Ovine Flashcards
1
Q
Psoroptic Mange
What does the mite look like?
A
- Caused by Psoroptes
- Psoropitc mange is the disease caused by the non-burrowing mite, Psoroptes ovis (common name Scab mite), which affects sheep.
- Psoroptes ovis is a highly contagious and severe infestation of sheep. This mite has been eradicated from sheep in Canada, New Zealand, and the USA. However, sheep scab persists in many countries, including some in Europe. Intense pruritus leads to large, scaly, crusted lesions that develop in more densely haired or woolly parts of the body
2
Q
Pregnancy toxemia may occur in ewes and does in the last 2-4 weeks of gestation secondary to insufficient energy intake.
Which of the following compounds is the body deficient in?
A
- Oxaloacetate
- During times of negative energy balance the body is unable to produce enough oxaloacetate to feed into the citric acid cycle.
- This results in mobilization of fat and subsequent production of ketones
3
Q
Treatment of Twin Lamb Disease
(pregnancy toxemia)
A
- prevent with scanning and proper diet changes!
4
Q
Dermatophilus congolensis
A
- branching “railroad tracks” of cocci bacteria causing FOOT ROT and RAIN SCALD
- Dermatophilus can also cause rain scald, a similar crusting condition associated with moisture, and affecting the ears, muzzle, face, tail and sometimes the dorsum. It tends to affect younger animals more severely.
- The granulation tissue under the crusts gives the “strawberry” appearance, and the cocci in “railroad tracks” are the other key to the diagnosis
5
Q
What agent is responsible for footrot in sheep?
A
- Dichelobacter nodosus
- gram - bacteria
- may find: a malodorous exudate and partial separation of the horn of the hoof from the skin. You stain the exudate and find gram negative barbell shaped rods
- often occur after introduction of a new animal or moving to an infected pasture
6
Q
Caprine Arthritis encephalitis
A
- Caprine arthritis and encephalitis (CAE) virus infection is manifested clinically as polysynovitis-arthritis in adult goats and less commonly as progressive paresis (leukoencephalomyelitis) in kids.
- Subclinical or clinical interstitial pneumonia, indurative mastitis (“hard udder”), and chronic wasting have also been attributed to infection with this virus. Most CAE virus infections, however, are subclinical
- The virus infects monocytes
- The chief mode of spread of CAE is through ingestion of virus-infected goat colostrum or milk by kids
- Clinical signs are seen in ~20% of CAE virus–infected goats during their lifetime. The most common manifestation of infection is polysynovitis-arthritis, which is primarily seen in adult goats but can occur in kids as young as 6 mo old.
- Signs of polysynovitis-arthritis include joint capsule distention and varying degrees of lameness.
7
Q
What is the main vector of Heartwater disease?
A
- Amblyomma spp.
- Heartwater is a disease found in Africa and the West Indies, caused by Ehrlichia ruminantium.
- The disease is tick borne and results in fatal encephalitis in sheep, goats and cattle
- Possible spread to the mainland threatens the livestock industry of regions from northern South America to Central America and the southern USA.
8
Q
Beta Mannosidosis
A
- Beta-mannosidosis is a rare inherited disorder affecting the way certain sugar molecules are processed in the body
- Beta mannosidosis is a disorder of Anglo-Nubian goats that causes fatal neurological symptoms in newborns and is an autosomal recessive mode of inheritance
9
Q
Ovine Progressive Pneumonia (OPP)
or
Maedi-Visna
A
- Ovine Progressive Pneumonia (OPP), also called Maedi-Visna, is caused by a retrovirus closely related to CAEV (Caprine arthritis and encephalitis virus) of goats.
- It usually affects sheep between 2 and 4 years of age.
- The disease progresses slowly, with increasing wasting and respiratory distress.
- Secondary bacterial infections can occur, leading to coughing, bronchial exudate, depression, and fever. Indurative mastitis (hardbag) may occur.
- In the encephalitic form, ataxia, muscle tremors, or circling may occur and progress to paresis and eventually paralysis.
- Diagnosis may be confirmed in live animals via agar gel immunodiffusion or ELISA testing. PCR may also be an effective diagnostic test but is not widely utilized due to its expense.
- farmer should perform serologic testing for ovine progressive pneumonia of the whole flock every 6-12 months with removal of positive animals
- No vaccine or treatment is effective
- In herds where this disease is a problem, animals should be re-tested annually due to the long incubation period.
- Additionally, neonatal lambs should be fed colostrum from seronegative ewes and potentially raised in isolation from the dams.
- For flocks with a high rate of seropositivity (>30%), aggressive separation or culling may not be an option for some farmers and an alternative approach to disease control will need to be considered.
10
Q
What is the duration of estrus in a goat?
A
- 18 to 48 hours
- The entire estrous cycle lasts about 21 days during the breeding season. The average duration of standing estrus is 36 hr but can range from 24 to 48 hr depending on age, breed, season, and presence of a male.
- Breed-specific estrus duration has been reported for Mossi (20 hr), Angora (22 hr), Creole (27 hr), French Alpine (31 hr), Boer (37 hr), and Matou (58 hr) breeds.
- Ovulation normally occurs about 24 hours after the start of estrus
11
Q
What level of Selenium is considered normal in a flock of sheep?
abnormal?
