The first cases of Bluetongue have been confirmed in Mid Wales, just days after a fresh positive test in Shropshire.
The government says one suckler cow in Monmouthshire and another bovine in Powys tested positive last Friday.
Bluetongue, which is spread by insects, is not a risk to humans or food but can be fatal for livestock.
Since July, 80 cases have been reported across England and Wales, leading to movement and trade restrictions.
Sheds housing nearly 200,000 broiler chickens at a Herefordshire farm are to be demolished and rebuilt to a higher standard.