Estimating milk yield for individual cows using measurements of total milk flow

In this study the ability to use a single milk flow meter that measures total milk flow in a dairy milking system to estimate milk yield for individual cows was investigated. This technology has the potential to provide estimates of the total milk yield produced over a season by individual cows that are comparable to traditional herd testing estimates. An algorithm was developed to estimate milk yield/composition for individual cows based on measurements of total milk flow in the main milk line, milking event start time, milking event duration, cow ID and bale number within the rotary milking system. The algorithm was based on the physical characteristics of the milking system, the properties of the measurement sensor and the physiological process of milk production by individual cows. The algorithm was tested using measured total flow with 3 months data (February − May) at a 60-bale rotary research farm with 772 cows milked at the start of the trial and 530 cows milked at the conclusion of the trial. The correlation between predicted (based on total flow) and measured average milk yield over the 3-month period from the 530 farm cows that were milked over the entire 3-month period was R = 0.59. The projected correlation between predicted (based on total flow) and measured average morning milk yield over a 320-day period was R = 0.83. This demonstrates that the current meter/model based on total milk flow from a 60-bale rotary milking system (with an estimated 10% error for total milk flow) provided milk yield estimates comparable to those based on two herd measurements obtained over a 320-day period (R = 0.85). Furthermore, based on the model simulations, a 2.5% error meter/model will provide milk yield and milk electrical conductivity (EC) estimates comparable to that based on six herd test measurements obtained every 60 days over a 320-day period. This demonstrates the feasibility of the single flow meter technology to estimate lactation milk yield and milk EC for individual cows.