By Murray Feist, M.Sc., P.Ag., Provincial Livestock Specialist
Facing a feed shortage in spring and summer is not an enviable position for bison producers. Back-to-back years of cool springs and dry summers have reduced feed stockpiles and increased pressure on pasture and hay-land. The result is adverse growing conditions that drive up the cost of forage, forcing producers to look at alternative feed and management options such as pasture supplementation, screenings, salvage crops and mixing of feeds for winter rations.
There are some feed and management options to consider. Early spring grazing of hay stands may work to stimulate plant growth and allow pastures to rest for later grazing. However, early spring grazing may require the provision of supplemental hay or concentrates to take the pressure off the pasture and hay stands. According to beef production advice, feeding a mature cow five to six pounds of oats will provide 25 per cent of the daily energy needs and can decrease grazing pressure by up to 25 per cent. Creep feeding of calves and early weaning will also reduce grazing pressure on pastures by both cows and calves and can offset forage consumption.
Alternative feed-forage sources are also potential feeds for bison producers. For example, many producers use annual cereal crops seeded in mid-spring for green feed or silage, and even harvested for the grain. Later-seeded cereals can be used for grazing (standing corn) or swath grazing in the fall and winter. During dry seasons, depending on crop insurance coverage status, salvage crops may also be used. Typically, salvage cereal crops like barley, oats or wheat can be cut and baled when close to maturity. In normal years, approximately half the weight of a mature cereal hay bale will be from the weight of the grain seeds and needs to be rationed accordingly. In dry years where crop yield is low, that proportion shifts so that the stem and leaves will contribute more to overall weight than the seeds. In dry years, the fibre content will also be higher, as plants would have increased in fibre content much more rapidly with less starch and lower yields.
When considering the use of straw, either for stubble grazing or baled for feed, rations must be fortified with energy from other forages or grains with minerals and vitamin supplements. Producers should be vigilant, as rations designed around using straw as a base forage should be including a supplemental source of Vitamin A to prevent deficiencies. Vitamin A-deficient bison cows may not be able to produce high-quality milk at calving, resulting in weak and immune-compromised calves with subsequent growth impairments and immune function. Straw-based diets also can be low in protein, as most straws only contain four to six per cent protein. For example, supplementation of a half a pound of canola meal or dried distiller grains to feedlot animals or mature cows late season grazing when forage protein content is declining can be beneficial. Pellets, meals and crumbles can be mixed with grain and/or other supplements or top dressed in bunks to boost the protein level. Increasing the protein provides an enriched opportunity for rumen bacteria to be more efficient in breaking down and degrading forage fibre. On low-quality forage rations, protein supplementation combined with energy supplementation from hay or concentrates assists to stabilize rumen function at peak performance for forage fibre digestion and absorption.
Remember that in dry seasons most forages will be higher in fibre, so boosting microbial performance is desired. However, if too much starch is provided in the ration, acidic rumen contents with a high proportion of starch-digesting microbes can inhibit fibre digestion. Feedlot diets based around low-quality/low-protein-content forages and self-fed concentrates should be based on a forage feed analysis to discern if protein and/or energy supplementation is required to optimize gains and feed:gain performance.
Other byproducts such as cereal screenings or pulse screenings can be used as supplemental feed for energy or partial forage replacement for bison either on pasture or in a winter feeding program. These products come in varying degrees of purity and fibre content. With these products come concerns for weed seed level and fusarium or ergot contamination. One benefit to a dry spring and growing conditions is that this year’s crops should be relatively free from fusarium or ergot contamination. However, use of screenings and stockpiled products still may carry the risk from previous years and should be examined and tested for toxins when appropriate.
Water for bison and other grazing livestock has been highlighted in the past couple of years due to animal health concerns from the concentration of minerals and other harmful elements. For example, surface and well water containing sulphate levels starting at 1,000 mg/L and higher have been proven to cause animal harm and are suspected in the impairment of production performance. Consumption of water with elevated sulphate levels can not only result in blindness, poor growth and possibly death, but there are also long-term implications with mineral binding and deficiencies, copper in particular. Bison producers are encouraged to test their water for quality to ensure that proper steps are taken to protect their animals from harm and design appropriate mineral supplementation programs. Bison producers should also be increasingly aware that if they graze canola (either as salvage crop or regrowth) or feed a canola or dried distiller grain byproduct (and even kochia bales!), the sulphur content of the feed can contribute to dietary sulphate levels, hastening health and deficiencies problems.
Mineral and vitamin supplementation in these dry seasons cannot be overlooked. In dry years a mineral or vitamin deficiency will manifest much more quickly and visibly than seasons with more adequate moisture, forage and grazing conditions. It is more important than ever to provide adequate mineral and vitamin supplements to bison consuming poor-quality feeds during the high production periods of late trimester and lactation, growth for grower feeder meat animals, flushing for breeding and first-time calf heifers. Minerals such as calcium and phosphorus support important muscle, milk and growth functions, while deficiencies will decrease feed intake, affecting growth and performance. Other macro and trace minerals are required, and some forages will not contain adequate amounts due to the dry conditions.
In conclusion, bison producers have to be a bit more creative to manage their feeding programs when faced with a dry pasture, grazing and haying season. Producers are encouraged to read publications on the use of alternative forage and grain sources, as well as continually explore new options. Protein and grain supplementation will likely be essential dietary requirements if current conditions continue, and the monitoring of water and mineral programs has to be included. Should crop insuring programs designate salvage status to crops, producers need to be aware of mineral content in the feed and water to prevent issues with sulphate toxicity or mineral deficiencies. And finally, as one recent article by Dr. John McKinnon suggests, producers should start planning their 2019/20 winter feeding program today.
For more information, please contact your local Saskatchewan Agriculture Livestock and Feed Specialist or call the Agriculture Knowledge Centre general inquiries line toll-free at 1-866-457-2377.