The cost of different types of lameness in dairy cows calculated by dynamic programming

Changes in Saliva Analytes Associated with Lameness in Cows: A Pilot Study

Simple Summary

Saliva may contain useful biomarkers which provide information about animal welfare using convenient and non-invasive sampling methods. In addition, the development of automated techniques of measuring analytes in saliva provides advantages from the technical point of view since they are cost-effective, reliable, and replicable. In this study, 21 salivary analytes measured by automated assays were tested as potential biomarkers of lameness, one of the most prevalent diseases in dairy cows producing significant economic losses. As a result, total esterase (TEA) showed increases in saliva in a group of 11 cows with lameness, decreasing when the lameness was solved after a specific treatment consisting of a hoof trimming and a medical treatment. In addition, TEA activity correlated with the severity of the lameness. Further studies using a larger population of cows with different causes of lameness and severity should be performed to determine the potential of TEA as a biomarker of lameness in cows.

Abstract

The possible changes in a panel of 21 salivary analytes on a population of cows with lameness before and after treating lameness by hoof trimming were analyzed. Then, the analytes that showed significant changes were studied in a larger population of cows with lameness and compared with healthy cows For this purpose, two groups of cows were made by a specialized veterinarian. One consisted of healthy cows with no external signs of diseases and no hematological or biochemical abnormalities, and showing no signs of lameness according to the numerical rating system of severity (NRS, 5-point scale); and the other composed of cows showing only lameness with a NRS of 3.1 ± 0.87 and a lesion scoring system (LSS, 4-point scale) of 3.3 ± 0.89. Both groups did not differ in parity (p = 0.140), days in milk (DIM) (p = 0.780), and body condition score (BCS) (p = 0.074). Initially, 21 biochemical analytes were determined in the saliva of six cows with lameness at the diagnosis time (T0) and twenty days after hoof trimming that successfully solved the lameness (TF). This exploratory study only showed significantly higher values in lipase (Lip) and total esterase (TEA) at T0 compared to TF (p < 0.001 and p = 0.034, respectively). When both analytes were measured in the additional five lame cows and the results of all the animals of the lame group (n = 11) were compared with the healthy group (n = 11), only TEA showed higher activities in the group of lame cows than healthy cows (p = 0.004). TEA was positively correlated with both NRS and LSS (r = 0.43, p = 0.004 and r = 0.35, p = 0.003). In conclusion, this study showed that cows with lameness in our experimental conditions had higher TEA values than healthy cows, and these values decreased after treatment. This is a pilot study, and further studies using a larger population of cows with lameness due to different causes and severity should be performed to determine the potential of TEA as a biomarker of lameness in cows.

Genome-Wide Association Studies Reveal Susceptibility Loci for Digital Dermatitis in Holstein Cattle

Digital dermatitis (DD) causes lameness in dairy cattle. To detect the quantitative trait loci (QTL) associated with DD, genome-wide association studies (GWAS) were performed using high-density single nucleotide polymorphism (SNP) genotypes and binary case/control, quantitative (average number of FW per hoof trimming record) and recurrent (cases with ≥2 DD episodes vs. controls) phenotypes from cows across four dairies (controls n = 129 vs. FW n = 85). Linear mixed model (LMM) and random forest (RF) approaches identified the top SNPs, which were used as predictors in Bayesian regression models to assess the SNP predictive value. The LMM and RF analyses identified QTL regions containing candidate genes on Bos taurus autosome (BTA) 2 for the binary and recurrent phenotypes and BTA7 and 20 for the quantitative phenotype that related to epidermal integrity, immune function, and wound healing. Although larger sample sizes are necessary to reaffirm these small effect loci amidst a strong environmental effect, the sample cohort used in this study was sufficient for estimating SNP effects with a high predictive value.

[Changes in claw and leg health and hair cortisol concentration in dairy cows during the transition from tie-stall to free-stall housing - A study of a medium-sized farm]

OBJECTIVE

Claw health and carpal and tarsal lesions were assessed in a dairy herd during the transition from a tie-stall to a free-stall barn. The stress associated with the change in housing was also evaluated.

MATERIALS AND METHODS

The initial size of the herd was 57 dairy cows, which were evaluated 4 times, 4-5 months apart, in a hoof-trimming chute. Claw horn and skin lesions of the foot were considered separately. The carpi and hocks were assessed for hair loss and skin lesions, and the hocks were also evaluated for swelling. Tail hair samples were collected from all cows during the second visit, and the cortisol concentration of 3 different sections of the hair was measured.

RESULTS

The high prevalence of digital dermatitis and other skin lesions in the hind legs seen in the tie-stall barn (49 %) did not change significantly during the 14-month study period and was 46 % at the last visit. Heel horn erosions of the hind feet were rare in the tie-stall barn (14 %), but had a prevalence of 100 % at the end of the study. There was a trend for a decrease in the prevalence of other claw horn lesions. The prevalence and severity of carpal and hock lesions decreased significantly in the free-stall barn. Compared to values in cows at the tie-stall barn, the hair cortisol concentration was significantly higher during the transition period and at the free-stall barn.

DISCUSSION AND CONCLUSIONS

The target variables were subjected to a multitude of factors but it can be assumed that the more comfortable lying surface in the free-stall barn had the most significant effect on carpal and tarsal joint health. The fluctuating prevalence of claw horn lesions indicates that claws health should be monitored closely. The increase in hair cortisol concentration after the transition to the free-stall barn could imply increased stress, but washout of cortisol in more distal hair segments could not be ruled out.

CLINICAL RELEVANCE

The results of the present report cannot be directly applied to other herds; however, the significance of cow comfort is highlighted by the presence of fewer carpal and hock lesions. The significant increase in the prevalence of heel horn erosions indicates that the horn capsule is compromised under free-stall conditions.

Prevalence of foot lesions in Québec dairy herds from 2015 to 2018

Our first objective was to estimate the prevalence of foot lesions by type of milking system in dairy cows examined during regular hoof-trimming sessions between 2015 and 2018 in Québec dairy herds. A secondary objective was to describe the effect of day-to-day variation, cow, and herd characteristics on the prevalence of foot lesions. Data included 52,427 observations (on a cow during a specific trimming session) performed on 28,470 cows (≥2 yr old) from 355 herds. Only observations from trimming sessions in which ≥90% of the lactating herd was trimmed were considered. Lesions were recorded at the hoof level by 17 trained hoof trimmers between March 23, 2015, and July 10, 2018, using a computerized recording system. Hoof-level information was then matched with cow information and centralized at the Eastern Canada Dairy Herd Improvement. Foot lesions were classified into 6 categories: infectious, white line disease, heel erosion, ulcers, hemorrhages, and any type of foot lesions. Prevalence of each outcome was quantified using the marginal predicted mean probability estimated from a null generalized linear mixed model with a logit link, and accounted for clustering of observations by cow and by herd. Variance was partitioned to assess the variation in the probability of the outcomes attributable to each level of the data structure (day of exam, cow, and herd). Prevalence of a given foot lesion as function of milking system and of various explanatory variables (mean herd size, herd average daily production, breed of the cow, age of the cow at trimming, and year of the visit) was then estimated using a generalized linear mixed model. At least 1 foot lesion was observed in 29% of cows examined during regular trimming sessions in Québec from 2015 to 2018. Prevalence for any type of lesion was 27% for pipeline, 38% for robotic milking, and 41% for milking parlors. The highest prevalence of infectious lesions (mainly digital dermatitis) was observed in milking parlors and robotic systems, while the most prevalent lesions in pipeline were hemorrhages. Herd-level factors explained most of the disease probability for infectious diseases, heel erosion, and hemorrhages. Therefore, control of these diseases should be based on applying best herd-management practices. On the other hand, probabilities of white line disease and sole ulcers were mainly determined by cow-level characteristics.

Treponema spp. Isolated from Bovine Digital Dermatitis Display Different Pathogenicity in a Murine Abscess Model

Digital dermatitis (DD) causes lameness in cattle with substantial negative impact on sustainability and animal welfare. Although several species of Treponema bacteria have been isolated from various DD stages, their individual or synergistic roles in the initiation or development of lesions remain largely unknown. The objective of this study was to compare effects of the three most common Treponema species isolated from DD lesions in cattle (T. phagedenis, T. medium and T. pedis), both as individual and as mixed inoculations, in a murine abscess model. A total of 109 or 5 × 108Treponema spp. were inoculated subcutaneously, and produced abscess was studied after 7 days post infection. There were no synergistic effects when two or three species were inoculated together; however, T. medium produced the largest abscesses, whereas those produced by T. phagedenis were the smallest and least severe. Treponema species were cultured from skin lesions at 7 days post infection and, additionally, from the kidneys of some mice (2/5), confirming systemic infection may occur. Taken together, these findings suggest that T. medium and T. pedis may have more important roles in DD lesion initiation and development than T. phagedenis.

