Bovine Flashcards
Trismus
- Trismus, also called lockjaw, is reduced opening of the jaws (limited jaw range of motion). It may be caused by spasm of the muscles of mastication or a variety of other causes.
What causes Tetanus?
Clinical Signs?
- Clostridium tetani
- Classic clinical signs include a sawhorse stance, lockjaw, and an elevated tail (“pump handle tail”)
- These animals are especially sensitive to tactile and auditory stimuli.
- Infection was probably through inoculation of a wound.
- However, there is evidence that infection may occur via ingestion
When formulating late gestation anionic diets for dairy cows to help prevent hypocalcemia in the last 2 to 3 weeks prior to calving, what formula is used?
DCAD = (Na + K) - (Cl + S)
- DCAD stands for Dietary Cation Anion Difference.
- Na=sodium, K=potassium, Cl=chloride, and S=sulfur.
- These are the 4 most important strong ions to be considered.
- When the diet is optimal the urine pH of Holstein cows should range between 6.2 and 6.8 for cows on the ration
Desribe the disease processs in adult cattle from Clostridium hemolyticum
(recently renamed C. Novyi Type D)
Treatment?
- Bacillary haemoglobinuria
- Infection of the liver by migrating flukes (Fasciola hepatica), results in anaerobic tracks that allow the Clostridium to bloom and cause disease
- NOT the same as C. Novyi Type B - causing “Black Disease” (Infectious Necrotic Hepatitis) - pathogenesis is similar!
- Treat with penicillin or oxytetracycline
Persistent infection of a bovine fetus with Bovine Viral Diarrhea (BVD) virus is most likely to occur when the non-immune dam is viremic with a non-cytopathic biotype of BVD at what stage of gestation?
- At 50 to 150 days gestation, the fetal immune system does not recognize the BVD virus as foreign and becomes persistently infected
Bovine Urolithiasis
What can it often lead to? Clinical signs of this phenomena?
- In the bovine, urolithiasis often results in rupture of the urethra.
- Urine then leaks into all the ventral tissues and causes this massive ventral edema, which progresses to necrosis and sometimes to gangrene
- may see: poor appetite, depressed attitude, and ventral swelling (pitting ventral oedema)
A 4 month old Holstein calf presents with a right sided head tilt, a unilateral right ear droop, right eye ptosis and epiphora of the right eye. Otherwise, the calf is bright and alert. The owner mentioned that the calf suffered from a respiratory infection the previous week.
What is the most likely diagnosis?
What is the most common cause? (pathogen)
Most common source of infection?
- Otitis media-externa
- Mycoplasma is a common cause of otitis media-externa
- Usually, the infection is a result of consuming contaminated milk
What is Otobius Megnini?
good differential diagnosis for?
- Otobius is a soft tick with predilection for ears - SPINOSE EAR TICK
- it is a good differential for otitis media - externa
- With Otobius the calf would probably not show such extreme clinical signs and would probably be scratching and rubbing at the ear
Polioencephalomalacia
What is it caused by?
List some clinical signs
Differential Diagnoses? (2)
- Polioencephalomalacia is more likely to present with stargazing, head pressing, depression, and blindness.
- Polioencephalomalacia is caused by a thiamine deficiency
- An excellent differential for the clinical signs described would be listeriosis and thromboembolic meningoencephalitis.
Regarding normal reproductive physiology, the cow differs from the sow, the mare, the ewe, and the nanny/doe in which of the following ways?
Which are seasonal breeders?
Which have an epithelio-chorial placenta?
Which species is in oestrus often for more than 5 days?
- An unusual feature of bovine reproductive physiology is the fact that the cow ovulates after she goes “out” of estrus. The practical implication of this is that one can successfully breed by artificial insemination later, relative to estrus.
- The mare, the ewe, and the nanny/doe are all seasonal breeders, but generally, the cow is not.
- All the animal species listed in the question have an epithelio-chorial placenta.
- Although twin births do occur in a minority of cows, the cow normally ovulates a single oocyte per cycle, as does the mare. Sheep and goats have been selected for fecundity, with the result that multiple ovulations/cycle are the rule, rather than the exception. Litter-bearing pigs ovulate large numbers of oocytes per estrous cycle.
- The sheep and goat are in estrus for only 1.5-3 days; the pig is similar. Only the mare, of the species listed, is physiologically in estrus for 5 days or more.
Is Brucellosis a notifiable disease in the United States?
A: Yes
- after a positive milk ring test, It is reported to state and all of the cows will be serologically tested within 30 days, reactors will be slaughtered
- Brucellosis is a reportable disease and is promptly reported to the appropriate agency in the state. Positive animals should be slaughtered, not treated.
What is this 1/2 inch grub that emerge from the back of cattle in spring?
- This is a cattle warble called Hypoderma.
- The 2 species are H. bovis and H. lineatum.
- They undergo a long migration in tissues and only emerge from the back of the animal in spring.
- The crucial treatment time is early fall when larvae are just beginning to migrate in tissues.
- Organophosphates or one of the macrocyclic lactones (ivermectin, doramectin, eprinomectin or moxidectin) are effective.
You are working with a farmer who is having trouble with calves between the age of 2 weeks and 6 months. They are alert, but weak, dyspneic and die suddenly. On necropsy they have pale cardiac and skeletal muscles. What is the farmer’s problem?
- Selenium Deficiency - “white muscle disease”
- The pale muscle and clinical signs are classic for vitamin E and selenium deficiency.
- This is important to remember!
- Other things that should be on your differential list for this case include cardiotoxic plants. - Milkweed, bacharris spp., etc.
- Struvite
- Struvite is composed of magnesium ammonium phosphate.
