Solid biosecurity practices, regular monitoring and timely vaccination are the three key pillars of effective Bovine Viral Diarrhoea (BVD) control on New Zealand farms. Implementation of a BVD control plan can help protect your herd from this avoidable disease. PI animals can only be born and are a result of cows becoming infected between 40 and 125 days of gestation. There are three key pillars of a good BVD control plan: biosecurity, testing and removal of PI animals, and vaccination. "Best practice is that you need to be thinking about all three pillars in your BVD control plan together rather than in isolation.