Ontogeny of observational learning in the dog (Canis familiaris)

A split-litter technique was used to test observational learning in 4 litters of Miniature Dachshund puppies, 21, 28, 38, and 60 days old at the beginning of the experiment. In one side of a duplicate cage, one puppy of a litter, the demonstrator, learned to pull in a food cart on a runner by means of a ribbon, while another puppy, the observer, watched from an adjacent compartment, separated by a wire screen. Observational learning was demonstrated by the saving in time for the 1st trial when the observer was given the same problem to solve. Maturation, particularly the development of visual function and motor coordination, set a lower age limit for the emergence of observational learning.     

The intermediate root of the trigeminal nerve in the dog (Canis familiaris)

The intermediate root of the trigeminal nerve in the dog has been investigated both macroscopically and microscopically. Sixty-two trigeminal complexes (trigeminal ganglion, trigeminal roots and the portion of the pons to which the roots were attached) in the dog were dissected out and removed. Each of the complexes was fixed in 10% formalin, dehydrated and embedded in paraffin. The paraffin blocks were cut serially at 10 μ. Every other slide was either stained with Luxol Fast Blue or impregnated with Bodian's silver method. In all cases, between the motor and sensory roots an intermediate root composed of one distinct rootlet was identified. Most frequently the intermediate root was attached to the pons from 0.5 to 3.0 mm lateral to the motor root and rostral to the sensory root from 0.5 to 2.0 mm. From its pontine attachment the intermediate root extended anteromedially for a distance of from 2.0 to 5.0 mm before it became incorporated in the lateral aspect of the free motor root. Closer to the trigeminal ganglion the motor root and the intermediate root fused with the expanding sensory root. The fibers in the intermediate root ranged from 1.5 to 7.5 μ in diameter with the majority of fibers (60 to 70%) having a diameter of from 4.0 to 6.0 μ. Approximately 10% of the fibers were unmyelinated. The total number of fibers in the intermediate root varied from 170 to 416 with an average of 266 fibers. The morphological data obtained in an experimental animal such as presented in this paper may provide a basis for future experimental work on the clarification of the functional role of the trigeminal intermediate root.     

Fibre types of M. pectineus of the dog (Canis familiaris)

As revealed by the NADH-diaphorase, M. pectineus of the dog possesses at least three main kind of fibres: 45.99% of small and slow contracting-red fibres, presenting an intense reaction, specially in the subsarcolemmal region; 45.55% of large and fast contracting-white fibres, presenting a less intense reaction. The remainder 8.46% fibres possess intermediate characteristics. These findings suggest that the movements of slow and fast contraction of M. pectineus are somewhat equilibrated.     

Behavioural and physiological correlates of impulsivity in the domestic dog (Canis familiaris)

Impulsivity is a trait related to inhibitory control which is expressed in a range of behaviours. Impulsive individuals show a decreased ability to tolerate delay of reinforcement, and more impulsive behaviour has been linked to decreased levels of serotonin and dopamine in a number of species. In domestic dogs, impulsivity is implicated in problem behaviours that result from a lack of self control, but currently there are no published studies that assess behavioural and physiological measures of impulsivity in relation to this trait. Impulsivity scores were calculated for 41 dogs using an owner-report assessment, the Dog Impulsivity Assessment Scale (DIAS). Twenty-three of these subjects completed an operant choice task based on a delayed reward paradigm, to assess their tolerance to delay of reinforcement. High Pressure Liquid Chromatography (HPLC) with Fluorometric Detection was used to detect levels of the metabolites of serotonin (5-HIAA) and dopamine (HVA) in the urine of 17 of the subjects. Higher impulsivity scores were found to be significantly correlated with more impulsive behaviour (reduced tolerance to delay of reinforcement) in the behaviour tests and lower levels of urinary 5-HIAA and 5-HIAA/HVA ratio. The results demonstrate convergent validity between impulsivity (as assessed by the DIAS) and behavioural and physiological parameters.     

