Body weight at 10 years of age and change in body composition between 8 and 10 years of age were related to survival in a longitudinal study of 39 Labrador retriever dogs.

BACKGROUND: Overweight and obesity have been adversely associated with longevity in dogs but there is scarce knowledge on the relation between body composition and lifespan. We aimed to investigate the effects of body composition, and within-dog changes over time, on survival in adult Labradors using a prospective cohort study design. The dogs had a median age of 6.5 years at study start and were kept in similar housing and management conditions throughout. The effects of the various predictors, including the effect of individual monthly-recorded change in body weight as a time varying covariate, were evaluated using survival analysis. RESULTS: All dogs were followed to end-of-life; median age at end-of-life was 14.0 years. Body composition was measured annually with dual-energy x-ray absorptiometer (DEXA) scans between 6.2 and 17.0  years. All 39 dogs had DEXA recorded at 8, 9 and 10 years of age. During the study the mean (± SD) percent of fat (PF) and lean mass (PL) was 32.8 (± 5.6) and 64.2 (± 5.5) %, respectively, with a mean lean:fat ratio (LFR) of 2.1 (± 0.6); body weight (BW) varied from 17.5 to 44.0 kg with a mean BW change of 9.9 kg (± 3.0). There was increased hazard of dying for every kg increase in BW at 10 years of age; for each additional kg of BW at 10 years, dogs had a 19% higher hazard (HR = 1.19, P = 0.004). For the change in both lean mass (LM) and LFR variables, it was protective to have a higher lean and/or lower fat mass (FM) at 10 years of age compared to 8 years of age, although the HR for change in LM was very close to 1.0. For age at study start, older dogs had an increased hazard. There was no observed effect for the potential confounders sex, coat colour and height at shoulders, or of the time-varying covariate. CONCLUSIONS: These results suggest that even rather late-life control efforts on body weight and the relationship between lean and fat mass may influence survival in dogs. Such "windows of opportunity" can be used to develop healthcare strategies that would help promote an increased healthspan in dogs.

Exceptional longevity and potential determinants of successful ageing in a cohort of 39 Labrador retrievers: results of a prospective longitudinal study.

BACKGROUND: The aim of this study was to describe the longevity and causes of mortality in 39 (12 males, 27 females) pedigree adult neutered Labrador retrievers with a median age of 6.5 years at the start of the study and kept under similar housing and management conditions. Body condition score was maintained between two and four on a 5-point scale by varying food allowances quarterly. The impact of change in body weight (BW) and body composition on longevity was analysed using linear mixed models with random slopes and intercepts. RESULTS: On 31 July 2014, 10 years after study start, dogs were classified into three lifespan groups: 13 (33 %) Expected (≥9 to ≤12.9 years), 15 (39 %) Long (≥13 to ≤15.5 years) and 11 (28 %) Exceptional (≥15.6 years) with five still alive. Gender and age at neutering were not associated with longevity (P ≥ 0.06). BW increased similarly for all lifespan groups up to age 9, thereafter, from 9 to 13 years, Exceptional dogs gained and Long-lifespan dogs lost weight (P = 0.007). Dual-energy x-ray absorptiometer scans revealed that absolute fat mass increase was slower to age 13 for Long compared with Expected lifespan dogs (P = 0.003) whilst all groups lost a similar amount of absolute lean mass (P > 0.05). Percent fat increase and percent lean loss were slower, whilst the change in fat:lean was smaller, in both the Exceptional and Long lifespan compared with Expected dogs to age 13 (P ≤ 0.02). Total bone mineral density was significantly lower for Expected compared to Exceptional and Long lifespan dogs (P < 0.04). CONCLUSIONS: This study shows that life-long maintenance of lean body mass and attenuated accumulation of body fat were key factors in achieving a longer lifespan. The results suggest that a combination of a high quality plane of nutrition with appropriate husbandry and healthcare are important in obtaining a greater than expected proportion of Labrador retrievers living well beyond that of the expected breed lifespan: 89.7 % (95 % CI 74.8-96.7 %) dogs were alive at 12 years of age and 28.2 % (95 % CI 15.6-45.1 %) reaching an exceptional lifespan of ≥15.6 years.

Computed tomographic documentation of the natural progression of humeral intracondylar fissure in a cocker spaniel.

OBJECTIVE: To report the computed tomographic (CT) documentation of humeral intracondylar fissure (HIF) developing after complete ossification of the humeral condyle (HC). STUDY DESIGN: Clinical report. ANIMALS: Male 3 year old working (English) Cocker Spaniel. METHODS: Sequential CT screening (659-day interval between analyses). RESULTS: A sagittal hypodense fissure typical of incomplete ossification of the humeral condyle (IOHC) was identified ≈ 22 months after screening CT examination documented a normal elbow joint. CONCLUSION: Even in dogs with clinical features typical of the condition most commonly termed IOHC, fissure formation and propagation can occur after ossification is complete.

Maxillomandibular circular external skeletal fixation for repair of bilateral fractures of the caudal aspect of the mandible in a dog.

