Growth and maintenance of the raccoon dog (Nyctereutes procyonoides Gray 1834) on various brewers' mash and basal diets

Voluntary regulation of energy balance in farmed raccoon dogs

1. Seasonal changes in body mass and voluntary feed intake were studied in juvenile raccoon dogs (Nyctereutes procyonoides, Gray 1834) under farm conditions. 2. The body weight maximum was achieved in mid-November. Thereafter, body weight gradually declined towards summer. This pattern was closely connected to voluntary regulation of feed consumption. During autumn, appetite of the animals was good enhancing gradual deposition of excessive fat reserves. 3. Excessive adiposity itself, together with factors like shortening daylength and decreasing air temperature, seemed to play as a trigger for starting of winter rest. 4. The results support the endogenic nature of energy balance regulation.

Growth and fur parameter variations of farmed raccoon dogs

Growth, body composition and hair coat parameter variations were evaluated in farmed raccoon dogs (Nyctereutes procyonoides) reared in a conventional two animals -in-cage-system. Daily rate of body weight gain (BWG) of litters very significantly (p less than 0.001) correlated with their time of birth (r = 0.879); the later in spring they were born the faster they gained weight. Final body weight (FBW) of the whelps was to be predicted from their body weight (BW) in early August (r = 0.689). There was no significant correlation between litter size and FBW, BWG or daily rate of BWG. Social competition for food produced great variation in FBW of the animals; the difference between the heavier and lighter raccoon dogs within a cage averaged 1.2 kg (p less than 0.001). Except in FBW and obesity index, there was no significant differences in other parameters between these social groups. Social status within a cage explained only 3.6% of the pelt quality variation while it could explain 52% of the BW variation. Litter explained 36% of the pelt quality, whereas it could explain 4.9% of the BW variation only. Social status and litter did not show any significant two-way interactions. Pelt weight very significantly (p less than 0.001) correlated with pelt quality (r = 0.48) and mass (r = 0.55). Also mass very positively (p less than 0.001) correlated with pelt quality (r = 0.82), indicating that the subjectively estimated pelt quality, in fact, can be derived directly from its weight. We conclude that differences in growth parameters and fur characteristics are mainly produced by social and hereditary factors, respectively.

Lipogenic hepatic enzyme activity of raccoon dogs (Nyctereutes procyonoides) fed various diets

Body weight, obesity and liver weights of male raccoon dogs fed diets of various energy content were higher than those of females. With increasing body weight and obesity the liver weight and glucose-6-phosphate dehydrogenase (G-6-PD) decreased significantly in both sexes. The liver weight correlated very positively with the G-6-PD activity. The alpha-glycerophosphate dehydrogenase (alpha-GPD) correlated with the liver weight only in females.

Organ scaling in the raccoon dog, Nyctereutes procyonoides Gray 1834, as monitored by influences of internal and external factors

1. Animals fed a high energy ration had bigger body weight, and bigger heart, brain and genitals then animals fed a normal diet, but they had substantially smaller liver, kidneys, adrenals and thyroid glands than the otherwise smaller animals. Restricted feeding did not necessarily produce smaller organ sizes than normal. 2. The yearly variation in organ sizes was astonishingly large whereas the sex differences were rather rare. 3. For organs like liver, kidneys and thyroid glands the conclusion from the results was independent of the method of expressing the organ mass. The organ sizes seemed to be influenced by many coexisting factors like yearly differences, sex and age of animals, feed and farm.

Response to cold in the blue fox and raccoon dog as evaluated by metabolism, heart rate and muscular shivering: a re-evaluation

Oxygen consumption (ml kg-0.75/min) in relation to ambient air temperature at or below the lower critical temperature (Tlc) of the winter-furred raccoon dog (+10 degrees C) and the blue fox (-6 degrees C) is described by the equations y = 14.8-0.28x and y = 7.5-0.20x, respectively. Muscular shivering activity (integrated EMG) of both species increased below thermoneutrality parallel with increasing oxygen uptake and heart rate. Seasonal changes in measured metabolic parameters were evident for both species. The results suggest that the overall body insulation or the metabolic response to cold are not essentially worse in the raccoon dog as compared with the blue fox. It is concluded that earlier speculations of surprisingly wide thermoneutral zone and very low Tlc of the Arctic fox are not evident for the blue fox.