Situational stocker supplementation
By: Paul A. Davis, Ph.D., PAS, DIPL, ACAS Nutritionist
Grazing stockers during the summer months when pasture is plentiful results in attractive costs of gain.After arrival and acclimation, intense management is usually not necessary which further reduces input costs. With the exception of a quality vitamin-mineral supplement, substantial feeding or supplementing may not be warranted for summer stockers. However, when grazing alone fails to provide the desired weight gains, supplementation is likely to provide an attractive return on investment. There are largely three situations that may require supplementation. Each situation is unique in the factors that necessitate supplementation but improved performance is the common goal.
As mentioned, supplementing nutrients when production goals are not met solely through pasture is the “classic” situation for supplementation. As nutritional content of pasture a.k.a. “forage quality” changes throughout the growing season, macronutrients such as protein and energy can wax and wane. These two can have the greatest impact on weight gain in growing calves. Monitoring calf weight gain and forage quality is paramount in knowing when and how to effectively supplement. Fortunately, the forage sampling and testing procedures are simple and relatively inexpensive.
If gains are less than acceptable and dietary protein is lacking, supplementation with a commercial protein supplement or an appropriate feed ingredient is likely an effective solutions. Convenience supplements such as protein blocks or tubs may be advantageous due to labor savings when compared to daily feedings. Cottonseed meal or distillers dried grains are among likely choices of by-product ingredients. Be cautious of using excess non-protein nitrogen (NPN) such as urea as a protein supplement, as forage is usually high in soluble protein and may not contain the carbohydrate needed for NPN to work safe and effectively.
When energy is the limiting dietary factor, the approach is largely the same. An energy dense commercial feed or feed ingredient must be offered to compensate for the grazing deficiency. Since energy is required as a much larger portion of the total diet, low intake convenience supplements may not be effective. As a word of caution, feeds or ingredients that are high in fat or starch will have a negative effect on overall forage utilization. It is possible to do more harm than good if supplemental energy comes from a source that in not “friendly” to forage digestibility. Ingredients or blends that provide energy from soluble fiber rather than excessive starch, sugar or fat are favorable choices.
Late summer grazing can bring what is known as the “tough grass” scenario. More mature grasses are inherently higher in lignin and lower in digestibility. Rate of passage through the animal can be significantly decreased. Though forage is available in abundance, calves may feel physically full for more time during the day and may graze less. Digestive microorganisms may be less active, further depressing forage digestion. The resolution in this case is supplementation more to stimulate microbial activity than correct a nutritional deficiency. The effect of a little supplementation in this scenario is like turpentine on a brush fire. The digestive bugs become more active, rate of passage through the calf increases, and more nutrition is gleaned from pasture.
Shortages of forage or drought situations also require supplementation. In this unfortunate instance, stockers will be lacking in dietary quality and quantity. While enough nutrition to maintain growth should be provided, enough physical fill for calves to feel full and satiated is equally important. Providing relatively large amounts of feed that mimics the nutritional content of forage is often required. If good quality hay is unavailable, commercial feeds or on-farm blends that utilize ingredients like cottonseed hulls, cotton gin by-product, rice hulls or peanut hulls may be effective both nutritionally and economically. It is not necessary for feeds in this situation to be as nutrient-dense as in aforementioned circumstances, as markedly larger quantities must usually be fed.
Keep in mind that an effective stocker health program that includes strategic deworming will help with efficiencies and production goals. Certain feed additives such as ionophores or antibiotics often provide a very favorable return on investment when used in grazing stockers. Efficient, effective supplementation, when needed, is the goal. Remember to leverage resources such as feed dealers, consultants, University Extension and veterinarians for help with forage testing and supplementation programs.