Randomized clinical trial evaluating the effect of bandaging on the healing of sole ulcers in dairy cattle

This randomized clinical trial investigated the effect of bandaging on 56 uncomplicated sole ulcers (SU) among a sample of 52 dairy cows. Following therapeutic hoof trimming and povidone-iodine treatment, all cows received a wooden block on the unaffected claw and were randomly assigned into either a bandaged or non-bandaged group. The bandaging process was standardized and applied by the same veterinarian. Wound size and locomotion were measured weekly. Overall, 19 of 32 SU (59.4%) in the non-bandaged group were healed at week 4 compared to 7 of 24 ulcers (29.2%) in the bandaged group. Healing was significantly higher for non-bandaged than bandaged SU (P = 0.024). Bandaging had no effect on locomotion (P = 0.9). Cows with a lower locomotion (Sprecher 1 + 2) had significantly smaller lesion sizes (median lesion size, 0.5 cm², IQR = 0.21 to 0.92 cm²) than animals with locomotion score 3-5 (median lesion size, 0.9 cm², IQR = 0.42 to 1.81 cm²; P < 0.001). A multivariate cox proportional hazard regression indicated that bandaging and parity had a significant effect on healing. Specifically, bandaged SU had a significantly lower hazard ratio (HR) to cure compared to non-bandaged SU (HR = 0.32; P = 0.01; 95% CI = 0.13 to 0.78). Furthermore, cows with parity ≥3 had a significantly higher HR to cure compared to cows in their first lactation (HR = 2.73; P = 0.025; 95% CI = 1.14 to 6.56).

A Prospective Cohort Study on the Development of Claw Horn Disruption Lesions in Dairy Cattle; Furthering our Understanding of the Role of the Digital Cushion

Claw horn disruption lesion (CHDL) is the collective term used to describe non-infectious foot lesions such as sole ulcers (SU), sole hemorrhage (SH), and white line disease (WLD) that commonly affect dairy cattle. The potential role of the bovine digital cushion, an anatomical structure located under the pedal bone and composed mostly of adipose and connective tissue, in the aetiopathogenesis of CHDL has recently been the subject of several studies. The aim of this prospective cohort study is to identify risk factors associated with the development of CHDL and to add further evidence regarding the role of the digital cushion. In order to achieve that we collected data from 500 lactations; 455 dairy cows from 3 farms were enrolled in this study. Data were collected from each animal on three occasions: 3–4 weeks before expected calving date, 1 week post calving, and 8–10 weeks post-calving. At each occasion, sole soft tissue thickness (the combined depth of the digital cushion and corium, SSTT) was measured using B-mode ultrasonography. At 8–10 weeks post-calving foot trimming was undertaken and the presence of CHDLs was recorded. Univariable analysis was undertaken between variables of interest, before multivariable regression models were constructed. Mixed effects multivariable linear regression models were created to describe the changes in SSTT and associations with various explanatory variables. Multivariable logistic regression models with the presence of SU, SH, or WLD as an outcome were also built. SSTT was shown to decrease from calving to early lactation (EL). Primiparous animals were found to have smaller SSTT, than multiparous animals. Animals with greater BCS had greater SSTT. Cows with a SU in early lactation had lower SSTT both at pre-calving and calving inspections comparing to cows without a SU. Cows that developed mastitis within 30 days of calving had approximately four times higher odds of developing SU compared to cows that did not develop mastitis. Our study advances our understanding of animal level risk factors associated with the development of CHDL and highlights the importance of the periparturient period.

Association of BoLA-DRB3.2 alleles with fusobacteriosis in cows

The Major Histocompatability Complex (MHC) determines the immune response to pathogens, and its genes are promising candidates for the search of associations with diseases. A special role is played by BoLA-DRB3 gene, the product of which directly participates in the binding of alien antigens and conditions the specificity of the immune response. The second exon of this gene codes β1-domain of class II antigens, which is necessary for binding a broad spectrum of alien antigens. Exon 2 of BoLA-DRB3 gene is extremely polymorphic, giving the possibility to search the associations of its alleles with various diseases. The article provides the results of the study on polymorphism of alleles of BoLA-DRB3.2 gene for detection of its associations with sensitivity to fusobacteriosis (necrobacteriosis) of cows. The survey was performed using PCR-RFLP method with DNA of blood from 176 cows of two herds of Ukrainian black-and-white dairy breed. As a result of the studies, in the first herd, 25 BoLA-DRB3.2 alleles were found. In the selections of nectobacteriosis susceptible and resistant cows, we found 22 and 21 variants respectively. In the second herd, in the general selection and group of healthy animals, 27 alleles were typed, and 22 in the group of susceptible cows. BoLA-DRB3.2*22 allele was the commonest in both herds in both general selections and groups of nectobacteriosis-resistant cows. In the selection of susceptible animals, the commonest was the variant BoLA-DRB3.2*16. We determined statistically significant associations of BoLA-DRB3.2 alleles with sensitivity to nectobacteriosis of cattle. BoLA-DRB3.2*03 and *22 alleles associate with nectobacteriosis-resistant, while *16 and *23 – with nectobacteriosis-susceptible cows of the both studied groups. Also, in the first herd, another allele was found – *24, indicating close relationship with the disease. The studies of polymorphism of BoLA-DRB3 gene expand the knowledge about genetic peculiarities of the Ukrainian black-and-white dairy breed. The identified molecular-genetic markers could be useful for breeders whose work is oriented towards the formation of herds which are resistant to diseases of the limbs in cattle.

In vitro biomechanical properties of sole tissues: Comparison between healthy and ulcerated bovine claws

Sole ulcers are reportedly one of the most prevalent diseases associated with lameness in dairy cattle, significantly affecting animal welfare and farm profitability. The degree to which sole soft tissues, healthy or ulcerated, are able to maintain their structure and function when subjected to compressive forces remains unknown. Therefore, the aims of the present study were to assess sole tissue biomechanics in healthy and ulcerated claws and to describe correlated histology. Cylindrical samples were harvested from zones 4 and 6, as described by the international foot map, from hind lateral healthy (n = 12) and ulcerated bovine claws (n = 8; animals n = 12). Tissue biomechanics and morphology were evaluated via compressive tests and hematoxylin-eosin-phloxine-saffron staining, respectively. A 2-sample t-test was used to compare zones' mechanical properties between healthy and ulcerated tissues, and the Cochran-Mantel-Haenszel test was used to measure the effect of claw zone on histology. The fibril modulus (E_f) and permeability (k) respectively increased and decreased in ulcerated claws (E_f = 0.201 ± 0.104 MPa; k = 0.128 ± 0.069 mm²/MPa·s) compared with healthy claws (E_f = 0.105 ± 0.050 MPa; k = 0.452 ± 0.365 mm²/MPa·s) only for zone 6. Histology scores equal to or greater than 3 were associated with macroscopic presence of ulceration. A higher proportion of adipose tissue (30% or more) was associated with zone 6 compared with zone 4, but no difference was seen between healthy and ulcerated claws. Ulcerated claws had a higher prevalence of exostoses compared with healthy ones (33% vs. 8%). Sole soft tissues showed, as hypothesized, a viscoelastic behavior using unconfined compression testing, which, however, may not reflect in vivo loading conditions. Clinical and histological signs of sole ulceration were not associated with decreased strength of the supportive apparatus of the distal phalanx in zone 4 in this study.

