Dairy farms are growing in size, while the total number of farms is decreasing. As herd sizes grow, technology is increasingly adopted for monitoring and managing cows. However, for technology to replace subjective and labor-intensive tasks, accurate technologies are needed. Camera-based systems are being explored for improving management, particularly around lameness and body condition scoring. A key requirement a camera-based technology is its ability to accurately identify the animal being observed. The primary objective of this study was to evaluate the cow identification (ID) accuracy of a camera-based technology that locomotion scores and body condition scores dairy cattle. Secondary objectives were to determine the number of days required for initial identification and evaluate the frequency of animal recognition. Two dairy sites in Minnesota were visited twice and a total of 105 cows were enrolled from site A (n = 40) and site B (n = 65). Each cow had their cow ID and radio frequency identification recorded. All cows that had been in the pen for 5 or less days were enrolled in the study and had a combination of colors, letters, and numbers painted on their rumps as unique identifiers (paint ID; PID). The video feed from the camera-based technology was observed daily from the company website for 7 d. A cow was recorded as correctly identified if the website had an uploaded video for a cow's ID that matched its PID. Successful identification was defined as the proportion of cow ID for which video was uploaded to the user platform within 7 d from the start of the study, regardless of accuracy. Correct identification was subsequently calculated as the proportion of these successfully identified cows that had a PID corresponding to their PID. The days under the camera were calculated by including the time cows would have been exposed to the camera before our 7-d observation period. Additionally, days identified reflect the total number of days that cows were identified (correctly or incorrectly) and scored during the observation period. Of the 103 cows enrolled, 87 (84.5%; 95% CI: 76%-91%) of cows were successfully identified during the 7-d study period. One cow from those 87 was incorrectly identified, resulting in a correct identification of 98.9% (95% CI: 94%-100%). Of the 86 correctly identified cows, all cows were observed between days 4 and 11 under the camera. Of the cows identified, they were identified 1 to 7 times. This technology accurately identifies cows, but 16 cows were not initially identified and ended with a minimum and maximum of 7 and 11 d under the camera, respectively. To allow management decisions to be made early in lactation or for new cows entering the herd, the technology will need to accurately identify all cows within the first week of being exposed to the camera.

The objective of this observational study was to describe the associations between preventive hoof trimming (HT) of cows with no lesions and several behavior- and productivity-outcome measures including activity, lying behavior, and milk yield. A convenience sample of 4 freestall farms in the United Kingdom (n = 2) and Canada (n = 2) were recruited for the study. Inclusion criteria for herds included having a regular trim schedule and use of a specific pedometer system. Cows were trimmed as per their farm's regular protocol and schedule and all HT events were recorded. Only cows with no lesions present on the first recorded HT event were used in the analysis. Activity (steps/d), resting time (min/d), and resting bouts (bouts/d) were recorded daily by pedometers and total daily milk yield (kg/d) was recorded by the farm's milk recording system. Cow-level data such as DIM, breed, and parity were collected from the farm's herd management software. A generalized linear mixed repeated measures model with an exchangeable correlation structure was built to compare the outcome for 7 d following HT to baseline measures for each outcome of interest. For each outcome the average from the 5 d before HT was used as a baseline. All models included the baseline status, lactation number, season, farm, and DIM as covariates. Days from HT and its interaction with farm were included in all models. A total of 1,573 cows with no lesion recorded in their first HT were included in the analysis. Activity and resting time were inversely related on the day of HT, with activity increasing on 3 out of 4 farms (+59 to +84 steps/d) and resting time decreasing (-28 to -52 min/d). Following the day of HT, activity decreased to levels lower than those reported at baseline and resting time increased compared with baseline on most farms. There was a reduction in milk yield on the day of HT on 3 out of 4 farms and a reduction in average yield across the 7 d following trimming for all farms (range: 0.6 to 1.3 kg/d). Results were found to be farm dependent. The impact of the degree of change from baseline in behaviors and milk yield reported in this study on welfare of the cow is unclear, but the results suggest that alterations in the outcomes evaluated can persist beyond the day of trimming compared with baseline, necessitating further investigation.

