Study evaluates ergot levels in lamb rations

CFIA feed guidelines put the maximum alkaloid content in feed for cattle, sheep and horses at two to three milligrams per kilogram. | File photo

A three-year study looked at alkaloid concentrations and the effect on lamb performance and behaviour

RED DEER — Toxins in ergot infected grains can seriously affect sheep productivity.

“If the concentration and the duration is high enough, you can have death. There are a huge variety of symptoms to make it tough to tell if it is ergot,” said researcher Kim Sandford of Alberta Agriculture.

“Because ergot has such really bad implications for breeding stock, it is just best if you can avoid having ergot in your feed for breeding stock.”

Sandford is part of a research team investigating the effects on growing lambs when they were fed different concentrations of ergot-infected rations.

Early results were presented at the Alberta Sheep Symposium held in Red Deer Oct. 20-21.

Ergot is a fungus affecting grasses and cereal grain when the plants are in flower.

Ergot does not stay in the bloodstream for more than about six hours and so is hard to detect. The symptoms of infection are variable but can be damaging.

Alkaloids are the troublesome part of ergot.

Each alkaloid has two forms called epimers in the form of S and R. The S epimers are less toxic than the R epimers, but they are able to change from one to the other, which makes it difficult to tell how toxic a sample might be. Other alkaloids may also be present.

There are no rapid tests for ergot alkaloids so feed companies may have to rely on visual observation and may refuse grain if there are more than four to six ergot bodies per litre of grain.

The current standard for laboratories is to use high performance liquid chromatography in combination with mass spectrography.

The Canadian Food Inspection Agency feed guidelines say the maximum alkaloid content in feed for cattle, sheep and horses is two to three milligrams per kilogram. Swine can handle up to four to six mg per kg.

There is limited research on cereal ergot and the effects on livestock. Nor is there much information on how alkaloids work together or against each other.

Researchers also want to know if the alkaloid profiles are confined to different regions of the country.

The feeder lamb study fed different concentrations of ergot to see how weight gain, feed intake and digestibility were affected.

They also measured for the hormone prolactin in the blood. It is known ergot fed in sufficient concentrations blocks prolactin and ultimately affects reproduction problems and an ewe’s ability to make milk.

Ergot also causes blood vessels to constrict and can lead to tissue necrosis. Eventually, animals could lose their hoofs if they are badly affected.

Year one of the study used low alkaloid concentrations. There were no significant production problems but the lambs that re-ceived a pelleted diet grew better than those on a mash diet even with the presence of ergot.

Researchers also theorized pelleted feed may be better all around.

“Pelleting, rather than being bad had protective effects to reduce the negative impacts of the alkaloids,” she said.

Feed intake was not a problem.

“There was absolutely no reduction in feed intake for the lambs fed the ergot diets compared to the control diets,” she said.

In other species, the first symptom of contamination is when animals go off feed.

There were no differences in carcass traits, but ergot can change how the fat is deposited and causes a crumbly appearance. Researchers did not detect that.

In year two, the alkaloid concentration was boosted and showed more of an effect on lamb performance.

This was six times higher than the diet used in year one, but there were no significant differences in feed intake, digestibility or feed conversion but prolactin levels and rectal temperature differed.

Lambs receiving higher levels of infected feed also displayed some behavior changes due to the alkaloids.

Further inspection showed there was more of one kind of alkaloid that led to psychedelic effects.

In the third year, an alkaloid binder product was used and appeared to have positive effects in preventing ergot-related problems but results are still being evaluated.

About the author


Stories from our other publications