Over the winter, adjustments will be made to rations. Declining feed inventories and changes in nutrient requirements from late pregnancy to a lactating ration, are two common reasons.
Quality differences between grass hay, mixed legume hay, greenfeed, silage, or grains need to be taken into account when balancing the ration for protein, energy, minerals, trace minerals, and vitamins. This can be done using a ration balancing program. How animals react to these adjustments, must also be considered.
Forage maturity and crop type influences nutrient content. Protein, energy, calcium, and magnesium vary. Protein and energy content is usually higher in feeds that contains legumes. Mixed hay or legume hays are high in calcium but low in magnesium. Grass hay, greenfeeds, and cereal or corn silages are typically deficient in calcium and magnesium. A 1 : 1 or 2 : 1 mineral is commonly used in a mixed hay ration, whereas a 3 : 1 or 4 : 1 mineral is recommended for rations that contain high amounts of cereal or grass forages.
Energy densities in cereal grains vary. Corn and wheat have the same energy content at 88% total digestible nutrients (TDN). Substituting wheat for corn is a pound for pound calculation. Barley with 83% TDN and oats with 77% TDN, requires increases in feeding rates by 10 and 20% respectfully. Changing grains should be done in a three to four step process to prevent digestive upsets. Make the switches every three to four days prevents digestive upsets.
Digestion rates vary between different grains. Wheat, triticale, and rye have the most rapid digestion. As a guideline to prevent digestive upsets, a maximum of six pounds per head per day should be fed to mature animals; and three pounds per head per day fed to 600 to 700 pound animals. Feeding other grains in addition to the wheat, triticale or rye is not a problem.
Gradual changes to a feeding program reduce the risk of digestive upsets or animals going off feed. Animals that are coming to eat when feed is delivered indicates that the transition to the new ration is going well. A normal, flat manure pat shows that the rumen is healthy. If this is not observed, increase the time between changes. It might be necessary to increase the number of steps to make the change.
For additional information on changing feeds in cattle rations, contact Barry at 403-741-6032 or firstname.lastname@example.org.