Small Ruminants Flashcards
A flock of sheep has been grazing on Sorghum halepense (Johnson grass), Tetradymia spp. (horse brush) and Artemisia nova (black sage).
Many of the exposed animals have edema, especially in their heads. THis lamb has edema around the eyes and the ears show hyperkeratinized tissue.
WHat is the photosensitizing agent responsible for this condition?
a. Tetradymia spp.
b. Chlorophyll
c. Phylloerythrin
d. Artemisia nova
e. Bile acids
c. Phylloerythrin
Phylloerythrin is a photosensitizing agent derived from microbial breakdown of chlorophyll in the GI tract.
If the liver is damaged, then phylloerythrin builds up in the plasma. This phylloerythrin absorbs and release light energy in the skin, causing SECONDARY photosensitization.
THis is the most common type of livestock photosensitization.
SO, when sheep eat hepatotoxic Tetradymia spp. and Artemisia nova, the compromised liver allows toxic photosensitizing phylloethrin to build up.
PRIMARY photosensitization occurs in the absence of hepatic disease when a photodynamic agent is ingested/injected/absorbed.
Hypericum perforatum (St. John’s wart) is an example of a plant that causes primary photosensitization. Tetracycline is a medication that can cause primary photosensitization.
COngenital inherited photosensitization is seen in some breeds of cattle and sheep
It is winter, and you are called to examine a herd of camels that have developed a severe skin condition over the last 2 weeks. The farmer noticed that the camels were losing hair around their head and neck and has now spread down the entire body. On exam, some areas appear swollen and there is hairloss and wrinkling of the skin. The camels are rubbing up against each other and against fences and trees due to intense pruritus. You tell the farmer that the camels most likely have which condition?
a. Selenium deficiency
b. Warbles
c. Zinc deficiency
d. Sarcoptic mange
e. Dermatophytosis
d. Sarcoptic mange
Infection with Sarcoptes scabiei var. cameli is most likely and is the only type of mange to infect camels. It is most common in the winter when the camels huddle together for warmth, thus increasing direct contact with each other. The mange typically starts around the head and neck and then spreads to the rest of the body.
In a flock of sheep, numerous animals develop crusting lesions around the coronary bands during a moist winter. As you remove the crusts, there is pink granulation tissue underlying the crusts. You perform cytology on one of the crusts and see branching “railroad tracks” of cocci bacteria. What are these bacteria?
a. Staphylococcus aureus
b. Dermatophilus congolensis
c. Staphylococcus intermedius
d. Dichelobacter nodosus
e. Clostridium nobyi
b. Dermatophilus congolensis
The disease described is commonly termed strawberry footrot. 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.
Staphylococcal dermatitis in sheep is usually due to S. aureus and is usually associated with a puncture or other injury to the skin, allowing invasion. Clostridium novyi in sheep and goats causes malignant edema or “bighead” which is a disease where clostridial spores enter through fighting wounds and cause head and neck edema. Dichelobacter nodosus is a cause of infectious footrot, which infects the claws of the feet.
Several lambs in a hobby flock are reported to be acting sick and not eating. On examination of the affected lambs, you note low grade fevers and lesions around the gums, and in some cases, the proliferative lesions seen in the photo. Several ewes also have similar lesions on their teats. Your diagnosis is ___________.
a. Contagious ecthyma
b. Foot and Mouth disease
c. Bovine papular stomatitis
d. Pseudocowpox
e. Bluetongue
a. Contagious ecthyma
Also known as orf and soremouth, CE is mainly a disease of sheep and goats. It also affects humans, as do the other two parapox viruses, bovine papular stomatitis and pseudocowpox, which are found in cattle. CE is rarely fatal but causes lesions in mouths of lambs/kids and sometimes on the teats of the mothers, making nursing a problem. The virus remains in the scabs that fall off.
What is the causative agent of ovine progressive pneumonia?
a. Mycoplasma
b. Retrovirus
c. Herpesvirus
d. Pasteurella
b. Retrovirus
OPP is caused by a nononcogenic single stranded RNA lentivirus of the family Retroviridae.
