Product effective in controlling pasture bloat

New research is showing a product used to control cattle bloat in Australia and New Zealand for more than 20 years could allow safe grazing of alfalfa in North America.
That would allow gains from grazing almost equal to feedlot levels.
According to a Lethbridge Research Station release, in recent studies,
scientists examined the effects of Blocare on cattle and sheep grazing alfalfa for short durations.
They found that if Blocare is adequately consumed, it is 100 percent effective for controlling bloat, without reducing productivity, said Lethbridge Research Centre scientist Dr. Tim McAllister, a rumen microbiology and nutrition scientist involved in evaluating the product.
Alfalfa is the only forage that maintains productivity similar to that in feedlot diets but the legume can cause pasture bloat–an accumulation of gas in the rumen which can lead to cattle loss.
Bloat is the number-one problem with cattle grazing. Many producers are reluctant to graze alfalfa, despite its productivity benefits, because of the potential for bloat.
Hopes are the results of the studies will lead to registration of the product in Canada and the U.S.
Bloat occurs when forage is digested too quickly. A number of factors can interact to produce pasture bloat in grazing cattle and sheep. These include the type of forage, forage maturity, rate of digestion, animal behaviour, genetics, ambient temperature, and precipitation.
Strategies to control pasture bloat include breeding alfalfa to reduce its initial rate of digestion, planting grass-legume mixes for grazing, and using a variety of commercial bloat control agents.
Currently, none prevent bloat completely.
The new studies, published in a recent edition of the Journal of Dairy Science, focused on three scenarios. One looked at Blocare’s effect on the digestibility of freshly-harvested alfalfa, using sheep in confinement.
A second looked at the product’s effect on grazing sheep, and a third looked at its effect on grazing cattle.
In the first study, half of the sheep were given a daily dose of Blocare solution one hour before feeding and the other half were given water.
The symptoms of bloat were reduced in Blocare-treated sheep, relative to the controls, for the first two hours after feeding but not at four hours after feeding and beyond.
Scientists found treatment with Blocare did not affect dry matter intake, digestibility of dry matter, acid or neutral detergent fibre, or nitrogen digestion and retention.
“That’s good news for cattle producers because it implies that Blocare likely would not affect production,” McAllister said.
In the second study, five sheep were given Blocare in drinking water. In this treatment, the product was 100 percent effective for preventing bloat in sheep grazing early-bloom alfalfa for four hours daily.
Similar results were found in the third study with dairy cattle.
Further study is required to develop an integrated model for best treatment under a variety of climatic conditions, McAllister said.
“There are some situations where the product may not be as effective. The animals have to consume the product in water for bloat prevention.
“Under conditions of high rain fall, the risk of bloat may increase because of a lack of consumption of the product in provided water,” he noted.