After a cool week last week an ‘Indian summer’ has moved in. Temperatures started rising mid-week and peaked on Sunday. This heat wave is set to run for the rest of the week only getting below a 25’C maximum on Sunday. Maize crops will be roaring away but this prolonged period of hot weather will continually overload the cows heat shedding capacity so that her heat load will increase all week. Any opportunity should be taken to help her shed this load. Fans should run at full power and probably 20 – 24 hrs a day. Avoid handling the cows in the heat of the day – for their sake and your staff. The collecting yard is a big problem area so go easy on the backing gate and give them space. If you see heads lifting up then they are grossly too tight. Feed additives will help support rumen function and should be fed at maximum rates to maintain rumen function and appetite in the face of the insults. After 10 days of high heat loads it will take several days of cooler weather for the cows to recover so keep everything in place well into next week.
At the time of writing this (3pm on Monday 4th Sept) it is 28 – 30’C in the sheds on our southern farms with milk yield losses being predicted as 2.5 – 3.5 l/cow/day. On top of this fertility will suffer and overlong standing times will be creating future lameness problems.