Dairy manure with up to 3 pounds of bedding per cow per day flows satisfactorily. Manure with excess bedding or with long hay or straw may not flow well unless extra water, such as milking center waste, is added. Extra bedding wasted on days when stalls are bedded should be well mixed with the manure. Calf-pack manure should be well mixed with more liquid manure before entering the collection hopper. Gravity systems do not handle frozen manure very well.
Low temperatures make manure more viscous, as does drying during hot weather.
Adding water helps both situations, but it is important not to use too much water. This may cause more rapid separation of solids and add to the volume of manure that must be handled later. An alternate handling method should be planned for those days when manure is frozen, is too dry, or is not mixed sufficiently to assure gravity flow. When manure is scraped or collected from the barn, a collecting hopper guides it into the transfer pipe. Manure may be fed into the hopper by a gutter cleaner or scraped into it by a front-end loader.