Browsing by Author "Dittmer K"

Now showing 1 - 6 of 6
  • Thumbnail Image
    Item
    A frameshift-deletion mutation in Reelin causes cerebellar hypoplasia in White Swiss Shepherd dogs
    (John Wiley & Sons Ltd on behalf of Stichting International Foundation for Animal Genetics, 2023-10) Littlejohn MD; Sneddon N; Dittmer K; Keehan M; Stephen M; Drögemüller M; Garrick D
    Cerebellar hypoplasia is a heterogeneous neurological condition in which the cerebellum is smaller than usual or not completely developed. The condition can have genetic origins, with Mendelian-effect mutations described in several mammalian species. Here, we describe a genetic investigation of cerebellar hypoplasia in White Swiss Shepherd dogs, where two affected puppies were identified from a litter with a recent common ancestor on both sides of their pedigree. Whole genome sequencing was conducted for 10 dogs in this family, and filtering of these data based on a recessive transmission hypothesis highlighted five protein-altering candidate variants - including a frameshift-deletion of the Reelin (RELN) gene (p.Val947*). Given the status of RELN as a gene responsible for cerebellar hypoplasia in humans, sheep and mice, these data strongly suggest the loss-of-function variant as underlying these effects. This variant has not been found in other dog breeds nor in a cohort of European White Swiss Shepherds, suggesting a recent mutation event. This finding will support the genotyping of a more diverse sample of dogs, and should aid future management of the harmful allele through optimised mating schemes.
  • Thumbnail Image
    Item
    Bone quality changes as measured by Raman and FTIR spectroscopy in primiparous cows with humeral fracture from New Zealand.
    (2023) Wehrle-Martinez A; Waterland MR; Naffa R; Lawrence K; Back PJ; Rogers CW; Dittmer K
    The occurrence of spontaneous humeral fractures in primiparous dairy cows from New Zealand prompted the study of bone material from affected cows to further characterize this condition and to outline a likely pathogenesis. Previous studies indicate that these cows developed osteoporosis due to periods of suboptimal bone formation followed by increased bone resorption during the period of lactation complicated by copper deficiency. We hypothesized that there are significant differences in the chemical composition/bone quality in bones from cows with spontaneous humeral fracture compared to cows without humeral fractures. In this study, Raman and Fourier transform infrared spectroscopy band ratios were, for the first time, measured, calculated, and compared in bone samples from 67 primiparous dairy cows that suffered a spontaneous fracture of the humerus and 14 age-matched post-calving cows without humeral fractures. Affected bone showed a significantly reduced mineral/matrix ratio, increased bone remodeling, newer bone tissue with lower mineralization and, lower carbonate substitution, and reduced crystallinity. As such, is likely that these have detrimentally impacted bone quality and strength in affected cows.
  • Thumbnail Image
    Item
    Editorial: Bone health and disease in veterinary species.
    (Frontiers Media S.A., 2023-09-20) Wehrle-Martinez A; Dittmer K; Rogers CW; Salguero FJ
    The days when bone was considered a static tissue providing only mechanical support for the body are long gone. In fact, bone is a highly dynamic tissue with numerous interactions and functions that provide not only movement, support, and protection but also influence in mineral metabolism and homeostasis, hematopoiesis, immune activity, glucose/energy metabolism, and the endocrine system (1, 2). The articles within this Research Topic addressed the changes and response of bone to trauma and repair using a variety of tools and techniques. For example, Bow et al. explored and characterized bone repair after trauma using radiography, computed tomography, histology, and biomechanical data. The authors also provided valuable information on the metabolic profile of bone repair using ultra-high-performance liquid chromatography-high resolution mass spectrometry which revealed distinct patterns of small molecule profiles associated with cell differentiation/function and changes in the extracellular matrix conformation that occur during bone healing.
