Canine perinatal mortality: a cohort study of 224 breeds.

Canine perinatal mortality is known to be relatively high. However, the literature on perinatal mortality in dogs is still sparse and often refers to a single or only a few breeds. The aim of this large-scale observational study was to describe the perinatal mortality in purebred dogs of various breeds at both puppy and litter level. In addition, the influence of breed, breed size, litter size, age of the bitch, litter number and season for whelping on the risk of perinatal mortality at litter level was studied and the mean litter size at eight days and eight wks after birth was calculated. A retrospective cohort study was performed by studying 10,810 litters of 224 breeds registered in the Norwegian Kennel Club in 2006 and 2007. Perinatal mortality was defined as the sum of stillborn puppies and puppies that died during the first wk after birth (early neonatal mortality) and was present in 24.6% of the litters. Eight percent of the puppies died before eight days after birth, with 4.3% as stillbirth and 3.7% as early neonatal mortality. For most breeds the perinatal mortality was low, but for some breeds a higher perinatal mortality was found. The mean litter size at eight days and eight wks after birth was 4.97 (±0.02) and 4.92 (±0.02) puppies, respectively. Of all puppies born, only 1% died during the period from eight days to eight wks after birth. Random effects logistic regression analysis indicated that increasing litter size and age of the bitch were associated with an increased risk of stillbirth, early neonatal mortality and total perinatal mortality at the litter level (P < 0.001). The random breed effect was significant for all outcomes. Litter number also had a significant effect on stillbirth, early neonatal mortality and total perinatal mortality at the litter level, with the highest risk of perinatal mortality found in the first litter (P < 0.001). Further, the risk of early neonatal mortality was doubled in litters with stillborn puppies. No significant effect of whelping season on perinatal mortality at litter level was found. An interaction existed between the age of the bitch and litter number and the risk of stillbirth was three times as high (odds ratio = 3.00) in litters from bitches having their first litter after the age of six y. Breed was a more important determinant of perinatal mortality in litters than breed size. However, more than 90% of the variation in perinatal mortality was found at the individual litter level and efforts to minimize puppy mortality should be targeted at the management of the individual litter rather than at the breed level.

Breed differences in the proportional morbidity of testicular tumours and distribution of histopathologic types in a population-based canine cancer registry.

Histologically verified tumours submitted to the Norwegian Canine Cancer Register from 1990 to 1998 were studied (n=14,401). The proportion of testicular tumours (n=345) was 2.4%, and the breakdown of histological tumour diagnoses is presented. The frequency of the most common histopathological types was 33% interstitial (Leydig), 26.4% Sertoli and 33.9% seminomas/germ cell tumours. The average age at diagnosis was 10 years, but was significantly lower for Sertoli cell tumours (8.6 years) than for the other tumour types. Following a histopathological re-evaluation, 22.5% of the original tumor diagnoses were modified. Proportional morbidity ratios were calculated and individuals from the breeds Shetland sheepdog and Collie were five times more likely to have testicular tumours than the overall average for the registry. Breed differences in the distribution of histopathologic types were observed. Shetland sheepdog and Collie were most commonly diagnosed with Sertoli cell tumours, while all tumours from Norwegian elkhound in this material were seminomas.

Glucosuria in Norwegian elkhounds and other breeds during dog shows.

Clinically healthy Norwegian elkhounds were tested for glucosuria by urine dipstick analysis and the results were compared with a group of dogs of other breeds during 15 dog shows. Fifty-two of 187 Norwegian elkhounds (27.3 per cent) and 15 of 202 dogs of other breeds (7.4 per cent) were glucosuric during the dog shows; the difference was statistically significant. Two of the glucosuric elkhounds and one non-glucosuric elkhound developed signs of kidney disease during the year of the study.

A study of inherited short tail and taillessness in Pembroke Welsh corgi.

OBJECTIVES: To study whether natural short tail in adult Pembroke Welsh corgi is associated with congenital spinal defects. To report anatomical defects in two newborn tailless puppies from short-tailed parents, and to check whether they were homozygous for the dominant mutation in the T-gene (C295G). METHODS: The vertebral column of 19 adult dogs with natural short tail, from short-tail x long-tail crossings, was radiographically examined. Two tailless puppies were radiographed and submitted for necropsy. Samples from the puppies, their parents and five siblings were analysed for the mutation of the T-gene. RESULTS: No congenital spinal defects were diagnosed in any of the short-tailed dogs. The tailless puppies had anorectal atresia, had multiple spinal defects and were homozygous for the mutation in the T-gene. CLINICAL SIGNIFICANCE: As tail docking is forbidden in many countries, breeding Pembroke Welsh corgis with natural short tail is becoming increasingly common. Previous studies indicated that the mutation in homozygotes is lethal in early fetal life. It is of clinical significance that natural short tail is probably not associated with congenital spinal defects, as is known from studies of other species, and that homozygotes for this mutation with serious anatomical defects may be born.

Risk factors affecting metaphyseal irregularities in the radius and ulna of growing Newfoundland dogs.

