The risk of cows experiencing bloat as a result of grazing clover is greater than that posed by grass tetany but less than milk fever, a Teagasc researcher has said.

Speaking on a Teagasc Signpost webinar, Dr James Humphreys of Moorepark said the risk of bloat needs to be managed appropriately, as other risks associated with cows grazing are.

“[When] you have high levels of clover because of these types of seed mixtures and low fertiliser nitrogen use, there is the risk of bloat. It’s a real risk to animal welfare. It’s also a risk to the welfare of the farmer because it adds stress, there’s no doubt about it.

“It’s a measurable risk and a manageable risk. In my experience, and I have a lot of experience with clover over the years, the risk [of bloat] is somewhere between grass tetany and milk fever.

“They’re two risks that are on farms and also two risks that need to be managed, and there’s a cost too associated with managing them,” he added.

Mitigations

Humphreys named bloat oil as the “obvious” way to manage bloat, but also said strip grazing and buffer feeding silage can be effective through increasing fibre in the diet.

“There are other management tools you can bring in, using a two-hour strip when you first put cows into a new allocation of high clover sward.

“The worst-case scenario is that you let cows in and they’ll just skim over the surface and just skim the clover off the surface of the sward, the clover leaves, which is probably going to lead to problems.

“If you can get them, when you’re introducing them first, to graze down into the butt of the sward, they get more fibre in their diet which tends to balance out. Then you can let them off over the remainder of it,” he added.

The Teagasc researcher said there is still a risk of bloat coming into October and November, and if you are buffer feeding silage at this time, this risk is negated almost entirely.

Research is needed to find a solution to bloat, he added, which Humphreys thinks will lie in increasing fibre in the diet.