Gender differences in the anatomy of the perineal glands in Guinea pigs and the effect of castration.

Perineal glands in guinea pigs are part of the sebaceous glandular complex. Their secretions are used for scent marking. This is important for social status and can be seen in both sexes and castrated males. Discrepancy exits about the existence of these glands in female guinea pigs and knowledge of the anatomical consequences of castration on the male perineal glands is sparse. To examine these uncertainties related to gender, perineal glands from 13 sexually mature pet guinea pigs were examined macro- and microscopically. Clear gender differences in the anatomy of perineal glands were found, and castrated males showed signs of atrophy and fatty infiltration in the glands. Females do have perineal glands, although smaller than the glands in the male. The glands are typically sebaceous with multiple excretory ducts. A macroscopic unique feature in the males was the clearly evident orifices of a large excretory duct on each side of the slightly everted perineal sac. However, the reason for this gender difference is not clear. In castrated males, the orifices were atrophied and difficult to see. In addition, the sebaceous glands of the hair follicles in the skin folds of the perineal opening were smaller and less abundant in females and castrated males. The changes in castrated males are presumably linked to the hormonal changes and decreased secretion after castration. The dense keratin layer in the perineal sac was thicker in males than in both castrated males and females and could contribute to the concrement formation seen mainly in males.

Exonization of a LINE1 fragment implicated in X-linked hypohidrotic ectodermal dysplasia in cattle.

A case of X-linked hypohidrotic ectodermal dysplasia (XHED) was identified in a family of Danish Red Holstein cattle. The ectodysplasin-signalling protein (EDA) is known to be central in the normal development of ectodermal structures, and mutations in the ectodysplasin A (EDA) gene have been reported to cause XHED. In this study, we analysed different EDA transcript variants in affected and unaffected cattle and identified a new transcript variant including a LINE1-derived pseudoexon between EDA exons 1 and 2. The 161-bp-long pseudoexon introduces a shift in reading frame and a premature stop codon early in EDA exon 2 and is probably the cause of XHED in this Danish Red Holstein family.

X-linked spondylo-epiphyseal dysplasia tarda in the Danish-Swedish farm hound.

In two litters from the same parents, three out of four males had an abnormally short leg and body length. Affected dogs showed signs of pain when moving, which could be eliminated by analgesia. On radiography, these animals had widened, radiolucent, irregularly bordered intervertebral disc spaces. When examined at seven months of age, the epiphyses appeared widened and irregular in shape and outline. General bone opacity in the vertebral column was lower in the affected male dogs than in the normal littermate. The affected dogs developed spondylosis and arthrosis of the larger limb joints. All affected dogs were euthanased on humane grounds, the eldest at the age of two years nine months. Based on the clinical and radiographic evidence, the condition seen in the male dogs described here resembles X-linked spondylo-epiphyseal dysplasia tarda caused by a collagenopathy due to malformation of COL2A1 as seen in human beings.

Evaluation of the inheritance of the complex vertebral malformation syndrome by breeding studies.

To investigate the congenital complex vertebral malformation syndrome (CVM) in Holstein calves, two breeding studies were performed including 262 and 363 cows, respectively. Cows were selected from the Danish Cattle Database based on pedigree and insemination records. Selected cows were progeny of sires with an established heterozygous CVM genotype and pregnant after insemination with semen from another sire with heterozygous CVM genotype. Following calving the breeders should state, if the calf was normal and was requested to submit dead calves for necropsy. In both studies, significantly fewer CVM affected calves than expected were obtained; a finding probably reflecting extensive intrauterine mortality in CVM affected foetuses. The findings illustrate increased intrauterine mortality as a major potential bias in observational studies of inherited disorders.

Complex vertebral malformation in holstein calves.

A recently observed lethal congenital defect of purebred Holstein calves is reported. Eighteen genetically related calves were necropsied. One calf had been aborted on gestation day 159, and the others were delivered between day 250 and day 285. Birth weights were reduced. The defect was characterized by shortening of the cervical and thoracic parts of the vertebral column due to multiple hemivertebrae, fused and misshaped vertebrae, and scoliosis. Symmetrical flexures of the carpal joints and the metacarpophalangeal joint in combination with a slight lateral rotation of the phalanges also were present. Similar low-grade arthrogryposis was present in the posterior limbs. Fifty percent of the calves had heart malformation. Other malformations occurred in a few calves. Complex vertebral malformation (CVM) is proposed as the designation for this defect. A genetic etiology is indicated because cases occurred following breeding between genetically related individuals. Two common ancestors were found; both were former elite sires of US Holstein origin. Because of the widespread international use of semen from sires occurring in the pedigrees of affected calves, CVM is expected to occur in several countries.