The main objective of this study was to study risk factors affecting metaphyseal irregularities (MI) in the distal radius and ulna of growing Newfoundland dogs. Risk factors studied included the genetic effects, effects of litters, BW, circumferences of the distal radius and ulna (CDRU), and total serum alkaline phosphatase (ALP) concentrations. The study included 118 Newfoundland dogs (60 females, 58 males), derived from 32 litters. Body weight, separated on sex and MI, was fitted to the Gompertz function. Occurrence of MI differed significantly between sexes, with 55% of males and 35% of females affected (P = 0.03). Growth curves for the 2 groups of dogs, with and without MI, diverged after 60 to 70 d, and dogs with irregularities were heavier at maturity than dogs of the same sex without irregularities. In univariate analysis, the litter effect was a significant predictor of MI, explaining 32% of total variability of the MI incidence, but the genetic effects were not significant. However, the latter were significant in bivariate analysis of MI and BW. In the bivariate analysis, the effects of litter on MI and BW were significantly correlated at all observational points except at birth, 180 d, and 536 d. Total ALP concentrations decreased with increasing age, and differences between groups diminished with increasing age, indicating a negative effect of total ALP on MI. Correlation between MI and total ALP concentrations of litters was estimated in a bivariate analysis. This correlation was significant and ranged between -0.34 and -0.62. Similarly, the genetic relationship between total ALP and MI from 120 d of age onward varied between -0.31 to -0.60. However, correlations were only significant at 356 d of age (genetic correlation = 0.60; P = 0.01). The mean CDRU increased from 90 d of age toward a peak at 180 d. Thereafter, CDRU declined and stabilized at about 1 yr of age. The mean CDRU between the groups of dogs with and without MI diverged most at 90 d of age, then was nearly stable until 180 d and gradually declined until 356 d, when the CDRU began to equalize. Metaphyseal irregularities and CDRU levels of litter were significantly correlated. Litter effect was a significant predictor of MI. The effects of litters and the genetic effects on BW and MI were correlated at most phases of the growth of the dog. Similar, but lower, correlations were found for CDRU and MI, and total ALP and MI.

A longitudinal study on growth and growth variables in dogs of four large breeds raised in domestic environments.

The main objective of this study was to describe the growth patterns of 4 large dog breeds [Newfoundland (NF), Labrador retriever (LR), Leonberger (LEO), and Irish wolfhound (IW)] raised in domestic environments and concomitant changes in 2 growth-related clinical variables: total serum alkaline phosphatase (ALP) and the circumference of the distal radius and ulna (CDRU). The second objective was to investigate whether these measurements were affected by a range of independent variables like age, sex, litter number, and birth weight. Seven hundred dogs were included in the study, and BW data, separated by breed and sex, were fitted to the Gompertz function. Birth weight, adjusted for litter number, differed significantly between sexes for 3 breeds (LEO, P = 0.004; NF, P = 0.02; LR, P = 0.009) and approached significance for IW (P = 0.07). Estimated mean BW increased rapidly during the first 100 d after birth in all 4 breeds, then plateaued, with maturity being reached between 351 (female LR) and 413 d (male NF). Estimated mature BW ranged from 30.8 kg for the female LR up to 65.7 kg for the male IW. Weight gain, as expressed by the derivative of the Gompertz function, reached its peak in the smallest breed (LR) at the youngest age, 89 d for the females and 95 d for males. Log-transformed BW was significantly related to age, breed, and sex, and the age x sex and age x breed interactions. Within breeds, age, birth weight, and litter number had a significant effect on log-transformed BW. The estimated average CDRU increased from 90 d of age toward a peak at 180 d. Thereafter, CDRU declined and stabilized at about 1 yr of age. The estimated total ALP concentrations decreased from 90 to 360 d of age, after which they stabilized, at mean concentrations varying among breeds from 98 to 131 IU/L. Maximum least squares mean total ALP concentrations were found at 3 mo of age in all breeds, with the greatest least squares mean concentration in the IW breed (713 IU/L). In a mixed model analysis of the complete data set, total ALP was affected (P < 0.001) by age, breed, and the interaction of age x breed. This study described the main factors influencing growth and provided reference data for other studies, including those related to nutrition and disorders of growth.

Prevalence of murmurs consistent with aortic stenosis among boxer dogs in Norway and Sweden.

The prevalence and severity of cardiac murmurs consistent with subclinical or clinically detectable aortic stenosis among purebred boxer dogs in Norway and Sweden were evaluated. Two hundred and thirty-one boxers, randomly selected or investigated at dog shows, were examined by phonocardiography by two veterinarians and classified on the basis of the characteristics of their murmurs into categories 0 to 4. No murmur was detected in 23 per cent of the dogs, murmurs classified as category 1 were diagnosed in 25 per cent of the dogs, as category 2 in 46 per cent, as category 3 in 7 per cent cent, and two dogs had category 4 murmurs. In 55 per cent of the dogs, primarily those with very soft murmurs, there was some variation in the intensity of the murmur from beat to beat. The prevalence of cardiac murmurs among Norwegian and Swedish boxers was high and similar to the prevalence reported in Great Britain.