- The alkaline urine in cattle along with high dietary phosphate and magnesium levels favors formation of struvite stones.
- Feedlot animals can also develop apatite stones composed of calcium phosphate.
Where would you find the following uroliths in livestock animals?
Silicate?
Calcium Carbonate?
Calcium Oxalate?
- Silicate stones are primarily found in sheep and cattle grazing western rangelands.
- Calcium carbonates are most commonly found in sheep grazing pastures high in calcium and oxalates.
- Calcium oxalate crystals are often present in ruminant urine and may be incorporated in small amounts into other types of stones.
What are benefits of of providing a DCAD (dietary cation-anion difference) diet to cattle?
- cows absorb calcium more readily
- cows remain more relatively acidotic
- There is a lower incidence of milk fever
- parathyroid hormone function is enhanced
- DCAD is used to help prevent milk fever. Cows eating a DCAD diet are actually more acidotic which enhances parathyroid hormone function along with a better ability to utilize dietary calcium. The easy measure is to check urine pH (it should be acid) on cows to be sure they are ingesting the diet.
- To review, DCAD is dietary cation-anion difference. A DCAD diet is enhanced with more anionic salts containing the strong ions chloride and sulfur, and has decreased amounts of strong cations such as sodium and potassium.
- Cations have a positive charge like sodium (Na), potassium (K), calcium (Ca), and magnesium (Mg).
- Cations in the diet promote a more alkaline (higher blood pH) metabolic state which has been associated with an increased incidence of milk fever.
- Anions have a negative charge such as chloride (Cl), sulfur (S) and phosphorus (P).
- Anions promote a more acidic metabolic state (lower blood pH) that is associated with a reduced incidence of milk fever.
- A cow adjusts to a lower blood pH by buffering the acidic condition.
Buffering the blood is done by the cow through mobilization of calcium phosphate from bones. When a lower pH is achieved by feeding more anions, the result causes the cow to mobilize stored calcium which can better prepare her for the time when calcium will be lost in milk. This is the reason that there are various anionic products on the market: to reduce the incidence of milk fever
Presence of dysphonia may indicate a lesion in __________.
CN X
Clinical signs of lesions of the vagus nerve include dysphagia, abnormal vocalizing, inspiratory dyspnea, and megaesophagus.
Bovine leukocyte adhesion deficiency
(BLAD)
- in Holstein Cattle
- autosomal recessive congenital disease characterized by recurrent bacterial infections, delayed wound healing and stunted growth, and is also associated with persistent marked neutrophilia
- The most common inheritance pattern of genetic disease in cattle is a simple recessive trait. The defective calf receives a recessive gene from its sire and dam.
- An autosomal recessive disorder means two copies of an abnormal gene must be present for the disease or trait to occur.
- Surgically remove the intussusception and anastomose the ends of the intestine
- Cows with intussusception usually have colic, scant dark red feces, dilated small bowel proximal to the lesion, and a distended abdomen from accumulated fluid in the proximal gut and forestomachs.
- They may also have a fever if there is leakage and peritonitis is developing.
- The lesion is sometimes palpable per rectum. They are most commonly suffering from hypochloremic hypokalemic metabolic alkalosis
You are called out to a dairy herd that has recently been experiencing reproductive problems. The cows were all acquired 1 year ago from an unknown source and have no known vaccinations or tattoos. The dairyman reports that several cows have had late abortions (6-7 months gestation) and weak or stillborn calves in the past year and he’s never had this problem before. Several of the cows that had abortions developed placental retention and/or metritis. None of the younger pre-pubescent heifers are displaying any clinical signs. You perform a necropsy on two recently aborted fetuses and find lung consolidation in one but no other obvious abnormalities.
What should you recommend?
- Serologic testing for Brucellosis
- You should be most suspicious of Brucellosis based on the assortment of signs (abortions, retained placenta, metritis and lack of signs in younger animals), the timing of abortions (last half of pregnancy), and the relatively normal appearance of the examined fetuses.
- Plus the cattle are not tattooed as they should be if they were given calfhood brucella vaccine.
When do Tritrichomonas fetus abortions generally occur in cattle?
- first half of gestation
- but do have placentitis and pneumonia in the fetus similar to Brucella abortions
Campylobacter fetus subsp venerealis in cattle
- It causes catarrhal inflammation in the female genital tract, temporary infertility and prolonged oestrus cycle
- usually causes early embryonic death
- strict international regulations require animals and animal products to be CFV-free for trade
Neopspora Abortions
- Neospora Caninum is a protozoan parasite that is an important infectious cause of weak calves and abortion in cattle.
- It can affect other species including sheep, goats and camelids, however these are thought to be less susceptible.
- Neospora is the most frequently diagnosed cause of bovine abortion
- Neospora abortions are usually mid gestation and cause necrosis of the cotyledons, with fetal lesions including myocarditis, hepatitis, myositis and encephalitis
Brucellosis
Describe?
Symptoms?
Diagnosis?
- Brucellosis is an infectious disease that occurs from contact with animals carrying Brucella bacteria.
- Brucella can infect cattle, goats, camels, dogs, and pigs.
- The bacteria can spread to humans if you come in contact with infected meat or the placenta of infected animals, or if you eat or drink unpasteurised milk or cheese.
- Brucella is highly contagious, spreading very easily between cattle as the calf, the membranes and the uterine fluids all contain large quantities of bacteria
Symptoms
- Abortion;
- Stillborn
- Weak calf born
- Retention of fetal membranes;
- Signs of infection in the membranes;
- Swollen testicles in bulls
- Infection of the testicles is also seen in bulls.
Diagnosis can be done by laboratory testing of blood or milk samples or by laboratory culture of brucella abortus from the placenta, vaginal discharge or the milk of infected cows.
