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Aims: To assess whether a whole-herd lameness score on a New Zealand dairy farm in spring could predict lameness prevalence on the same farm in summer (and vice versa) and whether a single-herd lameness score could be used to determine whether herd lameness prevalence was < 5% in both spring and summer., Methods: Prevalence data (proportion of the herd with lameness score ≥ 2 and with score 3; 0-3 scale) from a study where 120 dairy farms across New Zealand were scored in spring and in the following summer were analysed using limits-of-agreement analysis. In addition, farms were categorised as having either acceptable welfare (lameness prevalence < 5% in both spring and summer) or not (lameness prevalence ≥ 5% in either spring or summer or both). The accuracy and specificity of a single, whole-herd lameness score at identifying herds with acceptable welfare were then calculated., Results: The limits-of-agreement analysis suggests that 95% of the time, the prevalence of lameness in summer would be expected to be between 0.23 and 4.3 times that of the prevalence in spring. The specificity and accuracy of identifying a farm as acceptable on both occasions from a single observation were, respectively, 74% and 92% in spring, and 59% and 87% in summer., Conclusions: A single, one-off, whole-herd lameness score does not accurately predict future lameness prevalence. Similarly, acceptable status (lameness prevalence < 5%) in one season is not sufficiently specific to be used to predict welfare status in subsequent seasons., Clinical Relevance: Whole-herd lameness scoring should be used principally as a means of detecting lame cows for treatment. A single whole-herd lameness score by an independent assessor should not be used to determine a herd's welfare status.

Aims: 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.

Digital dermatitis is one of the most important causes of lameness in dairy cattle, particularly in housed, intensively-managed cattle. The number of modern intensive dairy farms in China has increased markedly in recent years; however, we lack research on digital dermatitis in Chinese dairy cattle. This preliminary study aimed to estimate the prevalence of digital dermatitis on three conveniently selected farms in Jiangsu, China. The washed hind feet of all lactating cows on all three farms were examined during milking with the aid of a mobile phone light source. True prevalence was then estimated from the apparent prevalence using a Bayesian superpopulation approach to account for the imperfect nature of identifying digital dermatitis in cows during milking. Despite none of the farms having thought it necessary to implement routine digital dermatitis monitoring or control, the disease was found on all three sampled farms. All lesions observed were either chronic M4 or M4.1 type-lesions, with no M2 lesions (i.e. acute ulcerated lesions) observed. The estimated true prevalences on the farms were 7.3% (95% credible interval [CrI]: 5.4%-9.6%), 8.3% (95%CrI: 6.3%-10.8%), and 29.8% (95%CrI: 22.9%-37.2%)., Competing Interests: Declaration of competing interest None of the authors has a financial or personal relationship with other people or organisations that could inappropriately influence or bias the content of this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Aims: To undertake a survey of the prevalence of tail deviations, trauma and shortening on a representative selection of New Zealand dairy farms, and to assess whether sampling based on milking order could be used instead of random sampling across the herd to estimate prevalence., Methods: This was a cross-sectional observational study, with 200 randomly selected farms enrolled across nine regions of New Zealand via selected veterinary practices (one/region). Veterinary clinics enrolled 20-25 farms each depending on region, with 1-2 trained technicians scoring per region. All cows (n = 92,348) present at a milking or pregnancy testing event were tail scored using a modified version of the New Zealand Veterinary Association Industry Scoring System. Palpated lesions were recorded as deviated (i.e. non-linear deformity), shortened (tail shorter than normal) or traumatic (all other lesions). The location of lesions was defined by dividing the tail into three equal zones: upper, middle and lower. A cow could have more than one lesion type and location, and/or multiple lesions of the same type, but for the prevalence calculation, only the presence or absence of a particular lesion was assessed. Prevalence of tail damage calculated using whole herd scoring was compared to random sampling across the herd and sampling from the front and back of the milking order. Bootstrap sampling with replacement was used to generate the sampling distributions across seven sample sizes ranging from 40-435 cows., Results: When scoring all cows, the median prevalence for deviation was 9.5 (min 0.9, max 40.3)%; trauma 0.9 (min 0, max 10.7)%, and shortening was 4.5 (min 1.3, max 10.8)%. Deviation and trauma prevalence varied between regions; the median prevalence of deviations ranged from 6% in the West Coast to 13% in Waikato, and the median prevalence of all tail damage from 7% in the West Coast to 29% in Southland. Sampling based on milking order was less precise than random sampling across the herd. With the latter and using 157 cows, 95% of prevalence estimates were within 5% of the whole herd estimate, but sampling based on milking order needed > 300 cows to achieve the same precision., Conclusions and Clinical Relevance: The proportion of cows identified as having damaged tails was consistent with recent reports from New Zealand and Ireland, but at 11.5%, the proportion of cows with trauma or deviation is below acceptable standards. An industry-wide programme is needed to reduce the proportion of affected cows.

Understanding 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., (The Authors. Published by Elsevier Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).)

Aims: 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.

To understand the current impact of lameness on a system, it is important to define lameness prevalence across a range of dairy farms in that system. Prevalence estimates from dairy systems where cows are permanently managed at pasture are uncommon, although the limited data suggest that they have a lower lameness prevalence than housed cattle. One hundred and 20 farms from eight of the major dairying regions of New Zealand were randomly enrolled into a cross-sectional lameness prevalence study. On each of the farms, 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). At each visit, all lactating animals were scored using a four-point 0-3 scoring system, and included animals that had previously been identified as lame by the farmer. Animals with a lameness score (LS) ≥2 were defined as lame. Mixed logistic regression models assessed the interaction between region and season and island and season, respectively, and differences between the lameness prevalence within farm across the two seasons reported descriptively. A total of 116,317 locomotion scores over two events were conducted across the 120 farms. At the spring scoring event, 2128/60,007 (3.5 %) cows had a LS ≥2 and 1868/56,310 (3.3 %) cows had a LS ≥ 2 at the summer scoring event. At the farm level, across both scoring events, median lameness prevalence was 2.8 (interquartile range 1.5 - 4.5) %, with a range of 0.0-17.0 %. The median farm-level prevalence of LS = 3 was 0.5 % with a range of 0-4.6 %. The effect of timing of scoring was modified by region (p < 0.001), and island (p = 0.006) and at the individual farm level, differences between spring and summer farm level lameness prevalence were generally small (interquartile range: -1.8 to 1.0 %) but potentially large on individual farms (range from -12.3 % to 7.6 %). The median farm-level lameness prevalence estimate of 2.8 % across a random representative sample of New Zealand dairy farms give confidence that the overall prevalence of cattle lameness on New Zealand dairy farms is low. This adds to the growing evidence that pasture is a good management system with respect to hoof health. The evidence of strong seasonality of lameness was lacking. Instead of using lameness scoring to identify farms with large lameness problems, lameness scoring should be encouraged to farmers as a tool to improve the identification of lame animals., Competing Interests: Declaration of Competing Interest We disclose the two funding sources for this project: The Ministry of Primary Industries Sustainable Food and Fibres Futures (SFFF19067) and DairyNZ. We declare that we have no conflict of interest as a result of these funding sources and are not affiliated with either source. We have no other conflicts to declare. We declare that we did not use any Generative AI and AI-assisted technologies in the writing process., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Aims: 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.

Aims: 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.

