What causes milk fever paresis?

Milk fever paresis, also known as parturient paresis, is primarily caused by low blood levels of ionized calcium. This condition typically occurs in dairy cows around the time of calving when the demand for calcium increases significantly to support milk production. The cow's body may struggle to mobilize sufficient calcium from its bones or to absorb enough calcium from feed, leading to a drop in blood calcium levels.

This deficiency in ionized calcium affects muscle function, leading to weakness and paralysis, particularly in the hindquarters. The onset of milk fever is especially common in high-producing dairy cows that have not adequately adjusted their calcium metabolism in anticipation of lactation. This highlights the importance of managing dietary calcium and ensuring that cows receive proper nutritional support before and after calving to prevent this condition.

Other factors, such as excessive phosphorus, vitamin D deficiency, or high blood pressure, do not directly cause milk fever. While these factors may influence overall health or nutrient balance, they are not the primary cause of the calcium deficiency that leads to milk fever paresis. Understanding the significance of calcium regulation in dairy cattle is crucial for effective herd health management and prevention strategies.