• MD-DE Forage Council

Grazing Math

by Brian Campbell, NRCS Grazing Specialist

There are helpful calculations available to help farmers design a new pasture system or avoid damaging existing pastures by not overstocking, overgrazing, or under-sizing. Grazing math can be used to answer questions like:

· How many animals can my pasture/paddock support?

· How many days will my pasture/paddock last?

· How many acres should my pasture/paddock be?

The calculations use some assumptions about (1) how much forage your livestock need to meet their daily dry-matter needs – based on the class of livestock; (2) how efficiently those animals can utilize the pasture – based on how intensively livestock are rotated through paddocks (i.e. pasture subdivisions); and (3) how much forage the pasture has available – based on pasture height and density:

Once you find the appropriate numbers for your situation, input them into the calculations below. Remember, when you enter percentages into a calculator, that they often need inputted as decimals – for example, 3% as 0.03. You will probably only need to use one of the calculations at a time because you will often only be changing one variable at a time: the number of animals on a pasture/paddock, the number of days your animals remain on a pasture/paddock, or the size of a pasture/paddock.

Our example calculations will assume the following scenario: five retired horses averaging 1,100 pounds graze a pasture of mixed cool-season forages; these horses are expected to meet their dry-matter needs on pasture alone (without supplemental feed) and are moved to a new paddock once a week.

If you would like assistance in improving your pasture management, please contact your local USDA Service Center.

USDA is an equal opportunity provider, employer, and lender. To file a complaint of discrimination, write: USDA, Office of the Assistant Secretary for Civil Rights, Office of Adjudication, 1400 Independence Ave., SW, Washington, D.C. 20250-9410 or call 866-632-9992 (toll-free customer service), 800-877-8339 (local or federal relay), 866-377-8642 (relay voice users).

It is the policy of the Maryland-Delaware Forage Council that no person shall be subjected to discrimination on the basis of race, color, sex, disability, age, or national origin.

© 2020 Maryland-Delaware Forage Council