Cost benefit analysis of automatic lameness detection systems in dairy herds: A dynamic programming approach

Epidemiological data establish that lameness is second only to mastitis as the dairy industry's most prevalent and costly animal welfare issue. Using an automatic lameness detection (ALD) system in which continuous, accurate detection is coupled with proper treatment, is key for reducing economic losses due to lameness. It is reasonable to assume that the cost of lameness would vary with its severity. Therefore, our first objective was to estimate the cost of different lameness severity levels as a function of milk production, lameness risk, conception probability, and treatment cost using a dynamic programming (DP) model. Our second objective was to conduct a cost benefit analysis for ALD systems which can reduce production losses through early detection and treatment of lameness, when compared to visual-detection (VD; i.e., performed by humans) systems. The default production loss parameters for the VD system used as inputs to the DP model were either sourced from the literature or were estimated based on data from a field trial. The production loss parameters for the ALD system used as inputs to the DP model were based on extrapolations of parameter values used for the VD system. The profit per present cow per year under assumed expenses and revenues decreased from $426.05 (when lameness incidence was assumed to be 0%) to $389.69 when lameness incidence was 19.5 %. Out of the 19.5 % lameness incidence in our default scenario, 9.8 % were moderate cases and 9.7 % were severe cases. Average cost of lameness was $36.36 at 19.5 % incidence. Average cost of lameness increased with increased incidence and was respectively $82.05, $195.05, and $286.87 at the low, medium, and high incidence scenarios. We used an operational framework which compared the lameness costs between the VD and ALD systems with 25 %, 50 % and 75 % net avoided costs (NAC) for the 10 year lifespan of the ALD system, at default, low, medium and high lameness incidence scenarios. The net return per cow per year from using an ALD system over a VD system was $13, at low incidence and 25 % NAC. The net return per cow per year for the ALD system was as high as $99 at high incidence and 75 % NAC. Out of 351 (3 system prices, 3 system efficiencies, 3 levels of lameness incidence and 13 different herd sizes) scenarios tested, 295 resulted in a net profit within the system lifespan of 10 years, thus justifying the investment in ALD systems.

Modelling the transmission dynamics of bovine digital dermatitis in New Zealand pastoral dairy production systems

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.

Association between hoof lesions and fertility in lactating Jersey cows

The objectives of this study were to evaluate the association between hoof lesions and fertility in dairy cows. Lactating Jersey cows (n = 1,639) were enrolled at 20 ± 3 d in milk (D20), examined and treated for presence of hoof lesions (HL), and evaluated for body condition score (BCS). Afterward, they were managed according to standard farm procedures, including estrus detection and presynchronization and a 5 d Cosynch-72 protocol for cows that failed to show estrus. Ovaries were scanned at 27 and 41 ± 3 d in milk, and cows with a corpus luteum greater than 20 mm on at least 1 exam were considered cyclic. At 120 ± 3 d in milk (D120), cows were re-examined for HL and BCS. Cows were classified at D20 according to HL status as healthy (n = 1,197) or having HL (n = 429), and according to HL category as healthy (n = 1,197) or having a sole hemorrhage (n = 280), noninfectious HL (sole ulcer, toe ulcer, or white line disease; n = 113), or infectious HL (digital dermatitis and foot rot; n = 36). Cows with HL at D20 had reduced odds of being cyclic (38.3 vs. 51.9%) and a longer interval from calving to first service (58 vs. 51 d) compared with healthy cows. Cows with infectious HL at D20 had reduced odds of pregnancy to first service (16.7 vs. 38.3%) compared with healthy cows. Cows with sole hemorrhage at D20 were more likely to lose pregnancies between d 32 and 64 after the first service postpartum compared with healthy cows (10.5 vs. 5.2%). Cows with sole hemorrhage at D20 had a smaller hazard of pregnancy (67.9 vs. 75.5%) at 150 d in milk and more days open (88 vs. 77d) compared with healthy cows. To assess the relationship between the development of HL and fertility, cows were classified as healthy (no HL at D20 and D120; n = 308), cured (any HL at D20 and no HL at D120; n = 72), new HL (no HL at D20 and any HL at D120; n = 597), and chronic (any HL at D20 and D120; n = 226). Sole hemorrhage accounted for 93% of new HL. The proportions of cows with HL at D20 and D120 were 26.9 and 68.4%, respectively. We found no evidence for a difference in pregnancy hazard at 150 d in milk between cows that remained healthy (n = 308) and cows that developed new HL (n = 597). Hoof lesions at D20, but not new HL, were associated with decreased odds of cyclicity, longer interval from calving to first service postpartum, and reduced pregnancy hazard in Jersey cows. The effect of an HL diagnosis in early lactation and management to reduce chronic HL in dairy cows warrants further investigation.

Bayesian assessment of diagnostic accuracy of a commercial borescope and of trimming chute exams for diagnosing digital dermatitis in dairy cows

Digital dermatitis (DD) is a worldwide infectious disease of cattle that causes lameness, discomfort, and economic losses. The reference standard test to diagnose DD is visual observation in a trimming chute, which cannot be practically performed daily on dairy farms. Moreover, some lesion misclassification may occur using this standard diagnostic method. The possibility of misclassification makes the use of a trimming chute debatable as a perfect reference standard test. The objective of this study was, therefore, to assess the diagnostic accuracy of a commercial borescope and trimming chute exam. The accuracy (sensitivity and specificity) of the tests and DD prevalence were investigated using Bayesian latent class analyses. Our hypothesis was that a commercial borescope can be routinely used to diagnose DD in a milking parlor without previous feet cleaning. A cross-sectional study was performed in a freestall facility. The lesions were scored (M0, M1, M2, M3, M4, M4.1) in the milking parlor with a borescope, followed by an examination in the trimming chute 48 to 72 h after the borescope exam. A total of 870 hind feet were scored during 2 sessions of trimming chute exams and borescope exams in the milking parlor. The data were analyzed in 2 ways. First, data were dichotomized into DD lesions (M1, M2, M3, M4, M4.1) and absence of DD lesions (M0). Second, data were dichotomized into active DD lesions (M1, M2, M4.1) and inactive lesions (M0, M3, M4). A Bayesian latent class model allowing for conditional dependence between tests was used to estimate tests' accuracy, likelihood ratio, and DD prevalence. When the data were dichotomized into DD lesions (M1-M4.1) versus absence of DD (M0) lesions, the sensitivity and specificity of the borescope was 55% [95% credible interval (CrI) 40-71%] and 81% (95% CrI 75-88%). The sensitivity of trimming chute exams was 79% (95% CrI 68-88%), and specificity was 80% (95% CrI 71-89%). When the data were dichotomized into active lesions (M1, M2, M4.1) versus inactive lesions or absence of lesions (M3, M4, M0), the sensitivity and specificity of the borescope were, respectively, 32% (95% CrI 13-58%) and 91% (95% CrI 88-95%). The sensitivity and specificity of trimming chute exams were 91% (95% CrI 81-97%) and 81% (95% CrI 75-89%), respectively. In conclusion, it is possible to use the borescope in the milking parlor without cleaning the feet to monitor prevalence of DD lesions. However, an isolated borescope examination, especially for diagnosing active DD lesions, has low sensitivity for use as a surveillance method. For such use, the sensitivity could be improved by repeating the borescope exam on a regular basis.

Genomic evaluation for wellness traits in US Jersey cattle

The number of Jersey cows in the United States has been steadily increasing in recent years according to Council on Dairy Cattle Breeding statistics. To help producers reduce the risk of health disorders in their Jersey animals, Zoetis has developed genomic predictions for wellness traits in Jersey cattle using producer-recorded data. The traits included mastitis (MAST), metritis, retained placenta, displaced abomasum (DA), ketosis, lameness, and milk fever in cows and respiratory disease, scours, and calf livability (DEAD) in calves. Phenotypic data on health events, pedigree, and genotypes were collected directly from producers upon obtaining their permission. Each trait was defined as a binary event, having a value of 1 if an animal has been recorded with a disorder and 0 otherwise. The number of phenotypic records ranged from 216,166 for DA to 628,958 for MAST for cow traits and from 186,505 for scours to 380,429 for DEAD for calf traits. The number of genotyped animals was 41,271. All traits were analyzed using a univariate threshold animal model. The model for cow wellness traits included the fixed effect of parity and random effects of herd × year × season of calving, animal, and permanent environment. The model for calf wellness traits included the fixed effect of year of birth × calving season × region and random effects of herd × year of birth and animal. A total of 45,163 SNP were used in genomic analyses. Animals genotyped with low-density chips were imputed to the required number of markers. All analyses were based on the single-step genomic BLUP. Heritabilities ranged from 0.061 for DA to 0.120 for lameness. Predicted transmitting abilities were expressed in percentage points as deviations from the average estimated probability of a disorder in the base population. Reliabilities of genomic predicted transmitting abilities had average values between 32% (DA) and 51% (MAST and DEAD). The results indicate that a direct evaluation of cow and calf wellness traits under a genomic threshold model is feasible and offers predictions with average reliabilities comparable with other lowly heritable traits for Jersey cattle.

