similar
- Avoid coarse food and improve hygiene