Lameness in dairy cattle is a clinical sign of impaired locomotion, mainly caused by painful foot lesions, compromising the US dairy industry's economic, environmental, and social sustainability goals. Combining technology and on-farm data may be a more precise and less labor-intensive lameness detection tool, particularly for early detection. The objective of this observational study was to describe the association between average weekly autonomous camera-based (AUTO) locomotion scores and hoof trimming (HT) data. The AUTO data were collected from 3 farms from April 2022 to March 2023. Historical farm HT data were collected from March 2016 to March 2023 and used to determine cow lesion history and date of HT event. The HT events were categorized as a regular HT (TRIM; n = 2,290) or a HT with a lesion recorded (LESION; n = 670). Events with LESION were subcategorized based on lesion category: digital dermatitis (DD; n = 276), sole ulcer (SU; n = 79), white line disease (WLD; n = 141), and other (n = 174). The data also contained the leg of the LESION, classified as front left (FL; n = 54), front right (FR; n = 146), rear left (RL; n = 281), or rear right (RR; n = 183) leg with 6 events missing the leg. Cows' HT histories were classified as follows: cows with no previous recorded instance of any lesion were classified as TRIM0 (n = 1,554). The first instance of any hoof lesion was classified as LESION1 (n = 238). This classification was retained until a subsequent TRIM occurred-recorded as TRIM1 (n = 632). The next unique instance of any lesion following a TRIM1 was classified as LESION2 (n = 86). Any LESION events occurring after LESION1 or LESION2 without a subsequent TRIM were considered a hoof lesion recurrence and classified as LESIONRE1 (n = 164) and LESIONRE2 (n = 22), respectively. TRIM events after LESION2 or LESION2RE (n = 104) or LESION events after LESIONRE1 or LESIONRE2 were classified as LESION_OTHER (n = 160). The AUTO scores from -28 to -1 d prior to the HT event were summarized into weekly scores and included if cows had at least 1 observation per week in the 4 wk before the event. For all weeks, LESION cows had a higher median AUTO score than TRIM cows. Cows with TRIM0 had the lowest and most consistent median weekly score compared to LESION and other TRIM classifications. Before HT cows with TRIM0 and TRIM1, both had median score increases of 1 across the 4 wk, whereas the LESION categories had an increase of 4 to 8. Scores increased with each subsequent LESION event compared to the previous LESION event. Cows with SU lesions had the highest median score across the 4 wk, WLD had the largest score increase, and DD had the lowest median score and score increase. When grouping a LESION event by leg the hoof lesion was found on, the AUTO scores for 4 groups displayed comparable median values. Due to the difference between TRIM and LESION events, this technology shows potential for the early detection of hoof lesions.

Acidogenic boluses can mitigate potential negative effects of high milk yield at dry-off on udder health. This randomized controlled trial aimed to investigate the effect of administering acidogenic boluses at dry-off on dry period intramammary infection (IMI) dynamics and on milk production parameters, somatic cell count linear score (LSCC), clinical mastitis (CM), and herd removal in the next lactation. A total of 901 cows from 3 dairy farms were randomly allocated to a control (CON, n = 458; no administration of acidogenic boluses at dry-off) or treatment group (TRT, n = 443; administration of 2 acidogenic boluses at dry-off). Quarter milk samples were collected at dry-off and after calving and submitted for bacteriological milk culture. The effects of treatment on the presence of quarter-level postpartum IMI, cure of existing IMI, and acquisition of new IMI, and on the prevalence of cow-level high LSCC (LSCC ≥4) in the first 30 days in milk (DIM) were analyzed using mixed effects logistic regression. Mixed linear regression was used to analyze cow-level milk production parameters (i.e., milk yield, fat corrected milk, fat and protein yield, and LSCC) in the first 90 DIM and until 300 DIM. For CM and herd removal, Cox proportional hazard regression models were used. In addition to treatment group, lactation group at dry-off, presence of high LSCC in the last test-day, average milk yield in the week before dry-off, presence of CM in the lactation of enrollment, and biologically relevant interactions were offered in all models. There was no evidence of a difference in IMI dynamics or in milk, fat corrected milk, protein or fat yields in the subsequent lactation between groups. The TRT group had a lower LSCC in the first 2 mo postpartum compared with the CON group (2.58 ± 0.3 vs. 2.92 ± 0.3 and 2.42 ± 0.3 vs. 2.81 ± 0.3, for first and second month postpartum). The prevalence of high LSCC in the first 30 DIM was 9.1% lower in the TRT compared with the CON group (16.3% vs. 25.5%; risk difference: -9.2; 95% confidence interval [CI]: -15.8, -2.5). Cows in the TRT group exhibited reduced hazards of CM in the subsequent lactation compared with cows in the CON group (hazard ratio: 0.75; 95% CI: 0.63, 0.89) as well as a reduced hazard of herd removal (hazard ratio: 0.82, 95% CI: 0.77, 0.88). The administration of acidogenic boluses as a component of dry-off management is a promising approach to maintain good udder health and reduce the hazard of CM and herd removal during the subsequent lactation.