The objectives of this systematic review were to investigate the association between nonsteroidal anti-inflammatory drug (NSAID) use during the treatment of claw horn lameness in dairy cattle and locomotion score (LS), nociceptive threshold, and lying times. A total of 229 studies were initially identified and had their title and abstract screened. From this, we screened the full text of 23 articles, identifying 6 articles for inclusion in the systematic review. Of these 6, 5 reported LS, 2 reported nociceptor thresholds, and 1 reported lying times. The quality of evidence was assessed using a Cochrane risk-of-bias tool and CONSORT items reported for each included study. Due to heterogeneity between the studies, data were reported following Cochrane's Synthesis without meta-analysis guidelines. Identified heterogeneity between the studies included differences in LS systems and statistical analyses, length of time from enrollment to outcome reported, the NSAID used, concomitant treatments administered, and severity and chronicity of lameness. Recommendations are made with respect to consistency of LS reporting and analysis, along with improvements that may be noted with compulsory reporting guidelines. There were at least some concerns over the risk of bias in 4 of the studies, with risks of bias present in missing outcome data between the study groups. Within the 5 studies included with LS outcomes, there were 22 different pairwise comparisons with either NSAID or NSAID + block as the intervention, with measures of association with presence or absence of lameness as the outcome available for 20 of these comparisons. Animals in the NSAID intervention groups had a lower point estimate lameness risk than animals in the comparison groups in 3 of 8 and 9 of 14 analyses for LS outcomes <10 and ≥10 d post-treatment, respectively. However, there was no difference identified between animals in the NSAID intervention groups compared with the animals in the control group in any of these pairwise comparisons with lameness as the outcome. Twelve pairwise comparisons were reported in the 2 studies with nociceptor threshold as an outcome. Animals in the NSAID intervention groups had a greater nociceptor threshold point estimate compared with animals in the comparison groups in 6 of 6 and 1 of 6 analyses for outcomes <10 and ≥10 d post-treatment, respectively. However, no differences were identified between animals in the NSAID intervention groups and those in the comparison groups. All 4 pairwise comparisons reported in the study with lying times as an outcome found no differences between animals in the NSAID groups and those in the comparison groups. Despite the widespread use of NSAID in the treatment of claw horn lameness, there is a lack of studies of NSAID association with LS, nociceptive thresholds, or lying times. The limited evidence is consistent with no association with NSAID use and those parameters, but comparability across studies was limited by heterogeneity., (The Authors. Published by Elsevier Inc. and Fass Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).)

This 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., (© 2022, The Authors. Published by Elsevier Inc. and Fass Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).)

Trace minerals, have a role in immune function and a trace mineral supplement (TMS) can improve animal health in dairy herds. This prospective randomised clinical study assessed whether subcutaneous injection of 5.5 mL of TMS (40 mg zinc, 10 mg manganese, 5 mg selenium, 15 mg copper per mL), 14-28 days before planned start of calving (PSC) reduced clinical mastitis (CM), subclinical mastitis (SCM) and purulent vaginal discharge (PVD). From four farms, half of 1700 cows stratified on somatic cell count, age and breed were randomly allocated to treatment or no treatment. Occurrence of CM from - 7 to PSC + 100 days, SCM at PSC + 60 days and PVD at PSC + 24 days was analysed using survival analysis and Bayesian generalised mixed multivariable models. From -7 to PSC +30 days, TMS reduced the adjusted hazard ratio (HR) for CM at quarter and cow level (P < 0.001), with no evidence for an effect beyond 30 days. The adjusted OR (and 95% highest density interval, HDI) for the effect of TMS on CM from -7 to PSC +30 days was 0.40 (95% HDI, 0.26-0.63) at quarter level, 0.51 (95% HDI, 0.38-0.69) at cow level and for SCM, 0.72 (95% HDI, 0.54-0.95). The difference in CM incidence from TMS at the cow level was -2.0% (95% HDI, -3.4 to -1.1%) and -1.2% (95% HDI, -3.2 to - 0.6%) at quarter level. No clear effect was identified of TMS on cumulative incidence of PVD., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Background: A novel ELISA test has been developed to detect antigen-specific IgG in early and late lactation cows in New Zealand., Objectives: This study was to evaluate the discriminatory ability of the ELISA based on the detection of S. aureus-specific IgG as a screening test., Methods: The ELISA was used for the composite milk samples taken during routine herd testing in 2018-2019 milking season in New Zealand. In the absence of a gold standard test, the diagnostic specificity and sensitivity was estimated using a Gaussian mixture model., Results: The ELISA test had a high accuracy (AUC = 0.98) to detect antigen-specific IgG in early and late lactation cows with high somatic cell count due to either subsequent to or contemporaneous with the S. aureus invasion. Using an S/P ratio = 0.3 as the cut-off value, the ELISA test has sensitivity of 0.9 and specificity of 0.95, while the sensitivity increased to 0.94 at a cost of a decreased specificity of 0.9 at a lower cut-off value 0.26., Conclusions: The integration of the ELISA test as a screening tool into specific control programs may be useful to reduce the spread of S. aureus infections, to aid with treatment decisions, and to establish a correct milking order., (© 2022 The Authors. Veterinary Medicine and Science published by John Wiley & Sons Ltd.)

Internal teat sealants (ITS) reduce the risk of new intramammary infections over the dry period by forming a physical barrier to pathogen ingress. As the first and last 2 wk of the dry period are high-risk periods for new infections, maintaining an effective barrier in this period is a key requirement. Few studies have systematically examined sealant retention and none have done so under New Zealand pastoral conditions, where cows frequently move to separate grazing for dry periods, typically 80 to 90 d long. This multi-herd study was a split-udder equivalence trial comparing 2 ITS formulations for retention and efficacy in preventing periparturient clinical and subclinical mastitis. Both ITS contained 65% (2.6 g) bismuth salts, which contribute to the barrier within the teat canal, emulsified in ≤1.4 g of mineral oil. However, one ITS additionally contained <10% amorphous silica. At dry-off, treatment was randomly allocated to diagonal teat-pairs within 409 cows on 4 farms. All cows met industry best practice criteria for ITS treatment alone. The study unit was quarter within cow and farm. Outcomes included clinical mastitis (CM) incidence for the last 7 d of the dry period and first 42 d of lactation, subclinical mastitis (SCM) incidence 96 h after calving, and quantity of residual after centrifuging 50 mL of colostrum collected from each quarter within 24 h of calving. Proportional outcomes were analyzed using Bayesian mixed models with a binomial distribution and logit link function, whereas the quantity of residual was analyzed using Bayesian finite mixture models and cluster bootstrapping. We set a region of probable equivalence (ROPE) of ±2.5% between proportions and ±0.2 g for residual weight. Records were available for 1,596 quarters (399 cows). We detected no meaningful difference in incidence of CM or SCM attributable to differences in sealant: the model predicted treatment differences of 0.00 with a 95% highest density interval (HDI) of ±1.00%. Across all cows and farms, the marginal difference in the percentage of quarters with CM was 0.11% (95% HDI: -2.11 to 2.49%), and for SCM 0.00 (95% HDI: -1.98 to 1.94%). Including the quantity of residual recovered at calving did not improve fit or predictive ability of the models predicting CM or SCM, and the coefficient spanned the null value. The distribution of the weight of material recovered at calving was multi-modal; for 25% of quarters, more residual was recovered than inserted. When the residual weight was less than or equal to the median residual weight (2.06 g; range: 0.19-6.03 g), there was a ≥90% probability that any treatment difference in residual was ≤0.2 g. When the residual weight was between the median and 75th percentile (4.40 g; 95% HDI: 4.00 to 4.75 g), there was no clear difference in residual between products. Above the 75th percentile, there was a 90% probability that the residual from quarters differed by product type (difference = 0.36 g, 90% HDI: 0.20 to 0.54 g). In conclusion, both products had equivalent efficacy for SCM and CM. As the quantity of residual increased, the difference in residual weight recovered increased but this may represent increases in debris rather than indicating a more effective barrier., (© 2022, The Authors. Published by Elsevier Inc. and Fass Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).)

