G. Cramer

Herd-and Cow-Level Prevalence of Foot Lesions in Ontario Dairy Cattle

The objectives of this cross-sectional study were to determine herd-level and cow-level prevalence estimates for 11 foot lesions in Ontario dairy cattle. Foot lesions were recorded by 5 hoof trimmers on 13,530 cows in 204 Ontario dairy herds from March 2004 to May 2005. Significant differences existed between free-stall and tie-stall housing. In free-stall housing systems, 46.4% of cows had a foot lesion, compared with 25.7% of cows in tie-stall barns. Digital dermatitis was the most common lesion in tie stalls, occurring in 9.3% of cows and 69.7% of the herds, whereas in free-stall herds, 22.7% of cows and 96.7% of the herds were affected. The most common hoof horn lesions were hemorrhages and ulcers, at 7.7 and 4.7% in tie-stall housing and 11.0 and 9.2% in free-stall housing, respectively. Foot blocks were used to treat 2.2% of cows in free stalls and 0.3% in tie stalls. Intraclass correlation coefficients ranged from 9.5 to 17.3 for hoof horn lesions and 28.0 to 38.7 for infectious lesions. In summary, foot lesions diagnosed at the time of hoof trimming are common in Ontario, and appropriate treatment for hoof horn lesions is low.

Herd-level risk factors for seven different foot lesions in Ontario Holstein cattle housed in tie stalls or free stalls.

Worldwide, there is considerable between-herd variation within individual foot lesion prevalence studies. This variation suggests that herd-level risk factors are important from a prevention perspective. The objective was to determine the effect of selected risk factors on the prevalence of 7 foot lesions in both tie-stall and free-stall housing systems. As part of a cross-sectional foot lesion study 5 hoof trimmers recorded lesions for all cows that were foot trimmed in a herd. In addition, they completed a risk factor questionnaire for each herd. The impact of specific risk factors was evaluated using separate multi-variable models for both free-stall and tie-stall herds. The lesions evaluated were digital dermatitis, sole ulcer, sole hemorrhage, heel horn erosion, white line separations, white line abscess, and interdigital fibroma. Model types were selected based on herd-level lesion distribution. Detrimental risk factors identified in free-stall housing included increased alley scraping frequency (2.2- to 2.4-fold for sole ulcers) and trimming in summer or fall (-0.2-fold vs. spring and winter for digital dermatitis). Protective risk factors in free stalls included intermediate bedding depth (0.4-fold for 2.5 to 7.5 cm vs. more or less bedding for interdigital fibroma) and trimming heifers before calving (0.1-fold for white line abscess). In tie-stall herds no protective risk factors were identified. Detrimental risk factors for lesions in tie stalls included year-round access to outside areas (2.1-fold increase in digital dermatitis, 3.5-fold for white line separation, and 7.0-fold for interdigital fibroma vs. no or only seasonal exercise access), routine spraying of feet (2.0-fold increase in digital dermatitis), larger herds (3.0-fold increase in interdigital fibroma vs. <41 cow herds), and the use of wood bedding material (6.5-fold vs. straw bedding for interdigital fibroma). The risk factors identified need further evaluation to determine the temporal relationships, as well as whether the relationships with foot lesions are causal.

Genetic parameters for hoof lesions and their relationship with feet and leg traits in Canadian Holstein cows

The objectives were (1) to estimate the genetic parameters and breeding values of hoof lesions, (2) to estimate the phenotypic effect of each feet and legs conformation traits on hoof lesions, and (3) to estimate genetic correlations between hoof lesions with feet and legs conformation traits. The presence or absence of specific hoof lesions was recorded for each hoof. Lesions were classified into infectious (digital and interdigital dermatitis, foot rot, and heel erosion), horn (sole and toe ulcer, sole hemorrhage, and white line disease), and other lesions (interdigital hyperplasia, fissures, thin soles, and corkscrew claw). A total of 34,905 hoof health records from 27,179 cows and 365 herds, collected by 18 different hoof-trimmers in Ontario, Alberta, and British Columbia, were analyzed using linear animal models. In addition, 5 feet and leg conformation traits (foot angle, heel depth, bone quality, rear leg side view, and rear leg rear view) and locomotion from primiparous cows were considered (n=11,419 and 6,966 cows, for conformation traits and locomotion, respectively). At least one lesion was found in nearly 40% of the hoof trimming records. The heritability estimates for hoof lesions ranged from 0.01 for front horn lesions to 0.09 for rear infectious lesions. Despite the low heritability estimates, we observed large variability in sire estimated breeding value (EBV) for resistance to hoof lesions. Positive genetic correlations were found between the occurrence of front and rear infectious lesions (0.77) and between front and rear horn lesions (0.61), but not between infectious and horn lesions (0.08). For most of the conformation traits, low scores were phenotypically associated with higher incidence of horn lesions, whereas we found no evidence of a phenotypic effect of feet and leg traits on infectious lesions. The heritability of the conformation traits ranged from 0.04 for rear leg rear view to 0.22 for bone quality, whereas that for locomotion was 0.03. The genetic correlations between hoof lesions and conformation traits were low to moderate, yet most of the estimates were associated with high standard errors. In conclusion, although hoof lesions are lowly heritable traits, sufficient genetic variation exists (as evidenced by large variability in sire EBV) for genetic improvement through direct selection in the long term. Standardization of hoof health data collection is encouraged.