Gestation of a cow?
What positive pregnancy diagnosis sign is present at 30 days?
75-90 days?
4-7 months?
Uterine artery fremitus?
- 283 days
- Chorioallantoic membrane slip present at 30 days
- Placentomes will be palpable starting between 75-90 days of gestation.
- The fetus itself will be palpable beginning at approximately 60 days gestation, but may be out of reach between months 4-7 of gestation.
- Uterine artery fremitus (palpable turbulence) will be evident on the ipsilateral pregnant horn at about 120 days of gestation.
- From 7 months on, you can feel the fremitus bilaterally. Fremitus does not necessarily always indicate a viable pregnancy
Rectal Temperature of Cow Normal?
calf?
- rectal temperature reference range for an adult cow is 37.8-39.2°Celsius [100.0-102.5°Fahrenheit],
- little higher for a calf at 38.6-39.4°Celsius [101.5-103.5°Fahrenheit].
Radial Nerve Disease - what would the presentation involve?
What would you see with the other thoracic limb nerves?
- With radial nerve disease, the elbow is dropped, the digits are knuckled onto their dorsal surface, and the limb is unable to bear weight.
- With time, the triceps and carpal extensor muscles may also atrophy in radial nerve disease.
- Note: With injury to the suprascapular nerve, the supraspinatus and infraspinatus muscles are atrophied, but little gait deficit is noted. Musculocutaneous nerve injury results in an inability to flex the elbow and biceps atrophy. With lesions to the ulnar nerve, superficial and deep digital flexor muscles atrophy
Thoracic Nerve Placement
canine
equine
bovine
At what age during gestation is a fetus most likely to become persistently infected with the noncytopathic form of bovine viral diarrhea?
- The correct answer is fetus infected before 125 days of gestation, with most of those occurring before 100 days.
- A fetus infected with BVD at any time during gestation can be aborted or be a stillbirth.
- Most congenital defects associated with BVD occur when a fetus is infected between days 90-150 of gestation.
- Persistent infection of fetuses is seen when they are infected before 125 days of gestation. This is of importance because they have a potential to affect many other herdmates since they shed virus but may show no clinical signs.
- About half of the persistently infected calves will die during their first year of life. Clinical signs in BVD carriers vary greatly. They may range from an asymptomatic animal to one that has diarrhea, fever, pneumonia, and oral ulcerations.
- Additionally, you may have infected animals that are just repeat breeders. You may also see abortions, stillbirth, and congenital anomalies. The most common congenital anomaly associated with BVD is cerebellar hypoplasia, but there are many others.
Heart Rate of Adult Cow
The adult cow has a heart rate of between 48 and 84 beats per minute
About 1 hour after a difficult labor where the calf had to be pulled out with force, the cow goes down. She is pale and her heart rate is 100/min. What happened?
- uterine tear.
- With a traumatic fracture or damage to nerves, the cow would have gone down right away rather than an hour later.
- Hypocalcemia is possible but less likely in this case where the calf had to be forcibly extracted which can result in a uterine tear, and would be unlikely to make her pale and tachycardic
Actinomycosis
- Actinomycosis is a specific disease characterized by a classical rarefying mandibular osteomyelitis and commonly known as “lumpy jaw” in cattle. It is caused by a Gram positive, branching filamentous organism—Actinomyces bovis
- caused by the bacteria Actinomyces bovis, which is a normal inhabitant of the bovine mouth.
- Actinomycosis is a chronic bacterial disease and is more common in cattle than in goats and sheep.
- The bacteria enter through cuts and abrasions (i.e. due to teeth eruptions or coarse feed) and migrate to the bone, leading to osteomyeltitis (inflammation and infection of the bony tissues).
- The mandible is affected more commonly than the maxilla. The defining feature of actinomycosis is the presence of a non-painful swelling under the jaw.
- This swelling can rupture and drain pus-type, smelly fluid which contaminates the environment.
Most common pathogens involved with Bovine Respiratory Disease (BRD)? (4)
calves with BRD? (3)
- There are many types of infectious agents involved.
- The most common viruses involved with BRD include Bovine Viral Diarrhea (BVD), Infectious Bovine Rhinotracheitis (IBR), Bovine Respiratory Synctial Virus (BRSV), and Parainfluenza Type-3 Virus (PI-3).
- Exposure to these viruses can cause severe damage to the respiratory tract of calves creating opportunities for bacteria to then settle in the lungs.
- Fortunately, many of these agents can be prevented through vaccination programs.
- The most common bacteria found in the lungs of calves with BRD include Mannheimia haemolytica and Pasteurella multocida.
- Haemophilus somnus may also be involved in cases of pneumonia and can cause severe damage to the heart muscles.
Johnes Disease
- Johne’s disease is a chronic enteritis of ruminants caused by Mycobacterium avium subspecies paratuberculosis (MAP).
- This bacteria embeds itself in the wall of the lower part of the small intestine known as the ileum. As an immune response, infected tissues attempt to regenerate healthy tissue which leads to visible thickening of the intestines.
- The main signs in cattle are progressive weight loss and chronic diarrhoea
Fusobacterium Necrophorum
- Fusobacterium necrophorum, a gram-negative, nonsporeforming anaerobe, is a normal inhabitant of the alimentary, respiratory, and genital tract of animals.
- The organism is an opportunistic pathogen and a primary causative agent of liver abscesses, an economically important disease of grain-fed cattle
FAMACHA Scoring
- FAMACHA scoring identifies anemia in small ruminants, the main symptom of barber’s pole worm infestation. Faffa Malan developed a five color FAMACHA scoring chart that corresponds to a sheep or goat’s bottom eyelid color.
