Peptidergic regulation of feeding in the dog (Canis familiaris)

Although the incidence of obesity in the domesticated dog is high, few studies have investigated the regulation of food intake in this species. In the present study we investigated the response of the dog to a number of putative satiety agents including cholecystokinin (CCK), bombesin, calcitonin and naloxone. CCK significantly suppressed food intake during a scheduled fifteen minute meal in intact dogs and in dogs receiving total subdiaphragmatic vagotomies. Emesis occurred following injection of higher doses of CCK in most dogs. Bombesin and calcitonin reduced intake in both normal and vagotomized dogs, although higher doses of calcitonin were needed to significantly suppress feeding in vagotomized dogs compared with intact animals. Naloxone reduced feeding by as much as 60% in intact and vagotomized animals. Glucagon suppressed feeding in intact dogs, but not in vagotomized animals. Somatostatin and pancreatic polypeptide did not alter food intake. Thus the domesticated dog responds somewhat differently to some neuropeptides compared with the laboratory rat stressing the importance of examining the regulation of food intake across species.     

Two-item sentence comprehension by a dog (Canis familiaris)

Syntax use by non-human animals remains a controversial issue. We present here evidence that a dog may respond to verbal requests composed of two independent terms, one referring to an object and the other to an action to be performed relative to the object. A female mongrel dog, Sofia, was initially trained to respond to action (point and fetch) and object (ball, key, stick, bottle and bear) terms which were then presented as simultaneous, combinatorial requests (e.g. ball fetch, stick point). Sofia successfully responded to object-action requests presented as single sentences, and was able to flexibly generalize her performance across different contexts. These results provide empirical evidence that dogs are able to extract the information contained in complex messages and to integrate it in directed performance, an ability which is shared with other linguistically trained animals and may represent a forerunner of syntactic functioning.     

The mechanics of jumping by a dog (Canis familiaris)

A force platform has been used to obtain records of the forces exerted on the ground by an Alsatian dog, during take-off for running long jumps and standing scale jumps. The records have been analysed in conjunction with cinematograph film, taken simultaneously, and anatomical data. Stresses in the principal muscles of the hind limb, and in the triceps, have been calculated and the values obtained are compared with the stresses found by other investigators in isometric experiments with excised mammal muscles. Stresses in certain tendons and bones have been calculated, and the values obtained are compared with published values for the strength of tendon and bone. Evidence is presented that the gastrocnemius and plantaris muscles behave, in take-off for a jump, essentially as passive elastic bodies. Most of the elastic energy is probably stored in their tendons. A tendency for distal limb muscles to be pinnate, with much shorter fibres than proximal limb muscles, is noted and discussed.     

Interspecies hormonal interactions between man and the domestic dog (Canis familiaris)

To date, hormonal influence in interspecies interaction has not been examined. In a study of a dog agility competition among human/dog teams, men's pre-competition basal testosterone (T) levels were positively related to changes in dogs' cortisol levels from pre- to post-competition, but only among losing teams. Furthermore, pre-competition basal T in men on losing teams predicted more than half of the variance in dogs' cortisol change. This relationship was mediated through men's punitive and affiliative behaviors towards their dogs immediately after competition. Men's T change was also a significant predictor of dogs' change in cortisol such that men who experienced greater decreases in T after a loss were associated with dogs that experienced greater increases in cortisol. In winning teams, men's pre-competition T and T changes were unrelated to dogs' cortisol changes. These results are discussed in light of T as a proxy for dominance motivation as well as T's relation to stress across the species boundary.     

Analysis of major repetitive DNA sequences in the dog (Canis familiaris) genome

A systematic screening and analysis of repeated DNA sequences from a dog genomic library composed of small DNA inserts enabled us to characterize abundant canine repetitive DNA families. Four main families were identified: i) a group of highly repeated tRNA-derived short interspersed repetitive DNA elements (tRNA-SINEs); ii) another type of SINE-like element that was mainly found inserted into long interspersed repetitive elements (LINEs); iii) LINEs of the L1 type; and iv) satellite or satellite-like DNA. Surprisingly, no SINEs derived from 7SL RNA were found in the dog genome. These data should help in the analysis of canine DNA sequences and in the design of canine genome mapping reagents. Received: 4 November 1998 / Accepted: 2 February 1999     

Lateralised behaviour in the domestic dog,Canis familiaris

Paw use on three tasks in 53 domestic dogs (Canis familiaris) was studied to determine whether the animals exhibited a significant paw preference, and, if so, to explore the direction and strength of the dogs' preferred paw use, both within, and between, tasks. The influence of the dogs' sex on their paw preferences was also explored. The findings revealed that lateralised behaviour was strongly sex related. Male and female showed paw preferences at the level of the population but in opposite directions. Female dogs had a greater preference for using their right paw on all tasks, whilst males were more inclined to adopt their left paw. Analysis revealed significant positive relationships for two of a possible three intertask correlations. Overall, the findings suggest that there are two distinct populations of paw preference in the domestic dog that cluster around the animals' sex. It is recommended that further work be conducted to explore the influence of pre-training on dogs' paw preferences before generalisations regarding laterality in this species are drawn.     

