NEWS
Key performance indicators
for dairy farmers
Dr Carel Muller
Current Address: Research Associate, Faculty of Animal Sciences, University of Stellenbosch
Reprinted From: https://www.agrikultuur.com/
M
ilk prices for dairy farmers are af-
fected by supply and demand.
Farmers have, for except, the
volume and quality of milk being pro-
duced, generally little effect on milk
prices. The profitability of a dairy herd is
affected mostly by the milk yield income
(+90% of farm income) and the produc-
tion cost of milk. The feeding cost of all
the animals in a dairy herd constitutes
the largest part of the production cost.
By feeding more concentrates to cows,
milk yield increases although feed cost
also increases. This increase in milk yield
may result in a lower income because of
the law of diminishing returns. The prof-
itability of a dairy herd can also be im-
proved by reducing the production cost
of milk.
This can be done in several ways. This
requires applying specific management
actions as suggested by key perfor-
mance indicators. Some of these indica-
tors are discussed in this paper.
Number of cows in milk
The number of cows in milk determines
the total milk yield of a dairy herd. A
dairy herd consists of first lactation cows
and older cows. The milk yield of cows
increases from first to fifth lactation,
therefore most cows in the herd should
be older cows (in second plus lacta-
tion). The genetic merit of first lactation
cows affects the herd’s future genetic
merit. At least 82% of all the cows in the
herd should be in milk. This percent-
age increases when cows are longer
(more days) in milk, i.e. when herd av-
erage days-in-milk (DIM) increases. The
growth of a dairy herd can be observed
by comparing the current number of
cows in milk to the number the previous
year(s). A trendline can be fitted using
records of at least three (or more) previ-
ous years. A dairy herd should increase
in numbers from year to year. When this
is not the case, two major problems may
be the cause, i.e. the culling rate among
cows is high or the survival rate of heif-
ers from birth to first calving is low. From
a dairy herd of 100 cows, at least 85%
should calve down every year when re-
production management is good. The
bull: heifer ratio is usually 50:50 unless
sexed semen is being used. Based on
this ratio, 42 heifers are available for
rearing to replace cows. If 85% of heif-
ers survive to first calving, it means
that 36 first lactation cows should enter
the dairy herd. At a culling rate of 25%
among cows, there are 11 surplus first
lactation cows; however, when the cull-
ing rate is higher, the number of surplus
cows is less. At a lower heifer survival
rate to first calving, fewer heifers are
available to rear to first lactation. The
survival rate of heifers from birth to first
calving is determined by the comparing
the number of heifers born in a specific
year to the number of these heifers calv-
ing down for the first time. When 100
heifers are born in a specific year and
80 heifers eventually calve down for the
Figure 1: Jersey cows utilizing a pasture
Grassroots
Vol 19
No 1
March 2019
24