- Pale pink to white indicates anemia; the animal should be dewormed.
- Robust red to salmon pink indicates the animal does not require deworming at time of test.
Bovine Respiratory Syncytial Virus
(BRSV)
- BRSV was named for its characteristic cytopathic effect, the formation in infected tissue of syncytial cells, giant multinuclear cells formed by the fusion of several cells. BRSV has a predilection for the lower respiratory tract, where it can cause varying degrees of pneumonia by itself.
- The key to being able to make this your top differential is noting that the calf has a “honking” cough, dyspnea, and tachypnea, that the calf is not septic
- Pulmonary lesions include severe edema and emphysema.
- Treatment is usually supportive and antibiotics are given to protect from secondary bacterial infection.
- Mannheimia hemolytica is the main culprit in shipping fever, and Haemophilus pleuropneumoniae is an occasional cause of shipping fever in cattle.
- Pasteurella multocida can be a secondary invader in any bovine pneumonia. P multocida also causes the most economic loss in swine with atrophic rhinitis.
Pathogens of “Shipping Fever”
- Mannheimia haemolytica
- Pasteurella multocida
- various other bacteria and viruses
Normally seen 10-30 days after transport
sudden onset
pyrexia, depressed appetite, increased respiratory rate, cough, increased respiratory noise, grunting
can be found dead
“Fog Fever”
Acute Bovine Pulmonary Oedema and Emphysema
Aytipcal Interstitial Pneumonia
Non Infectious Disease - Associated with cattle grazing lush pastures!
- normally cattle over 2 years old
- within 2 weeks of moving to lush autumn pastures
- up to 50% of group affected
- commonly fatal and difficult to treat/manage
- L-tryptophan in grass gets converted to Indole Acetic Acid (IAA) in rumen which is converted to 3- methyl Indole (3MI) which is toxic to cattle lungs and they become fibrous
Use of corticosteroids in pregnant cattle will…..
cause abortion!!
Death Camas Toxicity
- highly toxic to cattle!
- can be found in Montana
- onion-like plant that cattle like to eat when lush in the spring
- There is no treatment for death camas poisoning. The only way to avoid it is to minimize the concentration of the toxin in an animal’s diet. Livestock need to eat as little death camas, and as much grass, as possible
Bacillary hemoglobinuria
“red water disease”
- in cattle is an acute, toxemic and highly fatal clostridial disease exhibiting the clinical signs of hemoglobinuria, fever and jaundice
- caused by germination of Clostridium Novyi type D spores in the liver after anaerobic damage by migrating liver fluke larvae.
- Cl. Novyi was formerly called Cl. hemolyticum.
- Vaccination can prevent this disease.
A young bull presents for a breeding soundness exam. What is the minimum recommended percentage normal morphology of sperm?
- 70% normal
- To be a satisfactory potential breeder, a bull must meet certain requirements including a normal physical exam, adequate scrotal circumference, sperm motility of at least 30% motile, and sperm morphology of at least 70% normal.
What zoontoic infection is of concern from drinking unpasteurized cow’s milk?
- Mycobacterium bovis
- M. bovis is a very serious zoonosis transmitted to humans by raw milk and has been largely controlled by institutional measures and milk pasteurization in the United States
- Mycobacterium bovis (M. bovis) is a slow-growing (16- to 20-hour generation time) aerobic bacterium and the causative agent of tuberculosis in cattle (known as bovine TB).
- It is related to Mycobacterium tuberculosis, the bacterium which causes tuberculosis in humans
When is a chorioallantoic membrane slip first palpable in a heifer?
- 30-35 days
- This is known as the membrane slip and is considered a positive sign of pregnancy.
- gestation of cows: 283 days
Lipofuscinosis
- lipofuscinosis is the general name for a family of at least eight genetically separate lysosomal storage diseases that result from excessive accumulation of lipopigments (lipofuscin) in the body’s tissues.
- These lipopigments are made up of fats and proteins
- Lipofuscinosis is a storage disease that usually gives the liver a dark appearance
What is the main lesion associated with polioencephalomalacia in cattle?
- Necrosis of cortical gray matter
- A deficiency of thiamine is believed to be the main cause of the disease although others have been suggested, including excess intake of sulfur, lead, or sodium. Early recognition of the signs and treatment with thiamine is required to have success in treating the condition.
Predisposing Factors:
● High concentrate diets (pastured animals can also develop disease)
● Feed with corn or sugar cane byproducts
● High grain intake may promote proliferation of thiaminase producing bacteria
● Rations with added sulfate to limit intake
● Ingestion of plant thiaminases or thiamine analogs
Clinical Forms of Polioencephalomalacia
(acute vs. Subacute)
Acute Form
● Blindness
● Seizures
● Recumbency
Subacute Form
● Initial signs
a. Decreased appetite
b. Twitching (ears and face)
c. Separation from the herd
d. Hold head up in an elevated position
e. Staggering, hypermetric gait
Later signs
a. Cortical blindness
i. Absent menace, intact palpebral reflex and pupillary light response
b. Dorsomedial strabismus
c. Head pressing
d. Teeth grinding
e. Opisthotonus
Post-mortem findings of polioencephalomalacia
a. Gyral flattening, brain swelling.
b. Brain tissue may fluoresce under UV light. - accumulation of autofluorescent substances in degenerating neurons that seem to be localized to the mitochondria
c. Cerebrocortical neuronal necrosis.
d. Cortical spongiosis.
e. Cavitation of cortical tissue.
f. Multifocal vascular necrosis, hemorrhage, and necrosis in deep gray matter.
