Cow Grazing Behavior and Climatic Influences
by Roger Martyn
Findings on cow grazing behavior from research carried out in the 1950's is just as relevant as ever.
It found that in temperate climates, most of the grazing time carried out by dairy cows is done in two periods during day light hours.
The first commencing just after dawn, and the second starting in the early evening after milking and going on until about an hour after sunset.
About half the amount of grazing is done between evening and morning milkings with about 80-90% of that occurring during the daylight portion.
In hot conditions however, this pattern is reversed and as much as 2/3 of the grazing is done in the cooler hours of darkness.
Feed intake of dairy cows was observed to be reduced when the temperatures were high and even more so when the relative humidity was high as well.
An increase in the relative humidity of 20-40% was shown to cause the amount of feed eaten to fall by 15%.
This must have implications for how we manage cows and which paddocks we select as the night paddock over the hotter summer periods.
Perhaps we should be looking for the night paddocks to be the better (milk producing) ones during hot weather conditions and not the poorer ones as is often the case?