Global losses due to dairy cattle diseases: A comorbidity-adjusted economic analysis

An economic simulation was carried out over 183 milk-producing countries to estimate the global economic impacts of 12 dairy cattle diseases and health conditions: mastitis (subclinical and clinical), lameness, paratuberculosis (Johne's disease), displaced abomasum, dystocia, metritis, milk fever, ovarian cysts, retained placenta, and ketosis (subclinical and clinical). Estimates of disease impacts on milk yield, fertility, and culling were collected from the literature, standardized, meta-analyzed using a variety of methods ranging from simple averaging to random-effects models, and adjusted for comorbidities to prevent overestimation. These comorbidity-adjusted disease impacts were then combined with a set of country-level lactational incidence and/or prevalence estimates, herd characteristics, and price estimates within a series of Monte Carlo simulations that estimated and valued the economic losses due to these diseases. It was estimated that total annual global losses are USD 65 billion (B). Subclinical ketosis, clinical mastitis, and subclinical mastitis were the costliest diseases modeled, resulting in mean annual global losses of approximately USD 18B, USD 13B, and USD 9B, respectively. Estimated global annual losses due to clinical ketosis, displaced abomasum, dystocia, lameness, metritis, milk fever, ovarian cysts, paratuberculosis, and retained placenta were estimated to be USD 0.2B, 0.6B, 0.6B, 6B, 5B, 0.6B, 4B, 4B, and 3B, respectively. Without adjustment for comorbidities, when statistical associations between diseases were disregarded, mean aggregate global losses would have been overestimated by 45%. Although annual losses were greatest in India (USD 12B), the USA (USD 8B), and China (USD 5B), depending on the measure of losses used (losses as a percent of GDP, losses per capita, losses as a percent of gross milk revenue), the relative economic burden of these dairy cattle diseases across countries varied markedly.

Prevalence of lameness in dairy cows: A literature review

Lameness in dairy cows has major negative impacts on animal welfare and production economy. While previous studies have evaluated the prevalence of lameness in single countries, the present literature review is the first overview of the prevalence of lameness in dairy cows globally. This literature review identified 53 studies reporting prevalence of lameness among representative samples of dairy cows and fulfilling a number of specified inclusion criteria (e.g., at least 10 herds and 200 cows, and locomotion scoring by trained observers). A total of 414,950 cows from 3945 herds were included in these 53 studies, which spanned a 30-year period (1989-2020) and included herds from six continents, with the majority from Europe and North America. Across the studies, the mean prevalence of lameness (typically defined as score 3-5 on a 1-5 scale) was 22.8% with a median of 22.0% and a range between studies from 5.1% to 45%, and a within herd range from 0% to 88%. The mean prevalence of severely lame cows (typically defined as score 4-5 on a 1-5 scale) was 7.0% with a median of 6.5% and a range between studies from 1.8% to 21.2%, and a within herd range from 0% to 65%. Over time, it appears that the prevalence of lameness has changed very little. Several different locomotion scoring systems and definitions of (severe) lameness were used across the 53 studies, and this may have affected the reported lameness prevalence. Sampling of herds and cows, inclusion criteria and representativeness also differed between studies. This review offers recommendations for the future capture of information on lameness in dairy cows and identifies potential knowledge gaps.

Dairy cow hoof impact and slide measurements for common Ontario dairy farm floorings

In the context of understanding lameness and injury from slipping, our objective was to characterize hoof impact and slide of 5 cows walking on 6 flooring surfaces commonly used in Ontario dairy farms: diamond-grooved concrete (DC), sanded epoxy-covered concrete (EC), grooved rubber mat (GR), high-profile rubber mat (HR), low-profile rubber mat (LR), and turf grass (TG; Kentucky bluegrass/fescue mix). Surface hardness was measured on each surface using a Clegg Impact Soil Tester. Five trained lactating Holstein cows were each walked over all 6 surfaces sequentially in a randomized order. Walking speeds were determined from 60-fps videos. A 3-axis accelerometer attached to the lateral claw of each hindfoot captured continuous horizontal (aH), vertical (aV), lateral (aTLat), and medial (aTMed) accelerations at 2,500 Hz during each trial, from which peak values were identified. Data from 45°-rosette strain gauges glued to the dorsal surface of both medial and lateral hooves allowed for the calculation of principal strains (ε1 and ε2). From continuous data, several data points were extracted from 3 to 6 stances/trial: peak values of aH, aV, and aT for the impact phase of the stance; midstance values of ε1 and ε2 as proxies for force on the foot; magnitudes of normal (i.e., consistent and repeatable) sliding on the surface during the support phase; and 3 timing events to capture the cadence of the motion. All aH and aV signals were inspected onscreen to identify irregularities between the end of impact and beginning of breakover that indicated hoof slipping, which was observed on all surfaces. The effects on all measured variables of surface, cow, speed, and hoof (and all significant higher-order factors) were assessed by ANOVA in SAS 9.4 (SAS Institute Inc.), after verifying data normality. Values of aHmax, indicating grip on the surface from highest to lowest, ranked the surfaces in this order: LR, DC, HR, GR, EC, and TG. Ranking on aVmax, indicating most to least cushioning of the hoof on impact, ranked the surfaces in this order: DC, HR, GR, EC, LR, and TG. Differences in ranking among these and other significant impact variables indicate that future studies of lameness on different surfaces need to include all significant variables identified here. We detected no surface and strain interactions in either the ε1 or ε2 strain, indicating that the surfaces do not affect the overall loads on the foot at midstance. Additionally, lateral and medial hooves may have different roles in a stance. The results highlight the capacity to evaluate flooring types with this technology, and the study provides a tool for future work to examine the role of flooring types in the causation of lameness.

