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Item A blinded, placebo-controlled study on the clinical effects of vitamin E supplementation in dogs with osteoarthritis(Wiley Periodicals LLC. on behalf of the American College of Veterinary Internal Medicine., 2023-07-31) Gordon CL; Reeves SJ; Burchell RK; Thomson C; Gal A; Lopez-Villalobos N; Webster NSL; Litster KM; Mitchell RASBACKGROUND: Vitamin E has a positive effect in the management of osteoarthritis in humans, and in a previous study of dogs. It has been suggested to decrease C-reactive protein concentrations and liver enzyme activities in humans and animals. OBJECTIVE: To assess the effect of vitamin E supplementation on lameness, pain, pain medication requirement, clinical pathology variables, and quality of life in large-breed dogs with naturally occurring osteoarthritis. ANIMALS: Fifty-seven client-owned dogs with naturally occurring osteoarthritis. METHODS: Dogs received either vitamin E or placebo for 90 days in a randomized, placebo-controlled, double-blinded, prospective clinical trial. Clinical lameness scores, pain medication requirements, and owner questionnaires were used to assess response to treatment every 30 days. Blood samples were collected at enrollment and at the end of the study period. RESULTS: Vitamin E administration did not improve pain, lameness, or quality of life as assessed by owners and veterinarians. Vitamin E supplementation did not decrease the requirement for rescue pain relief. No changes in clinical pathology variables were observed after 90 days of vitamin E supplementation. Body weight was negatively associated with the lameness scores and requirement for rescue pain relief. CONCLUSION: Vitamin E supplementation did not have any observable positive effects in dogs with naturally occurring osteoarthritis.Item Etiology and epidemiology of digital dermatitis in Australian dairy herds.(Elsevier B.V., 2024-02-06) McPherson A; Tranter B; Phipps A; Laven R; House J; Zadoks RN; Rowe SABSTRACT Bovine digital dermatitis (BDD) is an important cause of lameness in dairy cows worldwide. However, there is very little known about this disease in Australian herds, which are predominantly managed on pasture. The primary objectives of this cross-sectional study were to describe the presence and prevalence of BDD in Australian dairy herds and to characterize the microbiota of healthy skin and M4 lesions of BDD-affected, pasture-managed cows. Cows from 71 dairy herds were examined at milking time to identify the presence of BDD lesions. True prevalence was estimated using Bayesian methods with informative priors for sensitivity and specificity. Biopsy samples (n = 60) were collected from cows with and without BDD-lesions in 7 pasture-based herds. The microbiota in the superficial and deep strata of each tissue biopsy were characterized via sequencing of the V3-V4 region of the bacterial ribosomal RNA gene. Lesions were detected in 1,817 (11.5%) of 15,813 cows, and in 68 of 71 (95.8%) herds. The median herd-level apparent and true prevalences of BDD were 8.5 and 18.1%, respectively, but this varied considerably between farms. On farms with BDD, M4 lesions accounted for 70 to 100% of all lesions (interquartile range = 95.1 to 100%, median = 100%). M2 lesions (i.e., large ulcerative lesions) were observed at low prevalence (<2.2%) in the few herds (7/71, 9.9%) where they were found. There was a statistically significant difference in the composition of the microbiota between healthy skin and M4 lesions but not between superficial and deep tissue layers. Several gut- and effluent-associated bacterial taxa, including Lentimicrobium and Porphyromonas, which have previously been associated with BDD, were abundant in BDD lesions but not in control biopsies. Our study supports the idea that such taxa are involved in, though possibly not essential to, lesion development and persistence in pasture-managed cows in Australia. Our results also suggest that Dichelobacter may contribute to the disease process. We conclude that BDD is likely to occur in most Australian dairy farms, but that further studies are needed to identify its impact on cow welfare and productivity. Further investigation of the etiology of BDD in Australian dairy herds is also necessary to inform prevention and control strategies. INTERPRETIVE SUMMARY: We visited 71 farms in Australia to estimate the prevalence of bovine digital dermatitis (an infectious skin disease that causes lameness in cows). Most farms (68 / 71) were identified to be endemic for the disease, but that the painful lesion types (score = M2) were uncommon. Microbiome analysis was conducted on 60 biopsy sample of cows with and without BDD lesions. We found that cows with BDD had higher abundances of gut- and effluent-associated bacterial taxa, including Lentimicrobium and Porphyromonas. We conclude that BDD is present on most Australian dairy farms.Item Investigating the effect of prophylactic claw trimming on the interval between calving and first observed elevated locomotion score in pasture-based dairy cows.