What to consider when grazing hay fields this fall

  From the September 4, 2018 issue of Agri-News
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 Hot and dry conditions - both this year and last - have stressed many pastures in the province. This year, some producers are pulling their cattle off pastures 60 to 70 days earlier than usual. Karin Lindquist, forage and beef specialist at the Alberta Ag-Info Centre, outlines grazing hay fields this fall an option to consider to keep livestock out as long as possible.

“Most hay stands will have a significant amount of alfalfa in them,” explains Lindquist. “Higher quality hay typically needs to have a legume component to provide sufficient protein and energy to meet animals’ needs. The grass component of a hay stand is more beneficial for grazing than a pure alfalfa stand, and alfalfa still poses a bloat risk in the fall.”

Lindquist says that the best time to begin grazing alfalfa-grass stands is after mid-September when plants have begun to slow growth and go into dormancy. “This time frame is also past the 45 day critical growth period, starting from the first of August, that alfalfa plants need to prevent winterkill. Alfalfa must be able to put energy down into its crown and roots to survive winter and to use those energy stores for regrowth in the spring.”

Fibre content is higher and digestible protein and energy content are lower when plants have already reached maturity and are going into dormancy. “That makes the plants harder for ruminants to digest,” says Lindquist. “It lowers bloat risk especially when cattle are first introduced onto hay stands. However, there is still some risk of bloat, so management practices to reduce incidences are still good to keep in mind.”

Lindquist says to introduce animals to the hay stand in the middle of the day and when they are not hungry. “If you have access to some hay or straw, leave a bale or two out for them for the first four to five days. As well, having access to another forage stand that is predominantly grass may also work, especially if hay is in short supply. Check on them at least twice a day during this first week, as you may have some chronic bloaters that will need to be removed as soon as possible.”

“Don’t be too alarmed if you start grazing and you get frost on the alfalfa when it comes to nitrates,” adds Lindquist. “Nitrate toxicity with alfalfa is not an issue because of its nitrogen-fixing capacity - as with all legumes - and most hay stands are usually not fertilized. Nitrates are more of a problem with annual cereals such as barley or oats.”

“However, frost tends to increase digestibility of the plants because it breaks apart the plant cell walls, making its contents more readily available to rumen microbes. This is a cause for concern, particularly when introducing animals onto hay stands. Avoiding introductions in the morning and supplying a more fibrous feed source will help,” notes Lindquist.

Once animals have become adjusted to the hay stand, Lindquist says that it is best not to remove them from that stand, even at night. “They would need to be re-introduced to the stand using the same practices that you would have used when they first entered the hay field. It is best to leave them there for as long as you need them to graze that stand.”

For more information, contact the Alberta Ag-Info Centre at 310-FARM (3276).

Alberta Ag-Info Centre
310-FARM (3276)

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For more information about the content of this document, contact Karin Lindquist.
This document is maintained by Christine Chomiak.
This information published to the web on August 28, 2018.