After the breeding season, bulls become a necessary evil or unwelcome visitor.  Many producers might like to forget about them for the balance of the year and some almost do.  While it is true that bulls during the post-breeding season don't require much management, adequate planning and care can help insure that bulls costs will be kept within reason and that bulls will be ready to go again the next time they are needed. 
 In most spring calving herds, the breeding season will commence in the spring or early summer and extend for two to three months.  If a 60-day pre-breeding conditioning period is allowed, this leaves a post-breeding season of about seven months, usually coming in the fall and winter.  Goals for this period are basically as follows:  Keep feed costs at a practical minimum; keep the bulls in moderate condition; minimize chance of injuries; allow growth of young bulls. 

Post-Breeding Appraisal

         As bulls come out of the breeding pasture, one of the first steps should be to appraise the bull battery and sort them three ways.  The largest group should be the mature bulls in good condition that won't require any special care.  Perhaps the most important group is the young bulls that are still growing and need higher quality feed during the winter.  Bulls that are extremely thin or need special care for other reasons can be placed in this group as well.  The last group is for old or crippled bulls that have completed their productive life and are to be marketed. 
         All bulls should have access at all times to a high-quality mineral mix.  Phosphorus is a critical mineral for successful reproduction and is not present in adequate amounts in dry or harvested forage.  Good sources of supplemental phosphorus are monocalcium phosphate or dicalcium phosphate.  These can be mixed with trace mineral salt in equal parts or two parts salt to one part mineral. 
         Vitamin A nutrition also is important to the resting bull.  Natural sources are green growing plants or high-quality hay with good green color.  Supplemental vitamin A can be added to the mineral mix or fed with a supplement.  It can also be administered in the form of an intramuscular injection once or twice during the winter, although the oral supplement is cheaper. 
         Mature bulls in good condition can exist very well on an essentially all-roughage diet.  While the amount will vary some with the size of the cattle, a good rule to remember is about 2 percent of their body weight in dry feed per day.  Protein needs will parallel closely those of a dry pregnant mature cow in the middle-third of gestation, so it can be supplemented as needed. 

Yearlings  

        Yearlings should be left with the cow herd for 60 days or less. Beyond that time their condition will fall off to such a degree that it may have long-range effects upon their growth.  After removal from the cow herd, yearlings should be kept separate from the older bulls at least through their second winter. 
 Yearlings should be placed on the best available roughage, such as regrowth from hay fields or high quality hay.  Their supplemental feeding regime can be equated to the program for bred-yearling heifers.  These cattle still are growing rapidly, in addition to replacing all the condition they lost in the breeding pasture.  Extra care and feed of yearling bulls after the breeding season will result in stronger, more attractive mature bulls with a much higher salvage value. 

Two-year Old Bulls 

         These cattle should have more of their mature size by breeding season, so their ration is not quite so critical.  A 1,300 pound 2-year-old in excellent body condition will probably only need to gain 1 pound per day at this stage in his life.  To do this, active bulls may need 35 pounds of feed or more, of which 5 to 7 pounds should be grain.  If body condition is at a BCS of 5 or below, the amount of grain will need to be increased to near 1 pound or more per 100 pounds of body weight.  Again make any increases in grain intake gradually so that digestive disorders are unlikely.  Continue to monitor the total protein content of the diet and keep the concentration of crude protein near 12%.  Depending on the forage available this again may require protein supplements such as soybean meal to be included in the grain mix.  Monitor the body condition of the bulls closely and make grain feeding adjustments to reach the body condition score of "6" before the next breeding season begins.   This is critical if the bulls will be used once again in a fall breeding season! 

Salvage Bulls

         Often bulls that have completed their productive life because of age or injury can be marketed to advantage after a brief period on a high-energy feed program.  Bulls will vary greatly in condition at the end of the breeding season, depending upon the number of cows per bull, the length of the breeding season and the quality of the feed available. 
         However, most bulls will gain very rapidly and efficiently after the breeding season if they are provided with the necessary nutritional level.  These bulls should be placed on excellent pasture or free-choice hay of high quality and then fed a full feed of the concentrate feed that provides the most economical energy source (usually a cereal grain).  Concentrates can be fed at the rate of 20 to 25 pounds per head per day, although when fed at this level the concentrate should be split into two equal feedings.  Start the bulls slowly and gradually increase the grain level to avoid digestive disturbances.  At this nutritional level bulls can be expected to gain between 3 and 5 pounds a day for at least 60 days.  Mature cattle also make excellent use of silage, if that feed is available. 

Bull Pastures

        It is a good idea to have a bull pasture that is somewhat isolated.  Bulls kept away from cows will remain quieter and will fight less.  A pasture with adequate area also will encourage exercise and will reduce confrontations between bulls. 

Much more information about bull management is available in the OSU Fact Sheet F-3254 "Management of Beef Bulls".