(Taylor and Francis Group, 2023-11-01) Werema CW; Hoekstra F; Laven LJ; Müller KR; Gifford D; Laven RAAIMS: To evaluate, in a pasture-based dairy herd, the response to a three-time point hoof trimming regime on lameness incidence and time from calving to observation of an elevated locomotion score (LS). METHODS: This study was conducted on a 940-cow spring-calving herd in New Zealand's North Island between May 2018 and May 2019. Cows (n = 250) were randomly allocated to the hoof trimming group, with the remainder assigned to the non-trim cohort. One trained professional hoof trimmer used the five-step Dutch method to trim the hind feet of the trimming group. Throughout the subsequent production season, the whole herd was locomotion-scored fortnightly using the 4-point (0-3) Dairy NZ lameness score. Kaplan-Meier survival curves were used to assess the univariable effect of trimming on the interval between calving and first LS of ≥ 2 and first LS ≥ 1. A multivariable Cox proportional hazards regression was used to further evaluate the effect of trimming on time to elevated LS. RESULTS: Mean lameness (LS ≥ 2) prevalence was 2.6%, with 30% of cows having ≥ 4 observations during the study period when at least one LS was ≥ 2. For LS ≥ 1, mean prevalence was 40%, with 98.6% of cows having ≥ 4 observations during the study period when at least one LS was ≥ 1 during lactation. Hoof trimming had no apparent effect on the incidence of clinical lameness (LS ≥ 2) (trimmed vs. non-trimmed: 33.2% vs. 28.8%, respectively), but for LS ≥ 1, there was a small decrease in the incidence of LS ≥ 1 (trimmed vs. non-trimmed: 96.9% vs. 99.3%, respectively). The hazard of a cow having a first observed LS ≥ 2 in the control group was 0.87 (95% CI = 0.66-1.14) times that of the trimmed group; however, the hazard of a cow having a first LS ≥ 1 was 1.60 (95% CI = 1.37-1.88) times higher in the control than in the trimmed group. CONCLUSION AND CLINICAL RELEVANCE: On this farm, prophylactic hoof trimming had no clinically relevant impact on the incidence of clinical lameness and was not associated with clinically beneficial reductions in time to first observed LS ≥ 2. This may be because claw horn imbalance was not pronounced on this farm, with 53% of cows needing no trim on either hind limb on the first trimming occasion. Further research on the response to prophylactic trimming in pasture-based dairy cattle is required.Item Lameness recovery rates following treatment of dairy cattle with claw horn lameness in the Waikato region of New Zealand.(Taylor and Francis Group, 2023-09-01) Mason W; Laven LJ; Cooper M; Laven RAAIMS: To describe the time in days for lame dairy cows to recover after diagnosis and treatment of claw horn lameness, and to investigate whether cure rates differed between farms. METHODS: Five dairy farms in the Waikato region were conveniently enrolled into a descriptive epidemiological study. Three of these farms had dairy cattle enrolled over two consecutive seasons, while two farms enrolled for one year. Lame cattle diagnosed by the farmers were enrolled into the study if they had a lameness score (LS ≥ 2 on a 0-3 scale) and claw horn lesions. All enrolled animals were treated by a single veterinarian following a consistent methodology, and subsequently assessed for LS at a median frequency of 4 days from enrolment until they were sound (LS = 0). The times (days) taken for animals to become sound and non-lame (LS < 2) were reported for all animals, and Kaplan-Meier survival curves used to present the results. A Cox-proportional hazard model was used to assess if the hazard of soundness was associated with farm, age, breed, lesion, number of limbs involved, and LS at enrolment. RESULTS: A total of 241 lame cattle with claw horn lesions were enrolled across the five farms. White line disease was the predominant pain-causing lesion in 225 (93%) animals, and