Cattle drug questions

[Orkneyboy]

A few questions:

1. How long should I wait after taking my cattle inside, before dosing them with closamectin pour-on?

2. Bulled some spring born heifers this past February to calve at 30/31 months. They were all injected with 2 doses of bovillis bvd vaccine 4 weeks apart, with the second dose being administered 4 weeks before the bull was put in with them as per instructions. They will not see the bull again until they go outside in May 2015 and join up with the rest of the herd who all calf in the spring.
My question is, do the heifers in question need just a single booster of bovillis vaccine in April before the start of their next gestation? Or, since it is over 12 months since they were last vaccinated, do they require 2 doses 4 weeks apart again? The label just says "the booster is required 4 weeks before the start of the next gestation", with no mention of the timespan in between.

3. Is there such a thing as a long acting contraceptive I could give older heifer calves to stop them from being bulled whilst their mothers are running with the bull?

Thanks.

 

[AF Salers]

Question 2.
Label says 6 monthly booster for bvd, but if your cattle are ring fenced and bull is only in for approx 12 weeks I wouldn't worry about the 6 monthly booster and just do them 28 days before bulling each year (after the initial 2 jabs). The one jab will cover them for the main risk period. If not ring fenced, ie at risk of contamination from a neighbours cattle I would do 6 monthly booster jabs.
Hope this makes sense and is of help

 

[bovine]

1. 7 weeks
2. BVD vaccines are technically hard to make. I have it in writing that Bovilis BVD will protect for 12 months, but not a lot longer. They need their booster 12 months after the second dose of the initial course. If going more than a couple of months over you ought to start the course again.
3. No. If they are old enough to get bulled then they should be weaned.