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The developing fetus is differentially susceptible to chemicals and pathogens depending on the stage of its development. In developmental studies, embryos or fetuses therefore must be exposed to experimental interventions at the same gestational stage. Acquiring sufficient numbers of embryos of the same developmental stage requires the use of timed-pregnant animals. Timed-pregnant Mongolian gerbils currently are not available for purchase. The authors developed a novel method for timed mating of virgin female gerbils. Female gerbils were housed in the same cage as males, but physically separated by a partition, for 3 d in order to expose the females to the males' pheromones before they were allowed to interact. Females were monitored for lordosis to determine sexual receptivity. Lordosis was observed in 10 of 15 females (67%), and 9 of these females (90%) became pregnant. When lordosis was not observed, none of the females became pregnant. These results demonstrate that the timed mating method produces a high rate of mating success and indicate that lordosis is a reliable predictor of sexual receptivity and subsequent successful mating in the Mongolian gerbil.

The primary goal of environmental enrichment should be the avoidance of abnormal behaviors in laboratory animals such as rodents, lagomorphs, dogs, cats, and nonhuman primates. A total of 13 male single-housed New Zealand White rabbits were offered 3 different toys, and the time spent chewing on the toys instead of on the cage was evaluated. Each rabbit was offered each of the toys for 2 separate 1-week periods. Each rabbit was monitored for 15 minutes 4 times a week for a total of total 1 hour per week. Observations included, 1-hour of baseline data before the toys were offered, for a total of 2 and 2 hours of observation per rabbit per toy. Having a toy available had a significant effect on the behavior of New Zealand White rabbits. Rabbits with toys spent significantly more time chewing than the rabbits without toys. They did not develop a preference between the offered toys and did not show stereotypies. This study highlights the importance of environmental enrichment to improve the welfare of laboratory animals.

Abdominal lavage is used in laboratory rodents for a variety of applications but carries an inherent risk of abdominal organ laceration; therefore, personnel carrying out this procedure must have considerable expertise. In this paper, the authors describe an improved method for delivering sterile media to and collecting peritoneal fluids from dark-clawed Mongolian gerbils (Meriones unguiculatus) that had been peritoneally infected with filarial nematode parasites (genus Brugia). To carry out this gravity-assisted technique, the authors used a catheter to introduce sterile media into the peritoneal cavity of each gerbil and then to passively drain peritoneal fluid and larval worms for collection. Average fluid recovery was consistently greater when using this gravity-assisted method than when using aspiration. Larval parasites were recovered by both methods. To recover large volumes of fluid using the standard method of abdominal lavage, personnel typically must euthanize rodents. This gravity-assisted technique allows researchers to collect large numbers of parasite larvae without euthanizing gerbils.

Numerous species of amphibians are frequently utilized as animal models in biomedical research. Despite their relatively common occurrence as laboratory animals, the regulatory guidelines that institutional animal care and use committees (IACUCs) must employ provide little in the way of written standards for ectothermic animals. Yet, as vertebrates, laboratory amphibians are covered by the National Research Council Guide for the Care and Use of Laboratory Animals and the Public Health Service (PHS) Policy for federally funded research. This article focuses on three issues that are relevant to IACUC oversight of the use of amphibians in research: (1) recommended educational requirements of investigators and animal care staff engaged in research with amphibians, (2) zoonoses and other issues of occupational health importance, and (3) indicators of stress and disease. Addressing these issues should enable investigators, IACUCs, and animal care staff to meet the regulatory expectations of the PHS and accrediting bodies such as the Association for Assessment and Accreditation of Laboratory Animal Care International.

As the use of chickens in biomedical research is increasing, demand is growing for technical skills involving poultry, particularly techniques such as venipuncture. Phlebotomy (blood collection) is an important diagnostic tool for determining causes of morbidity and mortality and for collection of other research-relevant data. This column describes four standard methods of blood collection from the domestic chicken.

Institutions can share information and orientation materials easily and effectively using modern media and communications technology. For this reason the Office of Animal Care and Use at the University of Georgia developed an online orientation resource for users of its animal housing facilities. Here the authors describe the resource and the planning and project management that accompanied its development. The authors explain the rationale behind each of their decisions and describe select organizational methods that contributed to the success of the project. They describe their own experience, in the context of their institutional circumstances, for the benefit of other institutions that might consider developing a similar resource.

Blood collection is a common procedure in animal research. This column describes humane methods of collecting blood from the rat and the gerbil that can be carried out by a single person on an awake animal.

Physiological and psychological effects of listening to music have been documented in humans. The changes in physiology, cognition and brain chemistry and morphology induced by music have been studied in animal models, providing evidence that music may affect animals similarly to humans. Information about the potential benefits of music to animals suggests that providing music may be used as a means of improving the welfare of laboratory animals, such as through environmental enrichment, stress relief and behavioral modification. The authors review the current research on music's effect on animals' physiology and behavior and discuss its potential for improving animal welfare. They conclude that the benefits of providing music to laboratory animals depend on the species and the type of music.