Development of intervertebral disk calcification in the dachshund: a prospective longitudinal radiographic study.

Plain spinal radiography was performed in 40 dachshunds at regular intervals from 6 or 12 months of age to 2 years of age. A follow-up study at 3 to 4 years of age included 12 dogs. High incidence rates of intervertebral disk calcification were seen at 6 to 18 months of age. The number of dogs affected and number of calcified disks seemed to reach a steady level or a maximum at about 24 to 27 months of age. Dissolution of previously calcified disks without clinical signs was demonstrated, causing decreasing numbers of visibly calcified disks after 2 years of age. Radiographic examination for calcified intervertebral disks in the dachshund is recommended at 24 to 30 months of age for heritability studies and selective breeding.

Abnormal growth plate function in pigs carrying a dominant mutation in type X collagen.

We have identified a naturally occurring, dominant mutation that causes dwarfism in domestic pigs (Sus scrofa). With a positional candidate gene approach, the dwarf phenotype was shown to be a result of a single amino acid change, G590R, in the alpha1 (X) chain of type X collagen. Type X collagen is a homotrimer of alpha1(X) chains encoded by the COL10A1 gene, which is expressed in hypertrophic chondrocytes during the process of endochondral ossification. An amino acid substitution at the equivalent position in human type X collagen, G595E, has previously been shown to cause Schmid metaphyseal chondrodysplasia (SMCD), which is a relatively mild skeletal disorder associated with dwarfism and growth plate abnormality. Consistent with the clinical phenotype of SMCD patients, radiological and histological examination of the dwarf pigs revealed metaphyseal chondrodysplasia in the long bones. Yeast-based, two-hybrid protein interaction studies and in vitro assembly experiments demonstrated that the amino acid substitution interfered with the ability of the mutated collagen molecules to engage in trimerization. This work establishes that the chondrodysplastic dwarf pigs by genetic, biochemical, radiological and histological criteria provide a valid animal model of SMCD.

Evaluation of radiology as a tool to diagnose pulmonic lesions in calves, for example prior to experimental infection studies.

The aim of the study was to evaluate radiology as a technique to visualize pulmonary lesions in young calves, e.g. as a selection criterion for research animals in order to eliminate animals with lung lesions prior to experimental studies of pneumonia. Five calves with acute clinical signs of pneumonia were included in a direct comparative study of radiological and post mortem findings. Also, a number of animals with no signs of pneumonia were included as controls. The study revealed good agreement between the radiological and post mortem findings. Thus, in conclusion, radiology should be considered as a useful objective tool to predict the presence of pulmonary lesions in young calves.

Recent information about hip dysplasia.

Dogs suffering from HD have a genetic background, but the releasing factors are many. Two of the most important are overnutrition and overexercising, especially in the young puppy. Radiography can give an estimate of the degree of secondary OA, and by evaluating the laxity in the hip joints at an early age, it seems to be possible to predict the chances for later development of OA. The eradication program has to be instituted in such a way that only the best dogs are accepted into breeding programs. It seems to be more efficient to eradicate the genetic part of the etiology by creating a breeding index by means of evaluating the offspring of the male dogs.

Immunocytochemical demonstration of pituitary adenylate cyclase activating polypeptide (PACAP) in the porcine epiphyseal cartilage canals.

Pituitary adenylate cyclase activating polypeptide (PACAP), a member of the vasoactive intestinal polypeptide (VIP)/secretin/glucagon family, is known to be a powerful stimulator of adenylate cyclase. Recently, PACAP has been shown to stimulate cAMP in osteoblast-like cells and mouse calvarian bones. In the present study, PACAP immunoreactivity (IR) was demonstrated in cartilage canals from newborn and 3-4-week-old pigs. In tissues from the femoral head and the patella with and without ossification centres, PACAP-IR nerve fibres were found in the cartilage canals innervating blood vessels. The pattern of distribution was not dependent on age or the occurrence of an ossification centre. Co-localization studies showed a high degree of co-localization with calcitonin gene-related peptide (CGRP) and substance P (SP) but little co-localization with VIP. Our findings support earlier findings of CGRP, SP and VIP in bone tissue and add PACAP to the group of neuropeptides with a sensory and/or modulatory function in bone tissue.

Idiopathic dental root replacement resorption in old dogs.

The roots of the teeth of 33 large dogs aged 10 years or older were radiographed. These dogs were euthanized for reasons other than oral diseases; dogs with obvious dental or periodontal diseases were excluded. The dogs had shown no clinical signs related to the teeth and the teeth were macroscopically normal. Of the 33 dogs, six had one or more teeth that had abnormally shaped and partially resorbed roots, with replacement of root structure by radiographically normal trabecular bone. Histological examination of radiographically abnormal roots revealed mid-root resorption, without signs of inflammation or hypercementosis. These findings are similar to the condition known as idiopathic dental root replacement resorption in the human dental literature. Possible etiologies of root resorption are discussed.

