How the Lely MQC helps optimise udder health

The Lely MQC (Milk Quality Control) identifies abnormalities in the milk that contribute to the detection of mastitis based on colour and conductivity. Continuous insight into the milk quality and milking performance helps to monitor cow health closely and offers the opportunity to intervene at an early stage if necessary.


The MQC is a part of the robot arm. During milking, the milk is continuously monitored per quarter in real time. This provides not only vital information about mastitis indications, but also gives fat and protein percentage indications.

In this article, we will explain milk colour and conductivity measurements and their relation to udder health attentions in Lely Horizon in depth. 

Colour measurements in milk

The colour of the milk is measured by LED light reception through the milk. This is also called optical transmission (Figure 1). Based upon the amount of light and the certain types of colour that are received through the milk, the milk is monitored for any abnormalities (Figure 2).  Blood milk, colostrum and milk with a colour deviation (for example caused by mastitis) are easily traced and, if required, automatically separated.

The colour measurements are compared with the herd average(s). There is an average of optical values per teat and the average on spread of optical values at herd level. With each new measurement (read: milking), these averages are updated. Should the measurement deviate too much, Lely Horizon will automatically generate an attention.



Deviation in the electrical conductivity of milk can be used to predict clinical mastitis (Milner et al., 1997). If the udder becomes inflamed, the composition in milk changes, including an increase in Na+ and Cl- in the milk and a decrease in K+ (Ogola et al., 2007). A conductivity attention appears in Horizon when the absolute and average conductivity of the quarter is higher than the quarter with the lowest conductivity (default 20%).

The parameters in the reports in Horizon are shown per quarter. The indicators used are conductivity and colour. There are some rules of thumb based upon the information shown in the Horizon reports:

  • Potential clinical mastitis: conductivity higher than 100 (70 is normal), colour attention and separation advice
  • Potential sub-clinical mastitis: conductivity between 90 and 100 in combination with a high cell count
  • Potential E. coli and Klebsiella: abnormal colour code and normal conductivity level

In Horizon

The sensor system monitors milk for various other parameters and makes it possible to follow the udder health of each cow per quarter using the Lely management software. Horizon processes the generated information into useable, combined attention lists and tasks. All cows that require attention are listed in the health tasks (report 10).  In the udder health task (report 12), attentions based on colour and conductivity (and therefore related to udder health) of the past 24 hours are shown. 

In conclusion

Colour and conductivity sensors in the MQC are of great help in identifying abnormalities in the milk that contribute to the early detection of mastitis. Continuous insight into the milk quality and milking performance helps to monitor cow health closely and offers the opportunity to intervene at an early stage if necessary. Fast treatment in response to early detection of mastitis helps limit the severity of the disease and therefore reduces milk loss.



Milner, P., Page, K. L., & Hillerton, J. E. (1997). The Effects of Early Antibiotic Treatment Following Diagnosis of Mastitis Detected by a Change in the Electrical Conductivity of Milk. Journal of Dairy Science, 80(5), 859–863.

Ogola, H., Shitandi, A., & Nanua, J. (2007). Effect of mastitis on raw milk compositional quality. Journal of Veterinary Science, 8(3), 237–242.