OBJECTIVE: To describe the novel use of circular external skeletal fixation (CESF) for repair of bilateral fractures of the caudal aspect of the mandibles. STUDY DESIGN: Clinical report. ANIMALS: A 5-month-old female Newfoundland. METHODS: A 2-ring CESF was used to immobilize the mandible relative to the maxillae. RESULTS: Anatomic dental occlusion and reduction of the right hemimandible were achieved with mild malalignment of the left hemimandible. Fracture healing occurred within 20 days. Transient epistaxis and reduced temporomandibular joint range of motion occurred at the time of fixator removal but normal use of the mandible was reported 6 months postoperatively. CONCLUSIONS: CESF effectively immobilized the mandible permitting rapid fracture healing with minimal morbidity. CLINICAL RELEVANCE: Maxillomandibular CESF may represent a simple, effective option for the management of challenging fractures involving the caudal aspect of the mandible.

The effect of weight loss on lameness in obese dogs with osteoarthritis.

This paper describes the effect of weight loss on lameness in obese dogs with osteoarthritis (OA). Fourteen obese client-owned dogs with clinical and radiographic signs of OA participated in an open prospective clinical trial. After a screening visit and a visit for collection of baseline data, the dogs were fed a restricted-calorie diet over a study period of 16 weeks that incorporated six follow-up visits. At each visit, body weight and pelvic circumference were measured and severity of lameness was assessed using a numeric rating scale (NRS), a visual analogue scale (VAS) and kinetic gait analysis. This is the first study to assess both subjectively and objectively, the effect of weight loss alone on lameness in obese dogs with OA. The results indicate that body weight reduction causes a significant decrease in lameness from a weight loss of 6.10% onwards. Kinetic gait analysis supported the results from a body weight reduction of 8.85% onwards. These results confirm that weight loss should be presented as an important treatment modality to owners of obese dogs with OA and that noticeable improvement may be seen after modest weight loss in the region of 6.10 - 8.85% body weight.

Ex vivo evaluation of the effect of tibial plateau osteotomy on the proximal tibial soft tissue envelope with and without the use of protective gauze sponges.

OBJECTIVE: To investigate the effect of tibial plateau leveling osteotomy (TPLO) on the proximal tibial soft tissue envelope with and without use of protective gauze sponges, and to determine whether the action of an oscillating saw blade on the gauze sponges would result in retention of particulate cotton debris. STUDY DESIGN: Cadaveric study. ANIMALS: Medium to large breed dog cadavers (n=10; 20 pelvic limbs). METHODS: TPLO was performed using the currently recommended technique involving dissection of the proximal tibial soft tissue envelope and its protection using cotton gauze sponges. In paired limbs, the procedure was repeated but no attempt was made to retract and protect the proximal tibial soft tissue envelope. Damage to the soft tissue envelope and presence of gross particulate cotton debris were investigated by direct observation and photographic analysis. Presence of microscopic cotton debris was investigated using light microscopic analysis of wound lavage fluid. RESULTS: No soft-tissue trauma was found in gauze sponge-protected specimens. When protective gauze sponges were not used, full-thickness (sagittal plane) lacerations to the caudoproximal tibial muscle group occurred in all specimens with a mean craniocaudal width of 9.5 mm (range 2-12 mm). The cranial tibial muscle was traumatized in only 1 specimen without protective gauze sponges. Trauma to the popliteal vessels was not identified in any specimen. No gross cotton debris was identified, but microscopic cotton fibers (diameter, 7-35 microm) were identified in lavage fluid from all gauze sponge-protected specimens. CONCLUSIONS: Use of protective gauze sponges is effective in protecting the proximal tibial soft tissue envelope from an oscillating TPLO saw blade, but results in retention of microscopic cotton particulate debris within the operative site. Significant soft tissue trauma is seen only in the caudoproximal tibial muscle group if protective gauze sponges are not used. CLINICAL RELEVANCE: Retraction and protection of the caudoproximal tibial soft tissue envelope is recommended during TPLO; however, to prevent retention of microscopic particulate cotton debris, alternatives to cotton gauze sponges should be considered as protective devices.

In vitro validation of a technique for assessment of canine and feline elbow joint collateral ligament integrity and description of a new method for collateral ligament prosthetic replacement.