Polioencephalomalacia
some causes: lead poisoning, lactic acidosis (grain overload - kill microbes req. to synthesize thiamine in the rumen), salt intoxication/water deprivation, bracken fern poisoning (produced thiamine destroying substance), sulfur intoxication, amprolium intoxication (competes for active sites wth thiamine)
Neurological Symptoms in Cattle based on location of lesion
Cerebral Cortex?
Brain Stem?
Cerebellum?
Spinal Cord?
Peripheral Nerves?
more common Brainstem lesions in Cattle
(5)
- Listeriosis is by far the most common
- TEME = Thromboembolic meningoencephalitis
Listeria
- Listeriosis is an infectious disease caused by a bacterium, Listeria monocytogenes. It is a zoonotic disease.
- poorly fermented silage - often silage that results in having a high pH
- cranial nerve deficits from microabscesses in the brainstem
signs:
- signs being asymmetrical (but can be symmetrical over time)
- dull, depressed (due to inflammation of reticular activating formation)
- see signs of CN’s being affected (CN. V and VII most commonly affected)
Diagnosis/Tx of Listeriosis
(8)
- Mononuclear (mixed) cell pleocytosis is an increased leucocyte count with a predominance of lymphocytes and macrophages
- definitive Dx often made on necropsies
- gram (+) bacteria that often respond well to these AB therapies
- can also have dysphagia due to CN 9,10,12 being affected - also drool saliva a lot –> need to correct acid/base derrangements (often metabolic acidosis bc as they drool, a lot of bicarbonate is lost and K+)
common cerebral diseases in cattle
(8)
- TEME - caused by histophilus somni (a gram - bacillus) –> can lead to pneumonia, polyarthritis, myocarditis, abortion, and meningoencephalitis
Pathophysiology of CCN (5)
(polioencephalomalacia)
what might CSF analysis show?
PPP = pathway to produce energy via ATP in the brain and red cells
sodium starts to move into the neuronal or RBC’s as a result and water tends to follow –> swelling
see more of a change in mentation than with listeriosis (which is related to brainstem lesions)
What neurological effect can BVDV cause?
- cerebellar hypoplasia
- tend to see signs of cerebellar lesions (in calves infected in utero) = hypermetria, tremors
Oleander toxicity
- All parts of the plant are toxic, including the dried leaves. Oleander contains a complex mixture of cardiac glycosides, mainly oleandrin, which are potent cardiac toxins
- oleander is cardiotoxic and causes arrhythmias
Hepatic Functions:
metabolic? (2)
Synthetic? (3)
Excretory? (2)
- phylloerythrin : a rose-red photosensitizing porphyrin pigment formed as a degradation product of chlorophyll in the digestive tract of herbivorous animals and normally excreted especially in the bile but absorbed by the blood in pathological conditions —> leads to photosensitization in animals with hepatic damage
Cases of Liver Damage that can e somewhat reversible
(a.k.a. not fibrotic or loss of blood supply)
Signs of Liver Failure in Cattle
- Hepatoencephalopathy is less dramatic in cattle than it is in horses
- photosensitization can be a more observable (peeling nose, watering eyes, general oedema of heads and eyes, affects depigmented areas)
Common causes of Liver Failure in Cattle
(4)
hepatic lipidosis: often late in pregnancy or early lactation
Lab Tests Indicating Liver Damage
- alk phos, GGT: comes from the bile ducts, so can reflect a chronic process with bile duct proliferation
- whereas, hepatocellular enzymes may come from the hepatocytes themselves and indicate acute damage
- clotting tests may also be abnormal
Pyrrolizidine Alkaloid Toxicity
(PA Toxicity)
- Ingested alkaloids are converted to pyrrolic esters by hepatic cytochrome p450 enzymes. These esters are alkylating agents, which react with cytosolic and nuclear proteins and nucleic acids
- basically the cells age and then grow and grow as they don’t die off (anitmitotic effects) - replaced by fibrosis when they die
- lesions from intoxication consist of: megalocytosis (enlarged hepatocytes), hepatic fibrosis, biliary proliferation, and in some cases nodular regeneration of parenchyma
- senecio = RAGWORT
- can be white fuzzy bits in alfalfa hay
Hepatic Lipodosis
- Cattle less prone to pregnancy toxemia than other species (ponies, sheep, etc.)
- can actually treat this condition sometimes with insulin as it decreases HSL (hormone sensitive lipase) which mobilizes fat tissue for use in gluconeogenensis
Spastic Paresis
“Elso heel”
- Spastic paresis, also known as Elso heel, affects cattle of many breeds (as well as pygmy goats) beginning from three weeks to 1 year of age.
- It is believed to be caused by a combination of genetic and environmental factors which somehow cause over stimulation of the gamma motor neurons of the spinal cord.
- A second disease, inherited periodic spasticity is a genetic disorder (probably single autosomal recessive) of most dairy breeds, and is seen rarely in beef breeds.
- It first appears at 3 to 7 years of age and gradually worsens, when the animals develop marked muscular spasms of the hip and upper leg muscles.
A dairyman’s favorite cow was bred by a new bull a few weeks ago and now his cow has pyometra.
What agent is most likely responsible for causing the cow’s pyometra?
- Tritrichomonas foetus
- This organism is commonly associated with a post-coital pyometra in addition to causing early embryonic death.
- Tritrichomonas foetus is an obligate parasite of the bovine reproductive tract causing a highly contagious venereal disease.
- Infection of cows with T foetus most often leads to pregnancy loss, but typically a return to normal fertility.
“Milk Fever”
- hypocalcemia!
