Journal Articles

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    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.
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    An Assessment of the Epidemiology and Herd-Level Impact of the Fractured Humerus Epidemic in New Zealand Dairy Cattle, 2007-2015: Results from Four Studies
    (MDPI (Basel, Switzerland), 2024-02-05) Hunnam JC; Lawrence K; Rashid ZBA; Hitchcock B; McDougall S; Wehrle-Martinez A; Weston JF; Miranda Castañón MI
    A multi-method approach integrating data from four independent sources was used to describe some key features of the epidemiology and estimate the herd and within-herd incidence of fractured humeri in New Zealand dairy cattle for the period 2007-2015. The first dataset was from a national case series where cases of humeral fractures in dairy cattle were identified by veterinarians across New Zealand between the 2007/2008 and 2011/2012 lactation seasons. The second dataset was from a pet food company based in the Waikato region, which collated the number of casualty first- and second-lactation cows found to have a fractured humerus post-slaughter in the 2014/2015 lactation season, and the third dataset was a case series conducted by veterinarians employed in a Waikato veterinary business, also from the 2014/2015 lactation season. For the final dataset, 505 randomly selected New Zealand dairy farmers completed a phone survey on the incidence of non-responsive, non-weight-bearing forelimb lameness in first- and second-lactation cows in the 2014/2015 lactation season. Using the telephone survey results, the within-herd and herd-level incidence of cases for first- and second-lactation dairy animals was calculated. The national case series reported 149 cases of humeral fractures in 22 dairy herds; the pet food case series identified 61 cases from 41 farms; and the practice-based case series found 14 cases from 10 farms. Humeral fractures exclusively affected first- and second-lactation dairy cows and had a peak incidence between calving and early mating. The national telephone survey found that non-weight-bearing forelimb lameness requiring euthanasia of first- or second-lactation cows occurred in 11.7% of herds, with a mean within-herd incidence of 2.6% for first lactation cows and 2.8% for second-lactation cows for affected herds. These combined datasets demonstrate that humeral fractures in young, lactating dairy cattle are more common than previously suspected and that they occur nationally and over multiple years on some farms. Further work on this condition is urgently required in New Zealand to establish cost-effective management practices that will reduce unnecessary animal suffering and waste.
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    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.
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    Ecological study of fractures in paedatric Melanesian communities with varying endemic environmental fluoride exposure
    (MDPI (Basel, Switzerland), 2021-09) Webb E; Elmansouri A; Ross R; Clynes M; Tangis J; Stewart C; Dennison EM; Bahamonde RG
    Introduction: Osteoporotic fracture is a major public health burden worldwide, causing significant mortality and morbidity. Studies that have reported bone health in areas of high endemic fluorosis have commonly reported adverse skeletal, as well as dental effects. Vanuatu, sited in the Pacific, and never previously studied with regard to bone health, has six continuous degassing volcanoes on separate islands, resulting in a natural experiment for an ecological study of relationships between naturally occurring fluoride exposure and fracture incidence in paediatric populations. Methods: This ecological study recruited 1026 lifetime residents of the rural Vanuatu islands. A short questionnaire was administered detailing gender, age, and residential history. Participants were asked if they had broken a bone and, if so, were asked to mark its location on a questionnaire manikin. Dental fluorosis was assessed using Dean’s index. Community drinking-water samples were sampled for fluoride concentration. Results: The measured water fluoride concentration and recorded dental fluorosis displayed expected gradients from Aneityum (low) to Ambrym (high) (p < 0.001). The age of participants studied varied from 7.8 (SD 1.2) in Aneityum to 10.6 (3.7) in Lamap/Uliveo. The highest self-reported fracture rates were recorded in the area with medium fluoride levels (Lamap/Uliveo), where 14.9% of boys and 15.6% of girls sampled reported a fracture. In Ambrym, where the mean age of participants was similar, corresponding fracture rates were 4.5% and 2.6%. (p value for differences all < 0.05). Conclusions: Reports of fractures were common in children living in Vanuatu, but demonstrably higher in Lamap, the region with medium fluoride concentrations, rather than Ambrym which had very high rates of naturally occurring fluoride levels. Longer term studies that report validated fracture after peak bone mass acquisition are required.
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    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.