The sequelae of fragmented anconeal process (FAP) lesion in pigs: a radiologic, macroscopic and histopathological investigation.

The development of the anconeal process its lesions and their sequelae were scrutinized during the follow-up radiographic study (every 5 months) of porcine osteochondrosis of elbow joint bones done in 80 Danish Landrace pigs from day 42 of age to 38 months of age. The anconeal process was observed radiologically to be ossified at the age of between 6 to 7 months. Normally it ossifies by pyramidal extension from the proximal ulna. However, fragmented/ separated anconeal process lesion was demonstrated in 15 pigs (the process was "ununited' with the rest of the proximal ulna). The diagnosis was confirmed in nine pigs at gross post-mortem and microscopically when the pigs were slaughtered due to other reasons than lameness of the front leg. These cases were interpreted as "fragmented/separated anconeal process' (FAP/SAP). This lesion showed a tendency to heal with increasing age. The lesions were healed in all surviving pigs at the age of 25-26 months.

Pathological and radiological investigations on osteochondrosis in pigs, associated with leg weakness.

Two-hundred and seventy-eight Danish Landrace boars were examined radiologically and pathologically for osteochondrosis and other joint lesions on the left legs at slaughter (95 kg). The joint changes were scored on a scale from 1 (normal) to 5 (very severe changes/osteochondritis dissecans). The correlations between radiological and pathological scores were highly significant in the humeral condyles (r = 0.66, P < 0.001), the distal ulna growth plate (r = 0.51, P < 0.001), the femoral condyles (r = 0.33, P < 0.001) and hock (distal tibia (r = 0.17, P < 0.01) and the medial trochlear ridge of the talus (r = 0.17, P < 0.01), indicating that radiographical examination is a useful method for diagnosing osteochondrosis in live pigs. Thickening of cartilage was strongly associated with subchondrial lesions in the three predilection sites: the humeral condyle, the femoral condyles and the distal ulna growth plate. Osteochondritis dissecans (OCD) in the humeral condyles was significantly associated with subchondral lesions (OR = 1.86; P < 0.001), but not with cartilage thickness when analysed simultaneously. There were no associations between lesions in the distal ulna growth plate, the humeral condyles, the femoral condyles or the anconeal process. There was no significant correlation between OCD in the humeral condyles and the anconeal process. Osteochondrosis could therefore not be stated to be a generalized disorder. Regression coefficients between joint changes and leg weakness symptoms judged before slaughter were very small and showed no clear trends. OCD in the humeral condyles was, however, significantly associated with 'legs turned out on fore (OR = 2.48; P < 0.001) and hind (OR = 1.62; P < 0.05) legs', and OCD in the anconeal process with 'stiff movement in front' (OR = 2.01; P < 0.05). Osteochondrosis is thus comparable with a threshold trait, where the threshold is the development of an OCD in an osteochondrosis injured joint.

Multiple dental developmental abnormalities following canine distemper infection.

Multiple dental developmental abnormalities (e.g., dental impaction, partial eruption, oligodontia, enamel hypoplasia, and dentin hypoplasia) in a 10-month-old, female, Tanzanian tropical mixed-breed puppy are reported. Various permanent teeth were involved. These included impacted mandibular canine and first and third premolar teeth; a partially erupted maxillary canine tooth; oligodontia of a mandibular fourth premolar tooth; enamel hypoplasia of the maxillary and mandibular canine teeth, incisors, and premolars; and dentin hypoplasia of the maxillary incisors, maxillary premolars, and mandibular premolars. The puppy had clinical canine distemper at the age of two months and had no history of any other systemic nor generalized infection prior to the time when the dental abnormalities were observed.

Radiological aspects on the course of development of porcine epiphyseal osteochondrosis (OCD) from 42 up to 147 days of age.

The articular-epiphyseal (A-E) cartilage complex of the distal humeral and femoral epiphyseal condyles of eight intact pigs (4 male & 4 female) of the same age were radiologically examined every 3 weeks, beginning at 42 days up to 147 days of age; to determine the age of onset, the course and trend of development of osteochondrosis (OCD). The earliest Dyschondroplasia (Osteochondrotic) lesions were demonstrated radiologically in the A-E complexes of the humeral condyles of 42-day-old pigs and in the femoral condyles at 63 days of age. Thus the radiographic examination of live animals to demonstrate subchondral radiolucency typical for OCD lesions in the condylar A-E complexes of pigs is not of limited value until the animals were > 100 days old as indicated in earlier reports. Also the course of further development of OCD lesions associated with A-E complexes was followed. The radiolucency was seen to develop to a certain extent, and then either to regress, and stabilize or even to progress as the animal grows. Some lesions regressed completely. Also some of the regressed lesions may become active again and become progressive. However, the course of development of femoral condyle A-E complexes OCD lesions was seen to be progressive continuously, or progressive then stable and then progressive again. The regressive course and trend of osteochondrotic lesions was not observed in the femoral condyle A-E complexes up to day 147 of age. Therefore, the course and trend of development of the A-E complexes OCD is not constantly the same.

