Variability in milk composition of the domestic ferret (Mustela putorius)

Ferret milk composition was analyzed among individuals, over time, and across teat pairs. Females differed in fat, protein, and lactose concentrations. Protein and fat concentrations varied over the course of lactation. Lactose was the only measured component which differed across teat pairs.     

Dirofilaria immitis: experimental infections in the ferret (Mustela putorius furo)

The ferret, Mustela putorius furo, was found to be susceptible to Dirofilaria immitis infection when exposed to low (14) or high (280-420) numbers of infective larvae harvested from Aedes aegypti. Eight ferrets (half of them cortisonized) were inoculated subcutaneously with 14 larvae each. All of them were subsequently found to harbor D. immitis in the heart, and all but one of them had worms of both sexes. Six of these ferrets were examined for microfilaremia at 31 to 35 weeks after inoculation; 3 were positive (one observed only at postmortem examination) and there was evidence that fertilization of female worms had occurred in one other. Females up to 25.5 cm and males up to 16.0 cm were recovered. There was no evidence that the cortisonization of some ferrets had affected the infections. Both male and female ferrets became infected. Four cortisonized ferrets were inoculated with 280 or 420 larvae of D. immitis (divided equally between subcutaneous and intraperitoneal routes). All of them died 16 to 18 weeks after inoculation, yielding 102 to 125 immature D. immitis. In these lethal infections, worms were recovered from the heart and adjoining vessels, and also from vascular and extravascular sites throughout the body.     

Pregnancy toxemia in the European ferret (Mustela putorius furo).

BACKGROUND AND OBJECTIVE: Pregnancy toxemia may lead to appreciable mortality among jills and their offspring. The objective of this report was to increase awareness of the disease, its likely cause, and practical prevention and treatment measures. METHODS: Ten cases of pregnancy toxemia were evaluated. Jills were in late gestation (mean, 38 days; range, 34 to 42 days) and had large litters (mean, 11.5 kits; range, 7 to 15 kits). RESULTS: The most common clinical signs of disease were lethargy, inappetence, dehydration, and excess shedding. Hematologic and clinical biochemical abnormalities included anemia (4 of 8 jills tested), hypoproteinemia (5 of 7), azotemia (7 of 7), hypocalcemia (5 of 6), hyperbilirubinemia (3 of 3), and high liver enzyme activities (6 of 6). Two jills were found dead; two jills were euthanized, six received supportive treatment, and cesarean section was performed on five. The three jills that survived tended to have less pronounced azotemia, hypoproteinemia, and liver enzyme activity increases and were not anemic. Hepatic lipidosis was observed grossly in all jills that died and was confirmed by histologic examination in four jills. CONCLUSIONS: Pregnancy toxemia in ferrets resembles metabolic diseases in several other animal species and requires aggressive treatment, including supportive care, nutritional supplementation, and cesarean section. Maintaining adequate nutrition and avoiding stress late in gestation may prevent the disease.     

Retro-orbital technique for blood collection from the ferret (Mustela putorius furo)

Blood samples were obtained from anesthetized ferrets of various ages, by venipuncture of the retro-orbital plexus with a heparinized capillary pipette. It is recommended that a cumulative collection of 20% of total blood volume not be exceeded for any two week period. This technique, when carefully performed on alternate orbits and at a frequency dictated by body weight and volume of blood needed, has been used repeatedly for months without apparent harm or distress to the animal.     

Macroscopic and roentgenographic anatomy of the skull of the ferret (Mustela putorius furo)

Normal macroscopic and roentgenographic features of the skull of the ferret (Mustela putorius furo) were examined and described. Data were based on a sample of 100 (50 male and 50 female) adult ferrets of known body weight and age. The skull was described macroscopically according to six standard views, i.e. dorsal, lateral, ventral, caudal, cranial and midsagittal. The mandible was described separately. The roentgenographic characteristics of the ferret skull were demonstrated only in lateral and dorsoventral projections. Furthermore, the skull length and width as well as the minimum frontal width were measured, and skull indices were derived from relevant measurements. Sexual dimorphism was examined both morphologically and craniometrically. Besides the common features of a carnivore skull, the ferret skull is relatively elongated and flat with a short facial region. The skulls of adult male ferrets are about 17% longer and 22% wider than those of the females. Significant sexual dimorphism also exists regarding certain skull indices. The general features and some dimensional parameters of the adult ferret skull support the contention that the ferret would be an interesting and workable alternative animal model in craniofacial research.     