OBJECTIVE: To assess the ability of an operator to differentiate intact from transected canine and feline elbow joint collateral ligaments (CL) using a reported manipulative test (Campbell's test) and to determine the potential for elbow joint luxation in canine and feline elbows with intact, transected, and surgically stabilized CL. STUDY DESIGN: In vitro biomechanical study. SAMPLE POPULATION: Canine (n=6) and feline cadavers (n=3). METHODS: Thoracic limb specimens were mounted on a custom-built jig with the elbows and carpi fixed in 90 degrees of flexion. Angles of pronation and supination were recorded after applying rotational forces to the manus. Attempts were made to manually luxate each elbow with intact CL. Constructs were re-evaluated after sequential sectioning of the medial (MCL) and lateral (LCL) collateral ligaments and after insertion of a new CL prosthesis. RESULTS: Mean (+/-SD) angles of rotation in dogs increased from 27.3+/-8 degrees (range, 16.7-41.3 degrees ) in pronation to 58.9+/-9.2 degrees (range, 38-88.3 degrees ) after sectioning the MCL and from 45.5+/-10.8 degrees (range, 30.7-67.3 degrees ) in supination to 68.9+/-17.2 degrees (range, 45-94 degrees ) after sectioning the LCL. Angles of pronation and supination were subject to significant interanimal variability, with a strong correlation between increasing animal weight and smaller angles of rotation. Elbow luxation in dogs was not possible unless at least the LCL was transected. In cats, mean angles of rotation increased from 49.8+/-14.9 degrees (range, 30.7-70 degrees ) in pronation to 99.1+/-17.6 degrees (range, 79-111.7 degrees ) after sectioning the MCL and from 128.7+/-18.8 degrees (range, 108.3-151.7 degrees ) in supination to 166.7+/-13.1 degrees (range, 157.3-181.7 degrees ) after sectioning the LCL. Luxation in cats was not possible unless both CL were cut. Use of the ligament prosthesis without primary CL repair reliably prevented reluxation in all canine and feline elbows. CONCLUSIONS: Campbell's test allowed reliable differentiation of intact, transected and surgically stabilized canine and feline elbow joint CL in a cadaveric model. Luxation could not be performed by application of rotational forces to specimens with intact CL. CLINICAL RELEVANCE: Clinical examination findings, specifically Campbell's test, can be used to determine elbow CL integrity in dogs and cats. The contralateral elbow should be used as a control, because of interanimal variability in angles of rotation.

Contour and volume assessment of repairing mandibular osteoperiosteal continuity defects in sheep using recombinant human osteogenic protein 1.

BACKGROUND: This study describes the contour and volume of reconstructed mandibles using recombinant human osteogenic protein 1. MATERIAL AND METHODS: The investigation was conducted on six adult sheep, where a unilateral 35 mm parasymphyseal osteoperiosteal continuity defect of the mandible was created. Recombinant human osteogenic protein 1 and type-I collagen (as carrier) were applied to the defects. Radiographic and ultrasonographic examinations were carried out at day 1 of the surgery and 2, 4, 8, and 12 weeks following the surgery. The animals were then sacrificed 3 months after the operation. Postmortem CT-scan was performed for volumetric, cross-sectional area, height and width measurements. RESULTS: Ultrasound was more efficient than radiographs in demonstrating early callus formation at 2 weeks, while radiographic evidence of bone formation was consistently detectable only after 4 weeks. Using the combination of recombinant human osteogenic protein type 1 and type-I collagen resulted in twice the volume, cross-sectional surface area, and height when compared with those of the corresponding region of the contra-lateral non-operated side of the mandible. CONCLUSION: Within 3 months, recombinant human osteogenic protein type 1 on type-I collagen carrier failed to restore the original contour and volume of mandibular osteoperiosteal continuity defects.

A minimally invasive novel design for a vascular-pedicled bone segment for experimental studies of reconstruction of mandibular defects.

We describe a new minimally invasive vascularised bone segment (VBS) for experimental reconstruction of the mandible. The study was validated and the feasibility was tested on fresh sheep cadavers. The integrity of the arterial blood supply was confirmed using inferior dental artery static arteriography. A pilot investigation was conducted on two adult sheep. Two full thickness bone cuts 35 mm apart were created in the parasymphyseal region. The inferior dental neurovascular bundle was preserved at the posterior bone cut but not anteriorly. A VBS was created, pedicled only on the inferior dental artery. The continuity of the mandible was maintained using fixation plates and the animals were followed up for 12 weeks. There was complete bony union and restoration of approximately 80% of the bony strength. The model is minimally invasive, reduces the operating time, and does not require special equipment and skills in microvascular anastomosis.

Type I immune-mediated polyarthritis in dogs: 39 cases (1997-2002).

OBJECTIVE: To determine clinical signs, laboratory findings, relationship to vaccination, and response to treatment for type I immune-mediated polyarthritis (IMPA) in dogs. DESIGN: Retrospective study. ANIMALS: 39 dogs PROCEDURE: Clinical records and radiographic reports from 3 university referral hospitals were reviewed. Clinical signs, laboratory and investigative findings, relationship to vaccination, and response to treatment were evaluated. RESULTS: Clinical signs and initial laboratory and clinical investigative findings were frequently abnormal but were nonspecific and not associated with likelihood of recovery. Time of vaccination was not associated with onset of disease. Chemotherapeutic immunosuppression resulted in complete cure in 56% of dogs. Continuous medication was required in 18% (7/39) of dogs, relapses were treated successfully in 13% (5/39) of dogs, and 15% (6/39) of dogs died or were euthanatized as a result of disease. CONCLUSIONS AND CLINICAL RELEVANCE: The possible involvement of vaccination in type I IMPA was not made clear from this study because of the small population size. Signalment, clinical signs, and results of diagnostic tests other than multiple synovial fluid analyses were generally nonspecific. Most dogs with type I IMPA responded to initial immunosuppressive treatment, but 31% (12/39) of dogs relapsed, required further treatment, or both.