Hair Whorls in the Dog (Canis familiaris), Part II: Asymmetries

In horses and cattle, hair whorls have been shown to act as a structural marker of reactivity and behavioral lateralization. Few studies on canine whorls have been reported and none have assessed whorl position or direction of flow. This study describes the distribution and characteristics of whorl in each of 10 regions in which whorls are typically located in dogs. Hair whorls were assessed in dogs (n = 120) and were recorded as clockwise or counterclockwise in the cephalic, cervical (dorsal, lateral, ventral), thoracic and brachial axillary, chest, shoulders, elbows, abdominal, and ischiatic regions. Bilateral whorls, including brachial axillary, elbow, abdominal and ischiatic whorls, rotated in opposing directions, allowing the dog's overall hair coat to be symmetrical. Cephalic, brachial axillary, and ischiatic whorls were consistent in their direction; cephalic and ischiatic whorls were clockwise on the right side of the body, and counterclockwise on the left, whereas right brachial axillary whorls were counterclockwise and left were clockwise. The central chest whorl was predominantly counterclockwise (91.21%). Direction of whorls was associated with several factors, including coat length, coat thickness, sex and source of the dog. Anat Rec, 2010. © 2009 Wiley‐Liss, Inc.     

Report on the progress of standardization of the G-banded canine (Canis familiaris) karyotype

Karyotyping of dog chromosomes is a difficult task owing to the high diploid number of chromosomes (2n=78) and the similar morphology of autosomes, all of which are acrocentrics. In this report 22 of the 39 G-banded chromosome pairs and their corresponding ideograms have been standardized. The ideogram comprises altogether 235 bands. The need for the introduction of molecular techniques such as chromosome painting and physical mapping of genetic markers for the identification of small acrocentrics is discussed.accepted for publication by H. C. Macgregor     

Structural and functional anatomy of the neck musculature of the dog (Canis familiaris)

The morphometric properties and the anatomical relationships of the entire musculature of the canine cervical spine are reported herein. These data were obtained from the dissection of cadavers of six dogs. Total muscle length, muscle weight, fascicle length and angles of pennation were recorded for each muscle comprising the canine cervical spine. Based upon these properties, physiological cross-section area (PCSA) and architectural index were estimated. When scaled by whole body mass, the values of each of these parameters were found to be similar between all dogs. Muscles that course from the cranial neck to the shoulder girdle or the rib cage (e.g. brachiocephalicus and rhomboideus capitis) were found to have relatively long fascicles and low PCSA values and thus appear to be designed for rapid excursions. By contrast, muscles that primarily support the neck and shoulder against gravitational forces (e.g. serratus ventralis and trapezius) were found to have relatively high PCSA values and short fascicle lengths, and thus have the capacity to generate large forces. Differences of morphometry as well as nomenclature were found between the canine and human neck musculature. Nevertheless, many similarities exist; in particular, both species have similar muscles adapted to force generation or large excursions. We thus conclude that the canine neck may be used as a modelling tool for biomechanical investigations of the human cervical region as long as the differences listed are borne in mind.     

Study of motor units of M. pectineus of the dog (Canis familiaris)

Cross sections of M. pectineus of 6 adult dogs were used to study the number of motor units. Our results revealed that M. pectineus possesses 29,451 muscle fibres and 165 large nerve fibres. Since 60% of these latter fibres are motor fibres, the number of fibres per motor unit of M. pectineus is 294. This fact suggests that this muscle executes finely adjusted movements.     

Hair Whorls in the Dog (Canis familiaris). I. Distribution

Hair whorl characteristics were assessed in the domestic dog (Canis familiaris) in the regions of cephalic, cervical (dorsal, ventral, and lateral), thoracic and brachial axillary regions, the chest, shoulders, elbows, ventral abdominal region, and on the caudal thighs (ischiatic). They were classified as simple or tufted, and their position was recorded as the distance between their centers and bony landmarks within each region. The distribution of whorls was explored in a cohort of domestic dogs (N = 120) comprising a variety of breeds and cross‐breeds, sourced from shelters (N = 60) and the general public (N = 60). Whorls observed in the majority of dogs in this cohort typically occurred on the chest, brachial axillary region, elbows, and ischiatic region. Atypical whorls were present in fewer than 20% of the population, and included those on the head (cephalic), cervical regions (dorsal, ventral, and lateral), shoulders, thoracic axillary region, and on the ventral abdominal region. The majority of whorls on dogs were classified as simple. In contrast, those located on the elbows and the majority of chest whorls were tufted. The presence and position of whorls were often associated with several variables including coat length and thickness, and the sex and source of the dog. The palpation and hair‐cluster method of whorl assessment described in this article is best suited to dogs with short‐to‐medium coat lengths. The current methodology developed to assess hair whorl characteristics provides a framework for future investigations into any associations between hair whorl characteristics and other canine traits such as temperament. Anat Rec, 293:338–350, 2010. © 2010 Wiley‐Liss, Inc.     

