A comparison of the effects of local analgesic solution in the navicular bursa of horses with lameness caused by solar toe or solar heel pain.

We hypothesised that analgesia of the navicular bursa is not selective for the navicular apparatus; and that solar pain in some horses can be temporarily abolished or attenuated by analgesia of the navicular bursa. To test this hypothesis, we caused lameness in horses by inducing pain in the dorsal margin or the angles of the sole and then evaluated the ability of a local analgesic solution administered into the navicular bursa to attenuate lameness. The response of horses with solar pain in the dorsal or palmar aspect of the foot to 3.5 ml local analgesic solution administered into the navicular bursa was examined. Lameness was induced in 6 horses by creating solar pain in the dorsal aspect of one forefoot and, at another time, the palmar aspect of the other forefoot, with set-screws inserted into a custom-made shoe. Horses were videotaped trotting before and after application of set-screws and after administering 3.5 ml local analgesic solution into the navicular bursa. Lameness scores were assigned by examining videotaped gaits. Scores were significantly lower (P<0.05) for all horses with set-screws applied to the dorsal margin of the sole after administration of local analgesic solution into the navicular bursa. In conclusion, analgesia of the navicular bursa was less effective in desensitising the angles of the sole than in desensitising the dorsal margin of the sole. Pain arising from the sole should not be excluded as a cause of lameness when lameness is attenuated by analgesia of the navicular bursa.

A comparison of the effects of two volumes of local analgesic solution in the distal interphalangeal joint of horses with lameness caused by solar toe or solar heel pain.

The response of horses, with solar pain in the dorsal or palmar aspect of the foot, to 6 or 10 ml local analgesic solution administered into the distal interphalangeal (DIP) joint was examined. Lameness was induced in 7 horses by creating solar pain in the dorsal aspect of one forefoot and, at another time, the palmar aspect of the other forefoot with set-screws inserted into a custom-made shoe. Horses were videotaped trotting before and after application of set-screws and, in separate trials, after 6 or 10 ml local analgesic solution was administered into the DIP joint. Lameness scores were assigned by examining videotaped gaits. Scores were significantly lower (P < 0.05) for horses with set-screws applied to the angles of the sole and receiving 10 ml, but not 6 ml, local analgesic solution into the DIP joint. Scores were significantly lower (P < 0.05) for all horses with set-screws in the dorsal margin of the sole receiving either volume of local analgesic solution. Analgesia of the DIP joint was less effective in desensitising the angles of the sole than in desensitising the dorsal margin of the sole, and 10 ml local analgesic solution was more effective than 6 ml in desensitising these regions. The response of horses with solar pain to local analgesic solution in the DIP joint was influenced by the volume administered and the region of sole affected.

Effects of analgesia of the distal interphalangeal joint or palmar digital nerves on lameness caused by solar pain in horses.

OBJECTIVE: To determine if pain of the dorsal margin of the sole in horses can be attenuated by anesthesia of either the distal interphalangeal (DIP) joint or the palmar digital (PD) nerves. STUDY DESIGN: A unilateral forelimb lameness was induced by creating solar pain. Response to administration of local anesthetic or saline solution into the DIP joint and to administration of local anesthetic around the PD nerves was evaluated. ANIMALS: Six horses. METHODS: Lameness was induced by creating pressure on the dorsal margin of the sole by screwing set-screws into a nut welded to the inside of each branch of a shoe. Gaits were evaluated before and after application of set-screws and after a local anesthetic or saline solution was administered into the DIP joint and, in a second trial, after a local anesthetic was injected around the PD nerves. Gaits recorded on videotape were evaluated, and lameness scores were assigned to each gait. RESULTS: Lameness scores were high after application of set-screws and remained high after saline solution was administered into the DIP joint. Scores decreased significantly (P < or = .05) after a local anesthetic was administered into the DIP joint or around the PD nerves. CONCLUSIONS: Analgesia of the DIP joint or the PD nerves desensitizes at least a portion of the sole. CLINICAL RELEVANCE: Pain arising from the sole should not be excluded as a cause of lameness when lameness is attenuated by analgesia of the DIP joint or PD nerves.

Ketoprofen concentrations in plasma and milk after intravenous administration in dairy cattle.

OBJECTIVE: To determine plasma and milk concentration-time profiles and pharmacokinetic variables after i.v. administration of ketoprofen to lactating dairy cows. DESIGN: Cows received a single i.v. bolus of ketoprofen (3.31 mg/kg of body weight). Blood and milk were collected at 0, 5, 10, 15, 25, 40, 60, 90, 120, 180, 240, 360, and 480 minutes. Ketoprofen concentrations in plasma and milk were determined. ANIMALS: 6-clinically normal lactating Holstein cows. PROCEDURE: Plasma and milk samples were processed by solvent extraction, and ketoprofen concentrations were determined, using high-performance liquid chromatography with octadecyl silane reverse-phase guard and analytic columns. A computer polyexponential curve-stripping program was used to fit ketoprofen concentration-time data and to calculate pharmacokinetic variables. RESULTS: The lower limit of detection for ketoprofen in plasma was 18 ng/ml; the lower limit of quantification was 60 ng/ml. The lower limit of detection for ketoprofen in milk was 27 ng/ml; the lower limit of quantification was 90 ng/ml. Plasma ketoprofen concentration-time curves best fit an open two-compartment pharmacokinetic model. Harmonic mean apparent volume of distribution at steady state was 0.11 (range, 0.095 to 0.13) L/kg, elimination half-life was 0.49 (range, 0.40 to 0.67) hour, and total clearance was 0.17 (range, 0.14 to 0.19) L/kg/h. Ketoprofen was detected in some milk samples, 10 to 120 minutes after administration, but all concentrations were below the limit of quantification. Adverse effects were not observed in cows given ketoprofen. CONCLUSIONS: The elimination of half-life for ketoprofen is short, and low concentrations of ketoprofen can be detected in normal milk, after i.v. treatment of cattle with ketoprofen. Milk and meat from cattle treated i.v. with ketoprofen should not be an important drug residue risk if appropriate withholding periods are used.