The recent hot weather has caused considerable issues for dairy cows which without sufficient shade, water or poor feeding can even prove fatal.  The above ration represents a current client ration at (1) 18°C and mid humidity (50-79%) and (2) 30°C and high humidity (79%+).  As you can see the second diet shows a marked loss in total dry matter intake.  Grazing take the biggest impact with a slight reduction in buffer and parlour intakes.  This also gives rise to an increase in other metabolic issues including Displaced Abomasa, Acidosis and Ketosis due to the reduction in forage to concentrate.  The loss of intakes means that milk production falls and energy issues increase, this can be seen clearly by the highlighted yellow boxes, where as you can see this cow is now 31MJ short a day even though she is eating the same in parlour, virtually the same buffer intakes, but crucially less grazing.

In short, we need to revise how we monitor heat stress and have a contingency for reducing its effect.  Solutions may include housing cows by day, grazing early and late, providing more cool water, more shade, increase ration energy density, increasing minerals, offer increased bi-carb’s in diet and reduce degradable protein available (i.e. Urea, Rape meal….).

If this sounds of interest to you, please contact Wesley at wesleyhabershon@fcgagric.com or your local FCG Office.