Christer Bergsten

Lameness in dairy cows, primarily caused by claw lesions, generates significant welfare and economic challenges. Hoof trimming is a key preventive measure, with scientific support for 2 to 3 trimmings per lactation. However, the optimal timing of these trimmings has not yet been fully explored. This retrospective cohort study aimed to investigate the association between timing of 2 hoof trimmings during first lactation and subsequent hoof health and culling in second lactation. Data from 10,349 primiparous cows across 185 Swedish dairy herds (2015-2018) were analyzed. Multivariable mixed-effect logistic (models L1 and L2) and multinomial logistic regression models (models ML1 and ML2) assessed associations with hoof health in early second lactation (within 90 DIM) and survival during second lactation (within 300 DIM). Explanatory variables included timings of the first and second trimmings, interval between trimmings, hoof health at trimming, and breed. Herd was incorporated as a random effect or cluster to account for herd-level variations. The L1 model indicated that most trimming combinations other than a late first trim (>120 d after calving) coupled with a late second trim (<61 d before calving) significantly reduced the odds of claw lesions. However, the ML2 model showed that the association varied somewhat depending on the type of claw lesion found. The L2 model generally displayed lower odds of culling (dead, euthanized, and slaughtered) for cows trimmed early in first lactation and further from second calving than 60 d. Although the ML2 model revealed no association between timing of trimming and mortality (dead and euthanized), it did find a significant association with being sent to slaughter. In summary, strategic timing of hoof trimming, early in first lactation and well before second calving, can improve hoof health and survival in dairy cows and consequently have the potential to improve animal welfare and sustainability within the dairy sector.

Lameness, mostly resulting from claw lesions, causes major welfare problems in the dairy industry. One way to prevent claw lesions is hoof trimming, but the overall effect and the optimal hoof trimming frequency are unknown. In a retrospective cohort study, we investigated the association between hoof trimming frequency in primiparous cows and hoof health and culling in second lactation. We based our analysis on breed, calving and culling data in the period 2015-2018 for 30,613 primiparous cows in 202 Swedish dairy herds. Of the cows enrolled, 20% were not hoof-trimmed, 30% were trimmed once, 34% were trimmed twice, 13% were trimmed 3 times, and 2% were trimmed ≥ 4 times. We used multivariable mixed-effect logistic and multivariable multinomial logistic regression models to investigate the association between trimming frequency and 2 outcomes: hoof lesions at first trimming occasion within 90 d from second calving and culling in second lactation within 300 d after second calving. In general, cows trimmed 2 or 3 times during first lactation were at lower odds of having claw lesions compared with cows that were not trimmed (Odds Ratio (OR) = 0.66, 95% CI = 0.62-0.71 and 0.60, 95% CI = 0.55-0.66, respectively) or cows trimmed once (OR = 0.80, 95% CI = 0.75-0.85 and OR = 0.72, 95% CI = 0.66-0.79, respectively), and this beneficial effect was observed for most types of claw lesions. Moreover, cows trimmed 2, 3, or ≥ 4 times were at lower odds of being culled compared with cows that were not trimmed (OR = 0.71, 95% CI = 0.65-0.77, 0.68, 95% CI = 0.61-0.76 and 0.70, 95% CI = 0.54-0.90, respectively) or trimmed once (OR = 0.77, 95% CI = 0.71-0.83, OR = 0.74, 95% CI = 0.66-0.82 and OR = 0.75, 95% CI = 0.59-0.97, respectively). In particular, 2 trimmings, compared with 1 or no trimming, lowered the relative risk-ratio of dying or being euthanized on-farm, or being culled due to claw and leg disorders. More than 1 hoof trimming in first lactation also reduced the relative-risk ratio of being culled for other reasons. In conclusion, 2 or 3 hoof trimmings during first lactation were generally beneficial for hoof health in early second lactation and survival in second lactation. These findings can help improve animal welfare and production by reducing claw lesions, and thereby lameness among dairy cows, which would increase the longevity of dairy cows and the sustainability of the dairy industry.

