Preventive Hoof Trimming and Animal-Based Welfare Measures Influence the Time to First Lameness Event and Hoof Lesion Prevalence in Dairy Cows

Exploring uses for an algorithmically generated Animal Welfare Indicator for welfare assessment of dairy herds

On-farm welfare assessment is time-consuming and costly. Assessing welfare using routinely collected herd data has been proposed as a more economical alternative. The online Animal Welfare Indicator (AWI), developed by a Norwegian dairy cooperative, applies an algorithm to routinely collected health, production, and management data to "indicate" aspects of animal welfare at herd level. The overall AWI score is based on 10 AWI subindicator scores, representative of elements of animal welfare such as claw health, udder health, and mortality. Our cross-sectional study explored 2 ways in which the AWI may enable more efficient welfare assessment of Norwegian dairy herds. First, we investigated using the AWI to reduce the duration of on-farm assessments by replacing on-farm measures. Second, we examined reducing the number of on-farm welfare assessments by using the AWI to predict which herds have poorer welfare with respect to specific on-farm measures. Using Spearman rank analyses, we investigated if the AWI scores for 157 herds were associated with 24 on-farm welfare variables measured contemporaneously by Welfare Quality assessment. The mortality AWI subindicator score and the percentage mortality in the previous 12 mo were moderately correlated, as were the udder health AWI subindicator score and the percentage high somatic cell count (SCC) in the previous 3 recordings. Only negligible or weak correlations were found between the other AWI scores and the on-farm assessment variables. We built Generalized Linear Models using AWI scores as independent variables to predict herds with poorer welfare. Herds were classified as having poorer welfare based on their results in specific on-farm welfare measures. We evaluated the models' predictive ability and accuracy. Moderately accurate models were built for predicting poorer herds with respect to high SCC, mortality, and moderate or severe lameness. The other models were less accurate. The AWI scores were generally unsuitable as replacements of on-farm welfare measures. The AWI subindicators for udder health and mortality could replace the on-farm welfare measures related to those 2 topics, but there was some overlap in the data used to calculate them. Despite a lack of independence, the use of those 2 AWI subindicators may marginally reduce the duration of on-farm assessments. A prediction model based on AWI scores showed potential for identifying herds with poorer welfare in terms of moderate or severe lameness, facilitating more efficient use of resources for on-farm lameness assessment. As a consequence of the data used in the AWI, it was only reflective of health-related welfare outcomes.

Prevalence and Risk Factors Associated with Rib Lesions in Dairy Cows

Unilateral or bilateral hard bony enlargement is sometimes palpated over dairy cows' ribs. Although usually not painful, these injuries may have welfare and economic implications and can be used as indicators of poor husbandry conditions. The objective of this study was to determine the prevalence of rib lesions in dairy cows kept in intensive systems and to identify the risk factors either associated with the housing or with the animal's clinical history. We examined the ribs of all 1319 lactating cows from 22 Portuguese dairy farms. In each farm, housing and animal potential risk factors were recorded. Additionally, clinical examination, including lameness scoring, was performed on all cows showing rib lesions. The global rib lesions' prevalence per farm was 2.3%, ranging from 0% (n = 12 farms) to 6.1% (n = 1 farm). Lesions were found in cows with an average of 3.7 lactations. The main farm risk factors were narrow stalls; insufficient feeding places; insufficient cubicles; and the presence of an exposed curb at the back end of the stalls. Rib lesions were associated with a history of lameness but not with lame cows at the moment of examination or a history of being a downer cow. In conclusion, rib lesions' prevalence can be high in some farms, being significantly associated with cubicle design and lameness. By being associated with chronic lameness and inadequate housing, rib lesions should be included in dairy cows' welfare assessment protocols.

Investigating the effect of prophylactic claw trimming on the interval between calving and first observed elevated locomotion score in pasture-based dairy cows

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.

Evaluating the Effect of Preventative Trimming on Distance from the Sole Surface to the Distal Phalanx Using Ultrasonography for Lameness Prevention in Pasture-Based Dairy Cows

