Osteoporosis in caged hens is one driving factor for the United States egg industry to explore options regarding alternative housing systems for laying hens. The aim of our research was to study the influence of housing systems on tibiae and humeri of 77-week-old Lohmann White hens. Pullets raised in an aviary system were either continued in aviary hen systems (AV) or conventional cages (AC) whereas pullets reared in conventional cages continued in conventional hen cages (CC) or enriched colony cages (EN) at 19 weeks. From each group, 120 hens were randomly euthanized and right and left tibae and humeri were excised for structural and mechanical analysis. Volumetric density of the cortical bone was measured using quantitative computed tomography (QCT). Aviary (AV) hens had greater cortical thickness and density but similar outer dimensions to AC hens (P < 0.05). Hens in EN system had humeri with similar cortical thickness and density but wider outer dimensions than the humeri of CC hens (P < 0.05). Cortical geometry of the tibiae was the same for the EN and CC hens, whereas EN hens had denser tibial cortex than CC hens (P < 0.05). Geometrical changes in the humeri suggest that hens in the AV system were better able to protect their structure from endosteal resorption during the laying phase. Humeri of AV and EN hens had increased second moment of area compared to the AC and CC hens; however, the changes were not observed in tibiae. Mechanical property differences were observed, with bones of AV hens having greater failure moment and stiffness than AC hens and the same difference was observed between the EN and CC hens, (P < 0.05). These findings indicate that movement limitation causes loss of bone mass and density whereas provision of moderate movement increases certain bone quality parameters during adulthood in laying hens.
We identified an intratesticular pressure at which vascular flow would cease in a testicular compartment syndrome model, defining a critical vascular stop flow pressure.A total of 52 male Sprague Dawley® rats were used for the study. The testicle of each rat was delivered from the scrotum and size measurements were taken. An intracompartment pressure monitor needle was inserted into the testis to record basal intratesticular pressure. The monitor needle remained in the testicle for the duration of the procedure. Vascular flow within the testis was measured using a variable frequency linear ultrasound transducer with color flow and pulse wave Doppler modalities. Saline was infused through the compartment monitor in 5 mm Hg increments via a pressure infusion pump. Following each 5 mm Hg increase intratesticular vascular blood flow and velocities were recorded using color flow and pulse wave, respectively. Data collection proceeded until color flow images indicated a complete absence of flow within the testis.Using a paired t-test (p <0.0001), mean color flow stop flow pressure was 52.17 mm Hg (95% CI 49.57-54.77) and pulse wave stop flow pressure was 36.34 mm Hg (95% CI 33.90-38.77). Regression analysis of pulse wave vs color flow showed a slope of 0.6960 ± 0.09112, a y-intercept of 0.02427 ± 4.824 and an x-intercept of -0.03486.This is the first known study to characterize a stop flow pressure within the testicular parenchyma resulting from an increased intracompartmental pressure. Due to probe sensitivity limitations, color flow appears to provide the most precise mean pressure of occlusion of 52.17 mm Hg.
Susceptibility of caged layers to osteoporosis and cage layer fatigue has generated interest in newer housing systems that favor increased load-bearing activities. However, high incidences of fractures incurred during lay period have been reported in these newer systems. This study is aimed at determining the housing and strain effects on bone properties: dry weight, percentage ash content, cortical density (CBD), cortical thickness (CBT), and keel bone deformities. Tibia, femur, and keel from Hy-Line Brown (HB), Hy-Line Silver Brown (SB), and Barred Plymouth Rock (BR) hens housed in conventional cages (CC), cage-free (CF), and cage-free with range (outdoor access; R) were studied. At 78 wk, 60 hens from each strain and housing system combination were euthanized and bones were excised for analysis. Quantitative computed tomography (QCT) was used to measure CBD and CBT in each bone. Three-dimensional images of keels were generated from software using QCT scans to analyze the deformities. Tibiae CBT was greater (P < 0.01) in BR compared to other two strains. Between housing systems, CBT was greater (P < 0.05) for mid and distal tibia of R and CF compared to CC. Tibiae and femoral cortex were denser (P < 0.05) in BR compared to HB and SB. There was no effect of housing system for femur CBD, but CBD was greater (P < 0.05) for middle and distal tibia of birds housed in R compared to CC. CBD for keel bone was greater (P < 0.05) in CF and R birds compared to CC birds. The housing system did not influence the dry bone weight and ash percentage of tibiae and femur. Each housing system was associated with high prevalence (>90%) of keel deformities and the housing and genotype influenced the type of deformity. These findings indicate that range and cage-free housing may have beneficial impact on tibia and keel bone integrity compared to conventional cages but the improvement may not be sufficient to prevent fractures or deformities of keel.
Abstract OBJECTIVE To determine whether previously described cutoffs for ultrasonographically determined kidney length-to-aorta diameter ratio (KL:Ao) for evaluation of kidney size in adult dogs are applicable to healthy dogs 1 to 18 months of age and to assess interobserver and intraobserver variability for ultrasonographic kidney and aorta measurements in these dogs grouped according to age. ANIMALS 82 dogs. PROCEDURES 41 university-owned dogs and 41 client- or staff-owned dogs of 3 age groups (approx 1, 6, and 12 to 18 months of age) underwent ultrasonographic examination by 3 observers. Kidney length, kidney width, and diameter of the aorta were measured by each observer 3 times, and KL:Ao and kidney length-to-body weight ratio were calculated for each dog. Measurements and calculated ratios for the 3 age groups were compared by statistical methods; interobserver and intraobserver variability were calculated. RESULTS Mean kidney length, kidney width, and aorta diameter were smaller, and calculated KL:Ao and kidney length-to-body weight ratio were larger, for dogs of the 1-month age group than for dogs of the 6-month and 12 to 18–month age groups. There were significant interobserver differences for ultrasonographic measurements in all age groups; these were most frequent in the youngest group of dogs and affected KL:Ao for that group only. CONCLUSIONS AND CLINICAL RELEVANCE Results revealed that 1-month-old dogs have larger kidneys relative to body weight and aorta diameter than do older dogs. Interobserver variability for the youngest group of dogs indicated limited usefulness of these measurements and related ratios for neonatal dogs in clinical practice. The KL:Ao values for dogs ≥ 6 months of age in this study were similar to values previously described for dogs > 12 months of age.
Indications for spinal imaging are numerous. Radiographs screen for occult spinal fractures in patients recently subjected to a traumatic event. Spinal imaging, particularly magnetic resonance imaging, is indicated in patients that are acutely paraplegic or display significant spinal pain. Despite the development of advanced cross-sectional techniques, radiography remains the most common first-line imaging test when evaluating patients with pain or neurologic symptoms localized to a spinal segment. Computed tomography provides better three-dimensional anatomy of the spine and better soft tissue contrast than radiography, allowing earlier diagnosis of many spinal diseases compared to radiography. Osteoarthritis is particularly common in the lumbar spine but also seen in the cervical or midthoracic regions. The spine is well protected from minor trauma but significant trauma such as a vehicular impact or fall from great height can result in fracture or luxation. Osteosarcoma is the most common primary vertebral tumor in dogs.