Aims: To assess whether adding glutamate dehydrogenase (GDH) activity measurements to measurements of gamma-glutamyl transferase (GGT) activity appreciably increases the accuracy of diagnosis of subclinical facial eczema (FE) in cattle., Methods: As part of a larger study on the impact of FE on productivity, GGT and GDH activities were measured in serum samples collected from 426 cattle from one dairy farm in the Taranaki region in April 2018. Bayesian latent class analysis was then used to estimate herd prevalence of subclinical FE as well as the specificity and sensitivity of the activity in serum of GGT or GDH alone, and of GGT and GDH activities combined, as diagnostic tests for subclinical FE., Results: The latent class analysis estimated the true prevalence of subclinical FE in the study population as 47.5 (95% probability interval (PI) = 38.3-55.3)%. There was no evidence of any clinically relevant difference between GGT and GDH activities as predictors of subclinical FE; the difference between the areas under the receiver operating characteristic curves for the two measures was 0.005 (95% PI = -0.02 to -0.03). Using the two tests in parallel, with a threshold of 50 IU/L for GGT and 225 IU/L for GDH resulted in specificity and sensitivity of >95%, markedly increasing the accuracy of diagnosis of subclinical FE compared to using GGT or GDH alone at any threshold., Conclusions and Clinical Relevance: In this herd, combining the two tests resulted in a clinically relevant improvement in the accuracy of diagnosis of subclinical FE compared to using either test alone, which if used at the individual level will result in fewer cattle being assigned the wrong FE status. This will also apply at the herd level, with combined testing producing fewer false-positive herd test results than using one enzyme alone. This is particularly important for monitoring the efficacy of FE control measures when the expectation should be that the proportion of cattle with FE is very low.

Aims: To design a monitoring strategy that could be applied to regular veterinary visits to dairy farms to assess the prevalence and association between health conditions (uterine disease, hyperketonaemia and suboptimal body condition score) when diagnosed and treated at 1-7 days post-calving (DPC) and then re-examined at 28-35 DPC., Methods: This study evaluated data from 187 high-yielding dairy cows (21 primiparous, 166 multiparous) on one South Australian dairy farm on two occasions; Visit A which was 1-7 DPC and Visit B which was 28-35 DPC. On each visit, the nature of vaginal discharge, concentration of beta-hydroxybutyrate (BOH) in blood and BCS were recorded and assigned a clinical score. This was converted to a categorical outcome denoting the presence or absence of an abnormal health event, namely metritis or endometritis, hyperketonaemia (BOH concentration ≥1.2 mm/L) and suboptimal body condition score (>0.5 from optimum score). Cows with uterine disease or hyperketonaemia at either visit were treated. The prevalence of abnormal health events at each visit was determined and the association between the prevalence of disease at Visit A and Visit B (following appropriate treatment at Visit A) was measured using regression analysis., Results: The prevalence of abnormal vaginal discharge, hyperketonaemia and suboptimal BCS at Visits A and B were 26%, 7%, 35% and 25%,16%, 33% respectively. A higher proportion of primiparous cows (Visit A: 0.86 (95% CI = 0.70-1.00); Visit B: 0.95 (95% CI = 0.86-1.00)) were found to have suboptimal BCS at both visits compared to multiparous cows (Visit A: 0.28 (95% CI = 0.20-0.35); Visit B: 0.24 (95% CI = 0.17-0.32)). A higher prevalence of hyperketonaemia at Visit B for multiparous compared to primiparous cows (19 (95% CI = 12-25)% vs . 0 (95% CI = 0-17) respectively) was identified. An increase in clinical discharge score at Visit A increased the odds of purulent vaginal discharge at Visit B (OR = 1.77 (95% CI = 1.31-2.40)). Failing to calve at target BCS was strongly associated with cows missing target BCS at Visit B (OR = 5.77 (95% CI = 2.35-13.11)) and for every unit increase in BCS at Visit A, BCS at Visit B increased by 0.40 (95% CI = 0.26-0.53)., Conclusions and Clinical Relevance: This study describes a pilot monitoring strategy for clinical parameters indicative of post-partum disease at 1-7 and 28-35 DPC. Determining the herd prevalence of these conditions will enable tracking of herd disease status over time. Abbreviations: BCS: Body condition score; BOH: Beta-hydroxybutyrate; DPC: Days post-calving; NEFA: Non-esterified fatty acids; SCHK: Subclinical hyperketonaemia.

Aims: To determine the association between production of milk solids (MS) and liver damage from facial eczema (FE) in dairy cattle during autumn and to determine the most practical cut-off for serum gamma-glutamyl transferase (GGT) activity in predicting production loss., Methods: Farm history and Pithomyces chartarum spore counts identified herds likely to be affected by raised GGT activity in serum during autumn 2018 or 2019. In these herds, a pilot blood sample from 30 cattle was collected, followed by a full herd blood test within 2 weeks if in those 30 cattle one or more had GGT activities >300 IU/L. Individual MS production was measured within -5 - +12 days of a full herd blood test. Information about feeding Brassica spp. was collected from the farmer. Pooled sera from 10 randomly selected cattle from 10/11 farms with GGT >40 IU/L were tested for anti- Fasciola antibodies., Statistical Analysis: The association of liver damage and production of MS was analysed using mixed linear regression. Potential risk factors included farm, cow age, MS at last herd test before the likely FE risk period, breed of cow and GGT activity. Subsequently, GGT activity thresholds, from 40-400 IU/L, were used to indicate varying severities of liver damage. For each threshold, a mixed linear model using herd test data produced estimated marginal mean differences in MS production for cows above or below threshold. The prevalence of animals above threshold was multiplied by the per cow loss to obtain the reduction in MS/day/100 cows for each cut-off., Results: The prevalence of animals with GGT activities > 40 IU/L ranged between farms from 11% (45/488) to 96% (139/145), and GGT activities for individual cows ranged from 3 - 6001 IU/L. From the model, an increase of 100 IU/L in GGT activity was associated with a decrease of 0.011 (95% CI = 0.010-0.012) kg MS/cow/day. A GGT activity threshold of 40 IU/L identified the largest association with MS production of 6.14 kg MS/day/100 cows. No evidence of significant liver fluke or brassica toxicosis was found., Conclusion and Clinical Relevance: Liver damage was most likely caused by sporidesmin toxicity and was associated with substantial linear reduction in MS., When assessing the impact liver damage has on herd milk production, threshold and prevalence of animals exceeding threshold should be considered by the practitioner in assessing economically significant facial eczema.

Aim: To measure the prevalence of gross pathological damage in the livers of dairy cows at slaughter in the North Island of New Zealand in 2018 and 2019 and to determine, using Bayesian latent class analysis, the specificity and sensitivity of gross liver pathology score (GLS) as a method for detecting moderate to severe facial eczema (FE) at processing plants., Method: Meat inspectors at four processing plants located in the Northland, Waikato, Bay of Plenty and Taranaki regions of New Zealand graded all dairy cattle livers on particular days in April and May of 2018 and 2019 using a gross liver pathology score (GLS) from 0-5 (0 = no damage, 1= fatty liver, 2 = cholangitis and early cirrhosis, 3 = cirrhosis, 4 = extensive cirrhosis, 5 = regeneration). Forty livers from each grade were selected for histopathology. Sections from the apical margin of the right and the left lobes were scored using a histology biliary score (HBS; scored from 1-16) based on the classical histological lesions of FE focussing on changes that differentiate FE from fasciolosis. Mean HBS was collapsed into scores 2-6 (no and mild damage) and score 7-12 (moderate and severe) and GLS was collapsed into grades 0-2 (no or mild damage) and grades 3-5 (moderate, severe and chronic damage). A Bayesian latent class model was developed to estimate sensitivity and specificity of HBS and GLS. The diagnostic target was moderate or severe, gross and/or histological changes in the liver consistent with FE., Results: A total of 2,899 dairy cow livers were graded at the four plants over the two study periods. There were 700/2,899 (24.1%) livers with at least some form of gross pathology damage (GLS≥1) and 130/2,899 (4.5%) livers with moderate, severe or chronic gross pathology damage (GLS≥3). The estimates (posterior median) for the sensitivity and specificity of GLS to liver damage were 0.844 (95% credible interval (CrI) = 0.757-0.905) and 0.932 (95% CrI = 0.866-0.973) respectively. Estimates for HBS were 0.834 (95% CrI = 0.765-0.892) and 0.778 (95% CrI = 0.707-0.854), respectively., Conclusion and Clinical Relevance: GLS is a useful means of estimating liver damage consistent with FE at slaughter. Increased use of liver scoring at slaughter could be useful for monitoring the likely impacts of FE at the country and regional levels.