The sequelae of distal ulna physeal dyschondroplasia (osteochondrosis) lesions in breeding swine--a radiological investigation in Danish Landrace pigs.

A radiological follow-up study of osteochondrotic lesions in the distal ulna was carried out in 58 Danish Landrace breeding sows for a period of 15 months (October 1992 to December 1993). This was part of a major project involving the radiological investigation of articular-epiphyseal and physeal development to investigate osteochondrotic lesions in pigs. The radiological lesions were graded from 1 to 5 with increasing severity. It was observed that not all pigs passed through all grades. Only 21% of the pigs had no radiological osteochondrotic lesions (grade 1) during the first radiography series. After 5-7 months, the number of pigs without osteochondrotic radiological lesions were observed to have increased dramatically (21-69%), but the converse was true for grades 2 (mild), 3 (moderate), 4 (severe) and 5 (very severe): (33-17%), (21-9%), (19-5%) and (7-0%) respectively. This was observed with increasing age and weight. The 3rd radiography series indicated that the percentage of pigs without osteochondrotic lesions increased up to 82%, and that grades 2, 3, and 4 had fallen to 14%, 2% and 2% respectively, while grade five remained at 0%. This indicated that the distal ulna osteochondrotic lesions can be important in breeding pigs during the period of growth before first pregnancy. During the first pregnancy the osteochondral ossification fault can be corrected, and the lesions heal. The ulna growth plates were not closed at the second, but mostly closing during the third radiography series.

Osteogenesis imperfecta in Holstein-Friesian calves.

Eight calves with osteogenesis imperfecta were born in a Danish Holstein-Friesian herd during a two-year period. In total 92 calves were born (84 normal), and all were sired by a clinically normal Holstein-Friesian bull. The defect was probably due to a de novo dominant mutation present as a gonadal mosaicism in the bull. Affected calves were characterised by multiple fractures, congenital bone deformations, general joint laxity, dentinogenesis imperfecta, and light blue sclerae. The skin seemed normal. Electron microscopical studies revealed slightly decreased average diameter of cutaneous collagen fibrils, while the diameter of collagen fibrils in tendons and ligaments was severely reduced. Abnormalities of collagen type I from skin and compact bone were not detected by biochemical analyses.

Distribution of feline blood types detected in the Copenhagen area of Denmark.

The purpose of the present study was to make the first survey of the distribution of feline AB blood types in the Copenhagen area of Denmark. A total of 244 cats (139 purebred cats and 105 Domestic Shorthair cats) were tested. 93% of all tested cats had blood type A. Neither an AB nor an O type cat was detected and thus, the frequency of blood type B among all tested cats was 7%. Most type B cats were purebred cats (Birman, British Shorthair and Persian cats). No association between sex and blood type could be demonstrated among British Shorthair and Persian cats. Thus, the present study indicates that cats in Denmark predominantly have blood type A, and that blood type B cats are rare, except for certain breeds such as Birman and British Shorthair cats.

Radiographic study of postnatal development of the tarsus in west African dwarf goats.

Seven goats of the West African dwarf breeds, three females and four males, from the same farm were studied by serial radiography from the first week of life and at 3, 6, 9, 16, 23, 28, 37 and 46 weeks of age. The radiological appearance of the developing tarsus as evaluated from radiographs is described. During the first week postnatally, eight loci were observed to be partially ossified. The talus, tarsi centrale (Tc), first (T1), second (T2), third (T3) and fourth (T4) tarsal bones had each a single loci. The calcaneus bone had two loci, one for the tuber calcanei and another for the calcaneus himself. Fusion of the locus for T2 and T3 was evident in radiographs taken at three weeks. The fused T2 + T3 also appeared fused with the Tc in one of the goats at 23 weeks. The Tc and T4 were observed to fuse in only three of the goats at 23 weeks while in others the bones remained separate throughout the study period. In those goats where the Tc and T4 tarsal bones were not fused, the three tarsal joints were linked by a radiolucent line between these bones. While in the goat where Tc and T2 + T3 bone fusion has occurred the distal intertarsal joint was blocked and the proximal intertarsal was communicating with the tarsometatarsal joint between the separate Tc and T4. The tarsus of the goat is variable and differs from that of sheep and cattle.