What is one consequence of a significant Horn Fly infestation?

A significant Horn Fly infestation can lead to weight loss in cattle due to the stress and irritation these pests cause. Horn Flies feeding on the blood of cattle can result in significant discomfort, leading to decreased feeding behavior. As the cattle spend more energy dealing with the infestations, their overall nutrition and health can diminish, resulting in weight loss.

The other options, such as improved milk production, enhanced feed utilization, and higher reproductive rates, are not accurate consequences of a Horn Fly infestation. In fact, the presence of these flies typically has the opposite effects, hindering milk production, reducing feed efficiency, and adversely impacting reproductive success due to stress on the animals.