Case history : Two commercial pasture-based farms within the North Canterbury district of New Zealand were feeding fodder beet ( Beta vulgaris vulgaris L.) as a large proportion of the diet to cows during the dry period. On each farm 25 multiparous cows were blood sampled up to six times from 28 days before, to 21 days after calving (Day 0). Plasma samples were analysed for concentrations of β-hydroxybutyrate (BHBA), non-esterified fatty acid (NEFA), Ca, Mg and P, and aspartate aminotransferase (AST) activity. The first sampling visit was performed when cows were being fed their maximum intake of fodder beet. Clinical findings : The mean body condition score (BCS) of cows on Farm 1 was 5.4 (95% CI = 5.3-5.6) and on Farm 2, 5.4 (95% CI = 5.3-5.6) at first sampling. Mean concentrations of BHBA increased between Days -15 and Day -8 then decreased postpartum on Day 2 before increasing again on Day 21. On Farm 2, concentrations remained low (<1.2 mmol/L) on all days of sampling. Mean concentrations of NEFA in plasma remained low during the periparturient period on Farm 1, then increased on Day 2. On Farm 2, concentrations were elevated above 0.3 mmol/L between Days -28 and -17 then decreased on Day -10, before increasing on Day 2. Mean concentrations of Ca, Mg and P were higher than threshold values on both farms prepartum. However on Day 2, there were 8/23 (35%) cows on Farm 1 and 6/23 (26%) cows on Farm 2 with concentrations of Ca in plasma <2.0 mmol/L, and 10/23 (44%) cows on Farm 1 and 8/23 (35%) cows on Farm 2 with concentrations of P in plasma <1.3 mmol/L. Mean AST activities remained relatively constant and below 130 IU/L on both farms at all sampling times. Clinical relevance : On both farms, post-partum hypocalcaemia and hypophosphataemia were common after calving despite differing fodder beet feeding and mineral supplementation regimes. There was more variation in energy status, especially prior to calving. More research is required on factors affecting mineral and energy status in dry cows fed fodder beet.

Aims: To evaluate agreement between the concentration of Zn in serum from samples collected from cattle and sheep into standard collection tubes for serum and from samples collected into tubes developed for trace element measurement. Methods: Eighty-eight animals (78 cattle and 10 sheep) on eight farms had paired blood samples collected into standard serum and trace element vacutainers. The paired samples were submitted the same day to the laboratory to be tested for the concentration of Zn in serum using atomic absorption spectrophotometry. The agreement between the paired results was then assessed using limits of agreement analysis. On one farm an additional 10 pairs of samples was taken from the same animals; this second set of paired samples was refrigerated for 48 hours prior to laboratory submission to identify the impact of delaying submission on the apparent concentration of Zn in serum. Results: The limits of agreement analysis found no evidence of a systematic difference between Zn concentrations in serum collected into standard serum tubes and into trace element tubes as neither the intercept nor the slope on the mean-difference plot were significantly different from zero. The SD of the difference between results increased as the concentration of Zn increased, so at the lowest Zn concentration reported in this study (6.9 μmol/L) the limits of agreement were ±1.07 μmol/L, while at the highest (23.5 μmol/L) they were ±3.39 μmol/L. Refrigerating the sample (as whole blood) for 48 hours prior to submission increased the apparent concentration of Zn in serum in both standard serum tubes and trace element tubes by 1.3 μmol/L (95% CI = 0.75-1.85). Conclusions: There was no evidence that the concentration of Zn in serum from standard serum tubes were artificially elevated. In contrast, delaying sample submission by 48 hours did elevate Zn concentrations. Clinical relevance: While these data apply only to the batch of vacutainers used in this study, there is unlikely to be much between batch variation in the potential for contamination. Thus these results suggest that monitoring zinc status in ruminants, by measuring the concentration of Zn in serum from samples collected into standard serum tubes does not result in clinically relevant alterations in Zn concentration compared to using specific trace element tubes. However delaying submission to the laboratory may result in significantly elevated concentrations of Zn in serum so should be avoided.

Bovine digital dermatitis (DD) is an important infectious cause of cattle lameness worldwide that has become increasingly prevalent in New Zealand pastoral dairy herds. In this study, a simplified DD scoring system after considering both M and Iowa DD scoring systems was applied to explore the transmission dynamics of DD in a typical spring-calving pastoral New Zealand dairy herd. The modified model only included three compartments: normal skin, early stage lesions and advanced lesions. Lesions regressing after treatment were excluded as DD lesions are rarely treated in New Zealand. Furthermore, sub-classes within each lesion class were not defined due to the lack of variability in DD lesion presentations within New Zealand. The model was validated based on longitudinal field data from three dairy herds in the Waikato region during one lactation season (2017-18). The model suggested that in infected dairy herds, although DD prevalence will tend to increase year-on-year it is likely to remain relatively low (< 18%) even after 10 years of within-herd transmission. It is likely that the low transmission rate during the late lactation (model assumption) results in more cases resolving than developing during this period and therefore results in the low prevalence of infectious cattle at the start of each subsequent lactation. Cattle with advanced lesions had a stronger influence on the establishment and maintenance of DD than cattle with early stage lesions highlighting the importance of targeting these animals for intervention. On-going monitoring of DD is highly recommended to assess the long-term progression of the disease in affected dairy herds.

Digital dermatitis (DD) is the leading infectious cause of lameness in dairy cattle, and it affects their welfare and productivity worldwide. At the herd level, DD is often assessed while cows are standing in a milking parlor, and lesions are most commonly evaluated using the M-score. The objective of this study was to examine the interobserver agreement for M-scores of the feet of standing cattle, based on digital color photographs of dairy cattle hind feet. A total of 88 photographs and written descriptors of the M-score were sent to 11 scorers working at 10 different institutions in 5 countries. The scorers received no formal training immediately before scoring the photographs; however, all regularly used the M-score to score DD. The answers for 36 photographs were excluded from the analysis because the photograph either had more than 1 M-stage as mode or not all scorers assigned an M-score to it. The M-scores of the 11 scorers from 52 photographs were available for analysis. Interobserver agreement was tested using Gwet's agreement coefficient (AC1) and the mode was assumed correct. Overall, moderate agreement emerged for the M-score (AC1 = 0.48). For the individual M-stages, almost perfect agreement existed for M0 (AC1 = 0.99), M1 (AC1 = 0.92), and M3 (AC1 = 0.82), and substantial agreement for M2 (AC1 = 0.61), M4 (AC1 = 0.65), and M4.1 (AC1 = 0.71). This outcome indicates the degree of individual variation in M-scoring in this context by unstandardized, experienced European observers, particularly for the M2, M4, and M4.1 stages. Standardized training is likely to improve the consistency of M-scoring and thus the generalizability of future DD research results on this important endemic disease., (Copyright © 2019 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

