Infectious Disease: Beef

Question 1

What is ‘Calf Scours’?

Answer 1

Diarrhea in newborn calves (<28-30 days of age) One of the most common maladies of production animals. Major economic Losses.

Question 2

What is the range of economic losses for scours? What does this include?

Answer 2

36% of all death between birth and 30 days of age. Economic loss 150-200$ per scouring calf. Including Cost dead calves, stunted calves, labour and medication.

Question 3

What is Calf Scours Related to?

Answer 3

Interaction between host / agent (pathogen) and environment. Complex interaction of viruses / bacteria / protozoa. Unusual to have a single agent as a lone cause of the disease.

Question 4

Name some Scours Agents

Answer 4

Rotavirus, K99 E.coli, Coronavirus, Clostridium perfringens, Cryptosporidium, Coccidia, Salmonella sp.

Question 5

What are some contributing factors to Calf Scours?

Answer 5

Cold wet weather, Sanitation, crowded housing - leads to increasing in exposure to neonates, nutrition (allows good quality colostrum for the calf)

Question 6

Treatment Calf Scours

Answer 6

Provide ‘stress free environment’
Treat with antimicrobial - protect against secondary infection
Fluid / electrolyte therapy
Colostrum

Question 7

Management / Prevention of calf scours?

Answer 7

Separate healthy cow / calf from sick ones.
Move healthy animals to clean pasture and remove soiled bedding (in calving area). Good sanitation (clean equipment, animal handlers. Healthy cows, good body condition scores, better calvings, less diarrhea
Vaccinate cows, rotavirus / coronavirus Cl perfringens / K99 E.coli.

Question 8

What is shipping fever? When is it normally seen?

Answer 8

Bovine respiratory disease Shipping fever pneumonia is associated with the assembly into feedlots of large groups of calves. Seen in feeder calves 7-10 days after assembly in feedlot. MORBIDITY can approach 35% and mortality is 5-10%.

Question 9

Shipping fever Primary pathogen Assault what is it?

Answer 9

PRIMARY ASSAULT is a Viral pathogen such as Bovine herpes virus (IBR) infectious bovine rhinotracheitis.
BVDV (togavirus)
BRSV (Bovine respiratory synctial virus) Paramyxovirus)
Bovine parainfluenza virus
Mycoplasma sp.

Question 10

Shipping Fever what are the secondary infections normally?

Answer 10

Manheimia (pasteurella) hemolytica
Histophillus somni
Pasteurella multicida

Question 11

What are strategies for evasion of the innate immunity?

Answer 11

1. Interference of physical barrier: Bovine herpes-1 infects respiratory epithelium and goblet cells resulting in the injury of epithelial barrier  and associated lymphoid tissue.
Mannheimia Hemolytica (invade from nasopharynx)
2. Interpherance with phagocytosis: Mannheimia hemolytica: produces leukotoxin that binds to B2 integrins and kills macrophages and neutrophils (oat cells) and binds to CD18 on lymphocytes and inactivates and often distroys lymphocytes.
3. Interference with intracellular killing: