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.
Delayed development
Glucose plays a major role in the cow. It is very important for calf development, ovum quality and immunity. The development and repair of udder tissue are also glucose-driven. During heat stress, the cow uses glucose as an energy source for its cooling mechanism. The extra glucose used for cooling comes at the expense of calf development and immunity, among other things.
Impact on the unborn calf
Heat stress in the foetal calf affects metabolism and gene expression in her later life. This epigenetics, which can be seen as the calf's software, determines how she will programme her genetics (hardware). An unborn calf with heat stress programs her genetics differently than an unborn calf without heat stress. As a result, they are often more vulnerable to infections, are less fertile and produce less milk.
Reduced fertility is due to delayed ovum development. Since ova develop before birth, they have lifelong effects on fertility. Glucose stimulates the production of the hormone IGF, which is important for ovum development. Therefore, insufficient glucose during dry heat has a direct effect on ova and thus on the fertility of the unborn calf.
Heat stress cannot be prevented, but the adverse effects of heat stress can be reduced. Fresh feed, good drinking water supply, ventilation and a sophisticated dry-off ration are key factors here.
We will be happy to advise you on feeding the right ration to your cows. Would you like to know more about our concepts or make an appointment with our specialists? Feel free to contact us.
