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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.
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