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Preventing Pasture Bloat

By Hue Karreman, V.M.D.

Pasture bloat in cattle can be prevented with a proper diet.

With grazing season starting again, please keep in mind that legume pastures (clover and alfalfa) tend to cause bloating problems at any time of the grazing year, but especially when frosts are still happening. Pasture bloat is entirely preventable, but unfortunately every year I hear of a few farmers that have lost a handful of animals.

How can it be prevented? In short, make sure there is effective dry fiber in the cows’ bellies prior to putting out to lush pure stands of legume pasture. Realize that it takes a few days for the same group of animals to be on the same legume pasture stand (rotating through it onto lush growth) before any problem will be noticed.

Generally, bloating will be seen by day 4 or day 5 of animals on heavy legume stands. This is especially true if the animals are fed very little if any forage in the barn during milking times. Granted, the animals want to eat the fresh feed compared to the preserved feeds they’ve been eating all winter, but they must be persuaded to eat some effective dry fiber in the barn area about a half hour before going out to pasture. Putting molasses or some other tasty type feed on (or in) the forage will work. Otherwise they will pig out on the lush pasture offered.

Treating Pasture Bloat

Prior to obvious distress on day 4 or 5, a bunch of cows will start to look “fuller” by day 3 — the animals will appear equally distended on their sides but not show any distress. Put this kind of cow back out on clover or alfalfa pasture another day and she will suffer from pasture bloat. This is especially true of animals put out to clover or alfalfa pasture which has been frosted. You must wait two hours until the frost is off before putting animals onto legume pasture. Otherwise you are asking for trouble. Clinical signs will be enlarged cows that start kicking at their bellies and don’t move around too well. It is at this time that you need to treat them — don’t delay.

cows in pasture
You should wait two hours until the frost is off before putting animals onto legume pasture.

Carefully administer a pint (16 ounces) orally of vegetable oil and make sure to walk the cow around for a good 15 minutes and then give another pint at the end of that 15 minutes. This course of action generally ends attacks. Hold the head just above parallel to the ground when giving the liquid orally — never have the nose to the sky when giving liquids orally as the fluid too easily can get into the windpipe and lungs. Poloxalene (Therabloat) is allowed for emergency use in organic livestock as well. Herbal laxatives like Cascara sagrada may have an effect as well — give 30-60 cc orally if you have it. Get cows off legumes and onto grass pasture!

If the animal is down, it is critical to quickly stab the rumen to help expel the excessive rumen pressure which is choking off the animal internally. By standing behind the cow, your left side is her left side, and that is the side to stab — generally where the biggest part of the bulge is, just below the short ribs and behind the big ribs. (Do NOT stab the right side of the abdomen — this will cause all sorts of problems since you will be stabbing the intestinal area.)

While having to stab a cow is not a pleasant thought, it is needed to save its life if the animal is down. Use a short, sturdy knife the length of your fist. Make a quick thrust in, and then turn your hand 45 degrees to open up the slit you just created. A small volcanic eruption with lots of tiny, tiny bubbles will burst forth and relief will be immediate. Amazingly, these stab wounds don’t usually cause too much of a problem afterward. Though they certainly can lead to peritonitis (generalized belly infection), it seems that the fresh forage (as opposed to the fermented stuff normally there in the non-grazing season) seems to cause much less of a bad effect. I can’t explain it, but I have seen surprisingly good results from stabs to cows severely bloated from pasture.

Prevention centers on correct feeding practices. Realize that just because there is lush pasture doesn’t mean that nothing else should be fed. Also keep in mind that although grass is a ruminant’s natural feed, any sudden feed changes (and especially to extremes) will cause harm to the rumen bugs, which must adapt over a few days to a week’s time (different bugs exist at different pH in the rumen and the correct bugs need time to build up).

Carbo veg is the main “go-to” remedy for bloat — give it every 15 minutes, orally, as needed. Homeopathically giving Colchicum or Colocynthis is also a possibility if early and the cows just seem a little fuller than normal. Use Colchicum if the cow doesn’t eat, is straining and doesn’t want to move; use Colocynthis if she’ll move and looks back at her flank.

Adding a sweetener like molasses will also somewhat increase the carbohydrate content of what they are eating, and this will help to keep the nitrogen to carbon balanced better in the rumen. This will help to keep milk urea nitrogen (MUN) down as well, since high MUN is common in lush pasture due to too much soluble protein (which has nitrogen) being in the rumen compared to energy (carbohydrate with carbon). Thus the nitrogen from the excessive protein is converted to urea in the liver and excreted from the animal as urea in the milk or urea through the kidneys into urine to the bladder.

Probably the best thing to do is to alternate through grassy pastures or legume pastures with a lot of grass rather than straight legume for many days. This is when “tall grazing” would make a lot of sense, though early in the season nothing is really tall yet. As far as grasses go, and since a lot of people have orchard grass in their stands, remember that if orchard grass heads out even once in a season, any re-growth will have a different and worse taste to the grazing animals. It is just the way the biology of orchard grass is.

For those of you growing sorghum-Sudan grass, the soil needs to be about 60°F for planting. Folks that waited to plant it until mid-June in southern Pennsylvania were gnashing their teeth when the hot, dry weather started hitting as the seedlings didn’t grow quick enough. For simple grazing needs of a 40-50 cow herd, 2-3 acres will do. If you plan to harvest sorghum- Sudan as baleage, plant more acres of course.

As we all know, sorghum-Sudan is an insurance policy as it grows well in July and August when our perennial pasture species don’t. And incidentally, to achieve the minimum of 30 percent dry matter intake with a 40-50 cow herd on sorghum- Sudan, it usually only takes on average about .10-.25 acres per 24-hour period (according to my measurements in 2010 on a bunch of farms). This is compared to about .4-.6 acres per 24 hours of perennial grasses when growing well to deliver at least 30 percent dry matter for the same size herd.

Article reprinted from The Moo News, newsletter of Penn Dutch Cow Care. Dr. Karreman is the Rodale Institute Veterinarian and has been involved with organic livestock health care since 1988 when he was a herdsman on Seven Stars Farm, a biodynamic farm in Kimberton, Pennsylvania. For more information visit   www.hubertkarreman.com.

Dr. Karreman is author of The Barn Guide to Treating Dairy Cows Naturally and Treating Dairy Cows Naturally, available from the Acres U.S.A. bookstore. For more information call 800-355-5313 or visit www.acresusa.com.

This article appears in the April 2014 issue of Acres U.S.A. magazine.