- Milk fever is caused by a temporary blood calcium deficiency (also known as hypocalcaemia) which usually occurs around the time of calving and is one of the most common metabolic disorder in dairy cattle
- may have teh resulting CS’s: acute recumbency, hypothermia, difficulty hearing HR, neck turned toward thorax (pleurothotonus), “s” shaped curve of spine, rumen motility decrease, nose dry
Actinomycosis
“lumpy jaw”
- can result in a swollen lower jaw with an adjacent hard, relatively non-painful swelling
- this condition results from the entry of the normal rumen inhabitant Actinomyces bovis into the bony mandible (usual site) or maxilla through a break in the mucous membranes or teeth.
- It may be arrested with therapy using sodium iodide, antimicrobials or even isoniazid off-label, but the bony swelling seldom changes much, even if arrested.
- These lumps are immovable hard swellings of the bones, usually at the level of the central molar teeth.
- The swellings develop slowly and may take months to reach the size of a tennis ball
- Infection with the bacterium Actinomyces bovis occasionally causes osteomyelitis in the maxilla (cheek) and mandible (jaw) of adult cattle, most often beef cattle. The organism may gain entry to the bone associated with permanent molar teeth eruption or traumatic buccal injury.
- There is marked enlargement of the mandible and often one or more discharging sinuses. Pain and physical deformity cause problems with masticating fibrous food with consequent rapid loss of milk yield and body condition.
Which of the following is the most common cause of pericarditis in cattle as shown in the photograph?
- Traumatic reticuloperitonitis (hardware disease)
- Cattle ingest wires which then perforate the reticulum and migrate into the pericardium and cause an infection.
- In small ruminants, Clostridium perfringens will cause pericarditis.
- In swine, pericarditis may be caused by haemophilus, streptococcus, and Stephanurus edentatus
Hydroallantois
- Hydrops allantois (hydroallantois) is a disorder of the placenta and the prognosis for life of the fetus and fertility of the cow is poor
- due to a defective placenta (the chorio-allantois). The fetus is normal. The condition is characterized by a rapid accumulation of watery, clear fluid (100-200L), usually in the last trimester
- The cow develops a rounded appearance to the abdomen and it is usually not possible to palpate the fetus or placentomes.
- The cow often becomes sick with anorexia, decreased rumen motility, dehydration and weakness. She may go down or rupture the prepubic tendon.
- The prognosis for the fetus is guarded and even with treatment, the cow will likely be infertile.
- Induction of parturition or C-section are treatment options but the majority of calves are not viable and the dam rarely has normal colostrum.
- If the pregnancy is terminated, it is unlikely that the cow will have a productive milk cycle.
- Usually salvage for slaughter is the preferred option unless the fetus is considered valuable and the cow is near term
Ringworm
(Dermatomycosis)
- Ringworm is a dermatomycosis that tends to occur most commonly in housed, crowded calves in winter when there is little UV light present.
- The most common dermatophyte in cattle tends to be Tricophyton verrucosum, with T. mentagrophytes second most common.
- Therapy includes such topical treatments as captan, diluted bleach, lime sulfur, or miconazol shampoos.
- Systemic treatment is rarely needed.
Infectious Bovine Keratoconjunctivitis (IBK)
Which pathogen is involved?
- Infectious bovine keratoconjunctivitis (IBK), also known as pinkeye, New Forest eye or blight, is a veterinary infection of cattle caused by Moraxella bovis, a Gram-negative, β-haemolytic, aerobic, rod-shaped bacterium. It is spread by direct contact or by flies serving as vectors
- most common bacteria causing this is Moraxella bovis, although other organisms including Neisseria species and Moraxella ovis can also induce similar lesions in cattle.
- Also, IBR and mycoplasma seem to be risk factors that may increase the risk of developing IBK
Calf Diptheria
- This is a disease associated with Fusobacterium necrophorum, which is a strict anaerobic bacteria found everywhere in the environment.
- The disease is usually trasmitted by oral ingestion of the bacteria.
- Also called necrotic laryngitis, or laryngeal necrobacillosis, this mainly feedlot condition strikes randomly but can result in death or a permanently misshapen larynx.
- The causes appear to be Histophilus somni and Fusobacterium necrophorum
- There are two forms of calf diptheria; oral (less than 3 months old) and laryngeal (older calves)
- Swelling of the rostral cheek and salivation are the main clinical signs
- Upon physical examination, there may be a foul smell emitting from the mouth and deep necrotic lesions may be found on the cheek or tongue
- If the larynx or pharynx are involved, swelling may lead to dyspnoea and the presence of pneumonia. These animals will also be pyrexic. They usually die fairly quickly as exudate may block the airways.
Lupine alkaloid Toxicity
- More common than direct toxicity, some lupine alkaloids produce birth defects in cattle if eaten during certain gestational times.
- Cows eating lupine during early gestation often give birth to calves with cleft palates, crooked legs and distorted/malformed spines. –> “crooked calf syndrome”
- Such deformed calves generally have to be euthanized. Epidemic outbreaks of such birth defects can have high morbidity resulting in enormous animal and economic losses.
Epizootic Bovine Abortion
“Foothill Abortion”
- Foothill abortion, also called Epizootic Bovine Abortion (EBA), affects cattle in California, Nevada and Oregon.
- It is caused by a bacterium that is vectored by the Pajaroella tick (Ornithodoros coriaceus). These ticks occur in areas with sage, bitter brush, pinyon pines, junipers, and oaks
- Abortion occurs more than 3 to 4 months after exposure, so keeping pregnant heifers out of the foothills until they are 6 months pregnant means they calve before fetal lesions occur.
- Raising heifers in the foothills until breeding does provide premunition immunity.
- Also, the rancher should keep these heifers that abort, as they will now be immune to EBA.