One common management strategy used to reduce the risk of lameness is prophylactic claw trimming. However, in pasture-based cattle, there is a concern that the immediate reduction in sole thickness resulting from sole trimming will lead to medium-to-long-term reductions in sole thickness, which may increase the risk of lameness. Nevertheless, there is a lack of data on sole thickness and trimming in pasture-based cows. Therefore, the aim of this study was to evaluate the effect of trimming on sole thickness over the medium-to-long term, as estimated using the ultrasound-measured distance from the external claw sole surface to the distal phalanx (DDP) and of DDP on the interval between calving and increased locomotion scores. A total of 38 cows were randomly selected from a 940-cow spring calving dairy farm in the North Island of New Zealand; 18 were allocated to the ultrasound hoof-trimming group and 20 were allocated to the ultrasound non-trimming group. Starting in May 2018, at the end of the 2017/18 lactation, ultrasound measurements of DDP of the right hind hoof were made on all 38 cows, and the hindlimbs of the trimming group cows were trimmed by an experienced professional hoof trimmer using the five-step Dutch method. This was repeated in October 2018 (early lactation) and May 2019 (late lactation). After calving, the cows were locomotion scored fortnightly until the end of lactation using the 4-point (0-3) scale DairyNZ system. The effect of DDP on the interval between calving and the first locomotion scores ≥1 and ≥2 was assessed using Cox proportional hazards models, and the association between trimming and DDP was explored using linear mixed models. The results suggest that DDP has no effect on the time to locomotion scores ≥1 or ≥2, although the wide confidence intervals of the latter suggest that more data are needed before any definitive conclusions can be drawn. The study failed to find any clinically important impact of prophylactic trimming on DDP. This is likely related to the finding that cows with the highest DDP at the first trimming were identified by the hoof trimmer as those needing the most trimming. The results of this study thus suggest that if the Dutch five-step method is properly applied, it is unlikely to affect sole thickness over the short-to-medium term in pasture-based cattle.

Historical Evolution of Cattle Management and Herd Health of Dairy Farms in OECD Countries

This work aimed to review the important aspects of the dairy industry evolution at herd level, interrelating production with health management systems. Since the beginning of the industrialization of the dairy cattle sector (1950s), driven by the need to feed the rapidly growing urban areas, this industry has experienced several improvements, evolving in management and technology. These changes have been felt above all in the terms of milking, rearing, nutrition, reproductive management, and design of facilities. Shortage of labor, emphasis on increasing farm efficiency, and quality of life of the farmers were the driving factors for these changes. To achieve it, in many areas of the world, pasture production has been abandoned, moving to indoor production, which allows for greater nutritional and reproductive control of the animals. To keep pace with this paradigm in milk production, animal health management has also been improved. Prevention and biosecurity have become essential to control and prevent pathologies that cause great economic losses. As such, veterinary herd health management programs were created, allowing the management of health of the herd as a whole, through the common work of veterinarians and farmers. These programs address the farms holistically, from breeding to nutrition, from prevention to consultancy. In addition, farmers are now faced with a consumer more concerned on animal production, valuing certified products that respect animal health and welfare, as well as environmental sustainability.

To meet or not to meet welfare outcome thresholds: a case-control study in dairy cow herds

Recently published thresholds allow classifying dairy cattle herds according to target, caution and alert ranges for welfare outcomes. Such normative thresholds provide one way to transparently assess production practices and are a straightforward communication tool with farmers. In an ordinal response case-control study, we investigated associations of animal, management and resource-related indicators with the risk of exceeding thresholds of prevalence for lameness, claw disorders, integument alterations and leg cleanliness. To this end, we used cumulative logistic regression models on 264 tethered and 392 loose-housed Austrian dairy herds. In tethered herds, the risk indicator average lactation milk yield was positively associated with the probability to exceed thresholds for integument alteration prevalence but negatively regarding leg cleanliness. Associations were also found for operation type regarding integument alterations (lower risk on organic vs conventional farms), for herd size regarding lameness (negative association) and dirty upper hind leg (positive association), and for percentage of fifth or higher parity cows in the herd regarding dirty lower hind leg (positive association). Stall type was identified as risk indicator regarding claw disorders (lower risk of long vs short stands). In loose housing systems, none of the analysed risk indicators was associated with the probability to exceed thresholds for total lameness and claw disorder prevalence. Negative associations with the probability to exceed caution or alert thresholds were identified for lifetime milk yield (dirty upper hind leg), lactation milk yield (dirty upper and lower hind leg), percentage of cows in the herd with a fat-protein-ratio <1 (integument alterations), and percentage of cows in the herd with a fat-protein-ratio >1.5 (dirty upper hind leg). Pasture access showed negative (severe lameness, integument alterations) and herd size positive associations (severe lameness) with the probability to exceed thresholds. Deep litter cubicles compared to raised cubicles with rubber mats showed a lower probability to exceed thresholds (integument alterations, dirty lower hind leg) as well as solid rubber compared to concrete slatted flooring in alleyways (integument alterations). Assessments carried out during the pasture period compared to during winter housing were associated with a lower risk of exceeding thresholds for leg cleanliness measures in both, tethered and loose-housed herds, and for integument alteration prevalence in tethered herds. In conclusion, no principal risk indicator was identified which consistently determined the probability of exceeding predefined thresholds of considered welfare outcomes. Nevertheless, outcome-specific factors show sufficient impact on the categorisation of farms according to prevalence ranges.