blocks were applied to 205 (85%) of enrolled animals. The overall median days from enrolment to becoming sound was 18 (95% CI = 14-21) days, and 7 (95% CI = 7-8) days to become non-lame. A difference in the hazards of lameness cure between farms was identified (p = 0.007), with median days to lameness cure between farms ranging from 11 to 21 days. No associations were identified between age, breed, limb, or LS at enrolment on the lameness cure rates. CONCLUSIONS: Treatment of claw horn lameness following industry-standard guidelines in dairy cattle on five New Zealand dairy farms resulted in rapid cure, although cure rates differed between farms. CLINICAL RELEVANCE: Following industry best-practice lameness treatment guidelines, including frequent use of blocks, can result in rapid lameness cure rates in New Zealand dairy cows. This study also suggests that management of lame cattle on pasture can positively benefit their welfare and recovery times. The reported cure rates provide veterinarians with benchmarks on the length of time after which a lame animal should be re-examined, and in the investigation of poor treatment response rates at the herd level.Item Can lameness prevalence in dairy herds be predicted from farmers' reports of their motivation to control lameness and barriers to doing so? An observational study from New Zealand.(Elsevier B.V., 2024-04-01) Mason WA; Laven LJ; Huxley JN; Laven RAUnderstanding what motivates and prevents behavioral change in farmers is a critical step in disease control in dairy cattle. A total of 101 New Zealand dairy farmers across 8 regions were randomly enrolled into a cross-sectional study to investigate farmer barriers and motivators to lameness control for cows managed 100% at pasture and the relationship between these responses and the true lameness status on farm. Trained technicians lameness scored all lactating cows on the enrolled farms on 2 occasions during one lactation. Farm-level prevalence proportions were calculated as the mean of the 2 lameness scores. Enrolled farmers were asked their perception of lameness in the current milking season and responded to 26 ordinal Likert-type items with 5 options ranging from not important at all to extremely important. The questions were grouped under 3 categories; barriers to lameness control (n = 9), impacts of lameness (n = 10), and motivators to control lameness (n = 7). The association between farmer perception of lameness and lameness prevalence was reported using linear regression. Multiple-factor analysis was conducted to identify latent variable themes within the responses. Linear discriminant analysis was used to assess whether barriers, impacts, and motivators could be used to predict farmer perception of lameness and lameness prevalence. Lameness prevalence was 0.8% greater on farms where farmers perceived lameness as a moderate or a major problem compared with farms where the farmer perceived lameness as a minor problem or not a problem. Farmers ranked all potential motivators to lameness control as important and declared few barriers to be important at preventing them from controlling lameness. Feeling sorry for lame cows and pride in a healthy herd were the most important motivators, with lack of time and skilled labor the most important barriers. The most important effects of lameness were cow-related factors such as pain and production, with farm and industry impacts of less importance. Farmers place different weightings of importance on barriers to lameness control compared with motivators for lameness control. The impacts and motivators were strongly correlated with the first dimension from the multiple-factor analysis, with only weak correlation between barriers and the first dimension. Linear discriminant analysis identified that the importance that farmers place on barriers, motivators, and impacts of lameness were poor predictors of farmers' belief in regard to their lameness problem or actual lameness prevalence (above or below the median lameness prevalence for the study cohort). Despite relatively low lameness prevalence, many New Zealand dairy farmers believe lameness is a problem on their farm, and they rank welfare effects of lameness of high importance. To investigate how farmer behavior change can be used to manage lameness, future studies should consider theoretical social science frameworks beyond the theory of planned behavior or involve prospective interventional studies investigating farmer actions instead of beliefs.Item Persistence of orthopaedic hoof blocks for the treatment of lame cattle kept permanently at pasture.