Professor GianCarlo Moschini and T. Jake Smith, assistant professor at University of Nebraska-Lincoln and former postdoctoral researcher at CARD, published an article in volume 108 issue 3 of American Journal of Agricultural Economics. Moschini and Smith authored "Spatial price competition and buyer power in the U.S. beef packing industry," which studies key questions related to competition in an oligopsony setting and finds that markdowns are moderate, about $3.69/cwt or 2.6% of the fed cattle price, on average. The full article is available here.
Spatial price competition and buyer power in the U.S. beef packing industry
GianCarlo Moschini and T. Jake Smith
American Journal of Agricultural Economics 118(3)
https://doi.org/10.1111/ajae.70003