Increasing shortages and costs of common bedding materials have led dairy farmers in Sweden to consider using recycled manure solids (RMS), which are readily available and low cost, as an alternative bedding mate-rial. The main risks are effects on udder health and milk quality, but RMS could also affect animal welfare and claw health. The advantages and disadvantages of us-ing RMS bedding have not been fully investigated, and findings in other countries cannot be directly applied to Swedish conditions and climate. This observational cross-sectional study investigated the use of RMS as bedding, regarding associations with certain aspects of animal welfare, herd health, milk quality, and bedding costs in Swedish dairy herds. Thirty-four dairy farms using RMS or wood shavings/sawdust (each n = 17) were compared. Each farm was visited 2 times during the housing period from 2020 to 2021, once from Oc-tober to December and once from March to May. Dairy barns were observed, animal welfare was assessed, and freestall dimensions were measured. Farm owners were interviewed about housing system characteristics, herd performance, and herd management. Data on milk pro-duction and herd health were obtained from the Swedish official milk recording scheme for the indoor period from October to March. The prevalence of claw disorders and abnormal claw conformation were collected from the na-tional claw health database for the period from October to May. On each farm visit, composite samples of unused bedding outside the barn and used bedding material from the freestalls, respectively, were taken for total bacte-rial count and DM analysis. Samples of bulk tank milk for determination of total bacterial count were taken in connection to the visits. In addition, samples of unused and used bedding material and manure from alleys for analysis of 3 Treponema species associated with digital dermatitis (DD) were gathered and analyzed. Total bacte-rial count was significantly higher in unused (8.50 log10cfu/g) and used RMS bedding (9.75 log10 cfu/g) than in wood shavings/sawdust (used 4.74; unused 8.63 log10cfu/g), but there were no significant differences in bulk milk total bacterial count (median 4.07 vs. 3.89 log10 cfu/mL) or SCC (median 243,800 vs. 229,200 cells/mL). The aspects of animal welfare assessed did not differ sig-nificantly between the 2 bedding systems, whereas the prevalence of total claw disorders (25.9% vs. 38.0% of trimmed cows), dermatitis (6.9% vs. 16.2% of trimmed cows) and sole ulcers (2.0% vs. 4.0% of trimmed cows) were significantly lower in the RMS herds. Treponemaspp. were not detected in unused RMS material, but all RMS herds had presence of DD recorded at foot trim-ming. An economic assessment based on the interview results and price level from winter 2021 revealed that the costs of RMS bedding varied with amount of RMS produced. Thus, RMS is a potential alternative bedding material for dairy cows in Sweden and can be a profitable option for large dairy herds. However, the high level of total bacteria in the material requires attention to bed-ding and milking routines as well as regular monitoring of herd health

Interdigital phlegmon (IP) is an important cause of lameness in cattle. The aim of this study was to evaluate the treatment effect of a salicylic acid bandage in the interdigital space in dairy cows with early detected IP. Dairy cows (n = 109) with IP diagnosed and treated by the farmer were included in the study. On day 0, the rectal temperature, general condition, coronary circumference, and lameness score were recorded. The cow was immobilized in a trimming chute and the interdigital space was cleaned and inspected. For treatment, 1–2 tablespoons of 100% salicylic acid powder were applied into the interdigital space followed by bandaging of the hoof. On days 1–2 and days 3–5, the rectal temperature, the general condition, and the lameness score were recorded. On days 3–5, the cow was restrained, the bandage was taken off, and the coronary circumference was recorded again. Treatment of IP with salicylic acid gave a satisfactory treatment result. Within three–five days, treated cows responded with reduced lameness, lower body temperature, decreased coronary swelling, and an improved general condition compared to the day when the treatment started. Salicylic acid therefore proved to be an alternative in the treatment of early-detected non-complicated IP.