(Taylor and Francis Group, 2023-09-01) Müller KR; Laven RA; Laven LJAIMS: To compare the retention by New Zealand dairy cows kept at pasture in a lame cow group, of three hoof block products commonly used in the remediation of lameness. METHODS: Sixty-seven farmer-presented Friesian and Friesian x Jersey dairy cows from a single herd in the Manawatū region (New Zealand) suffering from unilateral hind limb lameness attributable to a claw horn lesion (CHL) were randomly allocated to one of three treatments: foam block (FB), plastic shoe (PS) and a standard wooden block (WB). Blocks were applied to the contralateral healthy claw and checked daily by the farm staff (present/not present) and date of loss was recorded. Blocks were reassessed on Day 14 and Day 28 and then removed unless further elevation was indicated. Daily walking distances were calculated using a farm map and measurement software. Statistical analyses included a linear marginal model for distance walked until block loss and a Cox regression model for the relative hazard of a block being lost. RESULTS: Random allocation meant that differences between products in proportion used on left or right hind foot or lateral or medial claw were small. Mean distance walked/cow/day on farm tracks whilst the block was present was 0.32 (min 0.12, max 0.45) km/day; no biologically important difference between products in the mean distance walked was identified. Compared to PS, cows in the WB group were five times more likely to lose the block (HR = 4.8 (95% CI = 1.8-12.4)), while cows in the FB group were 9.5 times more likely to lose the block (HR = 9.5 (95% CI = 3.6-24.4)). CONCLUSIONS: In this study, PS were retained for much longer than either FB or WB. As cows were managed in a lame cow group for the study duration, walking distances were low and did not impact on the risk of block loss. More data are needed to define ideal block retention time. CLINICAL RELEVANCE: In cows with CHL the choice of block could be based on the type of lesion present and the expected re-epithelisation times.Item Farm-level risk factors and treatment protocols for lameness in New Zealand dairy cattle.(Taylor and Francis Group, 2024-05-08) Mason WA; Müller KR; Laven LJ; Huxley JN; Laven RAAims To identify farm-level risk factors for dairy cow lameness, and to describe lameness treatment protocols used on New Zealand dairy farms. Methods One hundred and nineteen farms from eight veterinary clinics within the major dairying regions of New Zealand were randomly enrolled into a cross-sectional lameness prevalence study. Each farmer completed a questionnaire on lameness risk factors and lameness treatment and management. Trained observers lameness scored cattle on two occasions, between October–December (spring, coinciding with peak lactation for most farms) and between January–March (summer, late lactation for most farms). A four-point (0–3) scoring system was used to assess lameness, with animals with a lameness score (LS) ≥2 defined as lame. At each visit, all lactating animals were scored including animals that had previously been identified lame by the farmer. Associations between the farmer-reported risk factors and lameness were determined using mixed logistic regression models in a Bayesian framework, with farm and score event as random effects. Results A lameness prevalence of 3.5% (2,113/59,631) was reported at the first LS event, and 3.3% (1,861/55,929) at the second LS event. There was a median prevalence of 2.8% (min 0, max 17.0%) from the 119 farms. Most farmers (90/117; 77%) relied on informal identification by farm staff to identify lame animals. On 65% (75/116) of farms, there was no external provider of lame cow treatments, with the farmer carrying out all lame cow treatments. Most farmers had no formal training (69/112; 62%). Animals from farms that used concrete stand-off pads during periods of inclement weather had 1.45 times the odds of lameness compared to animals on farms that did not use concrete stand-off pads (95% equal-tailed credible interval 1.07–1.88). Animals from farms that reported peak lameness incidence from January to June or all year-round, had 0.64 times odds of lameness compared to animals from farms that reported peak lameness incidence from July to December (95% equal-tailed credible interval 0.47–0.88). Conclusions Lameness prevalence was low