What Came First in EHD. The Midge or the Cow By Matt Brigner While midges can bite many types of animals, including deer, sheep, and other wildlife, their outbreaks of EHD and bluetongue are most strongly amplified by cattle or sheep. In this article, we focus on cattle because in most states and counties, cattle populations are higher than sheep. Cattle are also larger, produce more carbon dioxide, and provide midges with more consistent feeding opportunities. This makes them the primary driver