The application of FISH techniques for physical mapping in the dog (Canis familiaris)

The abundance of CA/GT repeats in the DNA of the dog (Canis familiaris) has established the importance of polymorphic microsatellites in the development of a low density map of the canine genome. The assignment of linkage groups of markers to chromosomes by physical mapping requires reliable cytogenetic techniques for routine production of metaphase cells. The dog has 78 chromosomes, many of which are smaller and more contracted than those of other mammals. Although the molecular study of inherited disease in dogs has important implications for both improved welfare in dogs and the provision of animal models for human diseases, the small size and large number of chromosomes in the canine genome has discouraged the inclusion of cytogenetic analysis in the planning of relevant research protocols. In this report, Fluorescence In Situ Hybridization (FISH) techniques have been optimized for the physical mapping of probes in C. familiaris. A method to obtain a good yield of early and midmetaphases from short-term peripheral blood cultures and the optimal conditions for hybridization and detection of probes is described. Thirteen microsatellite-containing cosmid probes from a canine genomic library in pWE15, a highly repetitive probe (human ribosomal DNA pHr14E3), and a human X Chromosome (Chr) paint have been mapped. Six microsatellites, two ribosomal sites, and the human paint have been assigned to specific chromosomes. Received: 5 June 1995 / Accepted: 1 September 1995     

Energetics of lactation in domestic dog (Canis familiaris) breeds of two sizes

The energetics of lactation was measured in two breeds of domestic dog during peak lactation. Labrador Retrievers (30 kg) had larger litter sizes than Miniature Schnauzers (6 kg). During the 7-day experimental period, Labrador pups increased more in mass than Schnauzer pups, both absolutely and relatively. Consequently, the energy demands of the litter, relative to maternal metabolism, were higher in Labradors than Schnauzers. Milk composition and gross efficiency of milk production were not significantly different between breeds and the costs of lactation were fuelled by increases in food intake. Metabolisable energy intake was higher than predicted in Labradors, but lower than predicted in Schnauzers. These patterns differ from interspecific expectations, which would predict larger animals to reproduce more slowly, have smaller litter sizes, and invest less energy in reproduction.     

Arterial supply to the stomach of indigenous dog (Canis familiaris) in Bangladesh.

Arterial supply to the stomach of dogs indigenous to Bangladesh was investigated by using latex. The hepatic, left gastric and splenic arteries sent their major branches to the stomach. The cranial and caudal branches of the left gastric artery supplied the lesser curvature of the stomach. The right gastric, and right and left gastroepiploic arteries also sent their branches to both the lesser and greater curvatures. Six or seven short gastric arteries from the splenic artery supplied the greater curvature. Anastomoses between the left and right gastric, between the left and right gastroepiploic, and between short gastric arteries and left gastric arteries were observed.     

Comparative NMR studies of diffusional water permeability of red blood cells from different species: XVI Dingo (Canis familiaris dingo) and dog (Canis familiaris)

As part of a programme of comparative measurements of P _d (diffusional water permeability) the RBCs (red blood cells) from dingo (Canis familiaris dingo) and greyhound dog (Canis familiaris) were studied. The morphologies of the dingo and greyhound RBCs [examined by light and SEM (scanning electron microscopy)] were found to be very similar, with regard to aspect ratio and size; the mean diameters were estimated to be the same (～7.2 μm) for both dingo and greyhound RBCs. The water diffusional permeability was monitored by using an Mn²⁺‐doping ¹H NMR technique at 400 MHz. The P _d (cm/s) values of dingo and greyhound RBCs were similar: 6.5×10^?3 at 25°C, 7.5×10^?3 at 30°C, 10×10^?3 at 37°C and 11.5×10^?3 at 42°C. The inhibitory effect of a mercury‐containing SH (sulfhydryl)‐modifying reagent PCMBS (p‐chloromercuribenzene sulfonate) was investigated. The maximal inhibition of dingo and greyhound RBCs was reached in 15–30 min at 37°C with 2 mmol/l PCMBS. The values of maximal inhibition were in the range 72–74% when measured at 25°C and 30°C, and ～66% at 37°C. The lowest value of P _d (corresponding to the basal permeability to water) was ～2–3×10^?3 cm/s in the temperature range 25–37°C. The E _a,d (activation energy of water diffusion) was 25 kJ/mol for dingo RBC and 23 kJ/mol for greyhound RBCs. After incubation with PCMBS, the values of E _a,d increased, reaching 46–48 kJ/mol in the condition of maximal inhibition of water exchange. The electrophoretograms of membrane polypeptides of the dingo and greyhound RBCs were compared and seen to be very similar. We postulate that the RBC parameters reported in the present study are characteristic of all canine species and, in particular in the two cases presented here, these parameters have not been changed by the peculiar Australian habitat over the millennia (as in the case of the dingo) or over shorter time periods, decades or centuries (as in the case of the domestic greyhound).     

