Parasitic diarrhoea and thin ewes Flashcards
How much feed space should ewes have for continuous vs discontinuous feeding
Continuou s= 20cm
discontinuous = 45 cm
How high should grass swards be
> 4cm
What % BW do dry ewes eat per day vs lactating
Dry ewes = 1.5%
Lactating ewes = 3%
How does Johne’s disease work
Mycobacterium avium subspecies paratuberculosis ingested in early life
Enters M cells in Peyer’s patches –> granulomatous inflammation –> latent period –> diffuse, severe granulomatous enteritis
Get death in sheep 2-6 years old
What response causes paucibacillary vs multibacillary form of Johne’s disease
Pauci = mainly Th1
Multi = Th2
Symptoms of Johne’s disease in sheep
WEight loss, faecal softening, high egg counts
NO DIARRHOEA
Enlarged mesenteric LNs
Vaccination for Johne’s disease
Killed vaccine can be given from 3 weeks age
- NOT sterile immunity; but decreases shedding and slows disease course
Small ruminant lentiviruses pathogenesis
Not oncogenic
HAve tropism for macrophages and denditic cells; infiltration into organs
In lungs: see progressive pneumonia
In udder: progressive mastitis
In CNS: meningoencephalitis (VIsna)
How does Maedi virus work
= lentivirus; so macrphage/dendritic cell tropism
See hard udder with no milk, exercise intolerance and on PM lungs are heavy and rubbery + don’t collapse
What is CAE in goats
Caprine arthritis encephalitis
= Lentivirus
Causes encephalitis and arthritis
How to deal with Maedi-Visna
Can be part of accreditation scheme; test all animals twice over a year to qualify
- Then a proportion every few years + keep isolated stock
Control: keeping a young flock helps; spread sheep out to reduce horizontal transmission
What is Jaagsiekte retrovirus
= oncogenic retrocirus that affects sheep and causes transformation of type II pneumocytes
> Virus inhaled/ingested –> WBCs –> via blood to lungs –> type II pneumocytes
Get adenocarcinomas
Clinical signs/PM findings with ovine pulmonary adenocarcinoma
Exercise intolerace, increased resp rate/effort, weight loss
On PM: consolidated areas of lungs, often grey/purple, secondary infections
Offspring from which age age sheep do we want to keep when controling ovine pulmonary adenocarcinoma
OLDER ones; if still no clinical signs, probably don’t have it
-> So offspring will be free
What bacteria causes caseous lymphadenitis in sheep
Corynebacterium pseudotuberculosis = gram + rods
>
Pathogenesis of caseous lymphadenitis
Bacteria enters via skin lesions, reaches local LN and causes cycles of necrosis and encapsulation (via phospholiapse D)
Then get haematogenous spread to other LNs and lungs
> NB eosinophil entry causes green colour
Onion skin lesions