Gastrointestinal Flashcards
Infectious causes of diarrhoea in cows
Salmonella
Eimeria spp.
Rotavirus
Coronavirus
Mycobacterium avium subspecies paratuberculosis
Cryptosporidium parvum
E. coli
Bovine viral diarrhoea cirus
Rinderpest
Clostridium spp.
Nematodes
Yersinia
Malignant catarrhal fever
Secondary to septicaemia
Non-infectious causes of diarrhoea in cattle
Nutritional
Poisonous substances
Mycotoxins
Acidosis
Copper deficiency/toxicity
Cobalt +/- selenium deficiency
Secondary to peritonitis
Pathogens that commonly cause scour outbreaks in cattle
Salmonella
Acidosis (population level)
Coronovirus (winter dysentry)
Mycotoxins (spoiled feed)
What is always a differential in scour?
Salmonella
What age are cattle affected by Eimeria spp.?
Pre-weaning from a few weeks old/post weaning
What pathogen can affect calves at any age pre-weaning?
Clostridium
Causes of scour in pre-weaning calves <14d of age
Rotavirus
E. coli
Coronavirus
Cryptosporidium parvum
Causes of scour in adult housed cattle
Winter dysentery (coronavirus)
MAP (Johne’s)
Differentials for scour in house cattle of any age
Salmonella (reportable)
Rinderpest (notifiable)
BVD
What causes death (+/- severe diarrhoea) and haemorrhagic, gas filled small intestines on post mortem in the pre-weaned calf?
Clostridium
Diagnosis of Eimeria
McMasters
Prevention of Eimeria
Oral drench (Diclazuril, Toltrazuril)
Decoquinate in feed
Hygiene (bedding management, stocking densities, group management)
What can cause proliferation of Clostridium perfringens?
Sudden diet change
Presentation of winter dysentery (coronovirus)
Short lived explosive D+
Highly contagious
Predominantly in winter
Cattle in close confinement
Clinical disease caused by Salmonella
Septicaemia (especially calves)
Enteritis
Abortion
Sources of Salmonella infection
Brought in animals
Birds
Contaminated feed (birds/rodents)
Contaminated water
Pathophysiology of Salmonella infection
Once ingested, Salmonella attaches to mucosal cells and destroys enterocytes
Stimulates inflammatory response and ingested by macrophages/PMNs
Rapid dissemination throughout body including lymph tissue
Bacteraemia
Approach if Salmonella is suspected in cattle
Contact APHA (reportable)
Salmonella treatment
Trimethoprim sulphonamide (gram -ve)
Meloxicam
Fluids (IV/oral)
Factors predisposing cows to sub-acute rumen acidosis
Excess starch (high concentrate/slug feeding)
Lack of fibre (dietary sorting/spring grass)
Decreased intake (heat stress/poor cow comfort/poor transition cow management)
Clinical signs of sub-acute rumen acidosis
Body condition loss
Variable faecal consistency
Reduced rumen contractility/feed intake
Periodic anorexia
Increased faecal contamination of tail/rump/perineum
Ejected cudballs or reduced rumination
Diagnosis of sub-acute rumen acidosis
Rumen fluid sampling (stomach tube/rumenocentesis)
Differentials for melaena
Abomasal ulcers
Bovine petechial fever
Arsenic poisoning
Seminal vesiculitis (male)
Causes of abomasal ulcers
Intensely managed herds (diets more acidic due to concentrates)
Maize silage
High yielding dairy cows (first 4-6w of lactation/dry period)
Long term NSAIDs
Lymphosarcoma
Abomasal displacement/volvulus
Clinical signs of abomasal ulcer
Intermittent occult blood in faeces or death from massive haemorrhage
Mild abdominal pain
Bruxism
Sudden onset anorexia
Tachycardia
Diagnosis of abomasal ulcer
Transabdominal ultrasonography
Haematology (PCV determines extent of haemorrhage)
Faecal evaluation for occult blood
Abdominocentesis (perforated ulcers = large quantities of abdominal fluid)
Treatment of abomasal ulcers
Improve dietary intake (food = buffer)
Decrease acid secretion (omeprazole)
Blood transfusion
Aetiology of LDA
(Calving also increases abdominal void)
Physiological consequences of L/RDA
(rehydrate cow after fixing DA to resolve)
Risk factors for LDA
Calving (especially large calf/dystocia)
Ketosis
Decreased DMI for any reason
Overconditioned cow near calving
Any periparturient disease (mastitis/metritis/hypocalcaemia etc.)