Anatomical closure of the ductus arteriosus in the dog (Canis familiaris).

The ductus arteriosus was studied in 138 dogs (80 female and 58 male) aged from 6 h to 21 days. This experiment led us to conclude that the anatomical closure of the d. arteriosus starts within 96 h and is obliterated after 6 days in 100% of the animals studied. We have also evidenced that the closure starts in the medial part of the d. arteriosus and progresses to the pulmonary artery and aorta.     

Banding analysis of the somatic chromosomes of the domestic dog (Canis familiaris).

The chromosomes of the domestic dog (Beagle) were investigated by several different staining techniques. G-banding, Q-banding, and the bis-benzimidazol derivative Hoechst 33258, make possible the identification of all 39 chromosome pairs. Constitutive heterochromatin (C-bands) was present on a few chromosomes as distinctive, large stained areas; on the other autosomes there was little or no heterochromatin detectable.     

Is there a caudal thyroid artery in the dog (Canis familiaris)?

Attempts have been made to establish extent of similarities as well as dissimilarities between the canine caudal thyroid and human inferior thyroid artery. On the basis of origin, course, relationship, branching pattern, major area of supply, level of anastomosis, occurrence, etc., it is proposed to rename the caudal thyroid of the dog as the tracheoesophageal artery.     

A Comparison of the Sensory Development of Wolves (Canis lupus lupus) and Dogs (Canis lupus familiaris)

Little is known about the development of the sensory systems of wolves. The timing of sensory development in wolves is usually extrapolated from studies on dogs, since they are members of the same species. However, early developmental differences between these two subspecies have already been identified. For example, wolves tend to approach and investigate objects in their environment 2 wk before dogs. These changes in developmental timing may play an important role in the behavioral differences between adult wolves and dogs. The purpose of this study is to compare the development of the sensory systems in wolves and dogs. Responses of seven wolf pups and 43 dog pups to familiar and novel olfactory, auditory, and visual stimuli were tested weekly from 2–7 wk of age. Eleven wolf pups were also observed for orientation towards auditory and visual stimuli during 2‐h sessions, 5 d a week, from 2–8 wk of age. These observations were supplemented by the daily records of caretakers. The results suggest that wolves and dogs both develop olfaction by 2 wk, audition by 4 wk, and vision by 6 wk on average, despite the 2‐wk shift in their ability to explore. This means that when wolves begin to explore at 2 wk, they are blind and deaf, and must rely primarily on their sense of smell. Thus, there is a significant alteration of how these subspecies experience their environment during the critical period of socialization. These findings lead to an alternative explanation for the difference in dogs' and wolves' abilities to form interspecies social attachments, such as those with humans.     

Isotope recycling in lactating dogs (Canis familiaris)

Isotope-based techniques for the measurement of water turnover, energy expenditure, and milk intake often assume that there is no recycling of isotopes once they have left the labeled animal. In experiments involving lactating females or their suckling offspring, there are several possible routes of isotope recycling. These include the consumption of labeled milk by offspring, the ingestion of labeled excreta, and the rebreathing of exhaled labeled CO(2) or water vapor by both mother and offspring. Isotope recycling might be especially important during lactation because the offspring are in close contact with each other and their mother for prolonged periods. We show here in 24- to 30-day-old domestic dog Canis familiaris puppies that there was no detectable transfer of (18)O or (2)H from labeled to unlabeled pups in two litters (16 pups, 8 labeled, 8 unlabeled) that were weaned early and independent of their mother. However, there was a significant transfer of both isotopes from labeled to unlabeled pups and from labeled pups to their mothers in nine equivalent nursing litters of the same age (27 labeled, 26 unlabeled pups). The increases in enrichment of isotopes in unlabeled offspring were greater than the increases in enrichment of the mothers. This indicates that maternal ingestion of offspring excreta and subsequent transfer of isotope in milk is not the sole pathway of recycling. Additional routes must also be important, such as exchange of isotope between pups on saliva-coated nipples and perhaps direct ingestion of excreta by unweaned young. Recycling is unlikely to be an important factor when determining maternal metabolic rate during peak lactation in domestic dogs. However, experiments that are designed to assess the energy demands of pups and isotope-based estimates of water turnover in offspring may need to take into account any effects of isotope recycling. In a theoretical example, removing the effects of recycling increased the measured energy expenditure in pups by up to 7% and increased the calculated elimination rates of both isotopes by up to 11.1% in (18)oxygen and 10.9% in (2)hydrogen.