Browsing by Author "Webster JR"

Now showing 1 - 4 of 4
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    Evaluating the long-term conformation and hoof growth effects of starting hoof trimming at 5 months of age in New Zealand dairy goats
    (Federation of Animal Science Societies and Elsevier Inc on behalf of the American Dairy Science Association, 2023-02) Deeming LE; Beausoleil NJ; Stafford KJ; Webster JR; Cox N; Zobel G
    Hoof overgrowth is associated with poor conformation, an altered weight-bearing surface, and a reduction in the hoof's anatomic and functional integrity. As a result of housing systems that promote hoof overgrowth, hoof trimming is considered a priority in dairy goats. However, there are few data on the effects of the timing of first trimming on hoof conformation and growth rate. The aims of this study were (1) to evaluate the long-term effects of 2 different hoof trimming start times and (2) to investigate the pattern of hoof growth across the first 2 yr of life. Eighty 5-mo-old female Saanen-cross commercially housed dairy goats were allocated randomly to 1 of 2 treatments: (1) early trimmed (trimming beginning at 5 mo old; hooves were trimmed every 4 mo thereafter) and (2) late trimmed (trimming beginning at 13 mo old; hooves were trimmed every 4 mo thereafter). Using a combination of photographs and radiographs, hoof conformation, joint positions, and hoof wall length were assessed before the 13- and 25-mo trimming events. Hoof growth was assessed every 12 wk using caliper measurements. Overall, starting hoof trimming earlier had minor and inconsistent effects. However, detrimental changes in conformation and joint positions occurred between trimming events, particularly in the hind hooves, regardless of trimming treatment. At both assessments, there was a high percentage of overgrown toes and dipped heels, with the hind hooves being more affected compared with the front (overgrown toes at 13 mo, 97.1 vs. 79.1 ± 5.2%; overgrown toes at 25 mo, 91.7 vs. 56.3 ± 6.7%; dipped heels at 13 mo, 98.5 vs. 19.3 ± 5.0%; dipped heels at 25 mo, 88.3 vs. 4.9 ± 4.8%). In addition, at both assessments, the distal interphalangeal joint angle was greater in the hind hooves compared with the front (13 mo, 79.5 vs. 65.2 ± 1.7°; 25 mo, 79.0 vs. 66.7 ± 0.9°), whereas heel angles were less in the hind hooves compared with the front (13 mo, 41.8 vs. 57.1 ± 1.5°; 25 mo, 44.9 vs. 55.9 ± 1.1°). On average, the front hooves grew 4.39 mm/mo and the hind hooves grew 4.20 mm/mo. Early trimming did not have consistent effects on hoof growth rate. Importantly, our results suggest that trimming every 4 mo is not sufficient to prevent hoof overgrowth, the development of poor conformation, and detrimental changes in joint positions, particularly in the hind hooves. Furthermore, the detrimental changes may have masked any long-term treatment effects. Therefore, trimming frequency and age of first trimming should be considered when devising hoof care protocols for dairy goats housed in environments that do not offer opportunities for natural hoof wear.
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    Heart Rate and Heart Rate Variability Change with Sleep Stage in Dairy Cows
    (MDPI (Basel, Switzerland), 2021-07-14) Hunter LB; Haskell MJ; Langford FM; O'Connor C; Webster JR; Stafford KJ; Van Eerdenburg FJCM
    Changes to the amount and patterns of sleep stages could be a useful tool to assess the effects of stress or changes to the environment in animal welfare research. However, the gold standard method, polysomnography PSG, is difficult to use with large animals such as dairy cows. Heart rate (HR) and heart rate variability (HRV) can be used to predict sleep stages in humans and could be useful as an easier method to identify sleep stages in cows. We compared the mean HR and HRV and lying posture of dairy cows at pasture and when housed, with sleep stages identified through PSG. HR and HRV were higher when cows were moving their heads or when lying flat on their side. Overall, mean HR decreased with depth of sleep. There was more variability in time between successive heart beats during REM sleep, and more variability in time between heart beats when cows were awake and in REM sleep. These shifts in HR measures between sleep stages followed similar patterns despite differences in mean HR between the groups. Our results show that HR and HRV measures could be a promising alternative method to PSG for assessing sleep in dairy cows.
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    Machine learning prediction of sleep stages in dairy cows from heart rate and muscle activity measures.
    (Springer Nature Limited, 2021-05-25) Hunter LB; Baten A; Haskell MJ; Langford FM; O'Connor C; Webster JR; Stafford K
    Sleep is important for cow health and shows promise as a tool for assessing welfare, but methods to accurately distinguish between important sleep stages are difficult and impractical to use with cattle in typical farm environments. The objective of this study was to determine if data from more easily applied non-invasive devices assessing neck muscle activity and heart rate (HR) alone could be used to differentiate between sleep stages. We developed, trained, and compared two machine learning models using neural networks and random forest algorithms to predict sleep stages from 15 variables (features) of the muscle activity and HR data collected from 12 cows in two environments. Using k-fold cross validation we compared the success of the models to the gold standard, Polysomnography (PSG). Overall, both models learned from the data and were able to accurately predict sleep stages from HR and muscle activity alone with classification accuracy in the range of similar human models. Further research is required to validate the models with a larger sample size, but the proposed methodology appears to give an accurate representation of sleep stages in cattle and could consequentially enable future sleep research into conditions affecting cow sleep and welfare.
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    Variability in growth rates of goat kids on 16 New Zealand dairy goat farms
    (New Zealand Society of Animal Production, 7/07/2016) Deeming LE; Beausoleil NJ; Stafford KJ; Webster JR; Zobel G
    Average daily weight gains (ADG) in early life are associated with health, welfare and future production potential of dairy animals. While this has yet to be established for goats, research in cows demonstrates a positive relationship between growth in early life and milk production (Shamay et al. 2005, Soberon et al. 2012). Early growth rates are largely determined by the management practices from birth onwards. It is therefore unsurprising that large differences in ADG under different management systems have been reported. In lambs, Mahgoub et al. (2000) reported a large range in ADG (84-154 g/day). Similarly, in calves, Bartlett et al. (2006) reported ADGs ranging from 251 g/day to 703 g/day. The ADGs reported in goats have not been as variable (152-170 g/day: Galina et al. 1995; 167-173 g/day: Goetsch et al. 2001); however, these were small, controlled studies. To our knowledge, no research has yet quantified variability in the ADG of goat kids on a large, multi-farm scale. Therefore, the aim of this study was to describe the variation in growth rates on multiple dairy goat farms in the Waikato region of NZ, providing a benchmark for dairy goat farmers.