infectious bovine rhinotracheitis

Question 1

Definition of BHV-1 free herd

Answer 1

• All animals over 6 months of age are tested 2x (interval 2-12 months)
• In dairy herd: milk samples: 3x (interval 2 months)
• IBR-free semen for insemination
• Embryo-transfer: free parents
• Introduced animals:
o First blood or milk test is negative
o Originating from free herd
o Test during the 30 days isolation: 2x (21 days

Question 2

Definition of BHV-1 infected herd

Answer 2

• Confirmed infection – PCR
• IgE positive animal
• Use of non-marker vaccine in the past 2 years
• Obligatory eradication plan → slaughtered, can go for Human consumption

Question 3

Eradication of BHV 1

Answer 3

• 1) Classic selection method
• 2) Selection with the use of marker vaccines
• 3) Generation shift
• 4) Herd change

Question 4

Classic selection method for BHV 1

Answer 4

• If infection is under 10%
o All animals over 6 months of age are tested
o Separation of seronegative
• Seronegative: blood test in every 3-6 weeks
o Minimum 2 negative test with an interval of 21 days for all animals
o Elimination of positive animals
• Seropositive:
o vaccination with inactivated vaccine 2x (3-5 weeks’ interval) and later in every half a year

Question 5

Generation shift in BHV-1

Answer 5

• Isolated keeping and rearing of free calves
• Pregnant cows (intrauterine infection!): vaccination before calving (conventional or marker vaccine)
• Calves:
o Isolation from 3 days of age
o 1st blood test: 6 months of age
o Elimination of positives
o Blood test in every 3-6 weeks, until 2 negative results of all animals

Question 6

Maintenance of free status of BHV 1

Answer 6

• All animals above 6 months of age: tested every 12 months
• Animals for slaughter: test before transport for slaughter
• Dairy herd: milk test in every 6 months
• Aborted animals: test 3-6 weeks after abortion
o → aborted materials and dam’s blood sent to lab
• Only animals from free herds are introduced (test: 2x, 21 days’ interval