Heat hits dry cows
HEAT stress can cause a dry dairy cow to produce less milk during her next lactation and affect her progeny for life, research from the US shows.
University of Florida’s Geoff Dahl, who has been presenting his findings at workshops in Victoria and NSW, said while the initial effect of heat stress on dry cows was bad, it had a significant carryover to their next lactation.
“Dry cows can produce five litres of milk per day less during their next lactation if they have been heat-stressed, compared to their herd mate who was cooled,” Dr Dahl said.
He said the cow’s immune system was also compromised.
Calves were born lighter after heat stress and had a lower immune status and Dr Dahl said when that calf matured it also produced about 5L a day less than herd mates and passed that on to its offspring
That essentially means one heat stress event can have an effect over three generations.