Development of a hoof horn lesion induction model in Holstein cows: The next step in lameness research to allow for the evaluation of therapeutic and preventative interventions

Objective

The objective of our study was to develop a sole ulcer induction model that can be used as a future tool in the evaluation of pain management and preventative treatment strategies of sole ulcers.

Materials and methods

The study was an iterative process involving three phases and employed multiple challenges chosen for their association with risk factors for sole ulcer development in dairy cattle. Eight Holstein heifers were enrolled in Phase 1 (P1; n = 4 /group), running from -14 to 84 DIM, and randomly assigned as a control (CON1) or treatment (BLK-R1) group. The same cohort was enrolled in mid-lactation in Phase 2 (P2; n = 4/group), running from 135 to 235 DIM, with cows assigned to one of two challenge treatments (BLK2 or BLK-R2). In Phase 3 (P3), 12 Holstein heifers (n = 4/group), enrolled from -28 to 84 DIM, were randomly assigned to one of three groups: BLK-R3, BLK-LPS3, or CON3. Over the course of a challenge period (duration: 28 days in P1; 42 days in P2 and P3), challenges applied to BLK-R1, BLK-R2, and BLK-R3 cows included a hoof block, applied to the lateral hoof of the right hind leg, and varying durations and frequencies of lying restriction. The BLK-R3 cows were also restricted in DMI. The BLK-LPS3 cows received the same restrictions as BLK-R3 cows in addition to a lipopolysaccharide (LPS) challenge 1x/wk for the first three weeks postpartum. Control cows (CON1 and CON3) received no challenges. Lying time was measured continuously in all phases using leg-mounted pedometers. Visual locomotion scoring and hoof evaluations were conducted at various time points across each phase’s study period. Additional measures of weight distribution using a weighing platform (P2 and P3) and blood, milk, rumination, and hoof thermography measures (P3) were also reported. As this research was intended as a proof-of-concept study, sample sizes were not selected to allow for statistical analysis of outcome measures. Results were evaluated descriptively. [...]