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Yikes ­— another crazy winter!

Nutrition with John McKinnon

The winter of 2017-18 is shaping up to be full of unexpected challenges, particularly for those wintering cows in Western Canada. Drought, as well as recent wildfires, have caused many producers to scramble for a forage supply. As well, “old man winter” in all his wisdom has arrived early, with November temperatures in the minus teens in many areas. As is typical in these circumstances, producers look to alternate feed sources to get their herd through the winter. These include cereal straw, poor-quality hay, and greedfeed as well as any number of energy and protein sources (i.e. grain screening pellets, mill run, feed barley or wheat grain, canola meal, dried distillers grains). When developing rations with these types of feeds, the primary goal is to meet the nutritional requirements of the herd with respect to stage of pregnancy and environmental conditions. However, in some cases it is necessary to understand the nature of the alternative feed, in order to ensure you do not run into any unexpected surprises. The intent of this article is to look at some of these alternatives and the issues you can encounter.

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Before we begin, remember the major nutrients you need to supply are energy and protein, particularly energy. Salt, minerals and vitamin, while important, can be supplemented as required. A major factor influencing the amount of feed required over the winter is the body condition of your cattle. Mature cows in good body condition in the fall can get through much of the winter on a ration that maintains body condition and allows for fetal growth, while thin/older cows and replacement heifers will need to gain weight over and above that related to pregnancy. Separating your herd into two or three groups based on age and/or body condition can help you develop rations that meet the specific needs of each group. Also remember that all groups as they enter the last trimester have increased energy and protein requirements that need to be met to avoid weight loss and possible negative effects on rebreeding.

As discussed previously in this column, cereal straw is usually the first alternative that producers turn to in drought situations. Barley or wheat straw can be successfully fed throughout pregnancy; however, the key is understanding its nutritional limitations. Cereal straw is deficient in energy, protein and most minerals and vitamins. As such, straw-based rations require supplementation with a source of energy and depending on diet makeup, there may also be a need for a protein. One of the major issues with feeding straw relates to its high fibre content and poor rumen digestibility. Cows, particularly those with free choice access, can become impacted when sudden drops in temperature occur. To prevent this, it is necessary to provide an adequate source of energy such as supplementing with a grain source and to limit the amount of straw consumed.

A handy rule when feeding cereal straw is to limit its intake to 1.5 per cent of body weight on a dry matter basis. For a 1,300-pound cow, this equates to 18 to 20 pounds of straw per day. To meet requirements for maintenance, weight gain and/or pregnancy, you will need to supplement this straw with either a good-quality hay or silage or turn to cereal grains and a protein supplement (i.e. canola meal, distillers grains or a commercial supplement). In the latter case, the amount of grain fed can reach 10 to 14 pounds per head per day. As such, be sure to adapt your cows to this high level of grain feeding. Byproducts such as grain screening pellets or mill run can substitute for barley although the amount fed would have to be increased since grain screenings are lower in energy.

If you planned ahead and seeded greenfeed as an alternative forage source, you should be in fairly good shape going into winter. Barley or oat greenfeed cut at an appropriate stage has an energy content similar to an alfalfa/grass hay, and protein levels similar to a good-quality grass hay. Limitations include the potential for nitrates if harvested under stress (i.e. drought). As well, there has been isolated issues with milk fever in cows fed greenfeed grown under drought conditions. This issue relates to imbalances in the mineral profile of the forage. If issues arise, feeding extra calcium and in some cases magnesium can help prevent this issue.

In terms of protein sources, canola meal and wheat or corn distillers grains should be relatively available. Canola meal is typically 36 to 38 per cent protein while distillers grains can range from 30 to 40 per cent, depending on the original grain source. Distillers grains are typically a better buy as they are higher in energy than canola meal and priced relative to cereal grains. By comparison, canola meal is priced as a protein source and thus brings a premium over barley or other cereals. Typically, 1.5 to two pounds of canola meal or DDGS can offset a protein deficiency in a straw/cereal grain-based diet.

These are just some of the alternatives that may be available. If you are short of forage this winter, I would strongly suggest you talk with your local livestock agrologist or nutritionist to determine the best alternative for your operation.

About the author

Contributor

John McKinnon is a beef cattle nutritionist at the University of Saskatchewan.

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