amongst the enrolled farms. Use of concrete stand-off pads and timing of peak lameness incidence were associated with odds of lameness. Clinical relevance Veterinarians should be encouraging farmers to have formal lameness identification protocols and lameness management plans in place. There is ample opportunity to provide training to farmers for lame cow treatment. Management of cows on stand-off pads should consider the likely impact on lameness.Item Randomized clinical trial investigating the effect of exercise and standing on concrete prior to first calving on time to first lameness event in dairy heifers(Elsevier Inc and Fass Inc on behalf of the American Dairy Science Association, 2022-09) Mason WA; Huxley JL; Laven RAThis controlled clinical trial investigated if an intervention immediately before the first calving event could reduce lameness incidence in pasture-based dairy heifers. Seven hundred ninety heifers across 6 farms in the Waikato region of New Zealand were randomly enrolled into treatment or control groups at a ratio of 1:1. The treatment consisted of heifers walking approximately 1 km from pasture along the farm race, standing on concrete for one hour, and then walking back to their paddock. This occurred once a day, 5 times a week, for 5 wk before calving. The control heifers were managed solely at pasture before calving. Just before calving, both groups were bought together and managed as one group for the remainder of the study. Heifers were followed for up to 28 wk, with fortnightly lameness scores collected to identify animals with a lameness score of ≥2 (lameness score 0–3). Lameness could also be diagnosed by the farmers, who had no formal lameness scoring training. The primary outcome of interest was time to first lame event. Secondary outcomes included milk solid production, change in body condition score during early lactation, time from onset of breeding season until conception, feasibility of the regimen and change in sole soft tissue thickness and profile. From a total of 782 heifers that had data collected on the outcomes, 102 (13.0%) individual first lameness events were recorded, 53 in heifers in the treatment group and 49 in control heifers. Of those 102 lameness events, 51 were first diagnosed by farmers. No apparent differences were detected in the hazard rate for time to first lame event between heifers in the 2 treatment groups. Treatment heifers had a 1.12 times hazard rate (95% confidence interval: 0.65–1.95) of a lame event compared with control heifers. No associations were identified between heifers in the 2 groups for any of the secondary outcome measures. However, farmers did report that the intervention was practical and easy to implement. It is possible that the intervention did not challenge the hoof enough, and that longer duration and distances walked may have resulted in a different outcome. Although no improvement in lameness outcomes were reported, no negative effects during and after the intervention were noted in animals in the intervention group. Further research into the area of lameness prevention is needed as there are few evidence-based solutions available to reduce lameness incidence in pasture-based systems.Item Morphology, adipocyte size, and fatty acid analysis of dairy cattle digital cushions, and the effect of body condition score and age(Elsevier Inc and Fass Inc on behalf of the American Dairy Science Association, 2021-05) Newsome RF; Mostyn A; Wilson JP; Alibhai A; Bollard N; Randall L; Chagunda MGG; Sturrock CJ; Keane M; Green M; Huxley JN; Rutland CSThe digital cushion is an essential part of maintaining a healthy foot, working to dissipate foot strike and body weight forces and lameness from claw horn disruption lesions. Despite the importance of the digital cushion, little is known about the basic anatomy, adipocyte morphology, and fatty acid composition in relation to age, limb position, and body condition score. In total, 60 claws (from 17 cows) were selected and collected from a herd, ensuring that body condition score data and computed micro-tomography were known for each animal. Digital cushion tissue underwent histological staining combined with stereology, systematic random sampling, and cell morphology analysis, in addition to lipid extraction followed by fatty acid analysis. The results describe digital cushion architecture and adipocyte sizes. Adipocyte size was similar across all 4 claws (distal left lateral and medial and distal right lateral