Machine milking of cows which also suckle their calves

Fact Sheet

One characteristic of the dam rearing system is that nursing cows are additionally machine milked. However, the gained milk yield is significantly reduced.

On the one hand, calves consume high amounts of milk and on the other hand, nursing cows react with a disturbed milk ejection during machine milking. Compared to calf sucking, during machine milking a lower amount of oxytocin, the hormone responsible for milk ejection, is released. Consequently, some milk remains in the udder. Unfortunately, this is the milk with the highest fat content, usually gained at the end of milking. Compared to non-suckling cows the fat content of milk from cows nursing their calf between machine milking times is lower. However, this is only of relevance when many cows of the same herd suckle their calves at the same time.

In order to allow a calf to suck, cows control the smell of the calf. Therefore, we tried to overcome the milk ejection disturbance in the milking parlour by providing the cows with tissues, which we rubbed on the fur of their calves.  Nonetheless we had no success: the milk yield of the cows did not improve. Also other stimuli like the sound of calf vocalization or intensive stimulation by hand had no effect on milk let down as shown by Zipp et al. (2013).

Fig.: Milk flow profiles of two different cows during machine milking

Cow suckled her calf between milkings (© Thünen-Institut)
Control cow without contact to a calf (© Thünen-Institut)