Assessing fresh urine puddle physics in commercial dairy cow houses

Ammonia emission from dairy barns can be reduced by measures that improve removal of urine from floors. Information characterizing physical and chemical properties of urine puddles on floors are essential to improve mitigation measures, however information representative for practical barn conditions is scanty. The objective of this paper is to assess the area (Ap) and depth (Dp) of fresh urine puddles in commercial dairy barns, and to investigate the effect of floor type, season and manure scraping on these variables. Sixteen farms were measured in a factorial design of four Floor-Management types (FMTypes). Each farm was measured in two seasons and underwent an intense-floor-cleaning treatment (PREclean) before puddle creation for the Dp measurement, which was compared with those created under normal floor conditions with on-farm manure scraping. Overall mean values were 0.83 m2 for Ap and 1.0 mm for Dp. For both Ap and Dp the variation within a farm was large but negligible between farms. FMType significantly affected both variables. The V-shaped asphalt floor resulted in larger Ap (1.04 m2) and Dp (1.5 mm) than those of slatted and grooved floors (mean values 0.76 m2, 0.93 mm). Our study demonstrates that the draining capacity of solid floors is a critical design issue in lowering ammonia emission. The PREclean treatment resulted in Dp values that were 3 times lower than values for puddles created under normal floor conditions. We conclude that there is a considerable potential to improve draining of excreted puddles by increasing the cleaning performance of manure scrapers.