DIVISION OF AGRICULTURE RESEARCH & EXTENSION University of Arkansas System Agriculture and Natural Resources FSA3091 Developing Beef Bulls ❚ Keep costs to a reasonable level Shane Gadberry, Ph.D. Introduction without cutting corners. Associate Professor ­ Developing beef bulls can be both ❚ Develop forage and feed programs Animal Science challenging and rewarding. Sale of that meet nutritional needs for breeding age bulls is often a signifi­ target weight gains. Jeremy Powell, cant source of revenue for seedstock ❚ Plan for bulls to be well­grown with­ DVM, Ph.D. producers. A comprehensive bull out excess condition as yearlings. development program addresses selec­ Professor ❚ Have bulls physically fit so they will tion and breeding strategies that will be active breeders. target the type of bull that fits pro­ ❚ Implement a well­designed herd duction and marketing conditions. health program. Nutrition, health and management strategies are also important compo­ Goals for a bull development nents of bull development programs. program may differ from one opera­ It is important from a profitability tion to the next depending on produc­ standpoint to keep development costs tion and marketing conditions and at acceptable levels while maintaining personal preferences. Goals may also an effective development program. change over time. Regular program The product of a successful develop­ evaluation can reveal areas where ment program is healthy, well­grown goals may need to be modified to bulls that are ready to serve as effective herd sires. enhance program direction. Goals for a Bull Selection of Bulls for Development Program Development A good bull development program Selection of bulls for a develop­ starts with good planning. Begin by ment program begins before the calves evaluating resources (time, capital, are born. Start with careful selection land, labor, facilities, forages, etc.) of sires that complement the cow herd required to develop a reasonable plan and are expected to produce a desired for developing young bulls. A proper type of bull calf. Not all bulls are suit­ bull development program involves able as herd sires, and likewise, not cost management and a well­designed all young bulls are worth developing nutrition and herd health program. into breeding bulls. Bulls being con­ Goals for a bull development program sidered for a development program Arkansas Is should include: should be physically sound, free from Our Campus ❚ Design breeding programs to genetic defects and exhibit an accept­ produce high­quality bulls. able level of reproductive potential. ❚ Develop selection criteria for The genetic potential of a bull will placing weaned bulls in a develop­ also impact his value as a herd sire Visit our web site at: s .uada ment program. and the price that he can command. http ://www.uaex .edu University of Arkansas, United States Department of Agriculture, and County Governments Cooperating Observe nursing bull calves for problems that generally termed “unproven.” If EPDs are unavailable may necessitate culling. Early identification of these for use in the selection process, then contemporary culls facilitates the implementation of cost­effective group performance ratios can be used and are often management practices such as early castration and more dependable than actual or adjusted individual implanting with growth promoters that would not performance information. otherwise be performed on bulls developed for breed­ ing purposes. This can help capture added value from animals not making the cut in a bull development Bull Nutrition Postweaning development of beef bulls is program. Weaning is a good time to cull low perform­ important for future effectiveness as herd sires. ing, unthrifty, structurally unsound or genetically Different management strategies are needed for bulls inferior bull calves and select those bull calves that of different ages. Bulls should be separated and man­ will continue into a postweaning development pro­ aged according to age groups (weanling bull calves, gram. Bulls also should be evaluated during selection yearling bulls, highly fitted or gain tested bulls, two­ and throughout the development program for their year­old bulls, mature bulls). Separating younger and disposition (temperament). Bulls that exhibit a poor older bulls may be particularly important in prevent­ disposition should be culled. ing injuries. Dividing bulls into management groups also allows for the development of diets that comple­ Expected progeny differences (EPDs) are avail­ ment the nutritional requirements of each group. able on many seedstock animals. They provide predictions of genetic merit for specific traits and As bulls mature, their nutritional requirements serve as a valuable selection and marketing tool. change (Table 1). Younger bulls require less quantity Accuracy (ACC) values give an indication of the but higher quality diets. While daily dry matter reliability of EPDs. The closer the ACC is to “1,” intake generally increases with increasing body the more reliable the EPD becomes. Typically, ACC weight, crude protein (CP) requirement as a percent­ values increase as a bull sires more calves with age of dry matter intake declines. Younger bulls reported performance records. Heavily used artificial require higher protein percentages for the rapid insemination sires often have high ACC values, while lean muscle growth that is occurring during young bulls often have low ACC values and are early development. Table 1. Nutrient requirements of bull calves less than 12 months of age with an expected mature weight of 2,000 pounds. Daily dry Total digestible Body weight, Average daily gain, matter intake, nutrients, Crude protein, lbs lbs lbs % dry matter % dry matter* 1.0 8.3 58 11.4 300 2.0 8.6 65 16.3 3.0 8.6 72 21.3 1.0 12.2 58 9.8* 500 2.0 12.6 65 12.9 3.0 12.6 72 16.3 1.0 15.6 58 9.1* 700 2.0 16.3 65 11.4 3.0 16.3 72 13.9 1.0 18.9 58 8.3* 900 2.0 19.6 65 9.9* 3.0 19.6 72 11.9* 1500 2.0 34.5 63 6.1* 2000 0.0 37.2 46 5.6* *Balancing rations based on these crude protein levels will likely result in inadequate rumen degradable protein for optimal rumen function and diet digestibility. Minimal protein levels for mature bulls are recommended to be no less than 8 percent. When possible, supplements should be formulated to keep starchy grain (ex., corn, milo) intake at no more than 0.5% of body weight to complement forage digestion. Table 2. Example feed supplements for a bull develop­ ment program targeting 2 pounds of gain per day. 1 Example supplements , % as­fed Cracked corn 87 60 Soybean meal, 48% 13 — Corn gluten feed — 40 Group of bulls at completion of development program. Feeding rate, % BW 0.70 0.75 Two basic nutritional programs are available for Minerals/vitamins2 Free­choice Free­choice developing young bulls. The first program is develop­ 1 ing bulls at a moderate rate of gain, and the second Formulated based on hay containing 12% CP, 58% TDN, program is developing bulls on a ration that is capa­ 0.45% calcium and 0.27% phosphorus, dry matter basis. 2 A complete mineral containing 24% calcium and 4% to 6% ble of supporting high rates of gain so genetic differ­ phosphorus should be fed free­choice. Alternatively (with the ences can be measured for selection and marketing exception of the corn plus corn gluten option), the local feed purposes. Developing bulls at a moderate rate of gain blender may add limestone, trace mineralized salt and a can be achieved with good quality pasture or hay and vitamin A, D and E premix. supplemental feed. Hay generally does not contain 1 Periodically weighing growing bulls will help enough nutrients to provide more than 1 ⁄2 pounds per determine if the level of supplementation is providing day gain for growing bulls. Cool­season, small grain the desired rate of gain. Remember, as bulls grow, pastures such as wheat, rye and annual ryegrass can intake increases. As the bulls get bigger, the supple­ support rates of gain in excess of 2 pounds per day. ment will represent a smaller amount of their intake Warm­season grass pasture may support good rates unless the level of supplementation is adjusted. of gain early in the growing season; however, in mid­ Supplemental feeding should not be based on the to late summer, quality will generally not be ade­ weight of the bulls the day they are weighed but quate to provide sufficient gains. Supplementation adjusted for the expected average weight over the will be necessary when using summer forages. feeding period (Table 3). Either a commercially available supplement can Table 3. Calculation of supplemental feeding rate. be purchased at a local feed supply store or a custom supplement can be blended at a local mill or on the Incorrect method Correct method farm with locally available feedstuffs. Developing a Initial weight 550 lbs 550 lbs supplement for fall­weaned bulls being fed for moder­ Days in each 30 days (adjusting 30 days (adjusting ate growth through the winter on hay should begin feeding period intake monthly) intake monthly) with an analysis of the hay for nutrient composition. Rate of gain 2 lbs/day 2 lbs/day The correct amount of a commercially available supplement or the composition and feeding rate of Weight used to 550 lbs (initial 30 days ÷ 2 = 15 calculate feeding weight at start of days (halfway point) a custom­blended supplement can be more accurately rate feeding period) determined with a hay analysis. The following are 2 lbs/day x 15 days = examples of custom­blended supplements for calves 30 lbs fed good quality hay [12% CP and 58% Total Digestible Nutrients (TDN), dry matter basis] with a 550 lbs + 30 lbs = desired rate of gain of 2 pounds per day (Table 2).