How much to cut hay when on pasture

[Pico_Banana]

When putting a horse on pasture with a grazing muzzle, how do people determine how much to cut back on the horse’s hay ration?

Is there any relatively easy way to determine how much hay is equivalent to, say, one hour on grass? Have there been any studies done to measure average consumption through a muzzle? I know there have been studies of eating rates of horses on pasture 24/7 versus grazing limited amounts of time, but I’m not aware of any studies that would help me figure out what to do in my situation.

It probably also depends on what kind of grazing muzzle, length/type of grass, etc. But I just am looking for rough justice, if anyone has any thoughts.

[Scribbler]

I have never found an hour of hand grazing to have any effect on weight. An hour is as long as I can stand on the powerlines doing nothing

[goodhors]

Minnesota University Extention, says a grazing muzzle only reduces grass intake 30%. So not really the helpful product on food intake that many consider it to be.

[wsmoak]

@Pico_Banana

Is there any relatively easy way to determine how much hay is equivalent to, say, one hour on grass?

I asked a friend who works at an equine research company this question several years ago and with the “it depends on the pasture” and “compensatory eating” caveats she suggested 1 lb of hay per hour of grazing as a place to start.

This seems reasonable to me based on feeding 1-2% of body weight in hay and the number of hours in a day.

[JB]

A 30% reduction in calories is pretty significant IMHO

Some studies put 4lb/hour grazing on decently lush grass. If you assume 25% dry matter (because decently lush grass), that’s about 1lb of hay, so that fits with what wsmoak stated. It’s not exact because hay still has some moisture, but for this purpose it’s close enough.

Summer grass with lower moisture and higher DM will equate to more “hay”

That said, it’s not a 1:1 comparison either, as in, you can’t assume that for every 10lb of dry matter from grass, you can reduce 10lb of hay and have it all be equal in the end. Grass is generally better at putting weight on horses than hay, all else equal.

I wouldn’t worry much about how much to reduce hay while on pasture. I would just look at the hours he’s not on pasture, and make sure he’s got enough hay to last him the majority of that time. Netted, scattered, however you do it.

If he’s not losing weight, or even gains, then reduce grass time or start netting/double netting the hay. Or both LOL

[candyappy]

This may not help but when my mare is out on grass all day(with muzzle) She gets her normal hay feeding for the time she is dry lotted overnight.

If your pasture is all tall grass the consumption will be drastically reduced as it is just really difficult for them to get anything significant when they can’t shove the muzzle down to the ground like when the grass is younger . At least in my horses case that is true.

I watch her daily to assess her condition and either let her be unmuzzled for a period of time or up her overnight hay. Or if she is gaining I reduce the hay for a bit. As the grass matures gradually she can go w/o for even several hours and maintain a steady weight.

[DawnJL]

@JB

I wouldn’t worry much about how much to reduce hay while on pasture. I would just look at the hours he’s not on pasture, and make sure he’s got enough hay to last him the majority of that time. Netted, scattered, however you do it.

This is what I do with my not yet EMS, but at risk horse.
FWIW, I’m using a Thinline/Flexible Filly grazing muzzle when he is on pasture for about 8 hours. Then he has hay in a slow feeder net overnight. He also gets a small amount of low-carb feed with a multi-vitamin/mineral supplement balanced for our geographic area and an EMS supplement.
Under current conditions his weight is good. If he started gaining, I’d probably shorten his grazing hours and/or up his exercise. If he began to lose, I’d increase his time on pasture.