Aims: To assess the inter-observer agreement for detecting bovine digital dermatitis (BDD) lesions in digital colour photographs of the hind feet of cows, which had been taken while the animals were standing to be milked, between two trained observers., Methods: Thirty-six photographs were selected from a total of 184 photographs held by the first author (R1), who had classified them as negative (n=11) or positive (n=25) for BDD. They were delivered to a technician (R2) who had previously visually inspected cattle for BDD lesions, and who then recorded the photographs as being either BDD-positive or BDD-negative. The percentage agreement between R1 and R2, and two other inter-observer agreement statistics, Cohen's κ and Gwet's first-order chance correction agreement coefficient (AC1), were calculated. The cumulative membership probabilities of Cohen's κ and Gwet's AC1 were then calculated for different benchmark ranges of κ., Results: The percentage agreement between R1 and R2 was 33/36 (92%), Cohen's κ was 0.80 (95% CI=0.57-1.0) and Gwet's AC1 was 0.86 (95% CI=0.69-1.0). Based on the cumulative membership probabilities for Gwet's AC1, there was 75% probability that the two observers had almost perfect agreement (κ≥0.81). For both Cohen's κ and Gwet's AC1, there was >95% probability that the two observers had at least substantial agreement (κ≥0.61)., Conclusions: The two trained observers had at least substantial agreement in identifying from a digital photograph as to whether BDD lesions were present or absent. Therefore results from the two could be used interchangeably., Clinical Relevance: Visual assessment for BDD lesions in the milking parlour can be subjective. However a high agreement between these two trained BDD inspectors means BDD prevalence reported from different regions in New Zealand by these two can be directly compared.

To investigate the effect of climate and farm management practices on prevalence of bovine digital dermatitis (BDD) in spring-calving farms in Taranaki, New Zealand, whole herd assessments of BDD were made on 57 farms which had been previously identified as having cows with BDD. Assessments of BDD lesions were made on five occasions between early lactation (September 2015) and drying-off (May 2016; at approximately 6-week intervals). Along with the clinical assessment, data on farm management practices were collected using questionnaires. In addition, climate data including rainfall and soil/air temperature were obtained from a local weather station. The raw temporal pattern was analysed using a generalised estimating equation method, followed by a mixed effects negative binomial model which modelled the associations between prevalence and the covariates including management practices, rainfall and soil temperature. The highest farm and cow level prevalences were seen on the second visit (27/Oct/2015-11/Dec/2015) and were lowest on the fourth visit (29/Jan/2016-10/Mar/2016). Farms with a higher prevalence at the first visit tended to have a higher prevalence at later visits, even though the affected individuals were often different. There was thus a strong correlation (0.94) between prevalence (proportion of cows affected at each time point) and incidence (proportion of cows with new affections at each time point). Two climate measurements were found to have associations with BDD prevalence. Firstly, increased rainfall in the previous month was associated with decreased cow level prevalence; secondly, there was a quadratic relationship between prevalence and soil temperature, with prevalence increasing as soil temperature increased from 11.8 °C to approximately 18 °C and then decreasing as soil temperature increased from approximately 18 °C to 23.9 °C. In addition to the effect of climate, using outside staff to perform hoof trimming was found to increase the risk of BDD affection (risk ratio [RR]: 2.06, 95% confidence interval [CI]: 1.05-4.06)., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Visual assessment in the milking parlour is a commonly used method to determine the prevalence and severity of bovine digital dermatitis (BDD). It is generally suggested that cows' feet are washed prior to examination to maximise the sensitivity of the assessment, but concern has been expressed that washing cows' feet could contaminate the teats and lead to intramammary infection. Furthermore, the evidence for washing cows' feet is equivocal, as some studies have reported similar sensitivities for detecting BDD without washing as that reported by studies which used washing. Furthermore most of these studies have used data from housed cattle. The findings from these studies may not be applicable to cattle at pasture where feet are often contaminated with mud rather than faeces and lesions may be smaller and less severe. The aim of this study was to compare, in cattle at pasture, the sensitivities of BDD examinations before and after washing. Two herds known to have BDD were enrolled and approximately half of each herd was screened for BDD by examining the cows' hind feet before and after washing. The sensitivities of these examinations were estimated using a Bayesian superpopulation approach, and were found to be 0.34 (95% credible interval [CrI]: 0.088-0.69) and 0.63 (95%CrI: 0.46-0.78) for pre- and post-washing, respectively. There was a 93.95% probability that the sensitivity of examination post-washing was greater than that pre-washing. These results suggest that in pasture-based herds, many BDD lesions will be missed if cattle are examined without their feet being washed., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Case History: A group of 39, 19-22-month-old Friesian bulls were administered an ivermectin/closantel anthelmintic via intended S/C injection in the ischiorectal fossa on 15 June 2017 (Day 0). Over the next 50 days, 22 affected bulls presented various degrees of anorexia, abdominal pain and urine dribbling. Seventeen bulls were examined by transrectal ultrasonography which revealed urinary bladder distension in all 17, and peritoneal fluid accumulation in some. Overall, eight bulls died or were subjected to euthanasia. On-farm postmortem examination of three bulls revealed urinary bladder rupture., Clinical Findings: On Day 50 one affected live bull was admitted to Massey University for further investigation. This bull continuously dribbled urine and had an overtly distended urinary bladder as determined by rectal palpation and ultrasonography., Pathological Findings: Postmortem examination of this bull revealed a markedly distended urinary bladder, massive subcapsular and pericapsular renal oedema with retroperitoneal fluid accumulation, minimal hydronephrosis and no evidence of mechanical urinary outflow obstruction. The right ischiorectal fossa contained multifocal areas of tissue fibrosis that extended into areas innervated by the distal cutaneous branch of the pudendal nerve and the pelvic nerve. Histopathological changes consisted of extensive fibrosis, myonecrosis and neurodegeneration, and evidence of granulation tissue and inflammation at the putative injection site and in surrounding tissues., Diagnosis: A local inflammatory reaction at the presumed injection site together with localised peripheral neurodegeneration and myelopathy may have led to detrusor-sphincter dyssynergia causing urine retention., Clinical Relevance: These cases of urine retention and bladder rupture in cattle were of putative iatrogenic origin. Veterinarians should be aware of this rare complication after S/C injections in the ischiorectal fossa.

Background: Bovine digital dermatitis (BDD) is considered the most important infectious cause of lameness in dairy cattle worldwide, but has only recently been observed in New Zealand. Although many studies have investigated the risk factors for BDD in confined dairy systems, information on risk factors in pasture-based system is limited. Therefore a cross-sectional study including 59,849 animals from 127 dairy herds in four regions of New Zealand was conducted to identify the herd-level factors associated with the probability of a herd being BDD-lesion positive and with within-herd BDD prevalence., Results: Purchasing heifers was associated with increased odds of a herd being BDD-lesion positive (odds ratio [OR]: 2.33, 95% probability interval [PI]: 1.26-4.42) and a cow being BDD affected (OR: 3.76, 95%PI: 1.73-8.38), respectively. Higher odds of a herd being BDD-lesion positive (OR: 2.06, 95%PI: 1.17-3.62) and a cow being BDD affected (OR: 2.87, 95%PI: 1.43-5.94) were also seen in herds where heifers co-grazed with cattle from other properties. In addition, using outside staff to treat lameness was associated with higher odds of a cow being BDD affected (OR: 2.18, 95%PI: 0.96-4.98)., Conclusion: This study highlighted that movements of heifers are significantly associated with the spread of BDD within and between dairy herds in New Zealand. To minimise the risk of disease introductions in herds where moving heifers cannot be avoided, it is best to purchase heifers only from herds where BDD-freedom has been confirmed and, if heifers have to graze-off a farm, they should be reared as a single biosecure management group, especially since animals may be BDD-infected without having clinically obvious lesions.