Digital dermatitis (DD) is one of the most prevalent types of hoof lesion reported in dairy cows. This higher prevalence in dairy herds is consequential, as DD can not only lead be painful and lead to lameness in severe instance, but DD has also been found to have a negative long-term impact on reproductive per­formance and longevity. However, the impact of a first instance of DD in cows with no previous lesion history on these negative outcomes is largely unknown, as most previous studies do not account or the impact of lesion chronicity. The objective of this study was to evaluate the effect of a first occurrence of DD in the first 60 days in milk (DIM) in cows with no previous record­ed instance of DD on risk of culling and time-to-pregnancy in the first 180 DIM in dairy cows.

Elevated milk production at dry-off can lead to increased udder pressure and, in turn, increased stress due to pain and discomfort, affecting natural behaviors. Administering acidogenic boluses at dry-off acts by inducing temporary and mild decreases in blood pH. This decreases dry matter intake, reduces milk yield, and increases cow comfort by lessening udder pressure. The objective of this study was to assess the effect of oral administration of acidogenic boluses at dry-off on total daily activity (TDA) and total daily rumination (TDR) behaviors in the first 2 wk of the dry period. This randomized clinical trial was conducted on a single farm and cows were randomly assigned to either treatment (TRT; n = 30) or control (CON; n = 34). The TRT group received 2 acidogenic boluses at dry-off and the CON group received no intervention. All cows received dry-cow therapy (intramammary antibiotic and internal teat sealant). The TDA and TDR data from 7 d before to 14 d after dry-off were measured using ear-mounted activity monitors. Analyses were performed using linear mixed-effects models with repeated measures. We observed a similar TDA in both groups throughout the study follow-up period. Overall, cows in the TRT group spent 17 min/d less time active than cows in the CON group in the first 2 wk after dry-off with the greatest difference observed on the second day of the dry period (TRT = 395 min/d; 95% CI: 370 to 420 vs. CON = 428 min/d; 95% CI: 404 to 451). The TRT group had lower TDR in the first 24 h after bolus administration (TRT = 437 min/d; 95% CI: 414 to 461 vs. CON = 488 min/d; 95% CI: 466 to 510) when compared with the CON group, but no differences were observed when comparing both groups in the 13 subsequent days. Our results indicate that administering acidogenic boluses at dry-off slightly decreased TDA during the first 2 wk of the dry period and decreased TDR on the first day after administration.

High milk production at dry off is a risk factor for intramam­mary infections (IMI) postpartum due to milk leakage and im­paired formation of the keratin plug during the dry period. The use of acidifying agents at dry off can induce a temporary feed intake reduction and decrease in milk yield of high-producing dairy cows. Thus, acidogenic boluses are a potential tool to help maintain udder health around the dry period. The study aim was to evaluate the effects of the administration of acidogenic boluses at dry off on udder health.

