It is possible that your neighbour has seen a decrease in lameness after removing automatic alley scrapers, depending on their management. This may be due to a reduction in cases of digital dermatitis (DD), a bacterial infection affecting cows’ feet, often resulting in lameness. Overall environmental hygiene and the level of contact between manure slurry and cows’ feet are important risk factors for DD. From our research in Alberta, we know that farms with poor leg cleanliness have higher prevalence levels of DD. In turn, leg cleanliness may be affected by suboptimal management of automatic scrapers if we let them act as ‘moving manure baths’ covering cows’ feet and legs on each pass. In regard to the effect of automatic scrapers on cows’ behaviour, Swiss and Dutch research studies have determined negative effects on the number of feeding bouts, duration of night-time feeding, stumbles and scraper-related hoof and leg injuries.
There is conflicting evidence on how frequently alleys should be scraped and on the method of scraping, probably due to the large variability in alley/scraper design and manure management practices. However, the aim is to provide cows with the cleanest, driest walking surfaces possible to limit the spread of DD. If you have automatic scrapers, consider adjusting the scraping frequency based on leg cleanliness and the size of the ‘manure bath’ in front of the scrapers (should be less than 1 stride for a cow to walk over), and avoid running the scrapers during feeding times and any herd health activity. Regardless of the method of scraping, improving cow comfort, specifically the floor’s slip resistance, floor hygiene and the provision of a comfortable lying surface will help reduce lameness.
– Dr. Laura Solano, Farm Animal Care Consultant