Ovine Flashcards
What problems may thin ewes have in a flock?
Decreased ovulation rates, increased foetal resorption, increased deaths, increased perinatal mortality due to smaller lambs and decreased colostrum, metabolic diseases such as pregnancy toxaemia, decreased lamb growth rates, welfare concerns.
What types of disease may cause ill thrift in adult sheep?
Sheep scab, lameness, Johnes, fluke, PGE (haemonchus),teeth problems in old ewes, triplet ewes, gimmers/ewe lambs, Chronic pneumonia (MVV, spa, pasteurellosis), chronic lameness, CLA, chronic abscessation, neoplasia, scrapie etc.
What is Johne’s disease?
Chronic bacterial enteritis of ruminants caused by mycobacterium avium subspecies paratuberculosis. Survives in the environment for months and is difficult to culture. There is a long preclinical stage with reduced production.
What are the clinical signs of Johne’s?
Progressive loss of condition - protein loss, muscle wasting, brought on by stress. Faeces is normal or slightly soft. Usually have a high GI parasite burden. Up to 5% mortality in adult sheep.
What gross pathology will be seen in ovine Johne’s disease?
The terminal ileum may be grossly thickened or congested, difficult to detect, may be pigmented yellow, may affect afferent lymphatics/nodes, and cause ascites etc.
What are the two forms of ovine johne’s disease?
Multibacillary - weak CMI, strong antibody. Numerous Map in macrophages.
Paucibacillary - strong CMI, weak antibody, map sparce or absent.
How can Johne’s be diagnosed?
Faecal smear, Faecal culture (8-14 weeks, sheep strains v poor growth), faecal PCR, Serology - ELISA, AGID, serum proteins.
What protein levels will be seen with chronic fasciolosis?
Hypoalbumin, hyperglobulin.
how is Johne’s trasnmitted?
Oral faecal, in milk, possibly semen, possibly in utero
What are the costs associated to the farmer with Johne’s?
Lost of cull ewe sale, cost of replacement, death /poor growth of lambs from affected ewes.
What are the control methods for Johne’s?
Reducing environmental contamination and spread of infection, limiting introduction of infection, vaccination, eradication, remove clinical disease, don’t keep lambs from affected ewes for breeding, diagnose and remove subclinical disease, farm hygiene, lambing is a high, avoid high stocking rates on bare pastures, purchase sheep from farms known to be free
Describe the gudair vaccination
Killed strain of MAP in oil. Give single cub cut dose 4 weeks to 6 months for replacements. £2-3 per dose.
Describe the problems seen with incisor loss in ewes?
Unable to bite short pasture so unable to raze - malnutrition, poor production and weight loss on marginal grazing and hill pastures.
What is the aetiology of incisor loss?
Repeated bouts of acute gingivitis, recession of gingival margin and damage to periodontal ligament, bacterial involvement, teeth appear elongated, loose then are lost, may take one to four years.
What are the clinical signs of respiratory disease in sheep?
Coughing, nasal discharge, dyspnoea, as well as crackles and wheeses.
How does Parainfluenza virus Type 3 infect sheep?
Most infections appear subclinical or mild but acute high morbidity outbreaks have been recorded. Infection with PI3 predisposes lambs to infection with manheimia haemolytica. Intranasal (cattle) vaccines have demonstrated a reduction in prevalence of pneumonia.
What type of disease does pasteurellosis cause?
Manhaemia haemolytica causes septicaemia in young lambs, pneumonia in growing lambs and mastitis in ewes. Pasteurella trehalosi causes septicaemia in 6-10 month old lambs. P multocida only rarely causes disease.
What are the clinical signs of infection with manhemia haemolytica?
Hyperacute - sudden death
Acute - sudden onset anorexia and dullness, pyrexia, hyperpnoea/dyspnoea, serous ocular and nasal discharges, frothy fluid at mouth in terminal stages. Chronic presentations may lead to ill thrift.
What findings are seen on pathology with manheimia haemolytica infections?
Ecchymoytic haemorrhages over the throat and over the ribs. The lungs are swollen and purple red in hyperacute cases, and the airways contain pink stained froth.
What are the clinical signs of septicaemic pasteurellosis?
This is an important cause of sudden death in lambs up to twelve weeks old. Affected lambs are depressed, easily caught, with injected mucous membranes and marked dyspnoea, most lambs are pyrexic.
What prediposing factors play a role in triggering clinical manheimia haemolytica?
Environmental conditions - extremes of temperature, wet weather, handling stress, PI3 virus, SPA, mycoplasma/bordetella.
What is the treatment for M haemolytica?
Clinical cases - oxytetracycline, NSAID. A decision must be made whether to gather and treat the lambs during an outbreak. handling may trigger further deaths/disease and most acute mortality occurs in the first day or two of the outbreak. Breeding ewes require a primary course four to six weeks apart followed by a booster four to six weeks before lambing often combined with clostridial vacicine.
What is the most common cause of sudden death in lambs between july and december?
Pasteurella trehalosi. confirmation via isolation of large numbers of P trehalosi from lung liver or spleen.
What are other causes of acute death in lambs?
Clostridial disease, ruminal acidosis, redgut (caecal torsion), acute fluke, brassica poisoning, nitrite poisoning, dog worry, phenol dip aspiration, rhododendron poisoning.