Hyperketonemia (HYK) in early lactation can have a different impact on health and productivity depending on the timing of HYK onset. While specific metabolites measured during the dry period may serve as biomarkers of HYK, the correlations between metabolites represent a challenge for the use of metabolic profiles dataset, and little has been explored on HYK. This exploratory cohort study aimed a) to characterize the correlations among metabolites measured during the late dry period in dairy cows, and b) to identify biomarkers in the late dry period associated with the onset of HYK at the first (wk1) and second (wk2) week of lactation. Individual blood samples from 440 Holstein dairy cows were collected at 21 ± 3 days before expected parturition. From each sample, 36 different metabolites were measured in serum and plasma. Hyperketonemia was diagnosed in wk1 and wk2 of lactation based on the blood concentration of beta-hydroxybutyrate (BHB > 1.2 mmol/L). Principal component analysis (PCA) was performed to reduce metabolites to a smaller number of uncorrelated components. Multivariable logistic regression models were applied to assess the associations between principal components (PC) and HYK at wk1 only (HYK+ wk1), wk2 only (HYK+ wk2), or both weeks (HYK+ wk1-2). The incidence of HYK was 16.2% in the first week, 13.0% in the second week, and 21.2% within the first two weeks of lactation. The results of PCA highlighted 10 PCs from which two were associated with HYK+ wk1 as compared with cows without HYK during the first two weeks of lactation (non-HYK); the PC a2 led by bilirubin and non-esterified fatty acids (OR = 1.29; 95%CI: 1.02–1.68), and the PC a5 led by alkaline phosphatase (ALP) and gamma-glutamyl transferase (GGT) (OR = 2.77; 95%CI: 1.61–4.97). There was no evidence of an association between any PC and HYK+ wk2 (vs. non-HYK cows). Cows with elevated PC a5 (led by ALP and GGT) in the dry period were 3.18 times more likely to be HYK+ wk1 than HYK+ wk2 (OR: 3.18, 95%CI: 1.34–8.73; P = 0.013). Overall, the main hypothesis generated by our exploratory study suggests that cows with biomarkers of liver dysfunction (ALP, GGT, bilirubin) assessed by PCA at 3 weeks before calving are more likely to develop HYK during the first week of lactation compared to the second week. In addition, results suggest that cows with HYK in both of the first two weeks of lactation had an overall metabolic disbalance during the onset of the late dry period, which based on PCs, encompass biomarkers related to glucogenic and ketogenic metabolic pathways as well as liver dysfunction and fatty liver. Further research is needed to determine the underlying mechanisms associated with the different adaptations between cows that develop HYK during the first and second week of lactation.

Digital dermatitis (DD), an infectious hoof lesion, is prevalent in U.S. dairies and compromises cow health, welfare and profit­ability. Footbaths are the main form of DD prevention and con­trol. Understanding the comparative efficacies among commer­cial footbath products in preventing and controlling DD cases within a herd is necessary to provide farms with the informa­tion required when selecting a product for use. Digital derma­titis (DD), an infectious hoof lesion, is prevalent in U.S. dairies and can rapidly become endemic to a herd if not proactively controlled, compromising cow health, welfare and profitabil­ity. Footbaths are the main form of DD prevention and control. Understanding the comparative efficacies among commercial footbath products in preventing and controlling DD cases with­in a herd is necessary to provide farms with the information re­quired when selecting a product for use. Our primary objective was to determine if a commercial footbath concentrate (Heal­max®) was non-inferior to a copper sulfate concentrate in the prevention of new cases of digital dermatitis (DD). As a second­ary objective, we sought to investigate the comparative effica­cies of the 2 products in the control of chronic DD cases.

