AASRP Research Summary
Milk Residue Depletion of Ketoprofen in Goats
| Date/Time: |
9/12/2025
17:30
|
| Author: |
Michelle Buckley |
| Clinic: |
Texas Tech University School of Veterinary Medicine |
| City, State, ZIP: |
Hereford , TX 79045 |
Jaedyn Johnson , BS
1
;
Palika Datta, PhD
2
;
Clinton Roof , DVM, MPH
1
;
Sarah Wagner , DVM, PhD DACVCP
1
;
Philippa Gibbons , BVetMed (Hons)
1
;
Michelle Buckley , DVM, PhD
1
;
1Texas Tech University School of Veterinary Medicine
2Texas Tech University Health Science Center - Amarillo
Introduction:
The drug ketoprofen is a non-steroidal anti-inflammatory agent approved for use in multiple use classes of cattle. However, there is limited data surrounding ketoprofen’s usage in small ruminant species. The goal of this project is to evaluate the milk residue depletion profile for ketoprofen in goat milk after a single subcutaneous injection. This information may be used to develop accurate drug withdrawal recommendations for the extra-label use of ketoprofen in goats.
Materials and methods:
Twenty dairy-breed goats at varying stages of lactation were treated with a single, 3 mg/kg subcutaneous dose of ketoprofen. Prior to treatment, each doe was hand-milked to collect a zero-hour (pre-treatment) sample. Samples were then collected from each doe at 12, 24, 36, 48, 60, 72, 84, 96, 108, and 120 hours post-treatment. Upon completion of collection, each milk sample was thoroughly homogenized, after which a 50 mL aliquot was transferred into a collection tube. Samples were frozen and stored at -20°C, then transported to Texas Tech University where they were stored at –80°C until analysis. All samples were analyzed using liquid chromatography tandem mass spectrometry (LC/MS/MS). The limit of detection for ketoprofen was 0.39 ppb (0.39 ng/mL), and the limit of quantification was 1.56 ppb (1.56 ng/mL).
Results:
Ketoprofen was detected in five samples at the twelve-hour time point with the highest concentration being 4.8 ng/mL. No ketoprofen was detected in any samples after 12 hours post-treatment.
Significance:
We used ketoprofen for this study due to its advantages for producers including a low risk of injection site reaction and the ease of subcutaneous administration. These characteristics of ketoprofen may increase the frequency of use of this analgesic drug, improving animal welfare. By contrast, flunixin meglumine, one of the other commonly used NSAIDs in ruminants, should only be injected intravenously due to its tissue reactivity and meloxicam, which is commonly used extra-label, is administered by mouth, which can be challenging in goats. The results of this study will enhance food safety following ketoprofen administration to goats by providing critical information about milk drug residue depletion and milk withholding after treatment.