A cross-sectional study of 127 dairy herds distributed across four regions of New Zealand (NZ) was conducted to estimate the regional herd-level prevalence of bovine digital dermatitis (BDD) and the prevalence of cows with BDD lesions within affected herds. Each herd was visited once during the 2016-2017 lactating season and the rear feet of all cows in the milking herd were examined to detect the presence of BDD lesions. Of the 127 herds examined, 63 had at least one cow with a detected BDD lesion. Of the 59 849 cows observed, 646 cows were observed with BDD lesions. All of the herds in which BBD was detected were located in three of the four regions (Waikato, Manawatu and South Canterbury). No convincing lesions were observed on the West Coast. The probability of BDD freedom on the West Coast was predicted to be 99.97% using a Bayesian latent class model. For the three regions where BDD lesions were observed, the true herd level and cow level prevalences were estimated using a Bayesian superpopulation approach which accounted for the imperfect diagnostic method. Based on priors obtained from previous research in another region of NZ (Taranaki), the true herd level prevalences in Waikato, Manawatu and South Canterbury were estimated to be 59.2% (95% probability interval [PI]: 44.3%-73.9%), 43.3% (95%PI: 29%-59%) and 65.9% (95%PI: 49.5%-79.9%), respectively, while the true median within-herd prevalences were estimated as 3.2% (95%PI: 2%-5%), 1.7% (95%PI: 0.9%-3.1%) and 3.7% (95%PI: 2.4%-5.5%), respectively. All of these estimates except for the true herd level prevalence in Manawatu were fairly robust to changes in the priors. For Manawatu region, changing from the prior obtained in Taranaki (the best estimate of the herd level prevalence = 60%, 95% sure > 40%) to one where the mode was 50% (95% sure < 80%) reduced the posterior from 43.3% to 35.2% (95%PI: 20.1%-53.5%). The marked variation in BDD prevalence between regions and between farms highlights the need for further exploration into risk factors for disease., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Aims: To describe and evaluate the current practices used to manage and prevent facial eczema (FE) in North Island dairy herds, and determine the within-herd prevalence of cows with elevated activities of gamma glutamyl transferase (GGT), and with concentrations of Zn in serum <18 μmol/L., Methods: Between January and May 2014, 105 herd managers from throughout the North Island of New Zealand were invited to participate in the study when regional spore counts for Pithomyces chartarum started to rise towards 30,000 spores/g pasture. Managers selected 10 representative cattle that were weighed and blood-sampled by the herd veterinarian. Blood samples were analysed for concentrations of Zn in serum and GGT activity. Pasture samples were also collected and submitted for spore count estimation. Finally a survey of farm management practices relating to prevention of FE was completed by the herd manager. A mixed-effects logistic regression model was used to determine associations between herd-level and cow-level explanatory variables and the probability of a cow having a concentration of Zn in serum <18 µmol/L., Results: Of the 1,071 cows tested, 79 (7.3 (95% CI=5.8-9.0)%) had GGT activity in serum >300 IU/L, and 35/106 (33 (95% CI=24.2-42.8)%) herds had ≥1 of the 10 cows sampled with GGT activity >300 IU/L. Of the 911 cows that were being treated with Zn, concentrations of Zn were between 18-35 μmol/L in 398 (43.6 (95% CI=40.4-46.9)%) cows, were >35 μmol/L in 32 (3.5 (95% CI=2.4-4.1)%) cows, and <18 μmol/L in 479 (52.6 (95% CI=49.3-55.9)%) cows. After adjusting for the confounding effect of region, the odds of a cow having concentrations of Zn in serum <18 μmol/L were 5.5 (95% CI=1.1-29) times greater for cows supplemented with zinc in water compared with those supplemented by drenching. Of the 105 herd managers, 103 (98%) stated that they had access to regional spore count data, but only 35/105 (33%) reported that they measured spore counts on their own farm. Overall, 98/105 (93%) managers reported that they had some form of FE management programme in place. Fungicides were used on their own or in combination with zinc treatments in 10 herds, ZnSO4 in water troughs was used in 68 herds, oral drenching with ZnO in nine herds, and ZnO supplied in-feed in 26 herds. Estimated daily dose rates of zinc were less than that required to treat a 400 kg cow on 42/68 farms that administered ZnSO4 in the water or ZnO as a drench., Conclusion and Clinical Relevance: This study has shown that FE management on dairy farms in the North Island of New Zealand could be substantially improved. It is likely that improved FE management would occur if herd managers were provided with more feedback on the success (or otherwise) of their FE management programmes.

Lameness is a significant welfare and economic issue in all dairy systems. However, there is only a limited amount of published data on the incidence and prevalence of lameness in the pasture-based systems used in New Zealand. One key area where knowledge is lacking is how well farmer perception of lameness matches that identified by more objective locomotion scoring. Previous studies of this topic have focussed on housed cows. Fifty-nine herds, 26 based in the South Island and 33 in the North Island, were surveyed. All farms were visited on one occasion at the expected peak time for lameness, and data were collected via a questionnaire which included details on farm size, and productivity as well as lameness. The latter included a farmer estimate of the number of lame cows which were currently on-farm and the number of lame cows there had been in the previous 12 months. Whole herd locomotion scoring, using the DairyCo 0-3 scale, was then used to estimate the prevalence of lameness in the herd. Farmers estimated that between 0 and 20% of their herd was lame (mean 2.2%), while locomotion scoring identified that between 1.2% and 36% of a herd was lame (mobility score ≥ 2; mean 8.1%). This finding indicated that, on a herd basis, only 27.3% (range 0-95%) of the cows with reduced mobility had been identified as such. There was no significant effect of herd size or geographical location on this percentage. The prevalence of lameness in this study was much lower than that reported in housed cattle, but the percentage of cows with reduced mobility recognised as lame was very similar. There is significant room for improvement in the detection of lameness on New Zealand farms, where routine mobility scoring, particularly at critical periods, could prove a valuable tool., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Aim: To determine the minimum number of samples required to obtain a robust estimate of the Cu and Se status of dairy herds, as assessed by determining liver Cu and serum Se concentrations., Methods: Results were collated from analyses of samples of liver from 18 dairy herds and serum from 19 herds, for concentrations of Cu and Se, respectively. All herds were in either the Manawatu or Rangitikei regions of the North Island of New Zealand. Data were used to determine the required sample size for each herd; firstly to estimate the population mean with 90% confidence with a precision of 27.5 nmol/L for Se in serum, and 100 μmol/kg fresh weight (FW) for Cu in liver; and secondly to ensure that the 90% CI of the sample mean did not include specified thresholds for concentrations of Se or Cu., Results: For Se concentration in serum, the SD of each batch varied from 0.5-147 nmol/L, and for Cu concentration in liver, the SD varied from 173-829 μmol/kg FW. For Se, the minimum sample size required to estimate the population mean to within 27.5 nmol/L with 90% confidence was >10 for 13/19 batches. For Cu, the minimum sample size required to estimate the population mean to within 100 μmol/kg FW was >10 for 17/18 batches. When estimating required sample size based on 90% CI and a threshold value, the minimum sample size to confirm the population mean of Se was >140 nmol/L was four in 17/18 batches where the sample mean was>140 nmol/L. For concentrations of Cu in liver, ≤8 samples would have been sufficient for a threshold of 45 μmol/kg FW in 16/18 batches. For the 95 μmol/kg threshold, the minimum required was 12. For the threshold of 300 μmol/kg FW, 6/17 batches with a mean >300 μmol/kg FW required ≤ 20 samples., Conclusions: From this dataset of 21 herds, the sample size recommendation for ensuring that the population mean of Se concentration was not below the marginal threshold was similar to previous recommendations. For Cu concentrations in liver, the estimated sample size recommendations for ensuring that the population mean was not below the marginal threshold was much larger than currently recommended., Clinical Relevance: In dairy cattle, five to six blood samples per group should be taken to determine Se status, and to effectively monitor Cu status a minimum of 12 liver samples should be taken, preferably in the autumn.

