An automated in-line clinical mastitis detection system using measurement of conductivity from foremilk of individual udder quarters.
OBJECTIVE
To assess a novel method for automatic in-line detection of clinical mastitis.


METHODS
For a brief period at the start of milking for each cow, electrical conductivity of foremilk was measured for each quarter in turn, using a single sensor installed in the long milk tube (LMT) about 1.5 m downstream from the milking-machine claw. Sequential separation of flow between udder quarters was achieved by control of pulsation to individual teat cups within a conventional cluster. The ratio of conductivity values between quarters was used as an indicator of mastitis status. The concept was evaluated initially in a pilot trial in a 200-cow herd milked in a 23-stall swing-over herringbone milking parlour. It was then tested rigorously in a field trial in a 640-cow herd milked in a 50-stall rotary milking parlour. Both trials were conducted in the Waikato region of New Zealand. In the latter trial, sensor results were compared with visual inspection of a commercial in-line mastitis filter fitted to each milking unit. These filters were inspected for clots immediately after every cow's milking, for 3 weeks. The dataset of approximately 27,000 individual milkings was tested against several published or potential alternative 'gold standards' for diagnosing clinical mastitis.


RESULTS
In the pilot trial, 12-14 clinical events were detected out of 19 true clinical quarters, with a false-alert rate of between three and five false electrical-conductivity alerts per 1,000 individual milkings. In the more rigorous field trial, sensitivity ranged from 68 to 88%, and the false-alert rate (false-alert episodes per 1,000 individual milkings) ranged from 2.3 to 7.0.


CONCLUSIONS
The novel clinical mastitis detection system, based on separation of the flow and measurement of electrical conductivity from foremilk of individual udder quarters, has the potential to provide a new tool for helping farmers to monitor clinical mastitis in herds milked with conventional clusters.
Claycomb
R W
RW
Delink Ltd, Wentworth Drive, Hamilton 3210, New Zealand. rod.claycomb@delink.co.nz
Johnstone
P T
PT
Mein
G A
GA
Sherlock
R A
RA
D000822:Animal Husbandry / Q000295:instrumentation / Q000379:methods; D000818:Animals; D001331:Automation / Q000295:instrumentation; D002417:Cattle; D003612:Dairying / Q000295:instrumentation* / Q000379:methods; D004553:Electric Conductivity; D005260:Female; D008414:Mastitis, Bovine / Q000175:diagnosis*; D008892:Milk / Q000737:chemistry*; D009520:New Zealand; D010865:Pilot Projects; D012680:Sensitivity and Specificity