Our objective was to develop a sole ulcer (SU) induction model that can be used to investigate new and more efficacious methods for the treatment and prevention of SU. Three iterations [phase (P)1, P2, and P3] of an SU induction model designed to mimic mechanical and presumed metabolic pathways for SU development were conducted. The results from P1 and P2 identified alterations for the subsequent phase. Each phase used cows with similar calving dates that were randomly assigned (n = 4) to treatments. Control cows (P1CON, P3CON) did not undergo any challenges to induce SU development. Treatment cows were challenged with a hoof block (B) applied to the right hind lateral hoof. Other treatments included restricted lying time (L), restricted feed intake (F), or systemic lipopolysaccharide (LPS) administration. Treatment comparisons were P1CON versus P1BL, P2B versus P2BL, and P3CON versus P3BLF and P3BLF+LPS for P1, P2, and P3, respectively. Pregnant nulliparous Holstein cows were used in P1 and P3, and the P1 cohort was used in P2 during mid-lactation [125.9 ± 7.20 d in milk (DIM)]. Challenges were applied during a set challenge period (P1: −14 to 14 DIM, P2: 126–168 DIM, P3: −14 to 28 DIM). The P1BL cows had a hoof block applied and lying time restricted for 5 h/d. The P2B and P2BL cows had a hoof block and P2BL cows also had their lying time restricted for 18 h/d for 2 d/wk. The P3BLF and P3BLF+LPS cows had a hoof block, 6 h/d of lying time restricted 2 d/wk, and had their DMI restricted by 30% for 2 d/wk. At weekly intervals during wk 1 to 3 postpartum, P3BLF+LPS cows received jugular administration of 0.031, 0.062, and 0.125 µg of LPS per kg of body weight, respectively. Primary response measurements included hoof lesion and locomotion scoring, lying time, hoof thermography, and weight distribution per hoof. No SU induction occurred but sole hemorrhages, a precursor to SU, occurred during the postchallenge period of all phases. Temperature of the blocked hoof at the end of the challenge period did not change for P3CON cows but increased by 5.5°C and 6.2°C for P3BLF and P3BLF+LPS, respectively. Notable increases in lameness and lack of weight-bearing on the blocked hind hoof occurred for challenge treatment cows during the challenge period of P2 and P3. These changes did not persist after the hoof blocks were removed, indicating that hoof blocks succeeded in altering cow gait mechanics, but not enough to induce long-term lameness or SU. Lying restriction challenged cows in P2 and P3, indicated by a compensatory increase in lying time on the day following lying restriction compared with that on the day before restriction. In P3, lying time had the greatest depression during restriction and compensation following restriction in P3BLF+LPS cows, with LPS challenges potentially increasing the other challenge's effects. Future iterations of the SU induction model should include hoof block use, evaluate longer and more frequent standing and inclusion of forced walking bouts, and include DMI and LPS metabolic challenges.

The purpose of this retrospective cohort study was to evaluate the effects of the timing of hyperketonemia (HYK) diagnosis during early lactation on milk yield and composition, reproductive performance, and herd removal. Plasma β-hydroxybutyrate (BHB) was measured twice a week during the first 2 wk of lactation in 362 multiparous Holstein cows for the diagnosis of HYK. In each week, cows were diagnosed as HYK positive (HYK+) if the plasma BHB concentrations were ≥1.2 mmol/L in at least one of the tests for the week evaluated. Milk-related outcomes (first 10 monthly milk tests) included milk yield, milk fat and protein content, milk urea nitrogen (MUN), and linear score of somatic cell count. Other performance outcomes of interest included risk of pregnancy within 150 d in milk (DIM) and herd removal (i.e., culling or death) within 300 DIM. Statistical models were built separately for cows diagnosed with HYK during the first week of lactation (wk1) and for cows diagnosed during the second week of lactation (wk2). All models for wk2 were adjusted by HYK diagnosed in wk1, along with other potential confounder variables. The association between HYK in each week and milk-related outcomes was assessed using generalized estimated equation models that accounted for repeated measures. Time to pregnancy and time to herd removal were analyzed using Cox's proportional hazard regression models. Seventy-eight cows (21.5%) tested positive for HYK during wk1, 60 cows (16.6%) in wk2, and 29 cows (8.0%) in both weeks. Hyperketonemia during wk1 was associated with a milk yield reduction of 3.7 kg [95% confidence interval (CI): -6.67 to -0.76] per cow per day throughout the lactation. Meanwhile, we did not observe evidence of an association between HYK diagnosed during wk2 and milk yield. During the first 2 monthly milk tests, cows diagnosed as HYK+ in wk1 had greater fat (0.42%; 95% CI: 0.16 to 0.67) and MUN (0.75 mg/dL; 95% CI: 0.26 to 1.24) content in milk than HYK-negative (HYK-) cows. We did not detect any evidence of an association between HYK diagnosed in wk2 and these outcomes. The HYK+ cows in wk1 had a 30% [hazard ratio (HR) = 0.70; 95% CI: 0.48 to 1.01] lower risk of pregnancy within 150 DIM and 2.48 times (95% CI: 1.63 to 2.89) higher risk of herd removal within 300 DIM than HYK- cows. Conversely, no evidence of association was observed between HYK+ cows in wk2 and risk of pregnancy by 150 DIM (HR = 0.98; 95% CI: 0.64 to 1.51) or removal from the herd within 300 DIM (HR = 0.91; 95% CI: 0.52 to 1.60). Our findings indicate that HYK diagnosed during wk1 of lactation is associated with negative performance in terms of milk yield, reproduction, and herd removal. No evidence of association was found for the same outcomes when HYK was diagnosed in wk2. Our results suggest the need to consider the timing when HYK is diagnosed when investigating its association with performance outcomes.