A
- Whole blood selenium is preferred over plasma or serum levels.
- If animals fall below 0.05 ppm Se, most of the animals will benefit from Se supplementation.
- Those with marginal Se (0.05 to 0.06 ppm) may sometimes also benefit, while those over 0.07 ppm are considered normal.
12
Q
Otitis Media in sheep
A
- Unilateral peripheral vestibular lesions are commonly associated with otitis media and ascending bacterial infection via the eustachian tube.
- Sheep typically present with a head tilt towards the affected side.
- There may be evidence of otitis externa and purulent aural discharge in some cases, but rupture of the tympanic membrane is not a common route of infection.
- Pasteurella, Streptococcus, and Arcanobacterium have been isolated from infected lesions.
- Middle ear trauma can also occur. This is usually treated effectively with procaine penicillin if disease is recognized early.
13
Q
What is the duration of estrus in sheep?
A
- 1.5-2 days
- Ovulation occurs about 24 hours after onset of estrus
14
Q
A sheep presents to you for nasal discharge and face rubbing. You perform cytology on the copious discharge and note numerous eosinophils and mast cells. What is the most likely diagnosis?
A
Oestrus Ovis
- Adult flies deposit larvae around the animals’ nostrils; the larvae then migrate up the nasal passages into the turbinates and sinuses.
- With time and multiplication of the larvae, hypersensitivity develops with the marked clinical signs of nasal discharge and face rubbing and shaking.
- Secondary bacterial infection can occur.
- The discharge usually contains numerous eosinophils and mast cells, which confirms the diagnosis in this case.
- Further confirmation could be achieved with radiographs showing mineralized bots or with endoscopy, but this is not usually necessary
- Treatment of Oestrus ovis is with ivermectin.
15
Q
Contagious ecthyma
(ORF)
A
- Also known as orf or soremouth, this parapoxvirus disease is common in lambs and kids.
- Humans can also be affected.
- Rarely fatal, it nonetheless can make affected kids or lambs end up smaller than their age mates.
- Lesions occasionally also occur on the teats of the dams.
- The scabs dry up in 2 to 4 weeks and fall off, with the virus overwintering in the scabs on the ground until more susceptible animals appear next year.
16
Q
What developmental defect is seen in lambs born from ewes infected with bluetongue virus during pregnancy?
A
- Hydranencephaly
- This abnormality is a condition in which the brain`s cerebral hemispheres are like swiss cheese or absent and replaced by sacs filled with cerebrospinal fluid.
- Ewes infected with bluetongue virus while pregnant can have lambs with this defect
17
Q
Clinical Signs of Bluetongue in Sheep
A
- often marked oedema of the head will be noticed! Maybe open mouth breathing
- sheep owners will often come to you thinking it is pneumonia –> but really is a result of the pulomary oedema
- epithelial changes will occur on the tongue leading to the blueish color
19
Q
What is the vector for Bluetongue?
What time of year does the disease present itself?
A
- cattle RARELY show clinical signs but they can harbor the virus
20
Q
Urinary Calculi and Diey
A
- can increase salt inake to promote diuresis and WATER INTAKE
- high grain diets can affect the Ca:PO4- ratio as they are high in Phosphorus!
21
Q
Infectious footrot of sheep and goats is considered to be caused by:
(3)
A
- wet conditions
- Fusobacterium necrophorum
- Dichelobacter nodosus
23
Q
Dictyocaulus filaria
A
sheep and goat lungworm
D filaria is similar to D viviparus (cows), but interstitial emphysema is not a common complication
24
Q
Muellerius capillaris
A
- Muellerius capillaris, also called the nodular lungworm, occurs in sheep and goats in most areas of the world and is the most common lung parasite of sheep in Europe and Northern Africa.
- It requires slugs or snails as intermediate hosts.
25
Q
Border Disease Virus
A
- This causes hairy shaker lambs
- This is a pestivirus and is antigenically related to BVD and hog cholera
- Problem if virus acquired early in pregnancy
- Can cause abortion, fetal resorption, mummification, death
- Classic finding is underweight lambs with muscle tremors and hairy fleece
- No effective treatment or vaccine
- Pathologic findings in lambs:
a. Cerebral cavitations
b. Glial cell hyperplasia and demyelination of CNS white matter.
* Treatment/Prevention
a. There is no effective treatment.
b. Available BVD vaccines are not effective due to differing antigens.
c. Dams with affected lambs should have antibody titers.
i. High levels imply subsequent immunity.
ii. Low levels indicate possible persistent infection.
d. Affected lambs that survive should not be used for breeding.
i. Can mingle with others well in advance of breeding season to provide opportunity for immunity to develop.
26
Q
2 common causes of infectious keratoconjunctivitis (IKC) in sheep
A
The two common causal organisms of IKC in sheep are:
Mycoplasma and Chlamydia
- Each are susceptible to a wide range of antibiotics including
- oxytetracycline. Topical oxytetracycline ophthalmic ointment or powder can be applied twice daily.
- Ewes with bilateral corneal lesions should be injected
- with long-acting oxytetracycline.
- Ewes with impaired vision in both eyes must be housed, thereby ensuring adequate feeding.
- Confinement also prevents deaths from misadventure. Ewes should be taken off exposed hill ground when storms are forecast but this is not always possible.
