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Beef Breeder MANUAL
to the calf. Often the cow is healthy and fat but the calf is poor, and this is a reason to consider culling
the cow • Death or injury to calf by misadventure. Like
mis-presentation at birth, misadventure has no genetic basis and herd productivity will not be
improved by removing afected cows. Under these circumstances, the cow can be retained if suicient
pasture is available to support her for a year before she breeds again
• Structural breakdown of the cow, reducing her ability to forage and maintain a productive body
condition score, and consequently being unable to supply suicient milk for her calf. These cows may
be culled. Determining when to cull a cow because of udder
faults is dependent on the impact the fault is having on production Fig. 5.18. Collapsed udders with ballooned
teats make drinking suicient milk diicult for the calf, and its growth may be afected. In such cases, the cow
should be culled. Less signiicant udder faults may not have immediate
production afects but udder and teat conformation are moderately heritable, so by selecting replacement
heifers only from dams with good teats and udders, the proportion of cows in the herd with well-structured
and productive udders increases substantially over successive generations. Cows with undesirably shaped
but functioning udders may be kept for producing feeder animals only. Otherwise, such animals should be
culled if adequate replacement breeders are available.
5.6.4. Cast-for-Age
Using data from commercial beef herds in the northern border region of the United States of America USA,
economic analysis suggests that beef cows managed in a cold climate are most economically culled after
weaning their 7
th
calf, at about 8.5 to 9 years of age, if irst mated at 15 months of age Harlan Hughes, North
Dakota State University, Table 5.2. The relative economic value of female cattle is made
up of several factors, including genetic improvement in the herd, sale values of progeny, the salvage value of the
cow at culling, livestock inventory value, reproductive
Figure 5.18. A range of udder shapes commonly seen in beef cows. 1 - Very tight and pronounced suspensory ligament, 2 - Tight, pronounced suspensory ligament, 3 - Intermediate, 4 - Loose, weak suspensory ligament, 5 - Very loose, very
weak suspensory ligament. Udder types 4 and 5 are likely to require management intervention to keep cows healthy and productive and may be considered for culling. Source: http:beef.unl.edulearningudder_score.shtml.
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Cold Winter Climates
rates, mortality rates, and feed supplementation costs. Based on this data, Hughes concludes that the
commercial beef cows in northern USA cold winter climates delivering their 8
th
calf are less proitable to the herd than irst calving cows relative value of 0.75 vs.
0.81. At this point, the herd beneits from their removal and replacement with heifers. Consequently, a culling
policy based on removing 8.5 to 9 year old cows and after weaning the 7
th
calf would generate the highest return for the commercial herd.
During a herd development phase, where Australian cattle are imported to form the foundation of a specialist
beef herd development program, it would be advisable to retain all imported cattle until after they wean their
8
th
calf at least, or are required to be culled for health or welfare reasons. This rationale is based on recovering
the greatest return on the signiicant expense incurred in importing heifers, and the relatively small 7.5
diference in proitability between 8
th
calvers and irst calving heifers, in particular.
5.7. Heifers
