Prevent Frothy Bloat in Beef Cows on Early Spring Pasture

rumen fluid. Natural gas release is slow, because gases are trapped inside small emulsified bubbles. This gaseous froth often interferes with the rumen nerve-receptors that open up the oesophagus for gas expulsion.

Cattle are often susceptible to frothy bloat when grazing lush alfalfa pastures compared to other types of sprouting legumes and grasses. This is due to alfalfa’s: (1) low fibre content that allow greater consumption in a short period of time, (2) a rumen digestion rate that is up to ten times greater than most grasses; produces lots of carbon dioxide and methane, and (3) a high level of soluble-protein that increases the thickness of rumen fluid, which can easily trap fermentative gas bubbles and prevents natural gas-expulsion.

The potential for frothy bloat in cattle grazing alfalfa pastures is greatest when alfalfa is in its lush vegetative to early stages of growth. As the grazing season progress, alfalfa like other pasture plants matures as it enters its bloom stage; fibre levels in its stems increase substantially and soluble protein levels in its leaves decrease. This natural maturation of alfalfa plants lessens overall bloat risk.

There are a couple of ways to treat the frothy bloat cases that pop up in the beef cowherd grazing lush pasture. For example, the Canadian Food Inspection Agency lists Poloxalene (Bloat-guard) to be fed at 1.0 g per 45.36 kg of bodyweight for moderate bloat cases and 2.0 g per 45.36 kg per 45.36 kg bodyweight for severe ones.

However, I talked to a couple of beef producers that graze pasture in the spring and they believe that prevention of frothy bloat is its best medicine in the first place:

There

By Peter Vitti

As a beef nutritionist, I haven’t heard about many fatal cow bloat cases over the last ten years. Of the few cases that I am aware of, it seems that it takes only a few things to come together to make bloat deadly. I am also aware, from talking to experienced beef producers that most potential for annual bloat problems are quickly defused, if common sense prevails. And some preventative steps are taken in the early spring, before letting cows out onto lush-green pasture. Most of these measures are simple and yet effective against bloat in cattle. That’s because, the development of bloat lends itself to simple ruminant biology. Normally, the rumen-microbes ferment a mouthful of pasture-forage into essential nutrients, which are utilized by the cow to perform its vital functions, nurse a calf and get ready for re-breeding.

As part of this process, end-gases such as carbon dioxide and methane are produced, which subtly distend the rumen, yet trigger ruminal nerves, which cause gas-expulsion during “cud-chewing”. Unfortunately, bloat develops when the same rumen for one reason or another cannot release this gas, which may accumulate to deadly asphyxiation.

Consequently, there are two types of bloats that can be fatal to beef cows on pasture. The first type is “free-gas” bloat which is straight accumulation of trapped gas in the rumen. It occurs in about 10% of all pasture bloat cases and is thought to be predominant among chronic bloaters. The other type of bloat is known as “frothy bloat”, which encompasses majority of bloat problems on pasture.

Frothy bloat occurs when the rate of forage consumption and digestion is so rapid that fermentation gases mix with the

- The first producer operates a 300 cow-calf operation. He and his wife put out barley straw bales on the first few acres of alfalfa-grass pastures that the cattle are initially released. Their idea is to let their cows fill up on straw. They keep putting out bales for the first couple weeks of the pasture season. It also seems having access to salt blocks and loose mineral on the same pasture reduces the incidence of bloat.

- The second producer operates a 150 cow-calf operation. He calves his cows on grass pastures and practices rotationalgrazing. His cows graze mostly grass-stands for the first few weeks of spring, because there isn’t much alfalfa fields to be grazed. Most of his cattle move onto predominantly alfalfafields in the mid-summer and by then pastures have matured.

These are two great testimonials that effectively control bloat in beef cows grazing early spring pastures. Yet their experiences are of timeless value. While its’ risk cannot be totally eliminated, frothy bloat can be substantially reduced with a sound preventative action plan, before the first cow steps foot onto lush-green fields.