Serum metabolic fingerprinting of pre-lameness dairy cows by GC-MS reveals typical profiles that can identify susceptible cows

The objectives of this study were to identify metabolite fingerprints in the serum related to amino acid (AA), carbohydrate, and lipid metabolism in transition dairy cows at -8 and -4 wks prior to parturition, at +2 wks postpartum during lameness diagnosis as well as at +4 and +8 wks after parturition. All cases of lameness occurred at around +2 wks after parturition. Out of 100 dairy cows included in this nested case-control study only 6 pregnant multiparous (parity: 3.0 ± 0.6, Mean ± SEM) Holstein dairy cows with lameness only and 20 healthy control cows (CON) were selected for serum GC-MS metabolomics analysis. All cows selected were not injured mechanically and had similar parity (3.3 ± 0.6) and body condition score (BCS). A total of 29 metabolites were identified and quantified in the serum. Results showed that 18 and 15 metabolites differentiated pre-lame cows from CON ones at -8 and -4 wks prior to parturition. Ten metabolites were found altered at the week of lameness diagnosis. Of note: pre-lame cows were characterized by greater concentrations of several amino acids including Gly, Leu, Phe, Ser, Val, D-mannose, Myo-inositol, and phosphoric acid (PA) at -8 and -4 wks prior to lameness and at the week of lameness diagnosis. At +4 wks after parturition 11 metabolites were altered in lameness cows, and at +8 wks there were 13 metabolites that differentiated the two groups. The high accuracy of the top 6 metabolites at -8 wks prior to parturition or approximately 9-11 wks before lameness diagnosis (Glu, Orn, Phe, Ser, Val, and PA) and another 5 metabolites at -4 wks before parturition, or approximately 5-7 wks before lameness diagnosis (Leu, Orn, Phe, Ser, and D-mannose) suggest that those metabolites may serve as potential monitoring biomarkers of lameness prior to lameness diagnosis. Data also showed multiple alterations during the week of lameness as well as at +4 and +8 wks postpartum suggesting lame cows are not metabolically healthy several weeks after the incidence of lameness. SIGNIFICANCE: Lameness is one of the top three health issues of dairy cows in Canada that influences early culling of dairy cows. Despite a few efforts, there is scarcity of data regarding metabolic alterations that precede, associate, and follow lameness. We investigated whether alterations in the metabolite signatures prior, during, and after development of lameness can be used to screen cows for susceptibility to lameness, characterize lameness from the metabolic prospective, and predict the outcome of this economically important health issue of dairy cows. The results demonstrate typical metabotypes as shown by increased serum concentrations of Val, Gly, Ser, Leu, Phe, D-mannose, myo-inositol, and phosphoric acid at -8 and -4 wks prior to parturition (or -6 to -10 wks prior to occurrence of lameness) and at the week of lameness diagnosis.

Quantitative Trait Loci Mapping for Lameness Associated Phenotypes in Holstein-Friesian Dairy Cattle

Lameness represents a significant challenge for the dairy cattle industry, resulting in economic losses and reduced animal health and welfare. The existence of underlying genomic variation for lameness associated traits has the potential to improve selection strategies by using genomic markers. Therefore, the aim of this study was to identify genomic regions and potential candidate genes associated with lameness traits. Lameness related lesions and digital cushion thickness were studied using records collected by our research team, farm records, and a combination of both. Genome-wide analyses were performed to identify significant genomic effects, and a combination of single SNP association analysis and regional heritability mapping was used to identify associated genomic regions. Significant genomic effects were identified for several lameness related traits: Two genomic regions were identified on chromosome 3 associated with digital dermatitis and interdigital hyperplasia, one genomic region on chromosome 23 associated with interdigital hyperplasia, and one genomic region on chromosome 2 associated with sole haemorrhage. Candidate genes in those regions are mainly related to immune response and fibroblast proliferation. Quantitative trait loci (QTL) identified in this study could enlighten the understanding of lameness pathogenesis, providing an opportunity to improve health and welfare in dairy cattle with the addition of these regions into selection programs.

Kinetic effect of different ground conditions on the sole of the claws of standing and walking dairy cows

For the first time, we analyzed the direct kinetic effects of concrete and rubber flooring on the soles of live dairy cows' claws while standing and walking. Ten adult dairy cows were equipped with foil-based pressure sensors (HoofSystem, Tekscan Inc., Boston, MA) under their left hind leg using a leather claw shoe. These sensors captured parameters of pressure distribution and vertical ground reaction forces while the cows walked on the 2 tested flooring types. The mean pressure was 15.1 to 21.1% lower on rubber flooring compared with concrete; mean pressure values (± standard deviation) were 36.32 ± 7.77 N/cm² for static measures and 57.33 ± 11.77 N/cm² for dynamic measures. We observed an even more obvious relief on rubber flooring in the maximum pressure loads, which were 30.1 to 32.7% lower on rubber flooring compared with concrete; mean pressure values (± standard deviation) were 98.79 ± 14.49 N/cm² for static measures and 150.45 ± 20.87 N/cm² for dynamic measures). The force-time curves of the dynamic measures essentially showed biphasic curve progression, with local peaks at 29 and 79% of the stance phase. However, we found considerable differences in curve progression between individuals and between the lateral and medial claws, which may be verified in further investigations with more animals. The study showed a noticeable reduction in mechanical load during standing and walking on rubber flooring compared with concrete.

Bovine digital dermatitis in Victoria, Australia

AIMS

The objectives of this study were to estimate the prevalence of digital dermatitis (DD) in Victoria, Australia, and to investigate which organisms are consistent with typical DD lesions. The prevalence and causative pathogens of DD are not clear yet in Australia and this paper is one of the first to explore these questions in this country.

METHODS

Examination and sampling of limbs was undertaken at three knackeries in Victoria, Australia. Limbs were classified as normal (N), active DD-lesion (A), dried or chronic DD-lesion (D) or suspected case of DD (S). A total of 823 cows were examined. Six skin biopsies were taken at each knackery, from which DNA was extracted for diversity profiling. Histochemical staining of samples was performed on eight of the skin biopsies.

RESULTS

DD was detected in 29.8% of all cows. The prevalence of DD was significantly higher in dairy cows (32.2%) than in beef cows (10.8%). The differential abundance of Treponema-species was significantly increased in dried lesions, compared with the normal skin biopsies. Actinobacteria, Proteobacteria, Firmicutes and Tenericutes were found to be significantly different in abundance in the DD lesions compared with normal skin biopsies. Silver staining of samples showed only mild inflammation and in two samples organisms with morphology consistent with Spirochaetes were detected.

CONCLUSIONS

The calculated prevalence indicates that DD is present in Victoria, Australia. The results of diversity profiling showed that the presence of Treponema-species was significantly different between the samples of DD lesions and normal skin.

Farm-specific failure costs of production disorders in European organic dairy herds

On-farm decision support in animal health management requires a tailor-made failure costs (FCs) assessment of production disorders for the individual farm. In our study we defined a generic framework to estimate the FC of production disorders in dairy cows. We converted the framework to a practical tool in which the farm-specific FC of mastitis, ketosis, lameness and metritis were estimated for 162 organic dairy farms in four European countries. Along with the structure of the framework, the FC estimation required three distinct types of model input: performance input (related to herd performance parameters), consequential input (related to the consequences of the disorders) and economic input (related to price levels). Input was derived from official herd recordings (e.g. test-day records and animal health recordings) and farmers' responses (e.g. questionnaire replies). The average FC of mastitis, ketosis, lameness and metritis amounted to € 96, € 21, € 43 and € 10 per cow per year, respectively. The variation in FC outcomes was high among farmers and countries. Overall ranking of the disorders based on absolute values was the same for all countries, with mastitis being the costliest disorder followed in order by lameness, ketosis, and metritis. Farm specific estimates can be used to rank production related disorders in terms of their associated failure costs and thus provide valuable insights for herd health management. The practical calculation tool developed in this study should be considered by farmers or herd health advisors to support their animal health practices or advice.

Detecting bovine digital dermatitis in the milking parlour: To wash or not to wash, a Bayesian superpopulation approach

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.

