Heat stress in dry cows affects udder and placenta development. Moreover, it affects not only the dry cows but also the unborn calf. It can affect the calf's lifetime production.
Studies have shown that heat stress in dry cows significantly affects udder tissue development and recovery. Among other things, it can lead to reduced milk production in the next lactation and a greater risk of udder infections. Production reduction can lead up to as much as 5 litres per day for 30 weeks.