- Tick control is very difficult on cattle running in the hills, but the ticks do not inhabit irrigated pastures (they live in the dry ground duff of needles and leaves), so bred heifers can be kept in irrigated pastures for months 1-6 of pregnancy
Pyelonephritis
- Pyelonephritis occurs most commonly in post-partum cows when bacteria enter via the urethra due to a post-partum uterine infection and vaginal damage at calving.
- The most common organisms found are coliforms or Corynebacterium renale.
- The resultant ascending infection causes renal swelling and pain (grinding teeth, swishing tail, repeatedly up and down), fever, and loss of appetite.
Infectious Bovine Rhinotracheitis (IBR)
- Infectious Bovine Rhinotracheitis (IBR) is a highly contagious, infectious respiratory disease that is caused by Bovine Herpesvirus-1 (BHV-1). It can affect young and older cattle.
- Diagnosis can be made from viral isolation of nasal or ocular swabs from live animals or from bronchial lymph nodes or tracheal tissue in deceased animals. Serology submitted 2-3 weeks apart can also confirm a diagnosis of IBR.
- The different strains of IBR tend to produce different syndromes
- The disease is characterised by inflammation of the upper respiratory tract.
- Bovine herpes virus 1 (BHV 1) also causes infectious pustular vulvovaginitis in the female, and infectious balanoposthitis in the male and can cause abortions and foetal deformities.
- IBR is endemic in the UK with around 40% of cattle having been exposed to the virus in the past. Infected cattle develop a latent infection once recovered from the initial infection and despite appearing clinically normal may suffer recrudescence of disease when under stress
Paradoxic aciduria
- Normally the kidney excretes some potassium because of the need to maintain an equal number of anions and cations in the urine. But when there is insufficient potassium available, in order to reabsorb sodium to maintain blood pressure, hydrogen ions are excreted rather than potassium.
- This results in acidic urine at the same time as metabolic alkalosis, a condition known as paradoxic aciduria.
Treatment and Prevention of IBK
- Small opaque region in center of cornea progresses to deep central ulceration
- a. Perforation of corneal ulcer is uncommon.
- Antibiotics
- a. Oxytetracycline (LA-200) systematically
- b. Labeled for treatment of IBK
- c. Ceftiofur (Naxcel) SQ - 3rd generation cephalosporin
- d. Penicillin subconjunctivally
- e. Florfenicol IM
- f. Tulathromycin SQ
● Surgical intervention
a. Can perform third eyelid flap or tarsorrhaphy.
Eliminate environmental factors
a. Protect eyes from UV light by using glue on eye patch
b. Control fly population with face rubbers and ear tags
c. Grass, weed, and brush control to minimize mechanical irritation d. Eliminate overhead feeding
● Prevent other predisposing diseases
a. Vaccinate for BVD and IBR
b. Isolate infected animals
● Vaccination for IBK
a. Mixed results. If both humoral IgG and secretory IgA directed at M. bovis antigens are present, these appear to be protective.
b. Not consistently effective therefore not yet in widespread use.
Possible causes of ulcerative necrotic interdigital lesions in cows?
- FMD
- BVD
- Interdigital necrobacillosis
- Malignant catarrhal fever
Adductor Muscles of Pelvic Limb
- Adductor brevis
- Aductor longus
- gracillis
- pectineus
Brisket Disease
- Brisket disease occurs as a result of lack of oxygen at high altitude.
- As the syndrome progresses, subacute edema develops in the brisket region. Marked distention and pulsation of the jugular veins are usually present.
- High mountain disease (brisket disease) is right heart failure due to hypoxic pulmonary hypertension in cattle residing at high altitudes.
- Hypoxia is the most potent stimulus for pulmonary hypertension, and the hypoxia of high altitude (>7,000 ft) is a well known cause.
- Can measure being prone to it at about 6000ft
“Cancer Eye”
- ocular squamous cell carcinoma (also known as “cancer eye”) which is one of the most common neoplasms of cattle and causes significant economic loss due to shortened productive life and condemnation at slaughter.
- The etiology is multifactorial but is believed to have a heritable component as well as association with sunlight, eyelid pigmentation, and nutrition.
- The diagnosis can be made from the clinical presentation and fine needle aspirate showing a cluster of epithelial cells with anisocytosis and basophilic, vacuolated cytoplasm.
What does eosophageal dysfunction in a calf lead to?
Rumen Acidosis
- Esophageal groove dysfunction is one of the major causes of ruminal bloat.
- This condition is fatal in new born calves if it is not treated early.
- In healthy, suckling calves, milk should bypass the forestomach (rumen and reticulum) and enter into the abomasum where enzymatic digestion of milk proteins takes place.
- the esophageal groove (also known as reticular groove) is a specialized part of the ruminant stomach that closes in response to drinking milk, directing it directly to the abomasum. When dysfunctional, milk goes to the rumen where it is fermented by rumen microbes and converted to volatile fatty acids and lactic acid. –> For this reason, this phenomenon is sometimes referred to as rumen drinking.
- might develop white, puddy-like feces
How do you diagnose the presence of Streptococcus agalactiae?
Perform a CAMP reaction
- This organism usually causes subclinical mastitis, but sometimes you may see high somatic cell counts and clinical signs with this organism.
- Perform a CAMP reaction to diagnose this organism.
- That is when you plate S. aureus and S. agalactiae and you see them act together to lyse red blood cells.
- This creates a clearing on your culture plate.
WInter Dysentery
- Winter dysentery is an epidemic disorder of housed cattle, usually occurring in cold months and affecting 10-90% of adult cows.
- If fever occurs at all, it usually precedes the diarrhea phase (brownish fetid liquid feces full of bubbles)
- The disease is thought to be caused by coronavirus, and lesions involve the colon. In typical outbreaks, the disease runs its course in weeks and the herd becomes immune and recovers, although milk production may not recover to previous levels.
