Dairy Manure Management

Bedding Addition is applied as a percentage increase to the volume calculation only — it accounts for the physical bulk that sand, straw, or sawdust adds when mixed with manure. Daily Manure Production in pounds and tons is calculated from Herd Size and Average Cow Weight alone, so it stays the same regardless of how much bedding you use.

Required Storage Volume scales directly with Herd Size, so adding cows increases the volume by roughly the same proportion — doubling the herd roughly doubles the required storage capacity, all else held constant. Average Cow Weight has a similarly direct effect, since both feed into the same daily-production estimate.

It uses an estimate of about 86 lbs of manure per 1,000 lbs of body weight per day, the representative dairy-cattle value published in the ASABE (ASAE) D384.2 standard, Manure Production and Characteristics — the engineering reference most manure-management planning tools draw from. Actual production varies with diet, water intake, and individual cow physiology, so treat this as a planning-grade estimate rather than a measured value for your specific herd.

Manure storage regulations in many jurisdictions specify a minimum number of days of capacity a facility must provide — commonly in the range of 120 to 180 days — so that manure can be held until field conditions and cropping schedules allow proper land application. Enter the requirement that applies to your operation rather than an arbitrary number, since Required Storage Volume scales directly with this input.

No — they use simplified average pounds-per-ton factors applied to your estimated annual manure tonnage, intended to give a planning-level sense of nutrient value. Regulatory nutrient management plans generally require actual laboratory manure testing, since nutrient content varies significantly with diet, bedding, and storage/handling losses that this calculator does not model.