Sequencing of candidate genes for obesity in Labrador retriever dogs identified a 14 bp deletion in pro-opiomelanocortin (POMC) with an allele frequency of 12%. The deletion disrupts the β-MSH and β-endorphin coding sequences and is associated with body weight (per allele effect of 0.33 SD), adiposity, and greater food motivation. Among other dog breeds, the deletion was only found in the closely related flat-coat retriever (FCR), where it is similarly associated with body weight and food motivation. The mutation is significantly more common in Labrador retrievers selected to become assistance dogs than pets. In conclusion, the deletion in POMC is a significant modifier of weight and appetite in Labrador retrievers and FCRs and may influence other behavioral traits.
The purpose of the study was to establish normal electroretinogram (ERG) parameters in 56 normal eyes of four common dog breeds in Thailand: Poodle, Labrador Retriever, Thai Ridgeback and Thai Bangkaew. Standard ERGs were bilaterally recorded using a handheld multi-species ERG unit with the ERG-jet lens electrode in 28 dogs under preanesthesia with diazepam, induction with propofol and anesthesia maintenance with isoflurane. There were significant differences in the means of ERG amplitudes and implicit times among the four dog breeds (P<0.05) except for the b-wave implicit time of the photopic 30 Hz flicker response with 3 cd.s/m(2) (P=0.610). Among all breeds, Thai Bangkaew had the longest implicit time (p<0.001) of scotopic low intensity responses, b-wave of scotopic standard intensity responses (3 cd.s/m(2)), a-wave of the higher intensity response (10 cd.s/m(2)) and a-wave of the photopic single flash response (3 cd.s/m(2)). For b/a ratio, only the ratio of the Cone response had a significant difference among dog breeds. This study reported normal ERG parameters in four dog breeds and supported that the breed-specific limits of normality to ERG response are necessary in each clinic and laboratory.
Genomic methods have proved to be important tools in the analysis of genetic diversity across the range of species and can be used to reveal processes underlying both short- and long-term evolutionary change. This study applied genomic methods to investigate population structure and inbreeding in a common UK dog breed, the Labrador Retriever.
Variation in the Quantity of Elastic Fibres with Degeneration in Canine Cranial Cruciate Ligaments from Labrador Retrievers
- Veterinary and comparative orthopaedics and traumatology : V.C.O.T
- Published about 2 years ago
Objectives This study aims to quantify numbers of elastic fibres in cranial cruciate ligaments from a dog breed at high risk of cranial cruciate ligament disease. Methods Macroscopically normal cranial cruciate ligaments were harvested from six Labrador retrievers. Sequential histological sections were assessed for extracellular matrix degeneration (haematoxylin and eosin stain) and elastic fibre staining (Miller’s stain). Elastic fibres were semi-quantified using previously published scoring systems. Each section was scored twice by two observers. Results Increased numbers of elastic fibres were seen with increasing cranial cruciate ligament degeneration (p = 0.001). Labrador retriever cranial cruciate ligaments had lower elastic fibre staining when compared with previous published findings in the racing greyhound. Clinical Significance The cranial cruciate ligaments from a dog breed at high risk of cranial cruciate ligament disease vary in the quantity of elastic fibres in association with ligament degeneration. Breed variation in the quantity of elastic fibres may reflect differing risk of cranial cruciate ligament disease.
Selection during the last decades has split some established dog breeds into morphologically and behaviourally divergent types. These breed splits are interesting models for behaviour genetics, since selection has often been for few and well-defined behavioural traits. The aim of this study was to explore behavioural differences between selection lines in golden and Labrador retriever, in both of which a split between a common type (pet and conformation) and a field type (hunting) has occurred. We hypothesised that the behavioural profiles of the types would be similar in both breeds. Pedigree data and results from a standardised behavioural test from 902 goldens (698 common and 204 field) and 1672 Labradors (1023 and 649) were analysed. Principal component analysis revealed six behavioural components: curiosity, play interest, chase proneness, social curiosity, social greeting and threat display. Breed and type affected all components, but interestingly there was an interaction between breed and type for most components. For example, in Labradors the common type had higher curiosity than the field type (F(1,1668) = 18.359; P < 0.001), while the opposite was found in goldens (F(1,897) = 65.201; P < 0.001). Heritability estimates showed considerable genetic contributions to the behavioural variations in both breeds, but different heritabilities between the types within breeds was also found, suggesting different selection pressures. In conclusion, in spite of similar genetic origin and similar recent selection criteria, types behave differently in the breeds. This suggests that the genetic architecture related to behaviour differs between the breeds.
The present study aimed at evaluating possible behavioural differences between guide dogs living in a kennel and interacting with a trainer and those living in a house and interacting with a blind person and their family, when they are faced with an unsolvable task. Fifty-two Labrador retrievers were tested: 13 Trained Guide dogs at the end of their training programme and 11 Working Guide dogs that had been living with their blind owner for at least 1 year. Two control groups of Labrador retrievers were also tested: 14 Young Untrained dogs of the same age as the Trained Guide and 14 Old Untrained dogs of the same age as the Working Guide dogs. Results showed that the Trained Guide dogs gazed towards the owner or the stranger for less time and with a higher latency and spent more time interacting with the experimental apparatus than the other three groups, which all behaved similarly. None of the groups tested showed preferences in gazing towards the stranger or the owner. Together, the results suggest that at the end of their training programme, guide dogs are less prone to engage in human-directed gazing behaviour and more likely to act independently when facing an unsolvable task. Conversely, guide dogs that have been living with a blind person (and their family) for 1 year behave like pet dogs. These findings indicate that guide dogs' gazing towards humans is favoured by living in close proximity with people and by interacting with them.
- Journal of the American Animal Hospital Association
- Published about 6 years ago
An 8 yr old castrated male Labrador retriever mixed-breed dog with osteosarcoma (OSA) of the left proximal humerus receiving carboplatin presented 10 days after the third chemotherapy treatment with hematuria, stranguria, and pollakiuria. A presumptive diagnosis of hemorrhagic cystitis was made based on clinical signs, urinalysis, and cytologic analysis of a traumatic catheterization sample. Carboplatin was removed from the chemotherapy treatment plan and was substituted with doxorubicin. The dog was treated with meloxicam for pain, and the cystitis signs subsided over a period of 4 wk. Carboplatin is commonly used as adjuvant chemotherapy for dogs with OSA following amputation and is not known to cause hematuria in dogs, although there are reports of this occurring in humans. To the authors' knowledge, there are no reports in the veterinary literature of this toxicity.