The causes of mid-lactation milk fever are different than calcium milk fever in fresh cows, which makes the term somewhat misleading. Mid-lactation milk fever often occurs in multiparous, high-producing cows that had no problem in previous milkings. The authors explain the need to focus on hypomagnesemia noting nutritional and inflammatory challenges that may lead to mid-lactation mishaps.
Source: Progressive Dairy, June 3, 2024. Link.