Bovine Diseases 2 Flashcards
Acute Diarrhea in Adult Cattle
- 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
Johne’s Disease
• 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.
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Control of Johne’s Disease:
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.
Salmonellosis
- 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!!!!!!
Clinical signs of Salmonellosis
- Profuse watery diarrhea.
- Chronic re-occuring bouts of diarrhea.
- Weight loss.
- Hypoprotienemia
- Leukopenia
- Electrolyte imbalances: low Na & K
Severe cases may have:
- Septicemia, especially calves.
- Abortion
- Endotoxic shock
- Death
Treatment of Salmonellosis
- Supportive care
- Antibiotics
- Anti-inflammatory drugs
- Chronically infected animals can be carriers.
- These animals need to be isolated!
- Carriers may need to be culled.
Mycoplasma pneumonia
- 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.
Black Leg and Malignant Edema
• Caused by infection with anaerobic bacteria in the Clostridium family.
o Black leg: Clostridium chauvoei
o Malignant edema: Clostridium septicum
Spores black leg from the bacteria enter the tissues through
o GI tract
o Injuries
Clinical Signs of Black Leg & Malignant Edema
- 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.
Prevention of Black Leg and Malignant Edema
- 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.
Anthrax
- 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.
Mastitis
- 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.
Types of Mastitis:
- Contagious mastitis:
* Environmental mastitis:
Contagious mastitis
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).
Environmental mastitis:
o Bacteria in the environment gain access to the udder and cause infection.
Contagious mastitis Organisms most common are
- Staphylococcus aureus
- Streptococcus agalactiae
- Corynebacterium bovis
- Mycoplasma bovis
Environmental Mastitis: Source is from the cow’s surroundings.
- Organisms most common are:
- Streptococcus dysgalactia
- Streptococcus uberus
- Clostridium perfringens
- Escherichia coli
- Klebsielaspp
Risk factors for mastitis:
- 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.
Clinical Signs of Mastitis
- Abnormal milk:
- Swollen and painful mammary glands.
- Chronic cases have fibrous, atrophied glands.
- Gangrene in rare cases.
Abnormal milk
o Blood o Clots o Pus o Flakes o Serum
Gangrenous Mastitis
- 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
How do cows get mastitis?
- 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.