Estimates of point prevalence suggest that locomotion scoring identifies three times as many lame cows than when estimated by farmers. The aim of this study was to ascertain the impact of this under-recognition on the interval between identification of lameness (using locomotion score) and treatment. The study was undertaken on a 463-cow, spring-calving, pasture-fed herd in the lower North Island of New Zealand. All cows were locomotion scored (using a 1-5 scale) weekly during one milking season (July 2008 to May 2009). Survival analyses were then used to quantify the number of days between identification of a specific locomotion score and presentation, by farm staff, of a cow for lameness treatment. All cows which had a locomotion score of >3 were presented for lameness treatment subsequently, although >40% were treated more than 3 weeks after being identified. Only 75% of events where cows had a locomotion score of 3 were followed by treatment with >65% of those treatments occurring >3 weeks after the first score of 3. Improving the recognition of lameness by farm staff is thus likely to appreciably reduce the interval between reduced mobility and lameness treatment., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

The effect of lameness on the fertility of dairy cattle is well recognized. But, the effect of lameness on the fertility of seasonally breeding cattle in pasture-based systems is less well characterized. This prospective cohort study of 463 cows on 1 farm in the lower North Island of New Zealand was designed to assess the effect of clinical lameness, as identified by farm staff, on the hazard of conception after the planned start-of-mating date. A Cox proportional hazards model with time-varying covariates was used. After controlling for the effect of parity, breed, body weight at calving, and calving-to-planned start of mating interval, the daily hazard of conception for cows identified as lame was 0.78 (95% confidence interval: 0.68-0.86) compared with non-lame cows. Lame cows took 12 d longer to get pregnant compared with their non-lame counterparts., (Copyright © 2011 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

Previous descriptive analysis of data collected from veterinary visits to lame cows in the Taranaki region of New Zealand between December 1995 and July 2007 showed an association between both breed and age and lesion type and site. However, that simple analysis had significant limitations as it did not take account of more than 2 factors at the same time and did not evaluate the effect of time (either year or season). This analysis was designed to overcome those limitations. First, correspondence analysis, a multivariate method of analysis, was used to simultaneously evaluate the relationship between the 3 most commonly recorded causes of lameness (i.e., white line disease, sole injury, and axial disease, all of which are diseases of the claw horn), and 4 groups of predictor variables: foot (front or hind), breed (Jersey or Friesian), age (heifer or cow), and claw (lateral or medial). Second, time series analysis was used to ascertain the effect of season on lesion type and identify the change over years in proportional morbidity. The correspondence analysis clearly separated the 3 diseases, showing that differences between these 3 diseases in their risk factors and their etiology. Each disease clustered with a group of predictor variables. White line disease was linked to lateral claw, hind foot, cow, and Friesian breed; sole injury was linked to heifer and medial claw; and axial disease to Jersey and front foot. As sole injury and axial disease are diseases that occur principally in cows at pasture, this is the first full analysis of risk factors for those diseases. The time series analysis further strengthened the conclusion that these 3 diseases have different risk factors, as, even in the strongly seasonal New Zealand system, significant differences in seasonality occurred between them. This analysis adds further to the data which show that claw horn diseases have different etiologies and need to be treated separately for both research purposes and for lameness management on-farm. This analysis is only a starting point; more research is required, particularly longitudinal studies, to better understand the differences in etiology between the main causes of lameness due to claw horn disease, especially in cows kept at pasture, so that we can better target prevention., (Copyright © 2011 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

Aims: To quantify the range of attitudes and perceptions of cattle practitioners to painful procedures and conditions in cattle, to identify some of the demographic factors affecting those attitudes and perceptions, and to compare results from veterinarians based in New Zealand with those from the United Kingdom (UK) and Europe., Methods: A questionnaire, based on one used for similar surveys in Europe, was sent to all 455 members of the Society of Dairy Cattle Veterinarians (DCV) of the New Zealand Veterinary Association. This questionnaire included a section on demographic data, e.g. gender, year of graduation, and pre-veterinary school background, and a section which asked the respondents to rate on a scale of 1 to 10 how painful they thought 24 procedures and conditions would be without any analgesia., Results: A total of 166 questionnaires were returned, a response rate of 37%. From the range of procedures and conditions outlined in the questionnaire, those perceived as most painful were claw amputation, then Caesarean section, followed by surgery for left-displaced abomasum (LDA). The two least painful were mastitis with milk clots only, and the effect on a calf of dystocia. There were significant differences between the pain scores assigned by men and women and by respondents who had graduated in different decades. Female respondents and more recent graduates tended to give a higher pain score for most conditions. These effects remained, even after the potential interaction between age and gender had been assessed. The effect on pain score of either background or time spent treating cattle was much less marked than the effect of age and gender. Overall, the results were very similar to results from similar surveys undertaken in the UK and Europe., Conclusions: The responses to this survey indicate that, as in the UK and Europe, dairy cattle practitioners in New Zealand have a wide range of attitudes to pain in cattle. The estimates of the severity of pain were subjective, but such a survey allows the majority opinion of a considerable number of informed assessors to be quantified., Clinical Relevance: The wide range of results suggests that more needs to be done to disseminate up-to-date knowledge of pain in cattle to veterinarians to ensure they provide appropriate levels of analgesia. In particular, the baseline data from this study can be used by practitioners to identify whether they are underestimating pain in cattle and, if they are, to assess whether they are using analgesia appropriately. Additionally, this dataset provides an informed and independent assessment of the pain associated with husbandry procedures, and could be used to better guide legislation concerning pain control of such procedures.

Case History: A 4-year-old Friesian cow was reported to be having difficulty calving. Palpation by farm staff identified a large mass in the uterus, but no calf., Clinical Findings: Veterinary examination per vaginam identified a small calf and a large immobile mass. The calf was delivered by Caesarean section, but the mass could not be extracted during surgery. Biopsying the mass resulted in the loss of a large amount of fluid from it, but it remained immovable; overnight, the mass was expelled per vaginam. Gross and histological examination of the mass showed it to comprise multiple oedematous chorionic villi, prominent stratified trophoblast, undifferentiated sub-trophoblastic mesenchymal tissue that contained adipose tissue, blood vessels and bizarre striated muscle fibres, as well as irregular cisterns in the centre. No recognisable embryonic or fetal tissue was found., Diagnosis: Based on the gross and histological appearance it was concluded the mass was a complete hydatidiform mole., Clinical Relevance: This is a rare, poorly understood condition of cattle. This is believed to be the first report in a cow in New Zealand.

Aim: To analyse the records made during routine veterinary treatment of lame cows, to identify the types of lesions causing lameness of dairy cows in north Taranaki, their relative prevalence and distribution, and some of the cow-associated factors which affect these parameters., Methods: Data concerning cow age and breed, lesion type, lesion site, and whether the examination was a revisit were collected from records of veterinary visits between December 1995 and July 2007. Data were analysed on a single- or two-factor basis, using chi(2) and, where suitable, calculation of OR., Results: The total number of individual cow treatments recorded was 4,488. The most commonly recorded lesion was white-line disease (WLD) (42% of diagnoses at first examination), and the second was sole injury (29%). Heifers accounted for 19% of cases, similar to the expected replacement rate. Jerseys accounted for 18% of cases, lower than the proportion of purebred Jerseys in the region (27%). There was a significant effect of age and breed on the prevalence and distribution of lesions. There were also significant differences between lesion types in their location, which were also influenced by breed and age., Conclusions: This study provided a comprehensive overview of the lesions causing lameness in dairy cattle in north Taranaki, and identified some of the factors which influence the development of lesions. More research is needed to better establish the aetiology and pathogenesis of lameness in cattle under New Zealand conditions., Clinical Relevance: This study provides baseline data with which veterinarians can compare their results to identify significant patterns on specific farms, which will suggest specific causal factors for lameness on those farms and thus better guide prevention programmes.