Prevalence of lameness and associated risk factors on dairy farms in the Maritime Provinces of Canada

Lameness in dairy cattle is a major issue for the industry due to the effects on the welfare of the animal, the economic impact, and consumer perception. The aim of this study was to determine the prevalence of lameness and explore potential risk factors in the Maritime Provinces of Canada. Cows were scored for lameness and potential risk factors and were assessed in 46 freestall herds and 33 tiestall herds in Nova Scotia, New Brunswick, and Prince Edward Island. In freestall herds, lameness was assessed using the most common method, locomotion scoring. A cow with a gait score of ≥3 out of 5 was considered to be lame. In tiestall herds, lameness was assessed using an alternative method known as stall lameness scoring. This assessment consisted of observation of the cow for 4 behavioral changes: standing on the edge of the stall, shifting weight, resting a limb, and uneven weight bearing when moved side to side. A cow displaying 2 or more of these behaviors was considered to be lame. At the time of the assessment, other animal-, environmental-, and management-based measurements were collected. These measurements were used in multivariable logistic regression analysis to determine risk factors that were associated with lameness for both freestalls and tiestalls independently. The prevalence of lameness was 21% for freestall-housed cattle and 15% for tiestall-housed cattle. Of the 1,488 tiestall-housed cows that were assessed, 68% showed no behavioral changes, whereas 15, 15, 2, and <1% showed 1, 2, 3, or 4 changes, respectively. In freestalls, higher odds of lameness were seen when cows spent ≥3 h/d in the holding area for milking compared with those that spent <3 h/d. In tiestall herds, higher odds of lameness were seen when bedding material was wet compared with when it was dry. For both lactating cow facility types, housing the dry cows and heifers on a deep bedded pack compared with tiestalls or freestalls was associated with a decreased odds of lameness. There were also many cow-level variables associated with lameness, including parity, daily milk production, stage of production, body condition, and width at the tuber coxae (hook bones). If producers become aware of the risk factors associated with lameness, they can make informed decisions on where to implement changes to help reduce the level of lameness in their herd.

Automatic lameness detection in cattle

There is an increasing demand for health and welfare monitoring in modern dairy farming. The development of various innovative techniques aims at improving animal behaviour monitoring and thus animal welfare indicators on-farm. Automated lameness detection systems have to be valid, reliable and practicable to be applied in veterinary practice or under farm conditions. The objective of this literature review was to describe the current automated systems for detection of lameness in cattle, which have been recently developed and investigated for application in dairy research and practice. The automatic methods of lameness detection broadly fall into three categories: kinematic, kinetic and indirect methods. The performance of the methods were compared with the reference standard (locomotion score and/or lesion score) and evaluated based on level-based scheme defining the degree of development (level I, sensor technique; level II, validation of algorithm; level III, performance for detection of lameness and/or lesion; level IV, decision support with early warning system). Many scientific studies have been performed on levels I-III, but there are no studies of level IV technology. The adoption rate of automated lameness detection systems by herd managers mainly yields returns on investment by the early identification of lame cows. Long-term studies, using validated automated lameness detection systems aiming at early lameness detection, are still needed in order to improve welfare and production under field conditions.

Smart Animal Agriculture: Application of Real-Time Sensors to Improve Animal Well-Being and Production

Consumption of animal products such as meat, milk, and eggs in first-world countries has leveled off, but it is rising precipitously in developing countries. Agriculture will have to increase its output to meet demand, opening the door to increased automation and technological innovation; intensified, sustainable farming; and precision livestock farming (PLF) applications. Early indicators of medical problems, which use sensors to alert cattle farmers early concerning individual animals that need special care, are proliferating. Wearable technologies dominate the market. In less-value-per-animal systems like sheep, goat, pig, poultry, and fish, one sensor, like a camera or robot per herd/flock/school, rather than one sensor per animal, will become common. PLF sensors generate huge amounts of data, and many actors benefit from PLF data. No standards currently exist for sharing sensor-generated data, limiting the use of commercial sensors. Technologies providing accurate data can enhance a well-managed farm. Development of methods to turn the data into actionable solutions is critical.

Evaluation of tetracycline in milk following extra-label administration of topical tetracycline for digital dermatitis in dairy cattle

Digital dermatitis (DD) is a painful infectious foot lesion commonly treated topically with extra-label tetracycline. Our objectives were to determine the concentrations of tetracycline in milk and plasma and to calculate a withdrawal interval following topical application at various doses. Another objective was to evaluate agreement between tests for measuring tetracycline in milk. A randomized block trial was conducted on 2 farms, where 50 cows with active DD lesions on 2 feet were allocated to 1 of 5 treatment groups (n = 10 cows per group). Treatment groups consisted of topical applications of tetracycline hydrochloride, in a paste or as a powdered form under a bandage, at 3 different dosing levels (2, 5, and 25 g) on each of the 2 affected feet. Following enrollment and treatment, samples were collected from milk, teat skin, and blood every 8 to 24 h for up to 7 d postdosing. Concentrations of tetracycline were measured by liquid chromatography-mass spectrometry and milk samples were further tested using the Charm ROSA TET test (Charm Sciences Inc., Lawrence, MA). Tetracycline was present in milk, plasma, and teat skin from all treatment groups. Tetracycline concentrations varied depending on time of sampling, method of application, and dosing level. At 8 h post-treatment, 11% of cows had tetracycline present in milk higher than 100 ng/mL (ppb) but none higher than 300 ng/mL. The 25-g treatment group had the longest estimated withdrawal interval, the highest observed concentrations (210-244 ng/mL) of tetracycline present in milk, and the longest observed consecutive period of tetracycline presence (from 8 to 72 h) among all treatment groups. Compared with liquid chromatography-mass spectrometry, the Charm test had a sensitivity of 77 and 100% for measuring tetracycline in milk at ≥30 and ≥100 ng/mL, respectively. Post-treatment samples of the teat skin were taken from 15 cows on 6 occasions, and every cow had tetracycline present in at least 1 of those 6 samples. This confirms an association between topical DD treatment with tetracycline and contamination of the teat. A total of 22% of blood samples had detectable tetracycline, and the majority (63%) occurred at 8 h post-treatment. At 100 ng/mL, the estimated cow-level milk withdrawal interval ranged from 0 to 70 h. At 300 ng/mL, the estimated cow-level withdrawal interval ranged from 0 to 34 h, and was 0 h at the bulk tank level. We recommend that conservative measures be adopted after extra-label use of topical tetracycline for DD treatment, including using a low dose and strategic post-treatment testing for tetracycline-class drugs in milk.

The effects of crossbreeding with Norwegian Red dairy cattle on common postpartum diseases, fertility and body condition score

Norwegian Red bulls, selected in Norway, have been used for crossbreeding with Israeli Holstein on commercial farms. The aim of this project was to investigate Norwegian Red×Israeli Holstein (NRX) performance to see how the daughters perform in a different environment than the one their sires were selected in. This was done by comparing health and fertility of NRX with their Israeli Holstein (HO) counterparts. The data consisted of 71 911 HO records and 10 595 NRX records from 33 855 cows in 23 Israeli dairy herds. Calving events took place between 2006 and 2016. Five postpartum disorders (mean frequency in HO v. NRX, %) recorded by veterinarians were analyzed: anestrus (37.4 v. 41.2), metritis (40.1 v. 28.6), ketosis (11.9 v. 7.1), lameness (7.1 v. 3.1) and retained placenta (6.2 v. 4.0). The incidence of abortions was also analyzed; HO had a mean frequency of 9.9% and NRX 8.2%. These traits were defined as binary traits, with '1' indicating that the disorder was present and a treatment took place at least once, or '0' if the cow did not show signs of that disorder. Days open (i.e. the number of days from calving to conception), body condition score (BCS) recorded on a 1 to 5 scale and changes in BCS from calving to peak lactation were also analyzed. A logistic model was used for the health traits, while days open and BCS were analyzed with linear models. The model included breed group, herd-year of calving, birth year and parity as fixed effects. There was a significantly higher risk (odds ratio for HO v. NRX in parentheses) of ketosis (1.46), metritis (1.78), lameness (2.07), retained placenta (1.41) and abortion (1.13) in HO compared with NRX. Israeli Holstein heifers and cows in parity 3 to 6 had fewer cases of anestrus than NRX but no differences were found between the groups in parities 1 and 2. Body condition score was higher for NRX than HO and there was less change in BCS from calving to peak lactation in NRX compared with HO. Likewise, NRX had fewer days open than HO. Results indicate that crossbreeding can produce cows with better fertility that are less susceptible to postpartum disorders.

