Sheep Flashcards
What is the superfamily of teladorsagia circumcinta?
Trichostrongyloidea
What is the life cycle of teladorsagia circumcinta?
Eggs pass out in faeces, hatch and moult. L1-L3.
L3 migrates onto pasture and is ingested.
L3 exsheaths in rumen and enters gastric gland of the abomasum and moults to L5.
Emerges from the glands and migrates in lumen.
What is the pre-patent period of teladorsagia circumcinta?
16-21 days
How long can L3 of teladorsagia circumcinta hypobiose?
<6 months
What size is the male and female adults of teladorsagia circumcinta?
Male: 6-8mm
Female: 8-10mm
What is the pathology of teladorsagia circumcinta?
Developing larvae in gastric glands causes distension of the glands, thickened hyperplastic mucosa and sloughed epithelium.
What are the clinical signs of teladorsagia circumcinta?
Summer/Autumn Anorexia Intermittent diarrhoea Dehydration Weight loss Death High plasma pepsinogen
What is the epidemiology of type I teladorsagia circumcinta?
Affects lambs or sheep with no previous exposure.
Relaxation in ewe immunity around parturition lead to periparturient rise in eggs excreted by ewes.
Once temperatures are conducive, these eggs develop to L3 and infect the lambs.
Overwintered L3 from the previous year can also infect the lambs.
Epidemiology is dependant on the temperature in the region.
How can teladorsagia circumcinta be diagnosed?
Detection of eggs in faeces.
Detection of worms post-mortem.
How can the spread of teladorsagia circumcinta be controlled?
Anthelmintic prophylaxis.
So treat the ewe around lambing to prevent periparturient egg count rising.
Treat lambs through grazing season every 3 weeks.
Treat and move at weaning.
Move lambs off of contaminated pasture.
Alternate grazing of pastures.
What is the superfamily of haemonchus contortus?
Trichostrongyloidea
What is the life cycle of haemonchus contortus
Eggs in faeces, L1 hatch and moults to L3.
L3 migrates onto pasture and are digested.
L3 exsheaths in rumen and moult to L4 in abomasum.
What do the adult haemonchus contortus feed on?
Blood
What is the pre-patent period of haemonchus contortus?
16-21 days
May undergo hypobiosis for <6 months
What are the size of the adult worms of haemonchus contortus and where are they located?
2-3cm in the abomasum
What is the pathology of haemonchus contortus?
Adults lacerate the mucosa and ingests blood.
Leads to acute blood loss and anaemia.
What are the acute clinical signs of haemonchus contortus?
Very high infection intensity can lead to severe hemorrhagic gastritis.
Sudden death.
What are the sub-acute clinical signs of haemonchus contortus?
Anaemia
Oedema - sub-mandibular and ascites
Ewes may stop their production of milk -> lamb death.
What are the chronic clinical signs of haemonchus contortus?
Low burdens, but continual loss of blood leads to: Weight loss Weakness Inappetence Chronic anaemia
What is the epidemiology of haemonchus contortus?
High biotic potential.
Rapid development in warm, humid conditions. So disease can appear suddenly.
Eggs/larvae do not overwinter, hypobiosis and re-emergence is due to spring contamination of pasture.
Mid-spring -> late autumn
No strong immunity.
How can haemonchus contortus be diagnosed?
History and clinical signs are sufficient alone.
Faecal egg count.
Post-mortem exam: abomasal haemorrhage, adults in abomasum, bone marrow expansion.
How can haemonchus contortus be controlled?
Treat and move
Anthelmintic prophylaxis is used to treat ewes for hypobiosed larvae/periparturient rise
During optimal conditions, it may need to be treated every 2-4 weeks.
What is the super family of nematodirus battus?
Trichostrongyloidea
What is the life cycle of nematodirus battus?
Eggs are passed in faeces.
L1-L3 develop in the egg.
L3 hatch due to climatic stimulus (cold snap followed by temperatures >10 degrees)
L3 exsheaths in rumen.
Moults to L4 in the small intestine mucosa.
Moults to L5 in the lumen
What is the pre-patent period of nematodirus battus?
14 days
What are the differences between male and female worms of nematodirus battus?
Males: 11-16mm
Females: 15-25mm
What is the pathology of nematodirus battus?
Damage to the small intestine epithelium due to concurrent developing larval stages. Severe enteritis.
Acute -> yellow/green diarrhoea during PPP, dehydration and death.
High mortality in untreated animals.
What is the epidemiology of nematodirus battus?
Eggs can survive on pasture <2 years.
Critical hatching requirements means that overwintered eggs hatch all at the same time when a cold snap is followed by temperatures >10c. Large numbers of L3 at spring.
Second mass hatching event / disease outbreak in the autumn.
Immunity to infection is strong in adults.
Impact of disease is dependent on the timing of hatching.
How can nematodirus battus be diagnosed?
Coccidiosis Clinical signs are throughout PPP, so faecal egg counts are not useful. Grazing history Clinical signs/age Post-mortem examination
How can nematodirus battus be controlled?
Avoid successive grazing of lambs on the same pasture.
Anthelmintic prophylaxis of young lambs every 3 weeks.
What is the superfamily of trichostrongylus axei/colubriformis/vitrinus?
Trichostrongyloidea
What is the life cycle of trichostrongylus axei/colubriformis/vitrinus?
Eggs are passed out in sheep faeces.
L1-L3 in faeces.
L3 migrates onto pasture and is ingested by the host.
Colubriformis/vitrinus - moults to L4 in the small intestine.
Axei - L3 moults to L4 in the abomasum
Females lay eggs, which pass out in the faeces.
What is the pre-patent period of trichostrongylus axei/colubriformis/vitrinus?
16-21 days
May hypobiose <6 months
What are the clinical signs of trichostrongylus axei/colubriformis/vitrinus?
Heavy infection - diarrhoea, rapid weight loss and death.
Low level of infection - poor growth rates
What is the superfamily of strongyloides papillosus?
Rhabditoidea
What is the life cycle of strongyloides papillosus?
Larvated egg passes into faeces.
Under certain conditions, may hatch and re-infect by ingestion or skin penetration.
Larvae migrates via venous system, lungs and trachea to develop to adults in SI.
Larvae may arrest in ventral abdominal wall and enter milk, leading to immediate infection of young.
What is the pre-patent period of strongyloides papillosus?
8-14 days
What can a high burden of strongyloides papillosus cause?
Enteritis in the very young
What is the superfamily of dictyocaulus filaria?
Trichostrongyloidea
What are the clinical signs of dictyocaulus filaria?
Dyspnoea and coughing in grazing animals in the autumn
How can dictyocaulus filaria infections be controlled?
Treat upon outbreak.
Treat ewes in late gestation.
Control for PGE will usually cover lungworm in sheep.
What is the difference between dictyocaulus viviparous and dictyocaulus filaria?
Dictyocaulus filaria is a much less severe infection in sheep.