The owner of a large flock of sheep consults you because several of his 2-to-3-year old sheep have become emaciated, lag behind the flock, and have breathing difficulty. You examine three and find emaciation, hard udders, expiratory dyspnea, tachypnea, open mouth breathing, and an occasional non-productive cough. Rectal temperatures are only slightly elevated. The owner agrees to a postmortem exam, and you find that the lungs do not collapse. They are meaty, gray-blue in color, and have enlarged mediastinal lymph nodes. The udder is fibrous and hard with indurative mastitis, with large associated lymph nodes. What disease is this?
a. Ovine progressive pneumonia
b. Mannheimia hemolytica pneumonia
c. Pneumoconiosis
d. Mycoplasma mycoides pneumonia and mastitis
e. Histophilus somni infection
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 by agar gel immunodiffusion or ELISA testing. PCR may also be an effective diagnostic test but is not widely utilized due to expense.
No vaccine or treatment is effective. The disease is controlled by serologic testing and removal of positive animals. 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.
Several kids are noted to be extremely lame and febrile. On physical exam you palpate markedly swollen joints. There are no adults noted to be lame or show any similar clinical signs. What is the most likely diagnosis?
a. Pasteurella multocida
b. Clostridium novyi
c. Mycoplasma mycoides spp. mycoides
d. Erysipelothrix
c. Mycoplasma mycoides spp. mycoides
Mycoplasma mycoides ssp. mycoides (large colony type) in kids will result in the clinical signs described. Sometimes pneumonia is also a prominent part of the syndrome. Age of onset is usually at 2-4 weeks, and treatment is controversial because some animals may remain carriers following treatment. Treatment consists of tetracyclines or other antimicrobial effective against mycoplasma. Prognosis for a complete recovery is guarded, and animals may become carriers. Thus, culling of all affected and test positive animals is recommended in some circumstances, depending on herd size and owner`s wishes. The disease is contagious and usually introduced by a mammary carrier, which is subclinical. This agent can also cause mastitis in does.
A flock of sheep is struggling with an outbreak of Dermatophilus congolensis in the lambs. What is your recommendation to the owner?
a. Shear all affected sheep
b. Isolate and euthanize affected individuals
c. Treat herd with ivermectin
d. Remove sheep from the rain
d. Remove sheep from the rain
The correct answer is remove sheep from the rain. D. congolensis is an actinomycete that primarily affects the dorsal surface of animals. Clinically, crusty lesions will form which are easy to pull off, and many people describe them as a paintbrush lesion. In sheep, this disease may be known as strawberry footrot when the claws are affected. Valuable individuals may benefit from dry conditions plus antimicrobial therapy. The main predisposing factor to infection is being in prolonged wet conditions such as frequent rain. Ivermectin is a poor answer choice because the organism is a gram positive branching actinomycete. Chronically infected sheep may be a source of infection, but euthanizing all affected is not necessary or practical if they are kept in dry conditions.
The carrier and reservoir of the herpes virus responsible for causing malignant catarrhal fever (MCF) in cattle in North America is chiefly the ____________?
a. Cattle persistently infected as a fetus
b. Culicoides sonorensia (a midge)
c. Sheep
d. Sand flies
e. Wildebeest
c. Sheep
A high percentage of normal appearing sheep in North America are infected with MCF virus. Wildebeests are the reservoir of the African form of MCF.
A 2 year old lactating Suffolk ewe in Kansas is one of several sheep you are called upon to examine and diagnose. One has died and this ewe is very ill; she has shown inappetence, lethargy, weakness, and today appears terminal. You find her temperature is 100F (37.8 C), HR 120, and respiration rapid. Her ocular sclera is icteric. The owner tells you in response to your question that she feeds the sheep steer feed and oat hay.
Based upon the history and exam, what is the most likely diagnosis?
a. Babesia ovis
b. Bluetongue
c. Hypocalcemia
d. Copper toxicosis
e. Scrapie
d. Copper toxicosis
Copper accumulates in the liver, suddenly causing massive hepatic necrosis, hemolysis, renal failure, and death. Cattle feed is a common source of copper toxicosis for sheep, which have a much lower copper requirement than cattle. Foot baths that use copper, fencing treated with copper compounds, and copper pipes are to be avoided. Molybdenum and sulfur protect against copper accumulation.