Association between lameness risk assessment and lameness and foot lesion prevalence on dairy farms in Alberta, Canada

Lameness is a detrimental health and welfare concern of dairy cattle with high prevalence in North American herds. As a practical and farm-specific approach toward its mitigation in Alberta, Canada, a score-based lameness risk assessment questionnaire (RAQ) was developed for veterinarians to conduct with their clients; however, its accuracy in identifying risk for lameness and hoof lesions has not been evaluated. Our objectives were to (1) provide an update on prevalence of lameness and hoof lesions in Alberta freestall herds, (2) validate the RAQ by determining the association between RAQ scores and the prevalence of herd lameness and herd lesions, and (3) determine the association between presence of common hoof lesions and lameness. For the first 2 objectives, 65 Alberta dairy farms were visited between March and October 2018 to collect a completed RAQ, hoof trimming records from their hoof trimmer, and video footage of the entire lactating herd. For the third objective, 10 participant herds were visited twice between November 2013 and June 2014 to take video footage of the entire lactating herd and collect hoof trimming records from their hoof trimmer within 48 h after video footage collection. Median herd-level lameness prevalence was 20% (range = 2-56%), infectious lesion prevalence was 10% (range = 0-49%), and noninfectious lesion prevalence was 15% (range = 2-39%). Of cows that were lame, 93% had a lesion, whereas 21% of cows with a lesion were lame. Cows with an infectious and noninfectious lesion were, respectively, 1.5 and 3.1 times more likely to be lame than cows with no lesion. Total RAQ score and herd lameness prevalence were correlated (r = 0.26) and noninfectious RAQ score and noninfectious lesion prevalence were correlated (r = 0.45), whereas infectious RAQ score and infectious lesion prevalence were not. Cow-level mixed logistic regression models indicated no associations between any of the RAQ scores and presence of lameness or a hoof lesion. Lameness prevalence in Alberta remains high, indicative of a low adoption rate of mitigation strategies by producers. Improvement of the RAQ could allow for better reflection of lameness and lesions on farm and can be achieved through further risk factor analysis within the RAQ, which may result in removal or addition of questions as well as the adjustment of scores based on risk factors' strength of association with lameness and lesions.

Associations between On-farm Welfare, Milk Production, and Reproductive Performance in Dairy Herds in Northwestern Spain

This study was conducted to evaluate the relationship between on-farm welfare, milk production, and reproductive performance in dairy herds in northwestern Spain. Data on the welfare status from 31 herds were collected using the Welfare Quality® protocol. Linear regression was applied to assess associations between WQ criteria/principle scores on farm average 305-d milk production and calving to conception interval (CCI). Results indicated that milk production was associated with the absence of prolonged hunger criterion (average increase of 22.33kg per unit score). Each one unit increase in the score for good feeding was also associated with a26.49kg increase in milk production. A10 unit increase in the scores for the absence of pain (by management procedures), expression of social behaviors, and absence of injuries was associated with reductions in CCI by 1.77, 0.8, and 0.29 days. CCI also decreased by 1.08 and 0.53 days when the principles of good health and appropriate behavior increased by 10 units. This study points out associations which can help encourage the dairy cattle sector to adopt practices that promote animal welfare.

Better recovery from lameness among dairy cows housed in hospital pens

Housing in hospital pens may be beneficial for lame cows due to soft flooring and less competition for resources. We compared recovery from lameness among dairy cows housed in designated hospital pens, with deep-litter straw, with recovery among cows housed together with the rest of the lactating cows in their home pens, with cubicles and slatted or solid concrete floors. Additionally, we compared lying behavior in the 2 groups of cows. A total of 168 lame dairy cows from 5 herds were included in the study. Each herd was visited once weekly, and lame cows (locomotion score 3 or 4 on a 5-point scale) were examined in a hoof-trimming chute, trimmed, and randomly assigned to 1 of 2 treatments: housing in a hospital pen (termed "treatment"; 72 cows) or housing under the herds' standard conditions together with the rest of the lactating cows in the herd (termed "control"; 96 cows). Cows were locomotion scored weekly until they were no longer lame or until they had been part of the trial for 3 weeks (i.e., 2, 3, or 4 locomotion scorings per cow). We categorized cows to describe the progression of lameness over time: recovery (divided into fast, medium, or slow), improvement without recovery, constant lameness, or worsening of lameness. Lying behavior was recorded in a sample of 60 of the 168 cows for a period of 5 d. Overall, recovery from lameness was significantly different between treatment and control cows. The proportion of cows included in the study with locomotion score 4 and a subsequent improvement was significantly higher among treatment cows than among control cows. Among cows included with locomotion score 4, 40% of treatment cows also had a locomotion score 4 at the fourth locomotion scoring, 46% had improved to a score 3, and 14% were no longer lame. In comparison, 73% of control cows had a locomotion score 4 at the fourth locomotion scoring, 16% had improved to a score 3, and 11% were no longer lame. We found no differences between treatment and control cows for mean daily lying time, number of steps per day, number of daily lying bouts, or mean duration of lying bouts. Housing of lame dairy cows in a hospital pen with a soft surface, easier access to feed and water, a smaller group size, and reduced waiting time for milking may have positive effects on recovery from lameness. Typically, farmers have housed only severely lame cows in hospital pens. However, our results indicate that less severely lame cows may also benefit from a stay in a hospital pen.