Use of a stochastic simulation model to estimate the cost per case of digital dermatitis, sole ulcer, and white line disease by parity group and incidence timing

A farm-level stochastic simulation model was modified to estimate the cost per case of 3 foot disorders (digital dermatitis, sole ulcer, and white line disease) by parity group and incidence timing. Disorder expenditures considered within the model included therapeutics, outside labor, and on-farm labor. Disorder losses considered within the model included discarded milk, reduced milk production, extended days open, an increased risk of culling, an increased risk of death (natural or euthanized), and disease recurrence. All estimates of expenditures and losses were defined using data from previously published research in stochastic distributions. Stochastic simulation was used to account for variation within the farm model; 1,000 iterations were run. Sensitivity of foot disorder costs to selected market prices (milk price, feed price, replacement heifer price, and slaughter price) and herd-specific performance variables (pregnancy rate) were analyzed. Using our model assumptions, the cost per disorder case over all combinations of parity group and incidence timing, regardless of incidence likelihood, was lowest for digital dermatitis ($64 ± 24; mean ± standard deviation), followed by white line disease ($152 ± 26) and sole ulcer ($178 ± 29). Disorder costs were greater in multiparous versus primiparous cows and were always highest at the beginning of lactation. The greatest contributing cost categories were decreased milk production, an increased risk of culling, and disease recurrence. The contribution of cost categories to the total cost of disorder varied by disorder type, parity group, and incidence timing. For all disorders, the cost per case increased as milk price or replacement heifer price increased and decreased as feed price, pregnancy rate, or slaughter price increased. Understanding how foot disorder costs change according to cow-specific conditions (i.e., disorder type, parity group, and days in milk at incidence) and herd-specific conditions (i.e., market prices and performance variables) can help improve on-farm decisions about treatment and prevention of foot disorders.

A longitudinal study of digital cushion thickness and its function as a predictor for compromised locomotion and hoof lesions in Holstein cows

Lameness is a major animal welfare and economic issue for the dairy industry and is a challenge to overcome due to multifaceted causes. Digital cushion thickness (DCT) is a strong predictor of lameness and is phenotypically associated with incidence of claw horn disruption lesions (CHDL; sole ulcers and white line disease). We hypothesized that DCT varies between digits and across lactation within the cow. This variation could be characterized to predict the occurrence of CHDL or compromised locomotion. BCS, visual locomotion score (VLS), DCT, and presence or absence of lesions were collected at 4 time points: <40 d prepartum (DPP), 1 to 30 d in milk (DIM), 90 to 120 DIM, and ≥255 DIM for 183 commercial Holstein cows enrolled in the study. Cows underwent digital sonographic examination for the measurement of DCT evaluated at the typical sole ulcer site beneath the flexor tuberosity for the right front medial and lateral digits and right hind medial and lateral digits. Factors such as parity number and stage in lactation were obtained from farm management software (DairyComp 305; Valley Agricultural Software, Tulare, CA). Cows were grouped by parity: primiparous (parity = 1) or multiparous (parity ≥ 2). The prevalence of CHDL among time points ranged from 0% to 4.2% for primiparous cows vs. 2.5% to 25% for multiparous cows, whereas the prevalence of lameness based on VLS of 3 to 5 ranged from 1.7% to 8.3% for primiparous cows vs. 12.7% to 33% for multiparous cows. DCT varied within primiparous and multiparous cows based on stage of lactation and digit (P < 0.05) and was thicker for both parity groups prior to dry off (≥255 DIM) and thinnest prior to calving (<40 DPP) and after peak lactation (90 to 120 DIM). The DCT of the front medial digit was thickest for primiparous heifers, whereas the hind lateral digit was thickest for multiparous cows. The DCT of the hind medial digit was thinnest for both parity groups. Parity group and DCT of the hind lateral digit <40 DPP were important predictors of CHDL (P < 0.05), whereas parity group and DCT of the hind lateral digit and front lateral digit at 1 to 30 DIM were key predictors of VLS lameness (P < 0.05). These results may help identify animals with higher odds of developing these diseases by highlighting key time points and specific digits of importance for monitoring. In addition, it improves our biological understanding of the relationship between DCT and lameness.

A Differential Innate Immune Response in Active and Chronic Stages of Bovine Infectious Digital Dermatitis

Digital dermatitis (DD) commonly associated with Treponema spp. infection is a prevalent infectious bovine foot disease characterized by ulcerative and necrotic lesions. Lesions associated with DD are often classified using the M-stage scoring system, with M0 indicating healthy heel skin and M4 indicating chronic lesions. Current treatments utilizing antimicrobials or chemical footbaths are often ineffective and rarely cure DD lesions. Understanding the function of the innate immune response in the pathogenesis of DD will help to identify novel therapeutic approaches. In this study, the expression of the local innate host defense peptides cathelicidins and β-defensins was investigated in cows with DD and associated with the presence of treponemes and inflammatory reactions. Samples from active ulcerative DD lesions (M2) had considerable epidermal neutrophilic infiltration and increased gene expression of β-defensin tracheal antimicrobial peptides compared to control skin. Samples from acute lesions also had elevated local Cxcl-8 and TLR4 gene expression and abundant treponemes as identified by direct visualization, immunohistochemistry, and culture. Conversely, the anti-inflammatory peptide IL-10 was elevated in skin from chronic (M4) lesions, whereas bovine cathelicidin myeloid antimicrobial peptide 28 (Bmap-28) was increased in skin from oxytetracycline-treated M2 lesions. Experiments using cultured human keratinocytes challenged with Treponema spp. isolated from clinical cases of bovine DD showed that structural products from treponemes are able to initiate the innate immune response, in part through TLR2 signaling. These findings indicate that neutrophil influx, Cxcl-8, and β-defensin are key markers of active DD. Cathelicidins and IL-10 seem important in response to treatment or during the chronic proliferative stages of the disease.

A survey of United States dairy hoof care professionals on costs associated with treatment of foot disorders

The objective of this study was to collect information regarding hoof care professionals' billing practices and to gather their opinions about foot disorders and the value of their prevention. Responses were gathered from veterinarians (n = 18) and hoof trimmers (n = 116) through both online and paper survey platforms. Because of the limited number of respondents, veterinarian responses were not further analyzed. Of the 6 foot disorders included in the survey, the treatment cost per case was greatest for toe ulcers (mean ± standard deviation; $20.2 ± 8.5), sole ulcers ($19.7 ± 8.6), white line disease ($19.5 ± 8.1), and thin soles ($18.1 ± 8.1), and least for infectious disorders (foot rot and digital dermatitis; $8.0 ± 7.6 and $7.5 ± 9.6, respectively). Of the disorders, digital dermatitis represented most of the foot disorder cases treated by respondents over the past year (43.9 ± 20.4%), whereas toe ulcers and thin soles represented the least (5.3 ± 4.1 and 5.3 ± 5.7%, respectively). Respondents that served mostly large herds (>500 lactating cows) reported a lower prevalence of digital dermatitis (31.6 ± 4.2 vs. 44.4 ± 3.4 and 46.7 ± 3.2% in small and medium herds, respectively) and a higher prevalence of sole ulcers (23.1 ± 3.0 vs. 13.4 ± 2.4 and 13.3 ± 2.3% in small and medium herds, respectively). Region of the United States (Northeast, Midwest, or other) also influenced foot disorder prevalence; respondents from the Northeast reported more sole ulcers than respondents from other regions (22.1 ± 2.3 vs. 12.4 ± 3.3%). When respondents were asked which disorder was associated with the greatest total cost per case to the producer (treatment and labor costs plus the reduction in milk yield, reduced reproductive performance, and so on), hoof trimmers ranked digital dermatitis as having the greatest total cost per case and thin soles as having the least total cost per case. Finally, respondents indicated that the most important benefits of reducing foot disorders were enhanced animal welfare and increased milk production, whereas the least important benefit was reduced veterinary and hoof trimmer fees. Results from this survey can be used to improve the accuracy of foot disorder cost estimates and contribute to better decision-making regarding both foot disorder treatment and prevention.

