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High prices for heifer calves as feeders and current market prices for
replacement bred heifers and cows brings to light the high cost associated
with herd replacement and the value of longevity or stayability in the herd.
Considering the differential cost between selling and culling a $600 cow and
replacing her with a $1200 bred female, or holding back a $650 heifer and
developing and breeding here at a cost $300 plus interest, the cost for
every percent of herd replacement is around $4 to $6 for every cow in the
herd. The depreciation and replacement cost at a 10% annual replacement rate
becomes $50 against every cow in the herd. It rises to $80 per head at a 16%
replacement rate. Replacement and deprecation are a major cost to cow-cow
operators.
Cows have a limited production life. Most enter the
herd as two year olds, come into greatest production from ages 5 to 9, and
then start to drop off. By age 12 or so production likely fallen off
significantly due to lose of teeth, unsoundness being less completive;
resulting in lower condition, less milk, later breeding and lighter calves.
Cows are routinely culled at some age or condition of teeth related to age
and accounts for a primary reason for culling.
However herd data suggests by the time cows reach the
age of ten, less than 20% of those brought in as two year olds are still in
the here. Many have been culled much earlier primarily for reproduction
reasons. They turned up open, lost a calf, or bred back to late for the herd
schedule. A smaller percentage is culled for a variety of non-age related
factors such as temperament, health, unsoundness, and low production. Some
data suggests over 50% of replacements are culled before they are in the
herd five years. This explains why typical herd replacement rates are often
much higher than a theoretical 10% due to age, often 15 to 17%.
Certainly the average age of culled cows and the rate
of replacement vary greatly and are highly affected by factors as operating
style, herd management, as well as feed resources, climate, and genetics.
Breeding and management studies and simulations suggest several factors that
help reduce the number of young cows that leave the herd.
From a genetic standpoint, differences have been
illustrated by breed type or crosses in the average years of productive life
or percent remaining in the herd at some advanced age. Due to heterosis,
crossbred cows tend to have a year of additional productive life than
straightbreds. Predicted survival to 12 years with management to remove all
open cows every year suggests differences between breeds and crosses of over
30% of cows remaining in the herd at age 12. An average advantage of
crossbreds over straightbreds being 8.5%.
Breed associations with data reporting on herd
inventories and cow disposal have developed a genetic evaluation for
stayability, relating to the probability of a sire’s daughters staying in
the herd to the age of six years. It is a fairly lowly heritable trait,
however stayability EPDs are useful particularly on older sires with
producing daughters to select for longevity. It is a compound trait composed
of all the factors causing a cow to be culled prior to six years of age.
Variation between sires is significant relating to about 7 percentage points
from bulls at the upper and lower third percentiles.(7 more of 100 daughters
likely to remain in herd at age 6.)
Heifer development and nutrition play a significant
role in their prospects for staying in the herd. Having heifers grown to 65%
of their projected mature weight at the start of the breeding season and be
at a body condition score of 6 at calving are sound recommendations. There
is a risk of over feeding yearling heifers of the wrong type and match to
herd resources, insuring they breed as yearlings only to fail as 2 and 3
year olds. It can be advantageous to moderately feed heifers and limit the
breeding season to identify the most fertile and fit heifers and finish
developing the second year. This requires bred heifers and young cows are
managed separate from the main herd for more targeted nutrition.
A pool of
crossbred heifers: of adapted breeds; by sires of the right type with
genetic superiority for stayability; growth and milk matched to feed
resources; screened for soundness and disposition; of high health status; of
appropriate age and weight for low cost development; fed to achieve targeted
size by breeding with modest input; bred to proven calving easier sires
wintered to calving at moderate condition; and then managed to avoid
nutritional stress the following year; will increase your odds of bringing
in replacements that stay in the herd a long time and minimize the herd
replacement rate. Hopefully resulting in more cows in their years of
greatest productivity, greater calf weights, lower depreciation/replacement
cost per cow, fewer feed resources being utilized for non-producers; and a
greater return to time, management, and a capitol invested in the cow
business. |
