Karteikarten
cattle- BVD
Karten in diesem Stapel (35)
- 1What genus and family is BVD?Pestivirus of the flaviviridae family
- 2Where are the two different types of BVD virus found? which is more severe1- worldwide, also in NZ
2- in North America, not in NZ
Type 2 more severe - 3What are the 2 biotypes the virus exists as? which causes disease in cattle?Cytopathic
non-cytopathic
the non-cytopathic - 4What disease of sheep is similar to BVD?border disease
- 5What losses from infection occur in cows?high MT rates
abortion
mummified foetus
EE loss
still born
congenitally deformed
PI calves - 6What losses from infection are seen in bulls?Increased body temperature= infertility for weeks
- 7how is BVD spread?Horizontal transmission
-Direct contact of infectious material- oral, occular, nasal discharge, semen, faeces, milk, urine
By PI animals
Biting insects
Contaminated instruments- last in enviro for a few hours
vertical transmission
-Mother to calf - 8What is the difference between TI and PI animals?TI's don't shed nearly as much virus as PI animals
- 9What is the pathogenesis of BVD infection?Animal infected through mm
-virus multiplies in LNs and spreads through blood stream
-get viraemia
-can be transmitted across placenta - 10When does an animal become viral antigen positive?3-10 days post infection
- 11When does an animal become antibody positive?2-3 weeks after infection
- 12What happens if a cows is infected in the: first trimester? 2nd trimester? 3rd trimester?EE loss, abortion, congenitally affected calves, PI animals
congenitally affected animals, abortion
born normal and antibody +ve - 13When does a cow need to be infected to produce a PI animal?day 45-110
- 14What clinical disease is seen in young stock?dehydration
diarrhea
stunted growth
more prone to other infections- pneumonia and GI - 15What clinical disease is seen in adult stock?often subclinical
if clinical lasts 2-3 days
immunosuppression
reduced milk yeild
diarrhoea - 16What clinical disease is seen in a bull?fever
diarrhoea
decreased fertility - 17how do you test for BVD infection in Calves less than 3 months old?-ear notch test for elisa antigen test
-skin is superior to blood ina young calf because high levels of colostrum antibody may interfere - 18How do you test cattle over 3 months old for BVD?Serum sample for Ag ELISA
- 19What does a positive sample to a BVD antigen test indicate?Either the animal is undergoing a transient infection and if re-sampled and tested in a few weeks will have become antigen negative
or the animal is PI - 20Why do PI animals not have antibodies?Because when they were infected with the virus their body interprets it as normal and doesn't recognize it as a foreign invader and therefore doesn't make antibodies against it
- 21What is another method of testing antigen besides ELISA? how is it usually tested (in terms of sample size)?PCR
pooled sample because it is expensive - 22What does a negative antibody ELISA test indicate?Animal has not been exposed to the virus in the past or it is PI
- 23What does a positive antibody ELISA test indicate?Either antibody is derived from colostrum
or animal has been exposed to virus in the past - 24What is measuring the AB levels in the bulk milk tank useful for?Determining the herd level of immunity- provides an average figure for the herd antibody levels
- 25Why are PI animals so bad?main source of infection in a herd- shed higher concentration of virus in all secretions
- 26How long do PI animals usually live? what is their health like?up to 2 years
most are poor doers
die of ill thrift related diseases- parasitism, pneumonia, MD
only 1% are healthy adult cows - 27Who can get MD disease? How?PI animals
non-cytopathic strain of BVD mutates into the cytopathic strain
One PI can get mutated strain via another PI animal - 28What age group does MD usually affect?6-24 months
- 29What are the lesions/CS caused by MD?terrible erosions in the mouth ad digestive tract
Causes severe diarrhoea nd weight loss - 30Can you prevent/ treat MD disease?Can't vaccinate- as PI calves don't have antibodies!
No treatment- need to cull or will die a terrible death - 31How do bulls spread BVD?through their semen
- 32What kinda vaccine s are there available for BVD? How many shots required?3 different Killed vaccines
Require 2 injections 4 weeks apart with annual boosters
no cross protection between strains- need to vaccinate with the dominant strain in the area - 33When are calves vaccinated?Weaning to prevent transient infection in young stock
or just before mating to prevent repro loss - 34How can you control/eradicate BVD?Want to control mainly the PI animals in your herd and being brought in
-Once a PI is detected it should be culled immediately to reduce further spread
-Biosecurity measures - 35What are some biosecurity measures?-test all brought in cattle for viral antigen before they come onto property- includes bulls for mating
-Boundary fences need to prevent animals mixing and contracting disease from neighbours
-keep boats and equipment clean
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- GCSE Cattle Karteikarten am cattle- BVD, erstellt von Hayley Pfeffer am 04/06/2016.
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- Hayley Pfeffer
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