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  • Author or Editor: Kristen A. Johnson x
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in Journal of the American Veterinary Medical Association


Five castrated male llamas (mean body weight, 94 kg) were studied in an energy balance trial to determine maintenance energy requirement of llamas. Llamas were fed a 50% oat hay-50% pelleted concentrate diet (2.43 Mcal of metabolizable energy/kg of diet dry matter) at approximately 1.6% of body weight (bw). An 8-day total collection digestion trial was used to determine fecal and urine energy losses. Heat production and methane emissions were determined via indirect respiration calorimetry-measurements on each llama fed at the same level of intake as during the digestion trial and subsequently on days 3 and 4 of a period of nonfeeding. Fecal, urine, and methane energy losses of the llamas fed near-maintenance intake were 32.5, 3.5, and 7.1% of gross energy intake, respectively. The postabsorptive metabolic rate, commonly called nonfed (fasting) heat production, was 59.3 kcal/bw 0.75. Using a linear relation between postabsorptive and maintenance energy requirement and efficiency of energy use below maintenance of 0.702, metabolizable energy requirement at maintenance was determined to be 84.5 kcal/bw 0.75.

Free access
in American Journal of Veterinary Research


Objective—To evaluate the reproducibility and accuracy of 4 portable pH meters, a reagent strip, and pH paper for measuring urine pH in dogs.

Design—Prospective masked randomized study.

Sample Population—201 free-catch urine samples from 114 hospitalized dogs.

Procedures—Urine samples were divided into 2-mL aliquots. Measurements of urine pH were obtained by use of a laboratory benchtop pH meter, 4 portable pH meters, a urine reagent strip, and pH paper. The pH of each aliquot was measured within 4 hours of collection by an evaluator unaware of the aliquot's origin.To assess reproducibility, the coefficient of variation for each pH measurement device was calculated. To determine which device was most accurate, the degree of agreement among the different devices was assessed in comparison with the benchtop pH meter, which was considered the reference method.

Results—3 of the 4 portable pH meters had nearly perfect agreement with the reference method. The reagent strip and pH paper had moderate to poor agreement with the reference method.

Conclusions and Clinical Relevance—Urine pH measurements should be made by use of a portable or benchtop pH meter when accurate measurements are crucial for diagnosis or treatment. Reagent strips and pH papers are useful in obtaining pH approximations but are not recommended when accurate measurements of urine pH are required.

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in Journal of the American Veterinary Medical Association



To examine stability of -glutamyltransferase (GGT) activity in stored serum from neonatal calves.


10 commercial beef calves between 36 and 60 hours old.


Serum samples were obtained from the calves, and each sample was divided into 8 aliquots. Serum GGT activity was measured on day 0 (fresh) and days 1, 2, 3, and 4 of refrigerated storage (4 C) and weeks 1, 2, and 3 of frozen storage (−20 C).


Serum GGT activities for each of the refrigerated aliquots did not significantly differ from day zero, with serum GGT activity (expressed as a percentage of initial activity) > 99% on all 4 days. Serum GGT activity in frozen aliquots decreased significantly after 1 and 2 weeks of frozen storage, 97 and 98%, respectively; however, this decrease in GGT activity was not biologically significant. The observed GGT activity did not decrease significantly in the samples stored frozen for 3 weeks; these samples retained 99% of initial activity.


The observed stability of serum GGT activity indicates that serum may be obtained, stored, and batch processed at a later time. This stability during storage is important to the success of a bovine passive transfer monitoring program based on GGT activity. (Am J Vet Res 1997;58:354-355)

Free access
in American Journal of Veterinary Research



This study sought to determine whether firocoxib (FIRO) or meloxicam (MEL) was effective at providing analgesia after surgical castration in goats.


18 intact male crossbred goats (6 to 8 months old) were enrolled with a mean weight of 32.6 (± 2.9) kg.


Surgical castration was done under injectable anesthesia by a licensed veterinarian. Twelve bucks were surgically castrated and given either FIRO (n = 6) or MEL (n = 6). Six bucks served as controls (CNTLs) and were not castrated. Outcome measurements included visual analogue scale, infrared thermography, plasma cortisol, plasma substance P, and kinetic gait analysis. All outcome measurements were obtained at –24, 4, 8, 24, 48, and 72 hours.


All 3 treatments were significantly different from each other at the 24- and 48-hour time points, with MEL animals having lower visual analogue scale scores when compared to FIRO animals; CNTL animals exhibited the lowest plasma cortisol levels (3.19 ng/mL; 95% CI, –1.21 to 7.59 ng/mL) followed by FIRO (7.45 ng/mL; 95% CI, 3.10 to 11.80 ng/mL) and MEL (10.24 ng/mL; 95% CI, 5.87 to 14.60 ng/mL). FIRO had an average mean decrease in gait velocity change (–54.17 cm/s; 95% CI, –92.99 to –15.35 cm/s), while MEL had an increase in gait velocity when compared to baseline values (14.54 cm/s; 95% CI, –24.27 to 53.36 cm/s). Control animals had an average mean of –3.06 cm/s (95% CI, –41.88 to 35.75 cm/s).


Results from this study showed that there were some analgesic effects from administering MEL when compared to bucks that received a placebo treatment (CNTL).

Open access
in Journal of the American Veterinary Medical Association