Horse Hay Analysis: What are ‘ADF’ and ‘NDF’?

Acid detergent fiber and neutral detergent fiber measurements can help you decide if hay is good for your easier keeper, broodmare, or growing foal.

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horse hay analysis
Generally, NDF content of 40-50% and ADF content of 30-35% is considered ideal for performance horses, young stock, and broodmares. | Photo: The Horse Staff

Q.I recently got my hay tested and received the analysis back. I have heard of water-soluble carbohydrates (WSC) and starch, but the analysis also lists “ADF” and “NDF” on it. What are they, and are they relevant?

—Via e-mail

A.The abbreviations “ADF” and “NDF” stand for “acid detergent fiber” and “neutral detergent fiber,” respectively. They are measures of feeds’ cell walls, or structural carbohydrate components

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Written by:

Clair Thunes, PhD, is an equine nutritionist who owns Clarity Equine Nutrition, based in Gilbert, Arizona. She works as a consultant with owners/trainers and veterinarians across the United States and globally to take the guesswork out of feeding horses and provides services to select companies. As a nutritionist she works with all equids, from WEG competitors to Miniature donkeys and everything in between. Born in England, she earned her undergraduate degree at Edinburgh University, in Scotland, and her master’s and doctorate in nutrition at the University of California, Davis. Growing up, she competed in a wide array of disciplines and was an active member of the U.K. Pony Club. Today, she serves as the district commissioner for the Salt River Pony Club.

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