Effects of some diseases observed at postpartum period of cows in dairy farms: Economic perspective

In this study, financial losses due to several endemic diseases at the postpartum period of dairy cows were calculated, using the incidence rates and the financial losses from each clinical case of the endemic diseases reported in the literature. The median values of the incidence rates reported in the literature for retained placenta, clinical hypocalcemia, subclinical hypocalcemia, clinical metritis, clinical mastitis, clinical ketosis, subclinical ketosis, lameness and displaced abomasum were 8.6, 3.9, 33, 13.3, 7, 2.5, 19.8, 4.3 and 1.8% respectively. The average losses per case arising from retained placenta, clinical hypocalcemia, clinical metritis, clinical mastitis, clinical ketosis, lameness and displaced abomasum were calculated to be $257, $279, $278, $212, $109, $223 and $340 respectively. Using the above stated findings, the financial losses for each average cow arising from retainedplacenta, clinical hypocalcemia, clinical metritis, clinical mastitis, clinical ketosis, lameness, displaced abomasum and the total of 7 diseases were estimated to be $22, $11, $37, $15, $3, $9, $6 and $103 respectively.

Housing, management characteristics, and factors associated with lameness, hock lesion, and hygiene of lactating dairy cattle on Upper Midwest United States dairy farms using automatic milking systems

The objectives of this cross-sectional study were to describe housing and management practices on farms using automatic milking systems (AMS) in 2 states of the upper Midwest and to evaluate the association of various housing and management factors with 3 measures of animal welfare: prevalence of lameness, severe hock lesions, and dirty cows. Fifty-four farms were visited once to collect facility measurements and observations, interview the dairy producer, and score cows for locomotion, hock lesions, and hygiene. Median number of AMS units/farm was 2 (interquartile range = 1; range = 1 to 8). Factors concerning labor were the most commonly cited reason by dairy producers for making the transition to the AMS; additional commonly cited factors were an improvement in lifestyle and human health. Number of cows fetched per AMS, or manually brought to the AMS if not milked voluntarily, was 4.7 ± 2.3 cows/AMS per day (8% of cows) for free traffic flow farms and 3.3 ± 1.8 cows/AMS per day (5% of cows) for guided traffic flow farms. Cow resting surface was significantly associated with prevalence of lameness and severe lameness. Farms with sand-bedded freestalls (17.2%) and bedded packs (17.4%) had significantly lower lameness prevalence (score ≥3 on a 1 to 5 scale, with 1 = normal locomotion) than farms with mattress freestalls (30.5%), waterbeds (25.0%), and mattresses with access to pasture (22.6%). Farms with mattresses and access to pasture had similar lameness prevalence to farms with waterbeds, but were lower than farms with mattresses only. A somewhat similar result was found for severe lameness prevalence (score ≥4 on a 1 to 5 scale, with 1 = normal locomotion); farms with sand-bedded freestalls (2.8%), bedded packs (0.0%), and mattress freestalls with access to pasture (1.5%) had significantly lower prevalence than farms with mattresses (7.1%) or waterbeds (10.8%). Severe hock lesion prevalence (score = 3 on a 1 to 3 scale, with 1 = normal, 3 = swelling) in herds with sand-bedded freestalls, waterbeds, and bedded packs were similar and significantly lower than the prevalence in mattress-based freestalls. Cows housed in sand-bedded freestalls had significantly lower prevalence of dirty cows (score = 3 or 3.5 on a 1 to 5 scale, with 1 = clean) than those housed on mattresses and waterbeds, and had significantly lower prevalence of severely dirty cows (score = 4, 4.5 or 5 on a 1 to 5 scale, with 1 = clean) than all other housing systems except waterbeds, which was similar. Manure removal system (manual, automatic, or slatted floor) was significantly associated with prevalence of severely dirty cows; farms with manual scraping had lower prevalence of severely dirty cows than farms where alley scraping was practiced automatically or slatted floors were used. Dairy producers using AMS appeared to be successful with a variety of facility designs and management practices. Cow resting surface in AMS herds was associated with some animal health and welfare measurements.

Optimising lameness detection in dairy cattle by using handheld infrared thermometers

Lameness is one of the most serious economic and welfare issues in the dairy industry. Early detection of lameness can be difficult, but provision of early treatment is crucial. Previous studies have used infrared thermography to show that increased foot temperature (FT) is associated with lameness and foot lesions. However, poor accuracy has limited the management application potential. This study analysed ambient-temperature (AT)-adjusted foot-surface temperatures and temperature differences between the hind feet of individual cows to enhance lameness detection. Cow FTs were recorded on a 990-cow farm using an infrared thermometer fortnightly for 6 months. Additionally, mobility level was scored using the AHDB Dairy 4-point scale. The averages of FTs and ATs were 23.83 ± 0.03°C and 13.99 ± 1.60°C, respectively. The FT of cows with lameness was significantly higher than that of cows without lameness (P < 0.001). Increases in FTs correlated with the mobility score (MS) (P < 0.001). According to receiver operating characteristic (ROC) curves, the optimal threshold based on actual FTs was 23.3°C with 78.5% sensitivity and 39.2% specificity. However, the ROC curve for the AT-adjusted FT and FT difference parameters showed minimal improvements over the FT in detecting lameness. In conclusion, the infrared thermometer results demonstrated the association between elevated FTs and lameness, but further improvements to this detection technique will be required before it can be implemented as a management tool for detecting cows that could benefit from treatment. With additional validation, the technique could be used as a screening device to identify cows in need of further assessment.

The farm cost of decreasing antimicrobial use in dairy production

Antimicrobials are used in animal agriculture to cure bacterial infectious diseases. However, antimicrobial use (AMU) inevitably leads to the selection of resistant bacteria, potentially infecting humans. As a global public threat, antimicrobial resistance has led policy makers to implement regulations supervising AMU. The objective of our research was to investigate the farm impact of several potential policies aimed at decreasing AMU. We modeled a dairy herd of 1000 cows with an average level of disease prevalence for the nine most frequent bacterial dairy diseases found in western countries. We calculated the farm net costs of AMU prohibition, as well as cost increases in antimicrobial treatments prices, and an increase in the milk withdrawal period after AMU. Sensitivity analyses were conducted to assess the impact of output and input prices, and disease prevalence. At a mean disease prevalence, the average net costs of not using antimicrobials were $61 per cow per year greater compared to a scenario modeling current farm AMU. The model predicted that the minimum and maximum increased costs associated with AMU prohibition were $46 and $73 per cow per year compared to current AMU. In each scenario, the cost difference increased with disease prevalence. Sensitivity analysis showed that the three stochastic variables which most significantly influenced the cost difference were respectively, cow replacement prices, cow slaughter price, and the milk price. Antimicrobial price increases of a factor of five, or extending the milk withdrawal period by 15 days, resulted in increasing the costs of diseases to a level where the farmer was better off not using antimicrobials. Our results suggest that the farm level costs of AMU prohibition in many cases might be minor, although the consequences of any policy instrument should be carefully evaluated to reach the ultimate goal of decreasing AMU without threatening the sustainability of milk production.

Animal board invited review: Dairy cow lameness expenditures, losses and total cost

Lameness is one of the most costly dairy cow diseases, yet adoption of lameness prevention strategies remains low. Low lameness prevention adoption might be attributable to a lack of understanding regarding total lameness costs. In this review, we evaluated the contribution of different expenditures and losses to total lameness costs. Evaluated expenditures included labor for treatment, therapeutic supplies, lameness detection and lameness control and prevention. Evaluated losses included non-saleable milk, reduced milk production, reduced reproductive performance, increased animal death, increased animal culling, disease interrelationships, lameness recurrence and reduced animal welfare. The previous literature on total lameness cost estimates was also summarized. The reviewed studies indicated that previous estimates of total lameness costs are variable and inconsistent in the expenditures and losses they include. Many of the identified expenditure and loss categories require further research to accurately include in total lameness cost estimates. Future research should focus on identifying costs associated with specific lameness conditions, differing lameness severity levels, and differing stages of lactation at onset of lameness to provide better total lameness cost estimates that can be useful for decision making at both the herd and individual cow level.

A comparison of a novel time-based summary measure of dairy cow health against cumulative disease frequency

Background

There is an increasing push for dairy production to be scientifically grounded and ethically responsible in the oversight of animal health and well-being. Addressing underlying challenges affecting the quality and length of productive life necessitates novel assessment and accountability metrics. Human medical epidemiologists developed the Disability-Adjusted Life Year metric as a summary measure of health addressing the complementary nature of disease and death. The goal of this project was to develop and implement a dairy Disease-Adjusted Lactation (DALact) summary measure of health, as a comparison against cumulative disease frequency.

Methods

A total of 5694 cows were enrolled at freshening from January 1st, 2014 through May 26th, 2015 on 3 similarly managed U.S. Midwestern Plains’ region dairies. Eleven health categories of interest were tracked from enrollment until culling, death, or the study’s completion date. The DALact accounted for the days of life lost due to illness, forced removal, and death relative to the average lactation length across the participating farms.