Case History: A 400-cow dairy unit in the Waikato suffered a severe outbreak of facial eczema (FE) despite consistent zinc supplementation and significantly elevated serum zinc concentrations., Clinical Findings: FE prevention had begun in mid-January 2006, via zinc sulphate supplementation in the water. Photosensitisation was reported on 06 April, contemporaneous with a marked increase in the number of Pithomyces chartarum spores in pasture samples. Within 10 days of this first clinical case, 100 affected cows had been dried off, eight of which subsequently died or were culled. Blood samples were collected from ten affected cows; all had serum zinc concentrations >17 micromol/L, and eight had gamma-glutamyl transferase (GGT) activities >200 U/ml, indicating that the photosensitisation was secondary to liver damage, i.e. probably FE. Further investigation identified that this herd had been receiving excess copper supplementation; 4/6 culled cows had liver copper concentrations within or above the marginal range for copper toxicity., Diagnosis: Severe FE despite zinc supplementation that increased serum zinc concentrations above recommended levels., Clinical Relevance: As zinc supplementation significantly reduces apparent copper status, copper supplementation is often used to counteract this. Previous excess copper intake may reduce the efficacy of zinc in preventing FE, thus copper intake should be assessed prior to the start of zinc supplementation.

Digital dermatitis is commonly reported to be most severe in first lactation heifers. It has been suggested that this initial infection is followed by the development of a limited immunity to the organisms which cause digital dermatitis. If this is the case then exposure to digital dermatitis prior to calving should reduce its severity after calving. A study was undertaken to examine whether such exposure significantly affected the development of digital dermatitis post-partum. Twelve weeks prior to calving, 60 Holstein heifers were blocked on the basis of their antibody titre to Borrelia burgdorferi and randomly allocated to one of three pre-calving environments: clean straw, used straw or cubicles. There was no significant effect of pre-calving environment on the development of digital dermatitis after calving indicating that "exposure" pre-calving did not reduce the development of digital dermatitis after calving. The most important factors determining the development of digital dermatitis after calving were presence of absence of visible lesions of digital dermatitis at Week-12 and at calving.

A 7-year-old dairy cow presented with clinical signs of neurologic disease. Despite treatment with penicillin, the cow died 36 hours after initial presentation. Necropsy examination revealed multiple foci of hemorrhage within the cerebrum and thickened meninges. Additionally, endometritis and consolidation of approximately 30% of both lungs was observed. Histology revealed necrotizing vasculitis, infarction, and hemorrhage within sections of the brain, uterus, and lung. Large numbers of intralesional fungal hyphae were visible. Because only formalin-fixed tissue was available, polymerase chain reaction was used to make an etiologic diagnosis of Mortierella wolfii.

Of the 4 main diseases causing lameness in UK dairy cattle, 2 (digital dermatitis and foul-in-the-foot, or interdigital necrobacillosis) are infectious diseases that are commonly associated with similar underfoot conditions, and 2 (sole ulcer and white-line disease) result from subclinical laminitis. Comparison of the seasonality of these 2 diseases can identify whether their own unique risk factors are more important than the risk factors they share. Using a database from 46 veterinarians distributed across the United Kingdom, the seasonality of treatments for these 4 diseases was evaluated. This analysis showed that the seasonality of lameness in UK dairy cattle was significantly reduced in comparison with previous reports from the 1980s. This was primarily due to 1) a reduction in the seasonality of digital dermatitis (outbreaks of which accounted for 6.7% of veterinary reports), with only 60% of reports during the winter as opposed to 72% in earlier studies, and 2) a change in the seasonality of white-line disease from a disease that was most commonly seen in the winter (55% of reports) to a disease that was most commonly reported in the late summer or early autumn, with significantly more reports in August and October than in February. Comparison of the seasonality of digital dermatitis and foul-in-the-foot showed a significant difference in the seasonality of the 2 diseases, with foul-in-the-foot being significantly more common compared with digital dermatitis in June and August. This implies that significant risk factors exist for digital dermatitis that are not as important for foul-in-the-foot. The difference in the seasonality of sole ulcer and white-line disease was even more marked, with white-line disease being significantly more common than sole ulcer from August to October, despite these diseases being more closely linked in the literature than digital dermatitis and foul-in-the-foot. This comparison shows that the seasonality of lameness has changed in the United Kingdom and that white-line disease has significantly different risk factors than sole ulcer.

Digital dermatitis is a worldwide disease causing lameness in cattle, especially when housed. Despite its widespread nature there are relatively few peer-reviewed articles providing experimental data concerning its treatment and control. At the risk of descending to anecdote, this review attempts to summarise the current state of knowledge. Three approaches to digital dermatitis treatment have been used: (1) systemic antibiotics, (2) individual topical treatment, and (3) mass topical therapy using a footbath. Systemic antibiotics have become a rare treatment because of their cost and perceived lack of efficacy. Individual topical treatment, mainly with antibiotic preparations, is the most commonly reported method. It is widely considered the treatment of choice by virtue of reliable information about efficacy, the advantage of precise targeting of antibiotic usage and the requirements of legislation. However, at least in the UK, mass treatment of digital dermatitis by foot bathing is commonly used on many farms. In some cases, for example with antibiotic footbath solutions, these treatments create legislative, health and safety and environmental difficulties. Despite the widespread use of many different treatments, there is a lack of good comparative data and the consequence is a very variable and somewhat anecdotal approach in the field. There is a pressing need for well-researched treatment strategies for different herd situations.

This study investigated the effects of housing and nutrition on the development of hoof horn disease (as identified by the appearance of hoof horn hemorrhages) in primiparous lactating Holstein cows. The first objective was to investigate whether replacing butyl rubber mats in cubicles (free stalls) with thicker mattresses filled with chopped rubber would significantly reduce hoof horn hemorrhages, and if this reduction would so affect the level of hoof horn hemorrhages as to make it similar to that observed in primiparous cows in straw yards. The second objective was to investigate the effect of methionine supplementation for the first 13 wk of lactation on the development of such hemorrhages. This study confirmed that both sole and white line hemorrhages increase during early lactation in housed cows, although the pattern of development of white line hemorrhages is not identical to that of sole hemorrhages. Housing primiparous cows in straw yards after calving significantly reduced the development of hoof horn hemorrhages, but replacing cubicle mats with thicker mattresses had no significant effect. Providing 115% of calculated methionine requirements had no significant impact on the development of hoof horn hemorrhages.

As part of a study of the development of hoof horn haemorrhages in first-lactation heifers, measurements were made of acute phase reactants to investigate the link between the acute phase response and the development of the haemorrhages. Over a period of two years, blood samples were taken from two separate groups of heifers, weekly in the three weeks before they calved and then twice weekly until eight weeks after calving. Plasma total protein, albumin, fibrinogen, haptoglobin, seromucoid and serum iron and caeruloplasmin were measured and the relationships between the peak concentration (or activity) or the area under the curve of each acute phase reactant and the peak scores for sole or white line haemorrhages were assessed by linear regression. The results suggested that the development of the hoof horn haemorrhages observed in the study was not accompanied by an acute phase response, and the haemorrhages were therefore not primarily caused by endotoxicosis. The diets and husbandry systems used were typical of dairy farms in the UK and the results therefore suggest that a significant proportion of hoof horn haemorrhages observed in UK dairy cows may not be caused by endotoxicosis.

The efficacy of three non-antibiotic products (copper sulphate, formalin and peracetic acid) was compared with the efficacy of erythromycin, when the four substances were applied in footbaths for the treatment of cows with digital dermatitis. The cows were divided into four groups on the basis of their current housing and randomly allocated to one of the four treatments. Cattle allocated to the non-antibiotic treatments were footbathed daily for seven days, but the cattle treated with erythromycin were footbathed for two days only. Complete records were obtained for 252 lesions from 169 cows. There were significant reductions in the lesion scores of all four groups, but there was no significant effect of treatment and no significant interaction between treatment and time.