Does water or blowing air stimulate cows to defecate?

Manure is an important cause of dirtiness and disease for cows and can affect milk quality and human health. The aim of this study was to test whether we could stimulate cows to defecate at a particular location in order to reduce the spread of manure. A series of four tests with 12 lactating Holstein cows (days in milk = 137.5 ± 17.5 days, parity = 3.3 ± 1.5) was conducted. In Test 1, cows walked through either an empty footbath or one filled with water (21 °C) following a balanced order with one treatment per day, for 6 days. Cows were more likely to defecate when walked through the water filled footbath (67% vs 42% of tests: P = 0.04). In Test 2, the cows stood for 2 min either in an empty footbath or in a footbath filled with still water or with running water, with one treatment per day, for 9 days. In Test 3, the cows stood for 2 min in an empty footbath with nothing, air or water sprayed on their feet, with one treatment per day, for 9 days. No significant treatment differences were found for Tests 2 and 3 (P > 0.10). After Test 3, we repeated one repetition of Test 1 (Test 4) but no treatment differences were found at that point (P > 0.10). None of our tests reliably stimulated defecation, which seemed to occur most when cows were exposed to novelty.