Changes in endometrial vascular permeability during the periimplantation period in the ferret (Mustela putorius)

A highly localized increase in permeability of uterine blood vessels in the immediate vicinity of implanting blastocysts was first detected on the morning of the 12th day of pregnancy (290 h post coitum). The amount of extravasated dye which accumulated at implantation sites continued to increase through the evening of Day 13 (321 h p.c.). Blastocyst expansion, as indicated by small uterine swellings, preceded a detectable change in vascular permeability by about 10 h, suggesting that the timing of increased permeability is closely associated with initial blastocyst attachment to the uterine epithelium. The results do not support the hypothesis that prostaglandins are required for increased uterine vascular permeability as two doses of indomethacin (4 and 8 mg/kg body wt) administered 5 times/day failed to decrease endometrial vascular permeability. However, the 8 mg dose did cause a significant reduction in size and number of uterine swellings and delayed or inhibited attachment of the trophoblast to the uterine epithelium in 2 of 5 ferrets. These findings suggest that prostaglandins play an important role in the process of implantation that is unrelated to decidual formation as the ferret is an adeciduate species.     

Effect of electro-ejaculation frequency on semen characteristics in the ferret (Mustela putorius) (a)

Ten sexually mature male ferrets were electro-ejaculated at 1, 3 and 5-day intervals to ascertain the effects of ejaculation frequency on semen quality. Semen volume, spermatozoa concentration, spermatozoal motility, as well as the number of stimuli required to obtain an ejaculation were recorded. No significant differences in these parameters were noted between the test intervals for 1 to 3-year-old males. The data indicated that male ferrets from 1 to 4 years of age may be ejaculated as frequently as once per day for short periods of time without any apparent adverse effects on semen quality.     

Dracunculus insignis: experimental infection in the ferret, Mustela putorius furo

The laboratory study of dracunculiasis has suffered from the lack of a suitable, readily available animal model. We have been able to experimentally infect ferrets. Mustela putorius furo, with the North American dracunculid, Dracunculus insignis. Ferrets were inoculated with 75 to 100 infective larvae and were necropsied 90 to 240 days later. Guinea worms were recovered from 10 (56%) of 18 ferrets. A total of 44 worms were recovered, for an average of 4.4 worms per infected ferret. Gravid female worms were recovered as early as 128 days postinoculation. Thirteen (87%) of 15 gravid female worms were recovered from the extremities. Living male worms were recovered at 200 days of age, indicating that not all male worms die shortly after mating. First-stage larvae recovered from gravid females as early as 200 days of age were found to be infective to the copepod, Acanthocyclops vernalis. These observations suggest that the ferret is an excellent laboratory animal for dracunculiasis research.     

Early embryonic development and in vitro culture of in vivo produced embryos in the farmed European polecat (Mustela putorius)

Early embryonic development and in vitro culture of in vivo produced embryos in the farmed European polecat (Mustela putorius) was investigated as a part of an ex situ conservation program of the endangered European mink (Mustela lutreola), using the European polecat as a model species. The oestrus cycles of 34 yearling polecat females were monitored by visual examination of the vulval swelling and, to induce ovulation, the females were mated once daily on two consecutive days. Sixteen yearling males were used for mating. The females were humanely killed 3-14 days after the first mating and the uteri and oviducts were collected for embryo recovery. Uterine and oviductal flushings yielded a total number of 295 embryos, representing developmental stages from the 1-cell stage to large expanded and hatched blastocysts. On Day 3 after the first mating, only 1-16-cell stage embryos were recovered. Between Days 4 and 6 after the first mating, 1-16-cell stage embryos and morulae were found. The first blastocysts were recovered on Day 7 after the first mating. The first implanted blastocysts were detected on Day 11 after the first mating. A total number of 85 embryos were in vitro cultured after recovery. Blastocyst production rates for in vitro cultured 1-16-cell stage embryos and for morulae/compact morulae were 68 and 84%, respectively. For all cultured embryos, the hatching rate was 15%. The in vitro culture requirements for the preimplantation embryos of the farmed European polecat remain to be determined before further utilization of the technique.     

Carnivora: the primary structure of the alpha-chains of ferret (Mustela putorius furo, Mustelidae) hemoglobins

Ferret erythrocytes contain two hemoglobins differing only by their alpha-chains. The primary structure of the common beta-chain has been previously described; the complete sequence of the two alpha-chains are reported in this paper. The globin chains were separated by ion-exchange chromatography; the alpha-chains (42 steps), their tryptic peptides as well as the prolyl-peptides were subjected to automatic liquid- and gas-phase Edman degradation. The two alpha-chains are very similar, differing at only one position (Asp15----Gly15). Comparison with human hemoglobin alpha-chain shows 16 and 17 exchanges, for alpha 1 and alpha II chains, respectively; two substitutions involve alpha 1/beta 1 contacts and one the heme contacts. A high degree of homology was noted when the alpha-chains were compared to the corresponding chains of other representatives of the Carnivora order.     