The vesical medial artery, Rauch 1963, of the dog (Canis familiaris)

The Authors study 30 adult dogs from both sexes, on the "vesical medial artery--Rauch, 1963" injected with latex through the aorta. They conclude that: 1--the vessel should be named "ventral vesical artery"; 2--it is a sharply defined structure and can't be confused with the "inferior" or "caudal vesical artery"; 3--emerging from the deep femoral artery (A. profunda femoris), caudal epigastric artery (A. epigastrica caudalis), or from the pudendoepigastric trunk (Truncus pudendoepigastricus), the "ventral vesical artery" appeared bilaterally (6.66%); unilaterally to the right (13.33%) and unilaterally to the left (3.33%); 4--when present, the "ventral vesical artery" supplies the ventral area of the bladder (Vesica urinaria) and regional fat, and eventually, gives a few branches to the prostate gland and urethra.     

The seminiferous epithelium cycle and its duration in different breeds of dog (Canis familiaris)

Testis structure and function in dogs are relatively poorly investigated. The aim of the present study was to carry out a comparative investigation of the stages of the seminiferous epithelium cycle and its duration in different breeds of dog. Fifty-six sexually mature dogs (mongrel, n  = 12; pinscher, n  = 12; beagle, n  = 5; American pit bull, n  = 9; poodle, n  = 12; and Labrador retriever, n  = 6) were analysed. Intratesticular injections of tritiated thymidine were given to determine the duration of spermatogenesis. Orchiectomy was performed at different time periods following injection (1 h, 2 and 4 weeks). Testis fragments were embedded in plastic and routinely prepared for histological and autoradiographic evaluations. Eight stages were characterized based on the acrosome system. Significant ( P  < 0.05) differences were found for the frequencies of the different stages characterized (except Stages V, VI and VIII), particularly for the mongrel. Stage IV (when spermiation occurs) was the most frequent in all six breeds (~25%), whereas Stages II and VIII were the least frequent (< 8%). Each spermatogenic cycle and the total duration of spermatogenesis lasted 13.73 ± 0.03 and 61.9 ± 0.14 days, respectively, for the mongrel, poodle, pinscher, beagle, and Labrador retriever. These values were ~10% lower ( P  < 0.03) for the American pit bull (12.55 ± 0.26 and 56.5 ± 1.17 days, respectively). To our knowledge, this is the first comprehensive study to perform a careful investigation of stage frequencies and seminiferous epithelium cycle duration in this very important domestic species.     

The DAPI Banded Karyotype of the Domestic Dog (Canis familiaris) Generated Using Chromosome-Specific Paint Probes

The domestic dog (Canis familiaris) is widely used as a model in the study of human disease. However, many of the 78 chromosomes comprising the canine karyotype are extremely difficult to identify reliably by classical cytogenetics. This has been a major hindrance to molecular cytogenetic studies of this species. The Animal Health Trust and the Sanger Centre have developed a set of canine whole chromosome-specific fluorescence in situ hybridisation (FISH) probes (chromosome paints). We have used these chromosome paints to identify unequivocally each chromosome in a metaphase spread. An increasing number of laboratories are making use of cooled CCD cameras and sophisticated software for FISH mapping. Consequently, there is a major trend towards the use of DAPI banding for concurrent chromosome identification during FISH analyses in a range of species. Here we present, for the first time, a complete DAPI banded karyotype of the dog in which each chromosome has been accurately placed, together with a 460-band DAPI ideogram. These data will facilitate the accurate assignment of FISH- mapped loci to all chromosomes comprising the karyotype and form the basis for an agreed standard of the dog karyotype.     

First isolation of Sarcocystis caninum sarcocysts from two domestic dogs (Canis familiaris) from China

Parasitology Research - The presence of Sarcocystis cysts in the muscle tissue of domestic dogs (Canis familiaris), which normally serve as definitive hosts, is unusual and infrequent. Here, S....     

Anatomical observations about the closure of the ductus venosus in the dog (Canis familiaris).

The observation of the anatomical closure of ductus venosus was carried out in 108 dogs (62 females and 46 males) with age varying between 3 hours and 21 days old. We have observed that within 2 days old, the ductus venosus was found pervious in 100% of the animals sacrified; 3 days old, in 81% of the animals; 4 days old, in 62% of pups; 5 days old, in 25% and over 6 days old, the ductus venosus was anatomical closed in 100% of the animals. We have also observed that the closure starts within 48 hours on the caudal vena cava caudal side.     