Results

The DALact consistently identified mastitis as the primary disease of concern on all 3 dairies (19,007–23,955 days lost). Secondary issues included musculoskeletal injuries (19,559 days), pneumonia (11,034 days), or lameness (8858 days). By comparison, cumulative frequency measures pointed to mastitis (31–50%) and lameness (25–54%) as the 2 most frequent diseases. Notably, the DALact provided a robust accounting of health events such as musculoskeletal injuries (5010–19,559 days) and calving trauma (2952–5868 days) otherwise overlooked by frequency measures (0–3%).

Conclusions

The DALact provides a time-based method for assessing the overall burden of disease on dairies. It is important to emphasize that a summary measure of dairy health goes beyond simply linking morbidity to culling and mortality in a standardized fashion. A summary measure speaks to the burden of disease on both the well-being and productivity of individuals and populations. When framed as lost days, years, or lactations the various health issues on a farm are more comprehensible than they may be by frequency measures alone. Such an alternative accounting of disease highlights the lost opportunity costs of production as well as the burden of disease on life as a whole.

Short communication: Detection of lameness in dairy cows using a grooming device

Lameness in dairy cattle is a common welfare problem with significant economic implications. All too often, appropriate treatment is delayed or neglected due to insufficient detection of lame cows. Brush usage is considered a low-resilience activity; that is, one that typically decreases when energy resources are limited or when the cost involved in the activity increases, such as during sickness and stress. The aim of this study was to determine the association between brush usage and different degrees of lameness. Locomotion scores of 209 lactating Holstein dairy cows were collected individually once a week for 14 consecutive weeks, using a 5-point visual assessment scoring system (1 = nonlame, 2 = uneven gait, 3 = mild lameness, 4 = lameness, 5 = severe lameness). Daily brush usage was collected automatically from 3 cowsheds of similar size and structure located on a commercial dairy farm. In each of the 3 cowsheds, 2 brushes were installed, one next to the feed bunk, and the other away from the feed bunk (on the opposite side of the cowshed). Linear and generalized linear mixed-effects models were used to evaluate the association between locomotion scores and daily measures of brush usage. We found a significant interaction between locomotion score and brush location (near to/distant from feed bunk) on the daily proportion of cows using the brush at least once and on daily duration of brush usage. Specifically, we showed that lame and severely lame cows did not use brushes that were installed away from the feed bunk but continued to use brushes that were installed next to the feed bunk. Brush usage by cows with uneven gait (locomotion score 2) or with mild lameness (locomotion score 3) did not differ from that of nonlame cows (locomotion score 1). The results of this study suggest that monitoring of daily usage of brushes located away from the feed bunk could be a useful method for detecting lameness and severe lameness in dairy cows. However, the use of this method to detect mild lameness or cases of abnormal gait is, at this stage, less promising.

Evaluation of agreement among digital dermatitis scoring methods in the milking parlor, pen, and hoof trimming chute

Digital dermatitis (DD) is the most common infectious foot lesion affecting welfare and productivity of dairy cattle. The key to DD control programs is routine and frequent identification of DD lesions. The objective was to evaluate accuracy of detecting and scoring DD lesions in 3 milking parlor designs and in 3 alternative settings compared with scoring in the hoof trimming chute as reference. A total of 552 cows and 1,104 hind feet from 17 freestall farms were scored by 1 observer in the milking parlor and in 1 other setting: pen, headlocks, or management rail. After being scored in the milking parlor and at least 1 other setting, cows were examined in the hoof trimming chute, considered the gold standard. In every setting, all hind feet were inspected visually using a flashlight and without prior washing of feet. Agreement of the scoring settings was assessed using the 5 M-stage scoring system and a dichotomous absence (M0 or M0/M1) or presence (M1 to M4.1 or M2 to M4.1) system. At trimming chute inspection, 44% of feet had a DD lesion, with estimates of 11, 5, 2, 10, and 16% for M1, M2, M3, M4, and M4.1 lesions, respectively. Apparent DD foot-level prevalence at the milking parlor, pen, management rail, and headlocks was 28, 22, 16, and 22%, respectively. M-stages were less discernible in the pen, management rail, and headlocks (apparent prevalence of M1, M2, M3, and M4.1 was ≤1%) compared with the trimming chute and milking parlor. Agreement beyond chance between any scoring setting and trimming chute scoring ranged from 0.48 to 0.70 for the dichotomous scoring system (absence = M0/M1 vs. presence = M2 to M4.1). Diagnostic test performance varied greatly among DD scoring settings but, in general, it had low sensitivity (<70%) and high specificity (>93%) for detecting any DD lesion. Agreement and test characteristics were not affected by the type of milking parlor. Although the milking parlor and headlocks were the most reliable settings in which to detect DD, none of the settings were reliable enough to replace inspection of feet in the trimming chute. However, scoring the presence or absence of DD in the milking parlor, pen, management rail, and headlocks could be used to estimate within-herd DD prevalence, to improve DD surveillance through routine monitoring, and to evaluate effects of interventions at the farm level.

Experimental Transmission of Bovine Digital Dermatitis to Sheep: Development of an Infection Model

Digital dermatitis is an infectious cause of lameness primarily affecting cattle but also described in sheep, goats, and wild elk. Digital dermatitis is a polymicrobial infection, involving several Treponema species and other anaerobic bacteria. Although the exact etiology has not been demonstrated, a number of bacterial, host, and environmental factors are thought to contribute to disease development. To study host-bacterial interactions, a reproducible laboratory model of infection is required. The objective of this study was to demonstrate key aspects of bovine digital dermatitis lesions in an easy-to-handle sheep model. Crossbred sheep were obtained from a flock free of hoof disease. Skin between the heel bulb and dewclaw was abraded before wrapping to emulate a moist, anaerobic environment. After 3 days, abraded areas were inoculated with macerated lesion material from active bovine digital dermatitis and remained wrapped. By 2 weeks postinoculation, experimentally inoculated feet developed erosive, erythematous lesions. At 4 weeks postinoculation, microscopic changes in the dermis and epidermis were consistent with those described for bovine digital dermatitis, including erosion, ulceration, hyperkeratosis, ballooning degeneration of keratinocytes, and the presence of neutrophilic infiltrates. Silver staining of lesion biopsy sections confirmed that spirochetes had penetrated the host epidermis. The model was then perpetuated by passaging lesion material from experimentally infected sheep into naïve sheep. This model of bovine digital dermatitis will allow for future novel insights into pathogenic mechanisms of infection, as well as the development of improved diagnostic methods and therapeutics for all affected ruminants.

Missing pieces of the puzzle to effectively control digital dermatitis

Since the first report of bovine digital dermatitis (DD) in 1974, there is a large body of the literature published; however, effective prevention and control of the disease remain elusive. Although many aspects of the pathogenesis of DD have been investigated, even some of the most basic questions such as the aetiology of this disease remain under debate. Treponema spp. have been strongly associated with DD lesions and occur in abundance in advanced lesions; however, efforts to induce disease with pure cultures of these organisms have been largely underwhelming and inconsistent. Furthermore, although the disease has been presented for several decades, there is limited scientific evidence regarding effective treatment of DD. Apparent discrepancies between effectiveness in vitro and in vivo have challenged the scientific community to identify new potential treatment options. With no treatment resulting in a 100% cure rate, the current expectation is manageable control, but prospects for the eradication of the disease are unlikely using current approaches. In order to develop more effective approaches to control DD on-farm, there is a critical need for a deeper understanding regarding the causation, ecology, transmission and treatment of this disease. In this article, we attempt to provide insights into specific research needs related to DD in order to assist the industry, researchers, pharmaceutical companies and research sponsors with decision-making and identified research gaps.

Clinical Perspectives of Digital Dermatitis in Dairy and Beef Cattle

Digital dermatitis is a polybacterial disease process of dairy and beef cattle. Lesions are most commonly identified on the plantar aspect of the interdigital cleft of the hind limbs. Treponema spp are routinely present in large numbers of active lesions. Lesions are painful to the touch and can result in clinical lameness. The infectious nature generally results in endemic infection of cattle herds and management requires a comprehensive and integrated multipronged approach. This article provides current perspectives regarding management and treatment of digital dermatitis on dairy and beef cattle operations and provides a review for clinicians dealing with a clinical outbreak.