Babesia ovis does not occur in the USA, but is found in Russia, Europe, Asia, and the Middle East.
Bluetongue virus causes fevers, edema, lameness, and oral lesions. Scrapie is a transmissible neurologic disorder caused by a prion.
What is the duration of estrus in sheep?
a. 2-4 days
b. 1.5-2 days
c. 24 hours
d. 12 hours
b. 1.5-2 days
The correct answer is 1.5-2 days. Ovulation occurs about 24 hours after onset of estrus.
A valuable Merino ram which has been on a high protein diet is brought to you because it has scabs on the mucocutaneous junction of the prepuce that were only recently noticed. The owner checked him closely when the ram appeared to experience pain upon attempting to breed, and had become reluctant to breed. It is the only animal affected, and the lambs, ewes, and 2 other rams appear normal. When you examine the lesions you find painful ulcers under the foul smelling scabs. Which of the following choices is the treatment of choice?
a. Remove all bracken fern from the grazing areas
b. Topical silver nitrate to cauterize the area, followed by gentamicin IM
c. Increase the dietary protein and vaccinate against contagious ecthyma
d. Add salt and ammonium chloride to the diet to dilute the urine
e. Isolation, reduce the dietary protein, and administer penicillin
e. Isolation, reduce the dietary protein, and administer penicillin
All the animals in the group should be carefully checked and all should have their dietary protein reduced. The high protein diet allows C. renale to proliferate and split urea to form ammonia, which ulcerates the area. Treatment of choice for C. renale includes isolation, reduction in dietary protein, and penicillin administration.
A 1-month old female alpaca presents to you for difficulty breathing and difficulty nursing. On your physical exam, you note that the cria is open mouth breathing. You also note that it has extra digits. What is the most likely diagnosis?
a. Guttural pouch emphysema
b. Nasopharyngeal polyp
c. Congenital hepatic lipidosis
d. Guttural pouch empyema
e. Parelaphostrongylus tenuis (meningeal worm)
f. Choanal atresia
f. Choanal atresia
There may be a few questions on camelids on your board exam. There are a few diseases that are specific to them that are worth knowing a little bit about for your exam including choanal atresia and meningeal worm infections.
Choanal atresia is one of the most common congenital defects in alpacas. It occurs when the normal opening between the nasal and pharyngeal areas is blocked by membranous tissue and/or bone. Signs of this condition are labored breathing, prolonged and difficult expiration, open-mouthed breathing, choking and gagging while nursing, cyanosis, weakness, lack of weight gain, and aerophagia.
Euthanasia is typically recommended, as the prognosis is poor even with surgical correction. These animals frequently have additional congenital abnormalities such as polydactyly, cardiac, renal or reproductive organ defects.
A goat herd is suffering from mastitis in does and concurrent polyarthritis and pneumonia in goat kids. The kids range from several days old to weaning age and have one or more swollen joints which are hot to the touch. Affected kids are running high fevers and are unwilling to move. Mastitic does have firm udders and brownish watery milk with occasional garget. The does are also depressed and febrile. The owner has tried treating with several different antibiotics and has had no success. What is your top differential?
a. E. coli
b. Mycoplasma mycoides ssp. mycoides
c. White muscle disease
d. Arcanobacterium pyogenes
b. Mycoplasma mycoides ssp. mycoides
The correct answer is Mycoplasma mycoides ssp. mycoides. Many times, this is a typical presentation in goats. All the other choices are not going to result in concurrent mastitis in does and polyarthritis and pneumonia in kids. This is usually a milk-borne disease that is introduced by asymptomatic carriers. The fact that the owner treated without success is a huge clue because Mycoplasma is not responsive to antibiotic therapy.
You are called to examine a herd of camels which are having diarrhea and exhibiting signs of weight loss and poor body condition. They are on appropriate feed and supplements and their environment appears suitable. The owner says she deworms them once monthy with Ivermectin. You explain that despite her de-worming efforts, there is a good chance they may have an infection of which intestinal parasite?
a. Hookworm
b. Giardia
c. Whipworm
d. Tapeworm
c. Whipworm
Camels are highly susceptible to whipworm infection. Whipworm is suspected to be the most common cause of diarrhea in adult camels in the US. Ivermectin, which is so commonly used, is not typically effective against whipworms which have developed a resistance over time. Panacur is the most effective and safe dewormer for whipworms in camels.