What causes grass tetany in cattle?
Hypomagnesemia
- Hypomagnesemic tetany (grass tetany) - It usually occurs in cold or cool weather in pastured lactating beef or dairy cows.
- Lush pastures that are high in potassium and nitrogen and low in magnesium and sodium are most often involved.
- CS’s: eyelids are fluttering, there is nystagmus, and champing of the jaws, on side and paddling, death
Salmonella Dublin in Calves
- S. dublin tends to cause septicemia in dairy calves 4 to 8 weeks of age
- The organism can be transmitted by carrier cows to neonates at birth or via their milk.
- Diarrhea is a common consequence of Salmonella infections. However, the common presenting sign of S. Dublin infections is respiratory disease in calves 2 to 12 weeks of age.
- The most effective control measures are to cull carriers and vaccinate calves using a modified live S. dublin vaccine.
A dairyman’s favorite cow was bred by a new bull a few weeks ago and now his cow has pyometra.
What agent is most likely responsible for causing the cow’s pyometra?
Tritrichomonas foetus
This organism is commonly associated with a post-coital pyometra in addition to causing early embryonic death
Spastic Paresis
(aka Elso heel)
- This is a hereditary disease which produces a continuous stiffness of the hocks.
- Spastic paresis or Elso-heel is a progressive neuromuscular disease which affects the hind limb in young cattle
- It is believed to be caused by a combination of genetic and environmental factors which somehow cause over stimulation of the gamma motor neurons of the spinal cord
- There could be bilateral or unilateral involvement. It is a recessive disease; therefore, affected animals should not be bred.
- A second disease, inherited periodic spasticity is a genetic disorder (probably single autosomal recessive) of most dairy breeds, and is seen rarely in beef breeds. It first appears at 3 to 7 years of age and gradually worsens, when the animals develop marked muscular spasms of the hip and upper leg muscles.
- Treatment involves a tibial neurectomy or gastrocnemius tenectomy.
2 most common pathogens of pyelonephritis in post-partum dam
- Pyelonephritis occurs most commonly in post-partum cows when bacteria enter via the urethra due to a post-partum uterine infection and vaginal damage at calving.
- The most common organisms found are coliforms or Corynebacterium renale.
- The resultant ascending infection causes renal swelling and pain (grinding teeth, swishing tail, repeatedly up and down), fever, and loss of appetite.
A “honking” cough can be indicative of which infection?
- Bovine respiratory syncytial virus
- often see mucopurulent nasal discharge as well
- white plaques are noticed on the conjunctiva and nasal epithelium
STRUVITE
- Struvite is composed of magnesium ammonium phosphate. The alkaline urine in cattle along with high dietary phosphate and magnesium levels favors formation of struvite stones.
- Feedlot animals can also develop apatite stones composed of calcium phosphate
Malignant catarrhal fever (MCF)
- Malignant catarrhal fever (MCF) in North America is caused by sheep-associated ovine herpesvirus-2.
- A very high percentage of sheep and goats in North America are infected with OHV-2 and can transmit the virus to susceptible cattle, bison, deer, and other related species, even if only in close proximity and not in direct contact.
- The virus causes lymphocytic vasculitis and can be fatal.
Prey-Predator Cycles of Sarcocystis spp.
- Sarcocystis spp normally develop in two-host cycles consisting of an intermediate host (prey) and the final host (predator).
- Species-specific prey-predator life cycles have been demonstrated for:
- cattle-dog (S cruzi)
- cattle-cat (S hirsuta)
- cattle-human (S hominis)
- sheep-dog (S capracanis, S hircicanis)
- sheep-cat (S gigantea, S medusiformis)
- goat-dog (S capracanis, S hircicanis)
- goat-cat (S moulei)
- pig-dog (S meischeriana)
- pig-human (S suihominis)
- pig-cat (S porcifelis)
- horse-dog (S fayeri)
- llama-dog (S aucheniae)
- pigeon-hawk (S calchasi)
Akabane Disease
- Arthropod-borne disease
- Akabane disease is an arthropod-borne viral disease that can affect cattle, sheep and goats.
- In the predominant syndrome, inapparent infections in adults can lead months later to abortions, stillbirths and congenital defects in newborns.
- Most affected neonates die or must be euthanized
- may see fetal brain lesions such as hydranencephaly or hydrocephalus in fetal calves
Infectious bovine rhinotracheitis ophthalmic lesions are caused by which virus?
-
Bovine Herpes Virus 1
- The virus infects the trigeminal ganglia and becomes latent.
- When an animal is immunosuppressed, the virus replicates and causes disease.
- The ocular signs of the disease include serous to mucopurulent conjunctivitis
- Herpes II causes bovine ulcerative mammilitis.
- Herpes III is the alcelaphine herpes virus (African malignant catarrhal fever)
4 Clinical Types of Abomasal Ulcers
Clinical Signs of Bleeding Ulcers
(5)
Ways to alter gastric/abomasal secretion
(4)
Treatment of Abomasal Ulcers
(6)
What disease in cattle and sheep is closely related to African Horse Sickness?
- BLUETONGUE
- (less virulent in endemic areas like California)
- strains of different serotypes vary greatly in terms of pathogenicity!
Bluetongue as a teratogen in cattle
Calf D+ before 6 days of age?
- could begin to think it may be the result of sepsis
- remember volume of colostrum is more important than quality these days! - make sure they get 4L of colostrum to ensure adequate intake of immunoglobulins!
- discard milk that may have antibiotics in it!
Flies, cats, dogs, mice, pigeons and Salmonella transfer
