I just mowed the grass in one of my pastures. How long to wait before I let my horses graze on it again?
ByI’ve heard mixed opinions about it being ok to let them graze on it as long as the grass has dried for at least 24 hours. I mowed a fairly big section and the grass was super long. I don’t want my horses to colic but I need to change pastures so I can mow the other one. Any words of advice?
If it was pretty long and the grass is in piles rather than spread around , then the grass is likely to begin fermenting fairly soon. It would not be safe for the horses when that happens. I always pull the drag and light harrow behind the mower to toss the grass around so it doesn’t form piles and ferment, and my horses stay in the pasture and eat with no problem.
Fermentation occurs when there is depth to a pile of grass. Anaerobic microbes deep in the pile begin to multiply because they thrive where it is moist and dark, and there is no air flow, so these microbes digest and decompose the grass. Toxic molds or deadly botulinum bacteria may be present in the grass and multiply, and if the horses eat it, they can become seriously ill. If the grass is left in piles, then even after 24 hours it is risky to let the horses eat it.
If you can harrow or drag it and spread it out so it doesn’t ferment, it would be safe. You can rake it by hand if the field is small. At this point it has already begun to ferment if it is piled up, so it would need to be spread out and dried in the sun for at least 24 hours to kill any microbes that have multiplied, and drying it for 48 hours would be safer.
But if it is left in piles, then fermentation can continue as ground moisture combined with the dark, low oxygen environment sustains it.
So it really depends on whether the grass is spread out well and exposed to air or not. If it is, then it should be safe for the horses to eat.
For the last five years, we’ve mowed and just let them turn out on it. We normally have it set up where there’s a rake thing on the back, but we’ve NEVER had any problems with colicing.
If you want to be extra careful, give it a full day. That’s what most people I know do.
I have a neighbor that waits a full month before turning out.
References :
If it was pretty long and the grass is in piles rather than spread around , then the grass is likely to begin fermenting fairly soon. It would not be safe for the horses when that happens. I always pull the drag and light harrow behind the mower to toss the grass around so it doesn’t form piles and ferment, and my horses stay in the pasture and eat with no problem.
Fermentation occurs when there is depth to a pile of grass. Anaerobic microbes deep in the pile begin to multiply because they thrive where it is moist and dark, and there is no air flow, so these microbes digest and decompose the grass. Toxic molds or deadly botulinum bacteria may be present in the grass and multiply, and if the horses eat it, they can become seriously ill. If the grass is left in piles, then even after 24 hours it is risky to let the horses eat it.
If you can harrow or drag it and spread it out so it doesn’t ferment, it would be safe. You can rake it by hand if the field is small. At this point it has already begun to ferment if it is piled up, so it would need to be spread out and dried in the sun for at least 24 hours to kill any microbes that have multiplied, and drying it for 48 hours would be safer.
But if it is left in piles, then fermentation can continue as ground moisture combined with the dark, low oxygen environment sustains it.
So it really depends on whether the grass is spread out well and exposed to air or not. If it is, then it should be safe for the horses to eat.
References :
RN and 57 years with horses