Wednesday, September 28, 2011


It's been a long tough day and my post is just not coming together so instead of serving up that mess I thought I'd ask a couple of questions. Hopefully some of you will have the answers to these.

Do you know what Acid Detergent Fiber is?

What about Neutral Detergent Fiber?

I know these are terms I could sure benefit from knowing more about. What about you?

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  1. Not a clue, the stuff I looked up seems to be related to crude protien available in feed

  2. Actually, yes, I do know what they are.

  3. Oh, crap, delete my other response, 'cause that was snarky and useless and, well, sorry.

    Fiber is ... hard to measure in many respects. What's fiber for humans is different than what's fiber for horses and that's different from what fiber is for ruminants.

    This is digging back into what I remember about nutrition from college and grad school (20 years and a totally different career ago). I can probably find my college notes / texts if people really want the detailed stuff, but here goes.

    When animal feed is analyzed it goes through a series of steps. One of those steps separates out what is soluble in water (usually proteins and some sugars) and what isn't (fiber, minerals, fats). Then they take the insoluble portion and separate out the fats.

    Acid detergent and neutral detergent are ways to measure different kinds of fiber (gives up and googles).

    OK, so acid detergent fiber measures cellulose and lignin. Neither are digestible by mammalian enzymes. Cellulose *can* be digested by bacteria in the gut (the large intestine and horses). Lignin can't be.

    Neutral detergent fiber is a mix of cellulose, lignin and hemicellulose.

    More ADF reflects a decrease in digestibility of a food. More NDF reflects a decrease in consumption of a forage.

    I am happy to answer questions (hey! I get to use that animal science degree I have!! Mother would be so proud!) but it may take some research.

  4. FV, me either until recently when I found out it was something I should know.

    Laura, I did't think your first answer was snarky at all but I'm glad you decided to elaborate. Do you know what a suitable range for either would be? Also if the numbers are too high is there a way to fix it?

  5. I don't know what the range is, but I'll poke at some of my nutrition texts and see if I can find it. A quick google on various co-op extension pages basically says "as low as possible" for both.

    Perdue says:
    "orage digestibility is indirectly measured by determining the level of acid detergent fiber (ADF) in the hay. As the plant matures, ADF (cellulose and lignin) increases, and digestibility decreases. Neutral detergent fiber (NDF), a measure of cell wall content, increases as the plant matures and is an indirect measure of how readily a forage is consumed.

    Immature hay is more easily digested by the horse (lower ADF percent) and more readily consumed (lower NDF percent), thus it is worth more to the horse owner. The maturity of the plant is not related to a particular cutting, but rather to the stage of maturity of the plant when cut."

    This is one of those bits of nutrition where I think the actual values are less relevant than how your horses are doing on the feed. If they're losing weight or condition with free choice forage, then they're not getting what they need. Some of that could be related to an overly mature hay that is too high in ADF (meaning it's not digested well) and/or two low in NDF (meaning it's not tasty and the horses won't eat it).

    But, these really are measures more of palatability and digestibility rather than actual needed nutrients.

  6. Oh, forgot this:

    If either value is too high, then you'll want to add a concentrate to the diet. The hay is still going to be *great* as a fiber and for keeping the gut moving, but may not be meeting all their energy and/or protein needs. So adding a pellet or grain will make up that shortfall.

    With horses that are not in heavy work, it's unlikely the exact numbers are going to be important. Body condition is going to be your best measure. For horses that are in intensive training, you may need to know the exact values and balance the diet more carefully.

  7. Sounded like knitting wool....oops!--guess you know where my feeble brain is centered these days. I am sooo fortunate in learning something new every day. Never heard of either but..I am being edjimicated to spite myself. How does this relate to our horses's feed? Or does it?

  8. Might as well be speaking a foreign language as far as what I understood from all of that.

    Points upwards in the comments that are literally over my head.

    Phaedra You're way beyond me- I don't even knit! LOL

  9. So good to hear from you Mikael!!! I have been on a little bloggy break so am so far behind with everyone. No I don't know what those terms are but I read your other comments so feel a little educated.

    Yes, I think Little Bud will get along fine as long as we keep good tabs on him as his eye condition deteriorates. He seems to be pulling away from the herd a bit more these days, probably because Scooter has taken over as head honcho and he doesn't want to get into anything with him. He still loves to go out on the trail and we have even gone through the woods and over roots etc and he does fine. I wouldn't think of riding at night anyhow so that's not an issue. My vet said that some blind horses get along very well but I don't think it will come to that. At 24 I won't put him through a surgery either. As long as he is getting around well, keeping his weight and having good quality of life we'll just keep on keeping on! :o)

    Now I need to go get caught up on your posts that I missed. Glad you are home and doing well!!!

  10. Laura, I really found this information useful and if you had to find it on google you did a much better job of tracking it down than I did but then it's obvious you understand the subject matter much better than I so knew what you were looking for. Me, I got nothing.

    I still do have more questions. I thought lignin was part of the NDF number but it sounds from what you are saying that it is part of the ADF. The precentages that show up on an analysis form are there groups that add up to 100%? I guess I'm asking if there is some rhyme or reason to the way the information is laid out that might help me understand which thing affect which other thing, like the Lignin and the ADF?

    Phaedra, I can sure understand why it would sound like wool and you are so right to question feed. It is totally about feed and more information will follow.

    CNJ, It meant about the same to me a couple of weeks ago but I hope to learn everything I can about it. All reasons and information will be coming as it falls in line in the journey.

    MM, I knew you'd been gone and I certainly missed you. Lil Bud couldn't be in better hands. I'll bet he hardly notices the changes and just goes with the flow. Such a special horse.

  11. Hey, MiKael, glad to help.

    Lignin is part of both the ADF fraction and the NDF fraction. But the ADF fraction has less other plant parts. There's a useful chart at the bottom of

    And you're not going to necessarily see numbers add up to 100.

    Basically ADF and NDF are a way to measure how digestible a feed is. Some of the ration balancing formulas don't use ADF or NDF they use "Total Digestible nutrition" (TDN) which is derived from ADF and NDF.