Grazing winter oats – a US perspective

Dairy farmers in the US state of Wisconsin are being encouraged to sow winter oats in early August and then graze the growing crops throughout the subsequent autumn months.

In some cases the crops are sufficiently advanced to allow their ensiling during the November period.

The strategy allows the production of an additional forage crop before winter.

The oats also “scavenge” excess nitrogen while the plant residues enrich the soil. To date, those farmers involved in the practise have grazed young heifers on the land planted out for six hours a day.

After two years of grazing, the results show that it’s better to put the cattle out early in the autumn rather than later, and it often is better to use late-maturing cultivars.

The heifers put out to graze early gained twice as much weight per day as the heifers put out later.

The late-maturing oat variety also produced higher quality forage, with greater energy density in the plant stems and leaves, and greater concentrations of water-soluble carbohydrates that support cattle growth.

But will the grazed or conserved oats grow-on the following spring?

The answer to that question is generally no,” said Wayne K. Coblentz, a research leader at the US Dairy Forage Research Center.

“This is one of those situations that is not applicable for everyone.

Generally, if the oat plant is planted early enough in the late summer such that it joints and then elongates, it will not regrow the following spring.

“In fact, it will not even regrow in the fall immediately after it is grazed.

“Oat does not have the same strict requirement for vernalization that would be observed for wheat, which will absolutely not joint and elongate until the following spring.

“Anyway, the ability of oats to elongate in the fall is both a curse and a blessing.

There may be no potential for regrowth. However, because oat will elongate, the potential for yield before winter is about twice that of wheat.

“As such, it must be viewed as stockpiled forage for a one-time grazing event that requires a different grazing management approach.

“From a grazing standpoint, the main goal would be to extend the grazing season as deep into the early winter as possible,” he said.

Coblentz continued:

“In Wisconsin, with an early August planting date, we can harvest an oat crop as silage in early November.

“This also opens up windows of opportunity for summer manure hauling, which is becoming increasingly important,” he said.