The objective of this retrospective cohort study was to investigate whether the association of hyperketonemia (HYK) with reproductive performance differs based on milk production during the first week of lactation (wk 1). Data between calving and 150 d in milk (DIM) from 2,091 Holstein dairy cows from 5 commercial dairy herds in Minnesota were collected. The concentration of β-hydroxybutyrate (BHB) was measured twice between 3 and 10 DIM in whole blood to diagnose HYK (defined as BHB ≥1.2 mmol/L). The average wk 1 milk yield was classified into 3 levels (low = lower 25th percentile; mid = 25th to 75th percentile; high = upper 75th percentile) according to parity and herd. Log-binomial regression, Cox-proportional hazard regression, and linear regression models were used to investigate the association of HYK with pregnancy to first insemination, pregnancy by 150 DIM, and calving-to-conception interval (CCI) between groups, respectively. To describe the differences in these estimates between each wk 1 milk yield level, an interaction term of HYK and stratified levels of wk 1 milk yield was added. The incidence of HYK between 3 to 10 DIM was 14.2% (4.6% in primiparous cows and 19.4% in multiparous cows). In the study population, the effect of HYK on reproduction was greater in cows with low milk yield. Among cows with low milk yield levels, HYK was associated with lower risk of pregnancy to first insemination [risk ratio = 0.62; 95% confidence interval (CI): 0.39–0.98], lower risk of pregnancy up to 150 DIM (hazard ratio = 0.70; 95% CI: 0.51–0.96), and extended days of CCI (mean difference = 13.0; 95% CI: 5.1–20.9). In contrast, among cows with mid and high wk 1 milk yield levels, hyperketonemic (HYK+) cows had a similar reproductive performance to non-HYK (HYK−) cows. Our results suggest that early-lactation milk yield plays a role in the association of hyperketonemia with reproductive performance. These results merit further investigation to determine the role that early milk yield has in the association of hyperketonemia with health and productivity outcomes.

Lameness represents a significant management challenge in the dairy industry worldwide. In addition to farmers, many advisors are involved in lameness management, including veterinarians, hoof trimmers, and nutritionists. These advisors support farmers through lameness prevention practices, treatments, and advice, but little is known about how advisors view others' roles and the extent to which they work together. This study used qualitative participatory methods to facilitate the formation of lameness advisory groups among 13 advisors (4 veterinarians, 5 hoof trimmers, and 4 nutritionists), with the aims of promoting advisors' engagement with one another and documenting their perceptions of the benefits and challenges of the research activities through semi-structured interviews and thematic analysis. Participants shared predominantly positive views toward the project and voiced appreciation about the quality of discussions and the opportunity to connect and build relationships with other advisors. Participants reported improved communication with others via sharing reports and farm information, as well as increased confidence in reaching out to other advisors. Reported challenges included time constraints and discomfort in leading the lameness advisory group meetings. Difficulties were also found in bringing issues to farmers' attention when they might not align with the farmers' goals or priorities, as well as participants' questioning other advisors' knowledge and intentions. This study describes a promising avenue of facilitating advisor engagement, although more work is needed to determine whether such engagement translates to a reduction of lameness on farms.

