Bovine Diseases 2

Question 1

Acute Diarrhea in Adult Cattle

Answer 1

• Coccidiosis: caused by a protozoal parasite, Emeria spp.
• Dietary Gastroenteritis: carbohydrate overload or rapid diet changes.
• Salmonellosis: caused by Salmonella bacteria.
• Acute Bovine Viral Diarrhea (BVD)
• Winter Dysentery or Cornonavirus

Question 2

Johne’s Disease

Answer 2

• Caused by Mycobacterium paratuberculosis.
• Chronic diarrhea and wasting.
• Terminal disease with no treatment.
• Calves > 6 mo. infected by oral-fecal route.
• Clinical signs develop after 2 yrs of age.
• Organism lives inside macrophages in Peyer’s patches.
• Causes thickening of the intestinal wall and malabsorbtion of nutrients.
.

Question 3

Control of Johne’s Disease:

Answer 3

Testing is available to detect infected animals.
• Testing is not very reliable.
• Animals showing signs are culled.
• Feed calves pasturized milk or milk replacer.
• Keep calves isolated from contact with manure of mature animals.
• Vaccination is available from the state for herds with a high incidence.

Question 4

Salmonellosis

Answer 4

• Suspect when chronic diarrhea follows an outbreak of acute diarrhea in a herd.
• Especially if the outbreak coincides with a change of feed, water or flooding.
• Testing is done by culturing feces.
• Salmonella is zoonotic!!!!!!

Question 5

Clinical signs of Salmonellosis

Answer 5

• Profuse watery diarrhea.
• Chronic re-occuring bouts of diarrhea.
• Weight loss.
• Hypoprotienemia
• Leukopenia
• Electrolyte imbalances: low Na & K

Question 6

Severe cases may have:

Answer 6

• Septicemia, especially calves.
• Abortion
• Endotoxic shock
• Death

Question 7

Treatment of Salmonellosis

Answer 7

• Supportive care
• Antibiotics
• Anti-inflammatory drugs
• Chronically infected animals can be carriers.
• These animals need to be isolated!
• Carriers may need to be culled.

Question 8

Mycoplasma pneumonia

Answer 8

• Caused by Mycoplasma bovis.
• May cause mycoplasma mastitis later in life in dairy cattle.
• Vaccination is available.
• Colostrum containing Mycoplasma bovis may be a source of infection.

Question 9

Black Leg and Malignant Edema

Answer 9

• Caused by infection with anaerobic bacteria in the Clostridium family.
o Black leg: Clostridium chauvoei
o Malignant edema: Clostridium septicum

Question 10

Spores black leg from the bacteria enter the tissues through

Answer 10

o GI tract

o Injuries

Question 11

Clinical Signs of Black Leg & Malignant Edema

Answer 11

• High fever.
• Severe lameness due to muscle damage.
• Swollen muscle mass contains gas subcutaneously, felt as “crepitice”.
• Death is rapid (animals usually found dead).
• Treatment is debridement and penicillin with very poor prognosis.

Question 12

Prevention of Black Leg and Malignant Edema

Answer 12

• Vaccination of calves at 2 months of age followed by a booster in 4 to 6 weeks.
• Vaccinate cows prior to calving to provide high amount of antibodies in the colostrum.

Question 13

Anthrax

Answer 13

• Caused by a spore forming bacteria, Bacillus anthracis.
• Endemic to the southern USA, spores survive for centuries in the soil.
• Zoonotic, take care when performing necropsies.
• If suspected, back away, and call the Federal Veterinarian.
• Vaccination is available to those in high risk areas.

Question 14

Mastitis

Answer 14

• Inflammation of the mammary gland.
• Caused by a variety of bacterial organisms.
• The most common disease in dairy cattle.
• The most economically important disease in the dairy industry.

Question 15

Types of Mastitis:

Answer 15

• Contagious mastitis:

* Environmental mastitis:

Question 16

Contagious mastitis

Answer 16

o The organism is spread from an infected udder to healthy udder by contaminated milking equipment, the milkers’ hands or nursing calf.
o Source of infection is from the cow(s).

Question 17

Environmental mastitis:

Answer 17

o Bacteria in the environment gain access to the udder and cause infection.

Question 18

Contagious mastitis Organisms most common are

Answer 18

• Staphylococcus aureus
• Streptococcus agalactiae
• Corynebacterium bovis
• Mycoplasma bovis

Question 19

Environmental Mastitis: Source is from the cow’s surroundings.

Answer 19

• Organisms most common are:
• Streptococcus dysgalactia
• Streptococcus uberus
• Clostridium perfringens
• Escherichia coli
• Klebsielaspp

Question 20

Risk factors for mastitis:

Answer 20

• Most new infections occur in early lactation.
• High producing cows are at higher risk.
• Poor management of housing and bedding.
• Poor maintenace of milking equipment.
• Poor milking hygiene.

Question 21

Clinical Signs of Mastitis

Answer 21

• Abnormal milk:
• Swollen and painful mammary glands.
• Chronic cases have fibrous, atrophied glands.
• Gangrene in rare cases.

Question 22

Abnormal milk

Answer 22

o	Blood
o	Clots
o	Pus
o	Flakes
o	Serum

Question 23

Gangrenous Mastitis

Answer 23

• Cause by Clostridium prefringens or Staphylococcus aureus.
• Gland becomes gangrenous with a distinct blue line demarcating normal and affected tissues.
• Affected tissues are cold.
• Cow is systemically ill.
• Cow may die from toxic shock

Question 24

How do cows get mastitis?

Answer 24

• Teat ends or streak canal is damaged, allowing bacteria to gain entry.
• Or, improperly functioning milking equipment force milk up the streak canal.
• Or, the cow lays down in manure and mud right after milking, when the streak canal is open.

Question 25

California Mastitis Test

Answer 25

o Milk is mixed with a special reagent in a four chambered paddle.
o The mixture thickens if white blood cells are present in the milk.
o The thickness of the gel corresponds with the number of wbc’s in the milk.

Question 26

Milk Cultures

Answer 26

o Milk is collected aseptically from each quarter.
o Milk is cultured on medium to help identify the type of bacteria present.
o Antibiotic sensitivity testing is done on the organism to determine which antibiotic is most effective.

Question 27

Treatment of Mastitis

Answer 27

• Intramammary and/or systemic antibiotics.
• Frequent milking to remove the pathogen from the udder.
• Supportive treatment for cows with systemic illness.
• Amputation of the quarter in severe cases.