A comparison of epigean and subterranean locomotion in the domestic ferret (Mustela putorius furo: Mustelidae: Carnivora)

Burrows are used by many mammals to escape predation, cache food and for parturition. Although the construction of burrows has been studied in some taxa, the locomotion while inside of them has received scant attention. In this study we collected simultaneous video and force data to characterize gaits, kinematics, peak ground reaction forces (GRFs) and external mechanical energy profiles in the domestic ferret, an animal that displays the typical morphology and behaviors associated with subterranean adaptations in mustelines. We compared kinematics and kinetics between locomotion in two experimental conditions: subterranean, simulated by a Plexiglass tunnel designed such that the ferrets’ peak back height was reduced by 40% and hip height by 25%, and epigean, or unconstrained overground. Despite the large change in posture, a striking number of gait and force variables were not statistically different between experimental conditions. In both subterranean and epigean conditions, the ferrets in our study traveled at similar average velocities (～0.8 m s^?1), preferred to use a lateral-sequence diagonal-couplet gait, and were more likely to demonstrate the in-phase fluctuations of external mechanical energy indicative of running mechanics (68% of all trials). The ferrets conformed to gait and mechanical patterns seen in a variety of other small (<1 kg) mammals rather than being unique, despite the divergent morphology of mustelines. Our results demonstrated biodynamically similar locomotion in both epigean and subterranean conditions and support the hypothesis that ferrets possess adaptations for tunnel locomotion.     

Establishment of the cat flea (Ctenocephalides felis felis) on the ferret (Mustela putorius furo) and its control with imidacloprid

As the ferret, Mustela putorius furo L. (Carnivora: Mustelidae), is becoming increasingly popular as a pet animal and as it is susceptible to the cat-flea, Ctenocephalides felis felis Bouché (Siphonaptera: Pulicidae), an experimental model was established for evaluating insecticidal treatments on this host. A high establishment rate (76.7-91.8%) was recorded when 60 unfed adult C. felis were placed on ferrets. This provided an adequate infestation for chemotherapeutic evaluation without causing undue discomfort to the host. Twelve ferrets were allocated to two groups matched for sex and individual ability to sustain a flea population. One group was treated topically with an imidacloprid spot-on formulation at a dose rate of 10 mg/kg body-weight on Day 0. All ferrets were infested with C. felis on Days -1, 7, 14, 21 and 28, and flea counts were performed 8 and 24 h post-treatment and one day after each subsequent infestation. Fleas were removed at all but the 8 h count (when they were returned to their host). Flea burdens were reduced by 95.3% (P < 0.001) within 8 h of treatment and 100% efficacy was recorded at 24 h. At 1, 2, 3 and 4 weeks post-treatment, protection against re-infestation was 92.9% (P < 0.001), 55.7% (P < 0.02), 18.3% (NS) and 7.4% (NS), respectively. Thus, at this dose rate, imidacloprid gave excellent efficacy against a resident C. felis population and provided a high level of residual activity for at least one week after treatment.     

Immunofluorescent localization, by use of anti-idiotypic antibody, of monoclonal anti-progesterone antibody in the mouse uterus before implantation

Mouse monoclonal anti-progesterone IgG1 antibody designated DB3 has an anti-fertility effect when injected into female mice shortly after mating. In BALB/c mice, pregnancy is blocked, probably as a result of progesterone withdrawal with inhibition of implantation. Rabbit polyclonal anti-idiotype raised against DB3 has been used in an indirect immunofluorescence method on frozen tissue sections to demonstrate the presence of DB3 on the surface of uterine luminal and glandular epithelia before implantation. DB3 was only detectable 30-60 h after a single parenteral injection (9 nmol antibody per mouse i.p. or i.v. at 32 h post coitum). Immunolocalization was both pregnancy-dependent and anti-progesterone antibody-specific, as it was not seen in pseudopregnant mice or mice treated with P3 (mouse myeloma IgG1 protein, using polyclonal anti-P3 anti-idiotype as a probe) or saline. The immunofluorescent reaction was completely blocked by addition of DB3 idiotype in vitro. The results indicate that anti-progesterone antibody binds to an antigen associated with luminal and glandular epithelia which may locally inhibit the uterine uptake of progesterone and disrupt the process of implantation.     

