Milk fever (parturient paresis) is clinical manifestation of parturient hypocalcemia. In 2018 3,5 percent of cows in milk recording were treated for milk fever in Finland. Milk fever occurs at or near the parturition and is a metabolic disease. Due to the onset of lactation the homeostatic mechanism can overwhelm resulting in insufficient availability of ionized calcium. The animal is then affected by hypocalcemia.

The objective of this study was to determine the treatment response and recurrence of milk fever and to find out whether milk fever affected to the reason for the cows to get culled. The three breeds were Ayrshire, Holstein and Western Finncattle.

The used data was collected by veterinarians and provided by Faba co-op. The data was collected in 2008 - 2018 from cows that were born in 2006 - 2010 in Finland and were treated for clinical milk fever. The data was collected from 29 566 cows from 5 855 herds. 51 percent of the cows were Ayrshire, 48 percent Holstein and 1 percent Western Finncattle.

The study shows that the cows were affected by milk fever on average 1,3 times in their lifetime. In the study milk fever was most common among fourth parity cows. There were approximately 1,5 treatments given per cow for each milk fever incident. In 73 percent of the milk fever incidents the cow was treated only once, in 18 percent of the incidents twice, in 7 percent of the incidents three times and in 2 percent of the incidents the cow was treated four times. Only in 0,5 percent of the incidents the cow was treated five or more times. First parity cows were treated approximately 1,6 times per milk fever incident. The cows that were affected by milk fever on their third to fifth parity were given 1,5 treatments. After the fifth parity the amount of treatments decreased.

During the time that data was collected 87,5 percent of the cows were culled and the reason for culling was recorded for 87 percent of them. In this study milk fever was the reason for culling for 10,2 percent of the Ayrshire, 13,4 percent of the Holstein and 4,8 percent of the Western Finncattle cows. Approximately 10,6 percent of the cows were culled in seven days after being affected by milk fever. The study shows that the treatment response of milk fever is relatively good. To get a reliable conclusion of the recurrence of the milk fever more studies are needed.