What condition is a down cow likely experiencing following a recent shift in diet from high energy to roughage?

A down cow that has recently shifted from a high-energy diet to roughage is likely experiencing milk fever. Milk fever, also known as parturient paresis, is a metabolic disorder most commonly seen in dairy cows around the time of calving. It results from a deficiency of calcium that occurs when the demand for calcium increases due to milk production, exceeding the cow's ability to mobilize calcium from its bones or absorb it from its diet.

When a cow transitions from a high-energy diet to one primarily composed of roughage, this can lead to a decrease in calcium availability and increase the risk of milk fever. The stress of parturition and the associated dietary changes further exacerbates the calcium demand, making it more likely for the cow to develop this condition.

Recognizing the signs and understanding the metabolic responses to dietary changes is vital for proper management of dairy cattle to prevent conditions like milk fever, especially during periods of significant physiological change such as calving.