Measuring oxygen saturation and pulse rate in dairy cows before and after machine milking using a low-cost pulse oximeter

Abstract

The present study was aimed to measure the haemoglobin oxygen saturation and the pulse rate at teat level on dairy cows after and before milking, using a low cost pulse oximeter developed especially. The pulse oximeter has been tested during a three days of field test involving 18 Holstein Friesian cows raised in a commercial farm located in Northern Italy. The results highlighted that there is a significant difference both in haemoglobin oxygen saturation (SpO2) and pulse rate before and after milking considering the entire sample of animals. By dividing the sample according to the milking time (fast < 8 min and slow > 8 min), a significant difference between fast and slow cows has been observed for SpO2, whilst no difference has been noted considering the lactation stage (< 70 DIM and 71-140 DIM). About the pulse rate, on the contrary, milking time and lactation stage were not significantly different. This confirms that machine milking can create stress to the teat evoking circulatory impairment of its tissue and that pulse oximetry could be useful for detecting machine milking-induced alterations of teats. In perspective, the pulse oximeter could be used as a part of a monitoring system of the milking machine, enabling to change its operating parameters in order to minimize the mechanical stress on the teats.