Publisher Summary Chinchillas possess several key anatomic, physiologic, and behavioral characteristics which in many ways are adaptations derived from their evolution in the high Andean mountains of South America. Chinchillas are useful animal models for a number of human diseases. This chapter discusses certain features in detail such as biological characteristics and behavioral patterns of chinchillas while treating other attributes only briefly, so that key differences can be explored in sufficient detail while leaving other sources to discuss systems in common with other mammals. Chinchillas weigh an average of 400–600 gm and their bodies, about 12–14 inches long, are short, stocky, and compact. The organ systems of chinchillas are essentially similar to those of most other mammals. However, they have unique biological attributes, which may either influence approaches to their medical care or demonstrate their value as research animals. Chinchillas are described as gentle, docile, quiet, and timid. They use their mouths to explore, and may perform trial bites when exploring an object or person. They also gnaw regularly similar to other rodents. Chinchillas are naturally nocturnal, being active at dusk and at night in the wild, but in captivity they can adapt to a diurnal lifestyle. They are active and agile, and enjoy climbing and jumping.

Transtracheal access enables researchers to obtain diagnostic samples from or infuse materials into the lower respiratory tract. This column describes transtracheal aspiration and infusion of horses.

Reptiles used for research and instruction may require surgical procedures, including biopsy, coelomic device implantation, ovariectomy, orchidectomy, and esophogostomy tube placement, to accomplish research goals. Providing veterinary care for unanticipated clinical problems may require surgical techniques such as amputation, bone or shell fracture repair, and coeliotomy. Although many principles of surgery are common between mammals and reptiles, important differences in anatomy and physiology exist. Veterinarians who provide care for these species should be aware of these differences. Most reptiles undergoing surgery are small and require specific instrumentation and positioning. In addition, because of the wide variety of unique physiologic and anatomic characteristics among snakes, chelonians, and lizards, different techniques may be necessary for different reptiles. This overview describes many common reptile surgery techniques and their application for research purposes or to provide medical care to research subjects.

Routine laboratory procedures can be stressful for laboratory animals. We wanted to determine whether human handling of adult rabbits could induce a degree of habituation, reducing stress and facilitating research-related manipulation. To this end, adult New Zealand white rabbits were handled either frequently or minimally. After being handled over 3 wk, these rabbits were evaluated by novel personnel and compared with minimally handled controls. Evaluators subjectively scored the rabbits for their relative compliance or resistance to being scruffed and removed from their cages, being transported to a treatment room, and their behavior at all stages of the exercise. Upon evaluation, handled rabbits scored significantly more compliant than nontreated controls. During evaluation, behaviors that the rabbits displayed when they were approached in their cages and while being handled outside their cages were recorded and compared between study groups. Handled rabbits displayed behavior consistent with a reduction in human-directed fear. This study illustrates the potential for handling to improve compliance in laboratory procedures and reduce fear-related behavior in laboratory rabbits. Such handling could be used to improve rabbit welfare through the reduction of stress and exposure to novel stimuli.

The domestic chicken (Gallus gallus) is increasing in popularity as a laboratory animal, as it is useful in multiple fields of biomedical research and has the practical benefits of being relatively inexpensive, easy to handle and able to adapt to various settings1. Here, we describe two procedures commonly used with chickens in research: endotracheal intubation and oral gavage.

Here we describe 5 cases of molar malocclusions in adult pine voles (Microtus pinetorum) used for behavioral endocrinology studies. This species belongs to the subfamily Microtinae, which possess aradicular hypsodont molars. The abnormal molars identified caused apparent difficulty in mastication, resulting in poor body condition necessitating euthanasia. Postmortem examination of the oral cavity revealed grossly elongated mandibular and maxillary molars with abnormal wear at occlusal surfaces. This colony health problem was addressed successfully by adding autoclaved hardwood sticks to each cage as an enrichment tool.

A Syrian hamster that had been treated with topical antibiotic ointment for 10 days following injuries sustained during fighting was presented moribund. Postmortem and microscopic examinations revealed lesions consistent with clostridial typhlitis and enteritis. Anaerobic culture of caecal contents resulted in the isolation of two Clostridium species, and caecal contents contained Clostridium difficile enterotoxins. Based on these findings, a diagnosis of acute C. difficile enterotoxaemia was made. This report discusses the pathogenesis of C. difficile enterotoxaemia and the potential role of topical antibiotic ointment therapy in initiating the disease.

Lab Anim. (NY) 44, 318–321 (2015); corrected after print 23 September 2015 In the version of this article that was initially published, the affiliations for the two authors were transposed. The error has been corrected in the HTML and PDF versions of the article.