A 1-year old pet wether sheep presents at your clinic with a complaint of restlessness, teeth grinding, vocalizing, stretching out, and straining. When you tickle the preputial opening, only a drop of urine appears. The wether has tachypnea and tachycardia, and is mildly bloated. When you palpate the abdomen externally using both hands, you detect a large turgid structure in the caudal abdomen; you diagnose urethral obstruction due to urolithiasis. You sedate the sheep and extrude the penis, where you find several stones in the urethral process and amputate it (see image of amputated process). The animal is still unable to urinate. What is the best treatment option for this pet now?
a. Penectomy
b. Perineal urethrostomy
c. Bladder marsupialization
d. Tube cystotomy
e. Xylazine and intravenous fluids
d. Tube cystotomy
Using local anesthesia, a Foley catheter is inserted percutaneously into the bladder immediately in front of the pubis and sutured in place. This option allows the urine to drain, and the relief often allows the urethal stones to pass. After one or two weeks the animal may once again be able to urinate through the urethra, and the catheter can be removed. The stone type should be determined by analysis and a corrective dietary measure initiated. The other surgical treatments listed are less likely to have favorable long term outcomes and are considered salvage procedures; the other medical treatments would likely result in a ruptured bladder.
A mature pet goat is brought to you for diagnosis and treatment one morning. The owner found the wether in the feed room eating a bag of horse sweet feed (grain and molasses) some 3 hours ago. His abdomen is large and full. On examination you, note that his T=101F (38.3 C), HR=120, RR=42, and his rumen is overfull with watery fluid. The goat is either a very quiet pet or is depressed, as he stands in place with no restraint and lies down as soon as he can (see photo). You pass a stomach tube and take a sample of rumen fluid and it has a pH of 4.5. Based on this history and PE findings, which of the following treatments would be most effective?
a. Oral antacids containing magnesium oxide and magnesium hydroxide; IV fluids containing sodium bicarbonate; systemic penicillin
b. Transfaunate with normal rumen contents; SQ 7% sodium bicarbonate; SQ tetracycline
c. Oral vinegarl IV saline; oral penicillin
d. Oral antacids containing magnesium hydroxide; IV 50% glucose; IM tetracycline
e. Oral antacids containing sodium bicarbonate; IV fluids containing sodium and chloride (saline); diuretics such as durosemide
a. Oral antacids containing magnesium oxide and magnesium hydroxide; IV fluids containing sodium bicarbonate; systemic penicillin
This goat has a classic history for grain overload, and the PE is compatible with rumen acidosis and metabolic acidosis. If not promptly and aggressively treated, this can result in death from metabolic acidosis and dehydration, as well as liver abscesses and mycotic rumenitis. Oral antacids, systemic buffers, and penicillin are all indicated. The safest effective oral antacids are MgO and MgOH. In some cases, a rumenotomy may also be indicated.
Which type of urolith (shown in the image below) occurs most commonly in sheep grazing lush clover pastures?
a. Silicate
b. Struvite
c. Calcium oxalate
d. Calcium carbonate
d. Calcium carbonate
The clover or alfalfa pasture contains high levels of calcium and often high levels of oxalates. In the gut, oxalate avidly binds calcium and makes it unavailable for absorption. With gradual introduction of oxalate-rich diets, ruminal bacteria efficiently metabolize oxalate to bicarbonate. Thus, microbial metabolism of oxalate in the rumen may increase the availability of dietary calcium. These factors may combine to increase urinary calcium excretion and alkalinize the urine, thereby promoting calcium carbonate calculogenesis.
Silicate stones are the result of high intakes of silica in mature range grasses, combined with other factors such as dehydration. Struvites (magnesium ammonium phosphate) tend to be found in feedlot animals receiving large amounts of grain which contains high levels of phosphorus.
Calcium oxalate crystals are often present in ruminant urine and may be incorporated in small amounts into other types of stones.