Big increase in concentrates
Surgical approaches to LDA
Right sided (Hannover)
Left sided (Utrecht)
Bilateral
Paramedian
Toggle (Grymer-Sterner)
Endoscopic (Christiansen)
Differential for scour in older ewes
Johnes
What causes watery mouth in lambs?
E. coli in young lambs (<4d)
Control of watery mouth
Good hygiene
Colostrum management
(Not prophylactic antibiotic treatment)
Clostridia causing sudden death and blood tinged diarrhoea in lambs <3w
Clostridia perfringens Type B/lamb dysentery
Control of lamb dysentery
Vaccination of ewes/lambs vaccinated from 2-3w
Which lambs are affected by coccidiosis?
Young lambs born early in season
3-12w lambs most at risk
Pathogenic Eimeria in sheep
E. ovinoidalis
E. crandallis
Clinical signs of coccidiosis in lambs
Straining
Abdominal pain
Diarrhoea +/- blood
Dehydration
Death
Ill thrift/poor growth
Protozoal parasite causing disease in young lambs (<10d) and calves, zoonotic with faeco-oral transmission
Cryptosporidium parvum
Why do Cryptosporidium levels build up over time?
Oocytes persist in environment and resistant to many common disinfectants
Diagnosis of cryptosporidium
Faecal sample/PM
Rainbow scour test (calf side)
Rotavirus
Coronavirus
E. coli
Cryptosporidium
Which endoparasites do sheep not develop immunity to?
Fluke
Haemonchus
Which endoparasites do cattle not develop immunity to?
Fluke
(Lungworm immunity short lived)
Pastures high risk for nematodirus
Pastures grazed by lambs the spring before
Which intestinal parasite of sheep is a pre-patent disease?
Nematodirus battus (larvae responsible for disease)
Organ affected by nematodirus
Small intestine
When is the peak risk period of Telodorsagia (Ostertagia) circumcincta in sheep?
Mid spring to late autumn
Parasites affecting sheep abomasum
Teladorsagia (Ostertagia) circumcincta
Haemonchus contortus
Trichostrongylus axei
Liver fluke
Fasciola hepatica
Nematode affecting abomasum in cattle
Ostertagia ostertagi
Nematode affecting small intestine in cattle
Cooperia oncophora
Nematode affecting lungs in cattle
Dictyocaulus viviparous
Anthelmintic effective against Nematodirus but with lots of resistance
Benzimadazole/BZ/Group 1/White
Which anthelmintic is useful for increasing the life of group 1, 2 or 3?
Group 4/Orange/AD
Which anthelmintic is a dual active product?
Group 5/purple (Spiriondole and abamectin)
How are farms reducing anthelmintic dependence?
Genetics
Grazing management (co grazing, sheep follow cattle, adult ewes on high risk pasture)
Bioactive forage (chicory)
In-refugia population
Population of worms that are not exposed to treatment to dilute eggs produced by anthelmintic resistant worms
How can farmers decide when anthelmintic treatment is required?
Pooled faecal egg count (regularly done to track rise)
Poor growth: >300epg
Clinical disease: >500epg
Death: >900epg
How should farmers decide which sheep to treat with anthelmintics?
Expected DLWG (underperforming = benefit from treatment)
How can anthelmintic resistance be monitored to inform anthelmintic choice?
Faecal egg count reduction test
How is an in-refugia population maintained?
Targeted strategic treatment or dose-delay-move
How is a faecal egg count reduction test done?
Individual samples pre and post drenching
Choose lambs with a high starting FEC (>500epg)
Split into 3 groups and worm each with a different class (BZ, LV, ML)
Resample lambs in 7-14d (<95% reduction = resistance, <50% reduction = drench failure)
How can you reduce risk of type 2 ostertagiosis in cattle?
Worm at housing with ML to remove inhibited O. ostertagi
Which common parasite are FECs not useful at detecting and how should they be treated?
Nematodirus
Strategic prophylactic treatment with BZ based on larvae peak (forecasts)
