Joe S. Smith

ASPIRATION PNEUMONIA IN TWO TIBETAN YAK BULLS (BOS GRUNNIENS) AS A COMPLICATION OF KETAMINE-XYLAZINE-BUTORPHANOL ANESTHESIA FOR RECUMBENT CASTRATION.

Abstract Among members of the genus Bos, aspiration pneumonia has been described in domestic cattle (Bos taurus and Bos indicus). In these species, aspiration pneumonia is most commonly a sequelae to oral administration of fluids or medications, as well as aspiration during procedures under anesthesia. Management of aspiration pneumonia secondary to complications from anesthesia for short duration surgical procedures is minimally reported in the Tibetan yak (Bos grunniens). Although regurgitation under anesthesia has been reported in the yak, there are no reports of aspiration pneumonia treatment. This case report describes the diagnosis and management of aspiration pneumonia in two Tibetan yaks undergoing castration under injectable ketamine-xylazine-butorphanol anesthesia. This case report also describes the gross and pathologic characteristics of anesthesia-induced aspiration pneumonia in one Tibetan yak, as well as successful treatment in another.

Mathematical modeling and simulation in animal health. Part III: Using nonlinear mixed-effects to characterize and quantify variability in drug pharmacokinetics

A common feature of human and veterinary pharmacokinetics is the importance of identifying and quantifying the key determinants of between-patient variability in drug disposition and effects. Some of these attributes are already well known to the field of human pharmacology such as bodyweight, age, or sex, while others are more specific to veterinary medicine, such as species, breed, and social behavior. Identification of these attributes has the potential to allow a better and more tailored use of therapeutic drugs both in companion and food-producing animals. Nonlinear mixed effects (NLME) have been purposely designed to characterize the sources of variability in drug disposition and response. The NLME approach can be used to explore the impact of population-associated variables on the relationship between drug administration, systemic exposure, and the levels of drug residues in tissues. The latter, while different from the method used by the US Food and Drug Administration for setting official withdrawal times (WT) can also be beneficial for estimating WT of approved animal drug products when used in an extralabel manner. Finally, NLME can also prove useful to optimize dosing schedules, or to analyze sparse data collected in situations where intensive blood collection is technically challenging, as in small animal species presenting limited blood volume such as poultry and fish.

Effect of age on the pharmacokinetics and pharmacodynamics of flunixin meglumine following intravenous and transdermal administration to Holstein calves

OBJECTIVE To determine the effect of age on the pharmacokinetics and pharmacodynamics of flunixin meglumine following IV and transdermal administration to calves. ANIMALS 8 healthy weaned Holstein bull calves. PROCEDURES At 2 months of age, all calves received an injectable solution of flunixin (2.2 mg/kg, IV); then, after a 10-day washout period, calves received a topical formulation of flunixin (3.33 mg/kg, transdermally). Blood samples were collected at predetermined times before and for 48 and 72 hours, respectively, after IV and transdermal administration. At 8 months of age, the experimental protocol was repeated except calves received flunixin by the transdermal route first. Plasma flunixin concentrations were determined by liquid chromatography-tandem mass spectroscopy. For each administration route, pharmacokinetic parameters were determined by noncompartmental methods and compared between the 2 ages. Plasma prostaglandin (PG) E2 concentration was determined with an ELISA. The effect of age on the percentage change in PGE2 concentration was assessed with repeated-measures analysis. The half maximal inhibitory concentration of flunixin on PGE2 concentration was determined by nonlinear regression. RESULTS Following IV administration, the mean half-life, area under the plasma concentration-time curve, and residence time were lower and the mean clearance was higher for calves at 8 months of age than at 2 months of age. Following transdermal administration, the mean maximum plasma drug concentration was lower and the mean absorption time and residence time were higher for calves at 8 months of age than at 2 months of age. The half maximal inhibitory concentration of flunixin on PGE2 concentration at 8 months of age was significantly higher than at 2 months of age. Age was not associated with the percentage change in PGE2 concentration following IV or transdermal flunixin administration. CONCLUSIONS AND CLINICAL RELEVANCE In calves, the clearance of flunixin at 2 months of age was slower than that at 8 months of age following IV administration. Flunixin administration to calves may require age-related adjustments to the dose and dosing interval and an extended withdrawal interval.

Disorders of performance-age bucking bulls

OBJECTIVE To describe disorders of performance-age bucking bulls. DESIGN Retrospective case-control study. ANIMALS 78 bucking (cases) and 236 nonbucking (controls) beef bulls. PROCEDURES The medical record database of a referral hospital was reviewed to identify beef bulls > 1 year old that were examined for a medical or musculoskeletal disorder between January 1, 2000, and April 1, 2014. Bucking bulls were designated as cases, and nonbucking bulls were designated as controls. For each bull, the signalment, history, physical examination and diagnostic test results, and clinical diagnosis were recorded. The frequency of each disorder was compared between cases and controls. RESULTS Fifteen of 78 (19%) cases and 132 of 236 (56%) controls had medical disorders; however, the frequency did not differ between the 2 groups for any medical disorder. Musculoskeletal disorders were identified in 55 (70.5%) cases and 109 (46%) controls. Cases were 10.55 times as likely as controls to have horn and sinus disorders. Of the 43 (55%) cases examined because of lameness, the thoracic limb was affected in 19 (44%). Compared with controls, cases were 13.37 and 3.31 times as likely to have a musculoskeletal disorder of the vertebral region and pelvic limb, respectively. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated bucking bulls were more likely than nonbucking bulls to develop horn and sinus disorders and musculoskeletal disorders of the vertebral region and pelvic limbs. The limb distribution of lameness for bucking bulls may differ from that for nonbucking bulls.

Methods of instruction of the incident command system and related topics at US veterinary schools.

OBJECTIVE The Incident Command System (ICS) is an adaptable construct designed to streamline response efforts to a disaster or other incident. We aimed to examine the methods used to teach the ICS at US veterinary schools and to explore alternative and novel methods for instruction of this material. METHODS A total of 29 US accredited veterinary schools (as of February 2012) were surveyed, and 18 of the 29 schools responded. RESULTS The ICS and related topics were taught by both classroom methods and online instruction by most of the surveyed schools. Several of the schools used readily available Federal Emergency Management Agency and US Department of Agriculture resources to aid in instruction. Most schools used one course to teach the ICS, and some schools also used unique methods such as field exercises, drills, side-by-side training with disaster response teams, elective courses, extracurricular clubs, and externships to reinforce the ICS and related topics. Some of the surveyed institutions also utilized fourth-year clinical rotations and field deployments during actual disasters as a component of their ICS and emergency response curriculum. CONCLUSION The ICS is being taught at some form at a significant number of US veterinary schools. Additional research is needed to evaluate the efficacy of the teaching methods of the ICS in US veterinary schools.