Abstract
The latest addition to the Laboratory Animal Pocket Reference Series, edited by Mark A. Suckow, provides a concise overview of ferret biology, husbandry, veterinary care, and experimental methodology. Compared to other volumes in the series, The Laboratory Ferret gives a more cursory review of these topics but is a good resource for a variety of pertinent ferret information in a single volume.
The tabular information in the opening chapter, “Important Biological Features,” is restricted to a rather short list of normative biologic data, hematology and serum chemistry data, and cerebrospinal fluid values; urine values (other than daily production) are absent. In contrast, another volume in the series, The Laboratory Rat, provides hematology and serum chemistry data in addition to respiratory and cardiovascular function values, reproductive values, much more extensive basic biologic parameters, and examples of vaginal cytology. Key anatomic and physiologic features of ferrets are summarized in 5 short pages (although the reader is referred elsewhere for an excellent review) and at a much lower level of detail than in the rat. However, these differences in depth of information do reflect the longer history and more widespread use of rats in research.
Hematology and serum chemistry values are provided for large sample sizes of ferrets from two major vendors (one an influenza, specific pathogen–free barrier facility). However, only values for male ferrets are shown and without clarification of whether they are intact or castrated. This information would also have been easier to navigate in a vertical layout, rather than the more cumbersome horizontal orientation chosen by the authors. For more extensive blood values from ferrets delineated by age, sex, and coat color, the reader is referred to sources with information generated on the ubiquitous Marshall Farms ferrets.
The husbandry and management sections are well organized and informative, hitting all the important points in a quick read. The management chapter in particular does an excellent job of highlighting the lack of specific ferret guidelines in the animal welfare and laboratory animal regulations, while also touching on zoonotic and occupational health concerns.
The veterinary care chapter is surprisingly brief, especially in comparison to the same chapter in other volumes of this series. Several pages are devoted to a practical breakdown of a thorough physical exam, along with useful reference parameters for body temperature, respiratory rate, and heart rate. Body condition scoring is commented on; however, minimal guidance in scoring is given, focusing only on ease or difficulty of seeing and palpating the ribs, which is likely to result in overweight ferrets being described as appropriate and ferrets of a healthy weight being misinterpreted as underweight.
In contrast to the rodent volumes, the main veterinary care text of the ferret handbook focuses on general clinical conditions in the laboratory ferret (diarrhea, weight loss/decreased food intake, alopecia, respiratory difficulty, and “other conditions”). Specific diseases and agents are only presented in tables, which, though easy to scan, are perhaps a bit brief for the laboratory animal veterinarian or veterinary pathologist. Emphasis is placed on clinical signs and diagnosis (much of it postmortem) but not treatment. This is likely a reflection of the ferret’s most common uses being for toxicologic and infectious disease research, where clinical intervention is often not compatible with the experimental aims. Descriptions of clinical, anatomical, or histologic pathology associated with certain diseases are sparse or absent; as a result, an observant veterinary pathologist could use the tables as a quick postmortem diagnostic guide but would need to consult additional sources for lesion descriptions or definitive diagnosis. The adrenal disease description lacks mention of prostatic enlargement leading to stranguria or urinary blockage, an important and potentially fatal condition in male laboratory ferrets (though much more common in pet ferrets). In general the disease tables are well organized, and the table of common gastrointestinal diseases is excellent for helping clinicians distinguish among the myriad of common gastrointestinal disorders, which tend to present with their own brand of diarrhea and accompanying signs. A warning comment to the reader that ferrets can decompensate rapidly in the face of acute or chronic diarrhea (due to severe dehydration and/or anemia) without intervention would be a useful addition to the diarrhea section of the text.
The many tables of sedative, anesthetic, analgesic, euthanasia, therapeutic, and miscellaneous agents for use in ferrets are a strength of this book and well organized for clinicians and researchers alike, although a few useful antibiotics are omitted. Vaccination of ferrets for canine distemper and rabies is touched on; however, no specific mention is made of the ferret’s relatively high propensity for vaccine-associated reactions, despite the mention of diphenhydramine in a table as pretreatment for “sensitive” ferrets. The section on parasite control could be improved by emphasizing the typically subclinical and persistent nature of Otodectes infestation in ferrets and the need for routine surveillance. Preoperative, anesthetic, surgical, and postoperative recommendations are described in sufficient detail, and suggested general criteria for euthanasia are provided.
Manual restraint of ferrets can be tricky and is thoroughly described in the experimental methodology chapter, along with mechanical restraint; routes of blood, respiratory, and urine sample collection; and administration techniques. The recommendations and descriptions of techniques for blood collection are particularly detailed and useful, with the exception of the inclusion of retro-orbital bleeding, a seldom-used or justified approach (as the authors do point out). A basic plan for necropsy is laid out for researchers, along with the strong recommendation that a laboratory animal veterinarian be consulted before necropsy.
The final chapter, “Resources and Additional Information,” lists organizations, publications, and electronic resources that researchers and ferret veterinarians will find helpful, although a list with vendors and contact information would be a practical addition.
The main strengths of this work are in its wide scope, coverage of regulatory and management issues, brevity, and easily accessible format. It is best suited for researchers, particularly those who are relatively new to ferrets, although animal care staff and IACUC members will also find valuable information within. Veterinarians treating ferrets at research institutions or in private practice will require more comprehensive and detailed information, such as what can be found in many of the references listed in the “Resources and Additional Information” chapter; however, they can still find this volume useful for its intended purpose, as a quick-reference handbook.