The bull sale season is just around the corner. Over the next several months there will be lot of bull buying opportunities and choices made. The new bulls brought home will have an impact on an operation for years, both in feeder calves produced and daughters retained. Bulls and their genetic role is a critical component of cow-calf production affecting both production costs and product revenues. In spite of advances in genetic evaluation programs and widespread EPD information, managing herd genetics and bringing home the “right” bulls is not easy.

Before we can select the “right” bulls we have to determine what genetic profile fits our resources and management to most likely maximize returns over time without unacceptable risk or compromised sustainability. This may be the hardest step to bull buying since available selection technologies are not easily related to economics or profitability. Their use needs to be guided by common sense and intuition based on a perspective of how various traits affect profitability. The level of production which can be economically supported by the forage base and locally advantaged feeds; limitations due to management, labor, and facilities; and if calves are sold at weaning, fed or marketed as replacements; are important in setting our genetic target.

Considerable genetic variation exists for body size and milking potential, both of which are important cow herd traits related to nutritional requirement and calf weight.
Matching cow type and requirements to the forage and feed base of an operation minimizes the need for additional supplemental feed inputs and lessens the risk cows are shorted and calf survival and cow fertility are adversely impacted.

Cow maintenance requirements are closely related to cow size. Larger cows need more and will eat more . A 1250 lb cow is 25% heavier than a 1000 lb cow and has a 18% higher maintenance energy requirement. You could stock a piece of ground with either 100 of the smaller cows or 85 of the larger cows. Weights are related at all stages of growth and it is expected the larger cows will wean proportionality larger calves that finish at heavier weights. Cows of various sizes can be equally efficient if nutrient needs are economially met. But under pinch periods where forage becomes sparse or nutrition is restricted the large cow will be penalized more. Cows at the extremes are likely to be high risk, less efficient, limited in complementary crossing options, and less profitable.

An upper limit to cow and calf size may be dictated by packer pricing differentials for carcass weight. Currently carcasses between 600 and 950 lbs are preferred which relate to live weights of about 1000 to 1400 lbs. This is a fairly wide window relating to frame score 4 heifers to frame score 7 steers. This range could even be further extended a frame score on each end with management to grow small cattle for longer times prior to finishing and getting large frame steers in the finishing lot at young ages by early weaning. In the feedlot, genetically larger animals gain faster and convert feed to weight more efficiently if fed for the same amount of time or to the same weight as smaller cattle. However if the cattle are fed to the same degree of fatness or degree of marbling this difference tends to actually favor some of the smaller breed types. Medium to large frame feeder cattle seem to be the most profitable and desired by feeders.

Great differences exist amongst breeds used for beef production and within breeds for potential milk production by females. The benefit of milk is realized in the saleable weight of suckling calves; however, there is a nutritional cost too consider. Unfortunately, unlike the case with larger body size, higher milking cows can not typically consume enough extra forage to meet this need. The higher milking cow needs a better quality diet not just more quantity as illustrated by the fact that a 1200 lb mid lactation low milk potential cow is likely to consume 26 pounds of a ration needing to contain 53% TDN and 8% crude protein versus a 1200 lb mid lactation high milk cow is likely to consume 29 lbs of a ration needing to contain 60% TDN and 11% crude protein to meet her requirement. These high producing cows also have higher maintenance requirements even when not lactating.

Knowing the optimum genetic target to maximize economic efficiency is difficult. The optimum is usually always less than maximum possible. Breed efficiency studies at MARC found the smaller breeds were most efficient at restricted feed allotments and large high milk types were most efficient under abundant feed scenarios and vice versa. ND IRM analysis indicated very high producing herds, while very profitable in years of good prices were often very unprofitable when prices were low because of high operating costs.

Once we know our genetic target and before we can select an individual bull we have to make a breed(s) choice which is dependant on our choice of a breeding system. If managed right, systematically crossing breeds capitalizes on some added vigor and performance for calf survival and cow fertility traits, allows the opportunity to combine breeds to utilize trait strengths while minimizing trait weaknesses, and will minimize variation. Simulation studies and industry experience suggest 50/50 British/Continental breed crosses are efficient in northern plains environments and well suited to mainstream carcass specifications.

For typical medium sized herds with the opportunity to have few breeding groups and wishing to their retain own replacements, text book rotation crossbreeding systems don’t work. Alternatively rotating breed of sires used every 2 to 3 years is easier to manage and can be very effective, particularly if only 2 or 3 breeds are included and the breeds and sires used are quite similar in performance characteristics. Another option is to utilize hybrid or composite bulls to stabilize breed contributions and capture some of the potential benefit of heterosis with the simplicity of straightbreeding. A draw back to using composites is a limited availability of genetically evaluated superior bulls and a concern over inconsistency for some traits. For situations were outside replacements are or can be sourced, terminal crossbreeding systems have the advantages of simplicity, consistency, and complementarity capitalizing on the “small cow big bull” strategy.

A final step in the genetic management of a cow herd is to go out a select and buy individual bulls of the breed chosen having the genetic package desired to deliver what the ranch needs. Genetic differences of bulls within breeds are large, but breed association and breeders have done a lot with performance testing and genetic evaluations to help. EPDs produced by associations based on records submitted by breeders and provided by breeders in marketing bulls can be a big help in predicting what a bull will transmit to progeny. EPDs don’t however tell the whole story. While we have them in most breeds for calving, growth, and milk traits there availability on carcass, fertility traits, and soundness traits is very limited. Therefore its still important to visually evaluate bulls and source them from operations with similar environment and management to your world.