[Sue B]

I have seen many posts on how people believe fresh grass compares to hay...how long a horse has to graze to get the same benefits from grass as hay. However, it seems that there are a variety of opinions.

How does everyone feel about how this difference might impact founder, colic or other digestive upset issues.

What is the general way that everyone determines how much grass a horse eats vs how much hay they feed?

[Shotgun93]

I have always wondered what the best way is to determine how much grass a horse is actually getting in a day. I know that there is a lot more water weight in fresh grass than in hay, and wondered how that came into effect too.

[wyldterv]

Sue, I personally believe that it varies greatly from horse to horse... SOME horses need to have 3% of their body weight in hay daily or graze 24/7 to maintain healthy gut, weight etc... SOME horses need to be kept at about 1.5% their body weight daily in hay or only allowed to graze for 8 hours a day total or they 'balloon'...

I also think it denpends on the quality of the hay and the quality of the fresh grazing available... Has the horse never been exposed to grazing before??? If not, and they're a breed more prone towards founder issues and/or colic issues, then you need to introduce grazing VERY gradually (Litterally at no more then 20-30 minute increments no more then 3 times a day initially and SLOWLY building up from there)... SOME horses that have spent their entire lives on pasture seem to handle it well...

I don't personally think there is a 'pat' answer as to how much grazing compares to how much hay because there is SUCH a wide variations of conditions ... You have the horse itself, they quality of the hay, the quality of the pasture...the amount of actual work the horse does daily, the acutally amount of true exercise the horse gets daily, etc...

[Commanderkins]

Well never having a horse founder, I have my horses on full pasture in the spring and summer. I find that when I switch to hay in the fall, my one TB gets colicky from the change from grass to dry roughage.
I think that fresh grass is no comparison to dry grass hay. I don't even feed grass hay in the winter I fedd strait alfalfa.

[Sue B]

OK....these are all excellent points...but let's keep this simple...and assume the same exact grass mix in the pastrure as in the hay....just for the purpose of hypothetical discussion.

[Sue B]

Originally Posted by Shotgun93

I know that there is a lot more water weight in fresh grass than in hay, and wondered how that came into effect too.

You are thinking in the right direction Shotgun. The DM (dry matter) vs as fed is a key element in deterring how much grass a horse should eat compared to its hay. The problem is that when similar pasture/hay samples are compared, the nutrient values are similar...especially in regard to NSC (sugars/starches). We know that there is an issue with some horses and high sugar levels during certain seasons in fresh pasture. But, believe it or not, the average NSC levels are similar in fresh grass compared to average hay values.

[wyldterv]

Originally Posted by Sue B

OK....these are all excellent points...but let's keep this simple...and assume the same exact grass mix in the pastrure as in the hay....just for the purpose of hypothetical discussion.

I still think it will vary because dried hay doesn't have the exact same nutritional make up as growing grass and each horse's needs will vary plus some horses graze faster then others as well... so while one horse may eat 10 lbs of growing grass in 3 hours grazing another may only consume 3 lbs in that same amount of time...

[wyldterv]

Originally Posted by Sue B

. The problem is that when similar pasture/hay samples are compared, the nutrient values are similar...especially in regard to NSC (sugars/starches). We know that there is an issue with some horses and high sugar levels during certain seasons in fresh pasture. But, believe it or not, the average NSC levels are similar in fresh grass compared to average hay values.

Now this is something NEW I've learned as I haven't yet read that anywhere ... and yet those horses put on the dried hay don't seem as prone to founder as when they are grazing on the grass... SO, it leads one to wonder if there is some OTHER, as yet, untested chemical process going on between consumption and digestion of grass versus dried grass....

[SalemsMom]

It also depends on whether you have a easy keeper,they tend to founder easier,like someone else has said,you let them out on it a little at a time,I start with fifteen minutes on grass,twice dailey,and then let then do that for several weeks,then I increase their time by ten minutes longer,and go through the same process,intill they eventully are grazing 8 to ten hours a day,longer for hard kept horses,untill I work them getting on it 24/7. Horses kept on pasture all winter seem to do better when the grass comes up,but I do watch out for the easy keepers,or the horses that can gain weight just lookingat food.I also will throw hay out for them,in the beginning to,with a bluegrass,orchard and alfalfa mix.

[Sue B]

Here is the nutrient comparisons between similar hay and grass. I did't list them all....just some that were more familiar and generally of concern. And yes, there are some slight variances...for 2 reasons: these are averages take from thousands of samples and there is an error margin in these tests. The big jumps are what I am interested in. Look at the nitrate/nitrite info. I'm not too familiar with this aspect of nutrition in hays and grass....maybe someone could explain some of it.

Nutrient - Hay vs Grass
% Dry Matter - 91.910 - 51.095
% Crude Protein - 10.489 - 15.258
Crude Fiber - 31.660 - 33.083
% Sugar - 10.722 - 10.267
% Starch - 2.501 - 3.259
% Non Structural Carbo. (NSC) - 13.128 - 12.541
% Crude Fat - 2.424 - 3.646
% Calcium - 0.523 - 0.566
% Phosphorus - 0.242 - 0.300
% Magnesium - 0.201 - 0.230
% Nitrate - - 0.060 -0.153
% Nitrates - 0.077 - 0.107
PPM Nitrate-Nitrogen - 174.302 - 240.708
Horse DE, Mcal/Lb. - 0.903 - 1.033
Horse TDN, % - 45.164 - 51.649