Dynamics and impact of footrot and climate on hoof horn length in 50 ewes from one farm over a period of 10 months.
Authors: Smith Edward M, Green Olivia D J, Calvo-Bado Leonides A, Witcomb Luci A, Grogono-Thomas Rosemary, Russell Claire L, Brown Judith C, Medley Graham F, KilBride Amy L, Wellington Elizabeth M H, Green Laura E
Journal: Veterinary journal (London, England : 1997)
Summary
# Editorial Summary This 10-month observational study tracked 50 ewes on a single farm to clarify the relationship between hoof horn overgrowth, footrot caused by *Dichelobacter nodosus*, and environmental conditions—challenging the common assumption that routine preventative foot trimming reduces lameness incidence. Researchers measured hoof horn length, clinical foot lesions and body condition at eight intervals, randomly assigning lame ewes to either trimming plus topical antibiotic or parenteral antibiotic alone, both with topical treatment. Environmental data showed that hoof horn length fluctuated seasonally in response to temperature and rainfall, whilst new footrot cases occurred year-round and were preceded by existing flock infection and specific climatic conditions; critically, overgrown horn appeared *after* lameness developed rather than preceding it. By the study's end, both treatment groups showed similar hoof horn lengths, indicating that horn growth self-regulated regardless of whether trimming formed part of lameness management. For practitioners, these findings suggest that routine prophylactic foot trimming offers no flock-level benefit on this farm, and that prompt, targeted antibiotic treatment of clinical footrot cases alone may be as effective as trimming-based protocols—potentially reducing unnecessary horn removal and allowing natural hoof dynamics to maintain appropriate length in non-lame animals.
Read the full abstract on PubMed
Practical Takeaways
- •Routine foot trimming of flocks is not justified as a preventive measure for footrot and lameness; treatment should focus on prompt antibiotic therapy
- •Hoof horn length is self-regulating in sheep whether lame or treated; overgrown horn is a symptom of lameness, not a cause, so aggressive trimming may delay recovery
- •Monitor environmental conditions (temperature and rainfall) as risk factors for footrot emergence and maintain active surveillance for early cases to enable prompt treatment
Key Findings
- •Hoof horn length in ewes at pasture varied seasonally and was associated with temperature and rainfall
- •Overgrown hoof horn occurred after lameness onset, not before it, indicating it is a consequence rather than a cause of footrot
- •New footrot cases occurred year-round and were associated with prior flock prevalence and prior weather conditions
- •One year of prompt footrot treatment reduced hoof horn length variation in both treatment groups regardless of whether trimming was included in the treatment protocol