This study assessed the slip resistance of different types of solid flooring in cattle housing using a range of technical tests and gait analysis. Dynamic and static coefficient of friction, skid resistance, and abrasiveness were tested on concrete flooring with a smooth finish, a grooved pattern, or a tamped pattern, acid-resistant mastic asphalt, soft rubber mats, and a worn slatted concrete floor. Coefficients of friction and skid resistance were tested under clean and slurry-soiled conditions. Linear kinematic variables were assessed in 40 cows with trackway measurements after the cows passed over the floors in a straight walk. All gait variables were assessed as deviations from those obtained on the slatted concrete floor, which was used as a baseline. The coefficient of friction tests divided the floors into 3 categories: concrete flooring, which had a low coefficient of friction (0.29-0.41); mastic asphalt flooring, which had medium values (0.38-0.45); and rubber mats, which had high values (0.49-0.57). The highest abrasion (g/10 m) was on the asphalt flooring (4.48), and the concrete flooring with a tamped pattern had significantly higher abrasiveness (2.77) than the other concrete floors (1.26-1.60). Lowest values on the skid-resistance tests (dry/wet) were for smooth concrete (79/35) and mastic asphalt (65/47), especially with a slurry layer on the surface. Gait analysis mainly differentiated floors with higher friction and abrasion by longer strides and better tracking. Step asymmetry was lower on floors with high skid-resistance values. The most secure cow gait, in almost every aspect, was observed on soft rubber mats. Relationships between gait variables and physical floor characteristics ranged from average to weak (partial correlations 0.54-0.16). Thus, none of the physical characteristics alone was informative enough to characterize slip resistance. With reference to gait analysis, the abrasiveness of the hard surfaces was more informative than the coefficient of friction, but the effect of pattern was better detected by skid-resistance measurements. Consequently, several physical characteristics are needed to objectively describe the slip resistance of cattle floors. Soft rubber mats gave better tracking than hard, solid floors, even with a grooved surface or a tamped pattern.

Our hypothesis was that grazing time, the number of days (duration) and number of hours per day, affected claw health. From Swedish freestall herds that fulfilled our criteria of claw-trimming routines, 201 herds were randomly selected for a telephone interview regarding grazing management. Herd data were retrieved from the Swedish Official Milk Recording Scheme. Claw disorders to be analyzed were recorded at maintenance claw trimming before and after the grazing period and included mild and severe dermatitis, severe heel-horn erosion, and sole ulcer (including severe sole hemorrhage). Any remark included one or more of these recorded disorders. The odds for having a recorded claw disorder at the autumn trimming in relation to grazing management, as well as to herd- and cow-related parameters, was tested using multilevel logistic regression models. The final statistical analysis included 17,600 cows in 174 herds, which were distributed from the south to the north of Sweden with decreasing length of mandatory grazing period because of climate. Grazing duration was statistically associated with the risk of sole ulcer, but it was not linear. However, grazing duration was not statistically associated with the odds for any remark, dermatitis, or heel-horn erosion. The odds for dermatitis were lower with access to pasture for 24 h compared with either day or night access. Otherwise, the number of hours that the animals had access to grazing per day was not significantly associated with any of the other analyzed claw disorders. Higher pasture stocking density (number of cow hours per day per hectare) was associated with a higher odds for dermatitis and sole ulcer. For all recorded claw disorders, the highest odds for having a disorder after the grazing period were consistently when the cow had the same claw disorder before the release to pasture. The positive effects of grazing on claw health were less than expected, and the previous known effects of breed, days in milk, parity, production system, housing environment, and management were verified for most claw disorders. If cows in today's loose housing systems have a more restrictive grazing than cows in tie-stall herds previously experienced, one cannot expect as strong an effect even if grazing is mandatory in all Swedish dairy cattle. Despite some positive effects of grazing, good stall environment and management during the housing period seem to be more important to obtain good claw health.