October 2013
Mothering ability of cows (heavy weaning weights relative to cow
maintenance requirements).
Growth rate within the nutritional and other environmental con-
straints, not only as an indicator of growth merit, but also as an indi-
cator for adaptation. Successful selection can also take place where
replacement bull calves are subjected to growth tests simulating
feedlot conditions while heifers are subjected to the same conditions
the cows have to perform.
Keeping the balance
Utilising the phenotypic and genetic variation among beef cattle to en-
sure profit at all levels of the production chain is important. There could
be some kind of tension between primary producers and feedlots (or
other finishers) regarding the traits and areas of importance.
For example, beef farmers should concentrate on traits enhancing repro-
duction, mothering ability and low cow costs, while feedlots should focus
on growth, feed efficiency and carcass characteristics.
It is however also important that the two groups should invest in the
other’s well-being. Allowing for selection for growth should therefore
also be a priority for seedstock (stud) breeders, while buyers of weaners
should acknowledge differences in genetic merit among the bought-in
stock and pay accordingly.
Utilising other means of reaping the full benefit of growth rate and ef-
ficiency differences as well as differences in maturity type performance
in feedlots, are also possible. These include the correct use of cross bred
cattle using sires of differing maturity types, depending on the price or
feed margin, as well as the possibility of adjusting weaning ages or back
rounding periods to allow for skeletal development to take place prior to
finishing in the feedlot.
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Figure 3: Changes in proportions of muscle, total body fat and bone at changes in body weight during growth of individual cattle.
Figure 4: Nutrient priorities at differing levels of nutrition in cattle.