Lameness is a major animal welfare issue in the dairy indus­try and its measurement is a component of both industry- and processor-led animal welfare audits. Although lameness is highly prevalent on dairy farms, farm personnel have difficul­ties identifying mild cases of lameness. Reasons for this diffi­culty include the time, human resources and training required to detect lameness, along with the lack of belief that early inter­vention works. Automatizing the process of lameness detection through the implementation of autonomous camera-based deep learning will provide dairy farms with an effective and easy-to-implement tool to reduce lameness duration. Combining early and accurate lameness detection with appropriate treatment protocols will result in lower levels of lameness. The objective of this project was to determine if changes in camera-based au­tonomous mobility scores could be used to reduce the duration of lameness.

This observational cohort study enrolled cows from 7 freestall dairy herds in Minnesota and Wisconsin. The objective was to estimate the causal role of hyperketonemia on new sole ulcer and white line hoof lesions (SUWL). Multiparous cows were enrolled at the time of their precalving hoof trim, at the end of their previous lactation. Enrolled cows were hoof trimmed twice: precalving between 90 to 21 d before calving (n = 2,037), and postcalving between 21 to 150 d after calving (n = 1,408). We trained 7 commercial hoof trimmers, employed by the farms, in lesion identification to standardize lesion recording. Hoof trimmers conducted therapeutic trimming as well as diagnosing and treating lesions. After parturition, cows between 3 and 16 d in milk were tested once weekly for hyperketonemia using a hand-held ketone meter. Farm staff and research personnel conducted the β-hydroxybutyrate (BHB) testing. Cows were classified as hyperketonemic (HYK+) if they had a blood BHB ≥1.2 mmol/L or hyperketonemia-negative (HYK-) if blood BHB <1.2 mmol/L. At the precalving hoof trim, 15.6% of cows trimmed had a lesion and 1.9% of cows had a SUWL; thus, cows with a SUWL were excluded from further analysis (n = 38). At the postcalving hoof trim, 25.8% of cows trimmed had a hoof lesion, and 3.6% of cows had a SUWL. The most prevalent lesions at the pre- and postcalving hoof trims were digital dermatitis and corkscrew lesions. The incidence of hyperketonemia among cows was 21.1% (421/1,999) and the incidence on farms ranged from 5.7 to 29.1%. After excluding cows due to being hoof trimmed outside our designated window, the multilevel logistic regression model for the odds of SUWL at the postcalving hoof trim included 1,209 cows (HYK+ = 257/1,209; SUWL = 42/1,209). The odds of having SUWL in HYK+ was 0.66 (95% confidence interval: 0.29, 1.49) times the odds of that for HYK- cows. For cows diagnosed with a lesion (digital dermatitis, corkscrew, toe, foot rot, or other lesion) at their precalving hoof trim (n = 199), the odds of having SUWL for HYK+ cows were 0.43 (95% confidence interval: 0.05, 3.92) times the odds of that for HYK- cows. The wide range of compatible causal estimates suggest that hyperketonemia likely has a limited role in the development of SUWL in cows with or without a hoof lesion precalving. Future research should investigate other transition period factors such as inflammation or structural changes to the foot that may have a causative role in the development of SUWL.

As a recent graduate, treating lame cows can be a practice growth opportunity that allows you to show your clinical acu­men and be a gateway to providing more consultative services as part of a foot health team. To seize this practice growth op­portunity, practitioners need to have a clear understanding of the diagnosis and treatment of common foot disorders. Current treatment strategies are not overly complex, however, the ma­jority lack large-scale scientific evidence leading to a variety of opinions and approaches among stakeholders. There are some key principles that should be considered when treating lame cows to reduce pain as soon as possible and to prevent chronic­ity. These key principles include early and appropriate inter­vention and appropriate aftercare. Practitioners who seize this opportunity will become a valuable part of a farm’s team and greatly improve the welfare of cattle.

Kelsey M. Wirt,1 MS; Jennifer M. Young,1 PhD; Gerard Cramer,2 DVM, DVSc; Sarah A. Wagner,1 DVM, PhD, DACVCP 1 Department of Animal Sciences, North Dakota State University, Fargo, ND 58105 2 College of Veterinary Medicine, University of Minnesota, Minneapolis, MN 55108 Dr. Wagner’s current address: School of Veterinary Medicine, Texas Tech University, Amarillo, TX 79106 Corresponding author: Dr. Sarah Wagner; S.Wagner@ttu.edu; 701-793-6162