profit margins by –R0.13 and –R0.06/kg of
milk, respectively. Increasing the average
lactation number of cows in the herd and
decreasing age at first calving resulted in an
improved profit margin of R0.06 and R0.03/
kg of milk. Increasing the proportion of heifers
surviving to first calving from 70% to 80%,
also increases the lifetime profit margin at
the end of third lactation by 5%. These traits
are strongly affected by management and
could be used as management indicators.
This example clearly shows the importance
of a longer productive life (PL) and an early
age at first calving. The average lactation
number of cows gives an indication of the
age of cows in a dairy herd. In many herds
this figure is less than three meaning that
only a small proportion of cows manage to
survive to an advanced age. Many cows are
lost from the herd because of involuntary (or
preventable) culling reasons. Recent research
by the ARC showed a positive relationship
between an early AFC and higher milk yields
in first lactation on the PL and lifetime of
cows as well as the e
ciency of production.
Overseas studies have shown that daughters
from higher genetic merit sires have longer
PLs than daughters from lower genetic merit
sires, i.e. 40% vs. 27% of daughters of high
and low genetic merit sires respectively
reach 6 th lactation.
While it is di
cult to improve PL genetically,
because the heritability estimate is less than
10%, the range among sires for the PL of
their daughters available for insemination,
varies from -1.4 to 8.1 months. This means
that over time it would be possible to improve
PL by using bulls with higher than average
breeding values for PL. However, PL is affected
mainly by environmental factors. This includes
all factors affecting the production of cows such
as feeding level, reproduction management,
mastitis and housing conditions. Farmers
should keep a cull list up to date, i.e. a list of
all animals leaving the herd. Over time, this
will give an indication of cull reasons.
Management should be aimed at improving
these problems.
In closing
To improve profit margins dairy farmers
should not consider the average milk yield of
cows alone. While high milk yield levels are
generally positively linked to higher profits, it
nonetheless does not ensure higher profits.
The reason for this can be linked to a range
of management factors affecting profit margins
while fixed costs also differ considerably
among dairy herds. The way to increase pro-
duction levels is through improved genetic
merit which comes at a lower cost than
through higher concentrate feeding levels.
Research has shown that the highest genetic
merit cows are the most profitable. It would
be advisable for farmers to know the lifetime
profit margin of the average cow in their
herds. Often small changes such as an earlier
AFC or a higher survival rate of heifers to first
calving or lower culling rate could improve
profit margins without incurring additional
costs.
Photo: Photography by Gillian