Nonsurgical collection and nonsurgical transfer of preimplantation embryos in the domestic rabbit (Oryctolagus cuniculus) and domestic ferret (Mustela putorius furo)

The objective of this study was to develop nonsurgical methods of embryo collection and transfer in domestic rabbits (Oryctolagus cuniculus) and domestic ferrets (Mustela putorius furo) to serve as models for use in mammals in which surgical procedures are the usual means for applying embryo transfer technology. Specially designed transcervical catheters were used together with a fibre optic endoscope to visualize and then catheterize the rabbit and ferret cervices. Five consecutive transcervical uterine flushes in each of eight superovulated female rabbits 78-89 h after an ovulatory injection of LH resulted in the retrieval of 187 embryos, for an average of 23 embryos per rabbit. A total of 116 embryos were nonsurgically transferred to the uteri of ten recipients, and resulted in 23 young (20%). Eight rabbits (80%) produced young with an average litter size of 2.88 (range 1-7). Ten consecutive transcervical uterine flushes in each of 37 female ferrets 145-178 h after an ovulatory injection of hCG resulted in the retrieval of 324 embryos, an average of 8.76 embryos per ferret. A total of 251 embryos from 27 donors were nonsurgically transferred to the uteri of 31 recipients, and resulted in 65 young (26%). Twenty-eight of the recipients (90%) were initially pregnant, as indicated by postpartum necropsies, and twenty-two ferrets (71%) produced young. The average litter size was 2.95 (range 1-7). This is the first report of live births resulting from the nonsurgical collection of embryos from a donor followed by nonsurgical transfer of those same embryos to a synchronous recipient. The methods reported here can serve as models for use in other mammals in which direct visualization and manipulation of the cervix are not possible, and will be particularly useful in endangered species.     

Brugia pahangi and Dirofilaria immitis: experimental infections in the ferret, Mustela putorius furo.

Ferrets were inoculated with 160 third-stage larvae of the filarial nematode Brugia pahangi, followed 23 days later by 15 larvae of another filarial nematode, Dirofilaria immitis. Other ferrets received only one of these species. Microfilaremia developed in some ferrets with single infections of each species and in some ferrets with dual infections. The nature of the experiment did not permit a thorough study of microfilaremia, but B. pahangi microfilariae were found in numbers as high as 15,650/ml. At necropsy, approximately 8 months after inoculation, adult B. pahangi were recovered from the lymphatic vessels of all 8 ferrets inoculated only with that species, the recovery rate (based on 6 animals only) varying from 2 to 50% of the inoculum (mean 25%). Adult D. immitis were recovered from the heart of all three ferrets inoculated only with that species, the recovery rate being 7, 47, and 60% (mean 38%) of the inoculum. All 5 ferrets inoculated with both species yielded both adult B. pahangi (6 to 23%, mean 16% of inoculum) and adult D. immitis (13 to 67%, mean 37% of inoculum). It is concluded that the ferret is highly susceptible to both species and that concurrent infections with both species may readily be established.     

Black-footed ferret (Mustela nigripes) behavioral development: aboveground activity and juvenile play

We studied the behavioral development of black-footed ferrets (Mustela nigripes) from 6 to 16 post-natal weeks. At 6 weeks of age, kits are still lactating and depend on their mother for survival, while at 16 weeks, ferret young start achieving independence from their mother and littermates. Behavioral observations were obtained by placing videomonitors in the litters’ cages, nest boxes and in outdoor naturalistic enclosures. Captive-raised black-footed ferrets displayed nocturnal activity patterns, although they tended to appear aboveground at certain daytime hours presumably influenced by the established feeding and cleaning regimes. Growing ferrets began emerging aboveground at approximately 7 post-natal weeks and diel activity steadily increased as kits matured. The most manifest behavioral changes (appearance of new motor patterns, increase in aboveground play and in neck-biting behaviors) occurred from post-natal week 8 to week 12. This coincides with the period of maximum growth for ferrets and with a sensitive phase for the development of food preferences in this species. Changes from the 12 to the 16 post-natal weeks involved an increase in aboveground activity, including a higher frequency of scent-marking behaviors. Information provided in this study has important implications for enhancing the captive management of this endangered carnivore.     

Mammotrope heterogeneity in the pituitary gland of European ferret,Mustela putorius furo: An immunoelectron-microscopic study

Employing the superimposition technique of electron-microscopic immunocytochemistry ultrastructural heterogeneity of the mammotropes in the pituitary gland of the European ferret,Mustela putorius furo,was studied. On the basis of the size of their secretory granules, the mammotropes were classified into three subtypes, type-I, type-II and type-Ill, which may correspond to different developmental or physiological states of a single cell type. Simultaneous study of mammotropes and somatotropes in several pairs of serial semithin sections demonstrated the occasional occurrence of bihormonal somatomammotropes /mammosomatotropes which may represent a transitional stage of the progenitor stem-somatotrope during its differentiation into mammotrope; alternatively it may be a functional intermediate during the cross-transformation of somatotrope into mammotrope or vice versa.