  • Thumbnail Image
    Item
    Novel Assessment of Collagen and Its Crosslink Content in the Humerus from Primiparous Dairy Cows with Spontaneous Humeral Fractures Due to Osteoporosis from New Zealand.
    (23/09/2022) Wehrle-Martinez A; Naffa R; Back P; Rogers CW; Lawrence K; Loo T; Sutherland-Smith A; Dittmer K
    Numerous cases of spontaneous humeral fracture in primiparous dairy cows from New Zealand have prompted the study of the condition to establish probable causes or risk factors associated with the condition. Previous studies identified inadequate protein-calorie malnutrition as an important contributory factor. Earlier case studies also reported that ~50% of cows have low liver and/or serum copper concentration at the time of humeral fracture. Because copper is so closely associated with the formation of collagen cross-links, the aim of this study was to compare collagen and collagen crosslink content in the humerus from primiparous cows with and without humeral fractures and to determine the role of copper in the occurrence of these fractures. Humeri were collected from cows with and without humeral fractures, ground, and the collagen and collagen cross-link content measured using high-performance liquid chromatography. Collagen content was significantly higher in the humeri of cows without humeral fractures, while total collagen crosslink content was significantly higher in the humerus of cows with humeral fractures. These results indicate other factor/s (e.g., protein-calorie undernutrition) might be more important than the copper status in the occurrence of humeral fractures in dairy cows in New Zealand.
  • Thumbnail Image
    Item
    The Effect of Sex and Age on Bone Morphology and Strength in the Metacarpus and Humerus in Beef-Cross-Dairy Cattle
    (MDPI (Basel, Switzerland), 2021-03-05) Gibson M; Hickson R; Back P; Dittmer K; Schreurs N; Rogers C
    In cattle, limited data have been reported about the relationship between live weight, bone size, and strength and how this relationship can be altered by factors such as sex and age. The aim of this study was to describe the relationship of peripheral quantitative computed tomography (pQCT)-derived parameters of bone strength and morphology with live weight, age and sex in beef-cross-dairy cattle. All animals were weighed the day before slaughter. The metacarpus and humerus were collected at slaughter and scanned at the mid-diaphysis using pQCT. Live weight was the primary explanatory variable for bone size and strength in all cohorts. However, the effect of age was significant, such that magnitude of response to liveweight was less in the 24-month-old cohort. Sex was significant within cohorts in that bulls had a shorter metacarpus than steers and heifers had a shorter metacarpus than steers at age of slaughter.
  • Thumbnail Image
    Item
    The Mid-Diaphysis Is a Poor Predictor of Humeral Fracture Risk Indicating That Predisposing Factors Are Recent
    (MDPI (Basel, Switzerland), 2021-09) Gibson M; Dittmer K; Hickson R; Back P; Wehrle-Martinez A; Rogers C; Bonanno A
    The incidence of spontaneous humeral fractures in first-lactation dairy heifers in New Zealand has emphasised the need to understand the thoracic limb bone growth of dairy heifers. Previous research has indicated that a predisposing factor to spontaneous humeral fracture is nutrition. In addition, it has been hypothesised that liver copper concentration affects bone strength and may be a potential factor associated with humeral fracture risk. The aim of this study was to compare bone morphology in the mid-diaphysis of the metacarpus and humerus of heifers affected and unaffected by spontaneous humeral fractures, and determine the effect of copper status at death on bone morphology. The metacarpus and humerus were collected from heifers affected and unaffected by humeral fractures, and scanned using peripheral quantitative computed tomography (pQCT). The mid-diaphysis of the humerus of the affected group had reduced cortical bone mineral density and a trend for reduced cortical content and total bone content, which contributed to a reduced stress–strain index. The trend for reduced bone length in affected humeri provides additional support for the hypothesis of inhibited humeral growth. Heifers with low copper liver concentrations had reduced humerus lengths and reduced cortical bone mineral densities. These data support the hypothesis that the developmental window for humeral fracture is recent, and possibly associated with periods of inadequate nutrition.