Acute Diarrhea

Question 1

what species and serovars of salmonella cause acute diarrhea in cows?

Answer 1

salmonella enterica, with many serovars including typhimurium, dublin, newport

Question 2

T or F, salmonella only causes diarrhea

Answer 2

false, it causes many things like abortion, septicemia, pneumonia, etc

Question 3

what clinical signs do you see with salmonella?

Answer 3

any age cow, pyrexia and diarrhea, can contain blood or fibrin, can result in septicemia/endotexemia

Question 4

you are examining a cow that has watery mucoid diarrhea. This cow’s temp is 39. what do you suspect and what do you do next? How are you going to treat this cow?

Answer 4

suspect salmonella; can do an aerobic culture of the feces or do PCR to confirm. ELISA also available for S dublin

treatment: fluids and NSAIDs, antibiotic use controversial (only consider in cases of septicemia or calves maybe?), if you’re gonna use one use TMPS

Question 5

how does salmonella spread, and who is most at risk? What can you to do prevent it?

Answer 5

cow to cow spread, carrier states possible, transition and fresh cows most at risk or any that have a suppressed immune system like calves, birds and rodents can also carry the disease

prevented via good hygeine (regular biosecurity protocols, sometimes hard to do), vaccines also available

Question 6

describe what winter dysentery is

Answer 6

caused by covine coronavirus (BCov), has high morbidity low mortality, is a fairly short lived disease, usually in housed cattle over the winter

Question 7

common clinical signs of winter dysentery

Answer 7

decreased appetite, bloody diarrhea, pyrexia, reduced milk production, resolved in 24-36 hours

Question 8

you are called out to a farm in January that has 2 month old calves with fevers and blood diarrhea and are also not eating. What will you do next?

Answer 8

probs winter dysentery/bovine coronavirus

can do PCR of the feces, antibody ELISA (paired sample)

supportive therapy only (if secondary infections, then reach for antibiotics)

Question 9

coccidiosis is caused by

Answer 9

eimeria parasite (not all species are pathogenic and almost no labs test for specific species identification, remember that)

Question 10

common history and presentation of cow with coccidiosis

Answer 10

younger animals but not neonates (PPP is 15-20 days), with large intestinal diarrhea (straining, fresh blood, mucus)

Question 11

what is nervous coccidiosis?

Answer 11

neurologic signs from coccidiosis infection, spasms, nystagmus, seizures, reported in NA feedlots only

Question 12

you are looking at a 2 month old cow that is straining to poop, and when it does pass feces there is fresh red blood and mucus in the feces. what do you do next?

Answer 12

im thinking coccidiosis, so I want to check for oocysts in the feces

treatment is supportive; coccidiostats can reduce shedding but can’t really be used theraputically, more used prophylactically

Question 13

true or false: coccidia species don’t last long in the environment

Answer 13

FALSE they are VERY persistent in the environment

Question 14

Parasitic Gastroenteritis is more common in what kind of animal?

Answer 14

grazing animals with poor growth

Question 15

what kind of virus is BVDV? does it always cause diarrhea?

Answer 15

pestivirus

and no, it usually does NOT cause diarrhea actually which is confusing given the name

Question 16

describe the difference between type 1 and type 2 BVDV in CALVES

Answer 16

type 1 (nCP): immunisuppression, makes other diseases worse, may get diarrhea, then antibodies develop and they get strong immunity

type 2 (CP): severe acute/peracute infection, sometimes found dead, severe thrombocytopenia, high morbid &mortal

Question 17

describe the difference between type 1 and type 2 BVDV in NON PREGNANT adult cow

Answer 17

type 1: mild fever, immunosuppression, virus is shed, antibodies are produced and get strong immunity and stop shedding

type 2: severe acute/peracute infection, sometimes found dead, severe thrombocytopenia, high morbid &mortal

Question 18

describe the difference between type 1 and type 2 BVDV in the BULL

Answer 18

type 1: mild fever, immunosuppression, virus is shed, antibodies are produced and get strong immunity and stop shedding (MAY PERSIST IN SEMEN)

type 2: severe acute/peracute infection, sometimes found dead, severe thrombocytopenia, high morbid &mortal

Question 19

describe the difference between type 1 and type 2 BVDV in the PREGNANT COW

Answer 19

type 1: mild fever, immunosuppression, virus is shed, antibodies are produced and get strong immunity and stop shedding, may cause loss of pregnancy

type 2: lose the calf for sure, severe acute/peracute infection, sometimes found dead, severe thrombocytopenia, high morbid & mortal

Question 20

describe the outcomes if a calf IN UTERO is exposed to BVDV type 1 for each of the following conditions:
- early gestation, <100 days
- mid gestation, 100-150 days
- late gestation >150 days
- BEFORE 125 days if survives

Answer 20

• early gestation: lose the fetus, resorption, mummification, etc
• mid gestation: congenital defects such as cerebellar hypoplasia or congenital cataracts
• late gestation: possible abortion or no effect at all, normal calf
• before 125 days if survives: fetal immune system not developed–:persistently infected calf=BAD NEWS

Question 21

how is a PI calf created?

Answer 21

if the dam is infected with the virus before 125 days gestation, the fetus has no immune system and therefore no defence against the virus, the calf recognizes the virus as self, the virus is found in almost all tissues, and NO antibodies will develop.

Question 22

what is the primary reservoir for BVD infection?

Answer 22

PI calves

Question 23

Do PI calves appear sick?

Answer 23

they can be “poor doers” but they can also appear completely normal!

Question 24

what is Mucosal Disease?

Answer 24

when BVDV in a PI calf mutates to a cytopathogenic strain, and since they have no immunity, they develop mucosal disease. it is severe and untreatable

Question 25

Clinical signs of Mucosal Disease?

Answer 25

fever, depression, oral mucosa lesions, diarrhea. BUT remember this is not contagious and does not spread from calf to calf

Question 26

what are the tests you can use to diagnose BVD?

Answer 26

antigen (virus) test: virus isolation via blood, immunohistochemistry on ear notch, antigen ELISA, PCR pooled blood, PCR bulk milk

antibody test: virus neutralization, blood ELISA

Question 27

explain what each of these means for BVDV:

antigen neg, antibody neg
antigen pos, antibody neg
antigen neg, antibody pos
antigen pos, antibody pos

Answer 27

• naive cow, has not been exposed
• PI calf, or an infected animal that hasn’t had time to develop antibodies yet
• exposed and then recovered, either via vaccine or exposure to virus
• acute infection

Question 28

what are some things to look for at a herd level if you suspect BVD?

Answer 28

poor calf health, BRD or diarrhea present, repro performance is suboptimal

Question 29

what are some techniques to manage BVD at the herd level?

Answer 29

screen youngstock, do bulk milk tests in dairy herds, routein ear tagging, if PI is confirmed, look for others and screen all adults, and remove all PIs from the herd

Question 30

how can you prevent BVD at the herd level?

Answer 30

vaccinate: will reduce PI creation and losses, make sure to vaccinate before first breeding