Hematology and Biochemistry Reference Values for the Ranch Fox

Hematology and Biochemistry Reference Values for the Ranch Fox D. M. Benn, D. B. McKeown and J. H. Lumsden*

Ions de sang, et gardes dans des conditions de regie comparables. Les auteurs analyserent leurs resulReference hematology and biochemistry values are presented from a tats de faqon a determiner les valeurs mixed population of 30 silver and red marginales et celles de la distribution foxes of both sexes, reared and living de Gauss, avant et apres trois under fox-farming conditions in transformations differentes. Ils utiliserent une analyse parametrique pour southern Ontario. Based on history and physical determiner les limites de reference examination, the animals in this study inferieures et superieures. La ou les were clinically healthy at the time of resultats ne'pousaient pas la distribublood collection and maintained tion de Gauss, ils donnerent des valeurs minimales et maximales. under similar husbandry practices. The observations were examined La presentation de ces valeurs de for outliers and Gaussian distribution reference se veut une premiere before and after one of three transfor- approximation utilisable par les mations. Parametric analysis was used cliniciens et les chercheurs, pour to determine lower and upper refer- l'interpretation des resultats qu'ils ence limits. Where observations were obtiennent chez des renards appartenot Gaussian, minimum and maxi- nant a des groupes comparables. mum values are given. These reference values are presented Mots cles: renard de ranch, renard as a usable first approximation of roux, renard argente, valeurs de population reference values to assist reference biochimiques, valeurs de clinicians and researchers in their reference hematologiques. interpretation of observations obtained from foxes of similar populations.

ABSTRACT

Key words: Ranch fox, red and silver foxes, biochemistry reference values, hematology reference values.

INTRODUCTION Extensive hematological studies foxes 40 to 50 have been many changes in methodology which necessitates updating and expanding the available information (1,2,3). There is limited information available regarding clinical biochemistry observations on wild or ranch fox. Reference values provide a range for a particular blood component within which the majority of healthy animals' values will fall. Values outside of this range are suggestive of a lack of good health. Reference values are influenced by the size of the test were conducted for years ago, but there

RESUME

Les auteurs presentent des valeurs de reference hematologiques et biochimiques, relatives a 18 renards argentes et 12 renards roux des deux sexes, eleves et gardes dans une renardiere du sud de l'Ontario. D'apres l'anamnese et l'examen physique, les renards impliques dans cette etude etaient cliniquement sains, au moment du prelevement d'echantil-

population, the type of laboratory methods used to determine the values, and the sex, age, nutrition, etc. of the individual animals when the samples are taken (4,5,6,7,8,9, 10). These values must be considered in conjunction with the history and clinical signs to provide a predictability of health and to be used for clinical diagnostic purposes (8, 10,1 1). The objective of this study was to develop reference values for blood variables from clinically healthy foxes for use by veterinary practitioners and scientific investigators interpreting

hematological and biochemical data determined by similar laboratory methods.

MATERIALS AND METHODS

Blood samples were collected from 13 nongravid, nonlactating female and 17 intact male foxes. These ranchraised foxes, 12 red and 18 silver, were clinically healthy and ranged in age from one to three years. The foxes were housed on two fur ranches, 12 km apart, in Wellington County, Ontario. Both ranches used similar husbandry practices including housing, diet, vaccination and anthelmintic treatment schedules. Outdoor open wire pens (1 x 1.5 m), were elevated 0.5 m off the ground, and had overhead wooden shelters (0.3 x 0.7 m). All of the foxes were fed a balanced, commercial, pelleted diet (National Fox Feed, Wisconsin, USA) for at least six months prior to sampling. Analysis of the feed indicated a protein level of 29.6%, fat 7.7%, fibre 2.05%, salt 2.1%, phospho-

*Animal Care Services (Benn), Department of Clinical Studies (McKeown) and Department of Pathology (Lumsden), Ontario Veterinary College, Universitv of G uelph, Guelph, Ontario NIG 2WI. Submitted April 5. 1984.

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Can J Vet Res 1986; 50: 54-58.

rus 1.0%, calcium 1.6%, vitamin E 4886 I.U. and vitamin D 280 I.U. Well water, not analyzed, was available ad libitum. All of the animals had been inoculated with a modified live canine distemper vaccine within the past 12 months. The specimen collection procedure was similar for all animals tested. Blood samples were collected between 0630 and 0750 h during May and June. Each fox was manually restrained and 11 mL of blood was collected from the jugular vein through a 20 gauge needle, into a 12 mL syringe. The blood was placed into vacuum tubes containing no anticoagulant, K-EDTA or sodium heparin (Vacutainer brand, BectonDickinson and Co., Rutherford, New Jersey). Serum and plasma were separated by double centrifugation. Cell counts and blood smears were made within 3 h of sample collection. Most laboratory tests were completed on the day of collection or on serum or plasma stored at 40 C or -20° C. The laboratory methods used for estimating hematology, plasma Na, K,

Cl and osmolality, and serum electrophoresis were similar to those outlined (12). Prepackaged reagents were used in an automated spectrophotometer (American Monitor KDA, American Monitor, Indiana, U.S.A.) for estimation of serum biochemistry variables as described by Friendship et al (13).

between color phases, we used a Student's t-test for data with equal variance, and a nonparametric t-test for data with unequal variance (p < 0.05).

In order to establish reference values, the data were analyzed according to the criteria previously outlined (9,11). Briefly, outliers were identified and discarded. The lower and upper reference limits were calculated on all data that had a Gaussian distribution before or after transformation (8,9,14). For those variables that did not have a Gaussian distribution, minimum and maximum observed values were given as the best estimates of the 95% range for the population (9,11). The means of each variable were determined for male and female as well as red and silver foxes, and a Bartlett's test was performed to examine for significant differences in variance for sex and color phase (p