Just thought I'd add this to this thread even though it's not about lambs. I Heptavac my ewes every year and have done for the last 8 years.I always use a clean needle and clean syringe for each sheep, I've only got 4. Every year some of them or all of them get abscesses. I make sure the injection site is clean and give the injection subcutaneously. Last year they were all very lethargic for a couple of days and all started coughing. which lasted about a day for 3 of them and 2 days for 1 of them. I reported all of this to the drug company, who said they'd never had a report like this. Just thought I'd share this and see if anyone else has had anything similar.