Randomized clinical trial of tetracycline hydrochloride bandage and paste treatments for resolution of lesions and pain associated with digital dermatitis in dairy cattle

Digital dermatitis is an infectious disease that causes lameness in dairy cattle, a primary welfare concern of the dairy industry. One of the common treatments for this painful hoof disease is through the application of an antibiotic bandage that must be removed following treatment. The objectives of this randomized clinical trial were to determine if topical application of tetracycline hydrochloride in a paste would be as therapeutically effective for the treatment of digital dermatitis as a powdered form of tetracycline hydrochloride held in place by a bandage, and to quantify pain associated with digital dermatitis lesions. Two hundred and fourteen Holstein cow hooves with digital dermatitis lesions were randomly assigned to 1 of 3 treatments: a tetracycline hydrochloride paste, tetracycline hydrochloride powder held in place with a bandage for 2 d, or a negative (untreated) control. Lesions were examined at 2 time periods: 3 to 7 d posttreatment and 8 to 12 d posttreatment to determine healing rates. Nociceptive thresholds were measured using a pressure algometer to quantify the pain at the lesion site. The tetracycline hydrochloride paste was as effective as the powdered bandage treatment in terms of healing rates, with 47.4 and 57.1% hooves healed at 8 to 12 d posttreatment, respectively. Both treatments were more effective than the control, in which no lesions healed 8 to 12 d following initial examination. Mean (±SE) nociceptive thresholds for active, healing, and healed lesions differed, with limb-withdrawal response occurring at 7.45 (±0.67) kg, 12.84 (±1.85) kg, and censored to 25 kg (maximum value of algometer) of force applied, respectively. However, active lesions were not consistently associated with pain, as maximum force was tolerated when applied to 19% of active lesions, perhaps due to variability in stoicism between individual cattle or due to changes in pain during the progression of infection. In conclusion, tetracycline hydrochloride paste was as effective as tetracycline hydrochloride bandage, eliminating the need for bandage removal following treatment application. Digital lesions can be painful during both active and healing stages, suggesting the need for treatment and husbandry interventions for pain mitigation.

An Observational Study of the Effects of Therapeutic Hoof Blocks on the Locomotion, Behavior, and Production of Healthy Dairy Cattle

Therapeutic hoof blocks have been recommended for treatment of sole ulcers in dairy cattle; however, they are underutilized in the industry. Twenty Holstein cows were randomly assigned to receive a wooden hoof block applied to the left hind leg (n = 5), to the right hind leg (n = 5), or no hoof blocks (n = 10). Accelerometers were affixed to both hind legs of 10 blocked cows and 5 control cows. Cows were observed for locomotion scores, and milk production was recorded. Mixed models were constructed to determine effects of block application on behavior, milk production, and locomotion. Activity was altered by day, with cows being most active on Day − 1. The mean number of daily lying bouts and lying bout duration did not differ by treatment. Locomotion scores were higher for blocked cows on Days 1, 2, and 3 compared with baseline; however, milk production did not differ between treatments. In conclusion, although block application affected the appearance of locomotion, it did not appear to adversely affect the behavior or milk production of sound dairy cows.

A Review of the Relationship Between Hoof Trimming and Dairy Cattle Welfare

A narrative integrative review on the evidence for hoof trimming found 16 articles on efficacy, frequency, and associations with behavior and physiologic parameters. Review of these studies revealed (1) hoof trimming is associated with behavior and physiologic changes; (2) increasing the frequency of hoof trimming seems to decrease the incidence of hoof lesions; (3) there is limited research to support any particular technique; and (4) descriptions of the hoof trimming techniques used is inadequate in most articles. To increase scientific support for hoof trimming practices, current knowledge gaps in technique, timing, and frequency of hoof trimming need to be addressed.

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.