Performance of a milk leukocyte differential test for decision-making in a selective dry cow therapy program

  • José Denis-Robichaud Amqui, Québec, Canada G5J 2N5
  • Raul A. Almeida Department of Animal Science, The University of Tennessee, Knoxville, TN 37996-4574
  • Susan Ivey Department of Animal Science, The University of Tennessee, Knoxville, TN 37996-4574
  • Rudy R. Rodriguez Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27606; Advanced Animal Diagnostics Inc., Durham, NC 27713
  • Martha Payne Advanced Animal Diagnostics Inc., Durham, NC 27713
  • Ken E. Leslie Advanced Animal Diagnostics Inc., Durham, NC 27713
  • Mitchell E. Hockett Advanced Animal Diagnostics Inc., Durham, NC 27713
Keywords: dairy cow, milk, leukocyte differential, selective dry-cow therapy, udder health

Abstract

The objectives of this study were 1) to determine the operating characteristics of a commercial milk leukocyte differential (MLD) test to detect intramammary infections in quarters of late-lactation dairy cows as compared to bacteriological culture and 2) to evaluate the milk production and udder health parameters between cows treated following blanket vs selective dry cow therapy (DCT) using the MLD test results. In a first experiment, the MLD test was compared to the bacteriological culture results (gold standard) of 363 quarters from 94 cows. The sensitivity, specificity, and predictive values for the identification of infection using the MLD test were determined. Sensitivity ranged from 44% to 77%, and specificity from 54% to 92%. In the second experiment blanket DCT was compared to selective DCT based on the results of MLD test, and treating only positive quarters; a total of 328 cows were randomly assigned to 1 of the 2 treatment groups. The proportion of quarters positive to bacteriological culture, and the incidence rate of moderate and severe cases of clinical mastitis events, did not differ between treatment groups. Results of these experiments provide information to support decision-making in a selective DCT program in low-SCC herds using the MLD test.

Author Biography

José Denis-Robichaud, Amqui, Québec, Canada G5J 2N5

Independent researcher

Published
2019-06-01
How to Cite
Denis-Robichaud, J., Almeida, R. A., Ivey, S., Rodriguez, R. R., Payne, M., Leslie, K. E., & Hockett, M. E. (2019). Performance of a milk leukocyte differential test for decision-making in a selective dry cow therapy program. The Bovine Practitioner, 53(2), 150-159. https://doi.org/10.21423/bovine-vol53no2p150-159
Section
Articles

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