and medial) and across the ages (aged 2–7 yr); however, animals with body condition score of 3.00 or more at slaughter had a significantly increased cell size in comparison to those with a score of less than 2.50. Of 37 fatty acid methyl esters identified, 5 differed between either the body condition score or different age groups. C10:0 capric acid, C14:0 myristic acid, C15:0 pentadecanoic acid, and C20:0 arachidic acid percentages were all lesser in lower body condition score cows, whereas C22:1n-9 erucic acid measurements were lesser in younger cows. Saturated fatty acid, monounsaturated fatty acid, and polyunsaturated fatty acid percentages were not altered in the different claws, ages, or body condition score groups. Triglyceride quantities did not differ for claw position or age but had decreased quantities in lower body condition score animals. Digital cushion anatomy, cellular morphology, and fatty acid composition have been described in general and also in animals with differing ages, body condition scores, and in the differing claws. Understanding fat deposition, mobilization, and composition are essential in not only understanding the roles that the digital cushion plays but also in preventing disorders and maintaining cattle health and welfare.Item Hoof lesions in partly housed pasture-based dairy cows(Elsevier Inc and Fass Inc on behalf of the American Dairy Science Association, 2022-11) Browne N; Hudson CD; Crossley RE; Sugrue K; Huxley JN; Conneely MLameness is a symptom of a painful disorder affecting the limbs, which impacts dairy cow welfare and productivity. Lameness is primarily caused by hoof lesions. The prevalence of different lesion types can differ depending on environmental conditions and farm management practices. The aims of this observational study were to establish the cow-level and herd-level lesion prevalence during both housing and grazing periods in a partly housed, pasture-based system, establish the prevalence of lesions always associated with pain (“alarm” lesion), identify the lesions associated with a higher lameness score, determine relationships between lesions, and identify risk factors for digital dermatitis. On 98 farms during the grazing period and on 74 of the same farms during the housing period, every cow was lameness scored (0–3 lameness scoring scale), and the hind hooves of lame cows (score 2 and 3) were examined (maximum 20 cows per visit) and the prevalence of each lesion type recorded. To gather data on potential predictors for the risk factor analysis, a questionnaire with the farmer was conducted on lameness management practices and infrastructure measurements were taken at each visit. Cow-level data were also collected (e.g., parity, breed, milk yield, and so on). Noninfectious lesions were found to be more prevalent than infectious lesions in this system type. The most prevalent lesion types during both grazing and housing periods were white line separation, sole hemorrhages and overgrown claws; all remaining lesions had a cow-level prevalence of less than 15%. The cow-level prevalence of alarm lesions was 19% during the grazing period and 25% during the housing period; the most prevalent alarm lesion was sole ulcers during both periods. We found significantly more foreign bodies within the hoof sole (grazing = 14%, housing = 7%) and overgrown claws (grazing = 71%, housing = 55%) during the grazing period compared with the housing period. Cows with foul of the foot, sole ulcer, white line abscess, toe necrosis or an amputated claw had higher odds of being more severely lame, compared with mildly lame. The strongest correlation between lesions were between toe necrosis and digital dermatitis (r = 0.40), overgrown claws and corkscrew claws (r = 0.33), and interdigital hyperplasia and digital dermatitis (r = 0.31) at herd level. At the cow level, the strongest correlation was between overgrown claws and corkscrew claws (r = 0.27), and digital dermatitis and heel erosion (r = 0.22). The farmers' perception of the presence of digital dermatitis (and lameness) was significantly correlated with the actual presence of digital dermatitis recorded. Additional risk factors for the presence of digital dermatitis were cow track and verge width near the collecting yard, and stone presence on the cow tracks. Results from this study help further our understanding of the causes of lameness in partly housed, pasture-based dairy cows, and can be used to guide prevention and treatment protocols.