Global seroprevalence and prevalence of infection of influenza in dogs (Canis familiaris): A systematic review and meta-analysis

Influenza in dogs holds considerable public health significance due to their close companionship with humans, yet several facets of this phenomenon remain largely unexplored. This study undertook a systematic review and meta-analysis of observational studies to gauge the global seroprevalence of influenza in dogs. We also assessed whether pet dogs exhibited a higher seroprevalence of influenza compared to non-pet dogs, explored seasonal variations in seroprevalence, scrutinised the design and reporting standards of existing studies, and elucidated the geographical distribution of canine influenza virus (cIV). A comprehensive analysis of 97 studies spanning 27 countries revealed that seroprevalence of various influenza strains in dogs consistently registered below 10% and exhibited relative stability over the past decade. Significantly, we noted that seroprevalence of human influenza virus was notably higher in pet dogs compared to their non-pet counterparts, whereas seroprevalence of other influenza strains remained relatively uniform among both categories of dogs. Seasonal variations in seroprevalence of cIV were not observed. In summary, our findings indicated the global circulation of cIV strains H3N2 and H3N8, with other strains primarily confined to China. Given the lack of reported cases of the transmission of cIV from dogs to humans, our findings suggest a higher risk of reverse zoonosis than zoonosis. Finally, we strongly advocate for standardised reporting guidelines to underpin future canine influenza research endeavours.     

Cloning and chromosomal localization of MYO15A to chromosome 5 of the dog (Canis familiaris)

Mutations in the myosin XVA gene (MYO15A) cause congenital non-syndromic deafness in humans and mice. Therefore, the MYO15A gene represents a candidate gene for hereditary hearing loss in dogs. Using a human cDNA to screen a dog BAC library, we isolated a canine BAC clone. Sequencing of the BAC ends confirmed homology to the human gene. To facilitate future linkage studies, we report the physical mapping of the canine MYO15A gene to CFA5q23-q24 by FISH and RH mapping. This revised version was published online in July 2006 with corrections to the Cover Date.     

狼和家犬消化道形态学和细胞学差异比较

目的 阐明家养驯化产生的食性差异所引起的狼(Canis lupus)和家犬(Canis familiaris)消化道形态学和消化道内分泌细胞数量和分布的异同. 方法 健康成年狼和家犬各6只,应用形态观察和石蜡切片法进行消化道解剖学和组织学比较;应用免疫组织化学染色法进行消化道内分泌细胞的分布和数量的比较. 结果 形态学比较发现,狼的消化道总长度和总重量,尤其是结肠的长度和重量均小于家犬;胃贲门腺区管壁较家犬偏薄,胃底腺区、空肠和结肠管壁偏厚;食管和贲门腺区的黏膜较家犬显著偏薄,大肠各部位黏膜显著偏厚.免疫组织化学染色发现,除胰多肽阳性细胞和P物质阳性细胞的分布位置和某些内分泌细胞的分布密度间存在较大差别外,狼和家犬大多数消化道内分泌细胞具有相同的分布特征. 结论 食性不同主要引起了狼和家犬的胃、盲肠和结肠解剖学和组织学的差异,小肠的差异相对不明显.两者消化道内分泌细胞分布和数量的一致性,说明家养驯化和食性差异尚未引起消化道细胞水平的适应性改变.     

Comparative functional anatomy of the epaxial musculature of dogs (Canis familiaris) bred for sprinting vs. fighting

The axial musculoskeletal system of quadrupedal mammals is not currently well understood despite its functional importance in terms of facilitating postural stability and locomotion. Here we examined the detailed architecture of the muscles of the vertebral column of two breeds of dog, the Staffordshire bull terrier (SBT) and the racing greyhound, which have been selectively bred for physical combat and high speed sprint performance, respectively. Dissections of the epaxial musculature of nine racing greyhounds and six SBTs were carried out; muscle mass, length, and fascicle lengths were measured and used to calculate muscle physiological cross‐sectional area (PCSA), and to estimate maximum muscle potential for force, work and power production. The longissimus dorsi muscle was found to have a high propensity for force production in both breeds of dog; however, when considered in combination with the iliocostalis lumborum muscle it showed enhanced potential for production of power and facilitating spinal extension during galloping gaits. This was particularly the case in the greyhound, where the m. longissimus dorsi and the m. iliocostalis lumborum were estimated to have the potential to augment hindlimb muscle power by ca. 12%. Breed differences were found within various other muscles of the axial musculoskeletal system, particularly in the cranial cervical muscles and also the deep muscles of the thorax which insert on the ribs. These may also highlight key functional adaptations between the two breeds of dog, which have been selectively bred for particular purposes. Additionally, in both breeds of dog, we illustrate specialisation of muscle function by spinal region, with differences in both mass and PCSA found between muscles at varying levels of the axial musculoskeletal system, and between muscle functional groups.