236 E
.P.C. Koenen et al. Livestock Production Science 66 2000 235 –250
aggregate genotype constant. Efforts have been made and management that is left over after all other costs
to estimate the EV of LW e.g. VanRaden, 1988 and have been paid. Circumstances that limit input or
DMIC e.g. Groen and Korver, 1989. The EV of LW output, e.g. a quota system for milk production or
is related to feed costs for maintenance requirements environmental legislation, might effect the EV of a
and returns from beef production. The EV of DMIC trait Groen, 1989c. It is not fully clear from
is related to the relative costs of roughages and literature what the EVs of LW and DMIC will be
concentrates. In
most situations,
DMIC limits
under expected future production circumstances with roughage intake such that the energy and protein
different market situations, production intensities and requirements are not completely met and concen-
environmental legislation. trates have to be supplemented. When roughage is
The aims of this paper are to review literature the cheapest feed available, genetic improvement of
estimates for the EV of LW and DMIC and to ¨
DMIC increases profitability Kohne, 1968. estimate these EVs for Dutch Friesian dairy cattle
Estimates for the EVs depend on the definition of under current and possible future production circum-
the production system, the goals to be optimised and stances.
particular production circumstances Groen et al., 1997. A production system can be defined at
different levels, e.g. animal, farm or sector level
2. Literature
Groen, 1989a. Production systems can be optimised to different goals, e.g. maximum profit, minimal
Literature estimates for the EV of LW have been costs of product or maximum return on investment
derived using different bio-economic models Table Harris, 1970. Many studies on dairy cattle breeding
1. Most studies modelled the effect of genetic maximised labour income remuneration for labour
changes at animal level. Groen 1989b,c simulated
Table 1 Model characteristics and estimates for the economic value for live weight
Source Level
Elements Restrictions
Economic value
a
kg cow year VanRaden, 1988
Animal Beef production
20.23
b
Energy requirements Housing
Health and fertility Dempfle, 1989
Animal Beef production
Farm roughage input 20.11
Energy requirements Groen, 1989b
Animal Beef production
20.46 to 20.39 Energy requirements
Groen, 1989c Farm
Beef production Roughage input
21.28 to 20.42 Energy requirements
Milk output Steverink et al., 1994a
Farm Beef production
Milk output 20.17 to 0.02
Energy requirements Nitrogen use
Protein requirements Phosphate use
Crop production Visscher et al., 1994
Farm Beef production
Roughage input 20.42 to 20.34
Energy requirements Veerkamp, 1996
Animal Energy requirements
20.64 to 20.41 Harris, 1998
Farm Beef production
Dry-matter intake 20.25 to 20.19
Energy requirements
c
Van der Werf et al., 1998 Sector
Beef production 20.21
Energy requirements
a
1.00 50.58 AUD50.68 GBP50.45 NLG50.49 NZD50.91 USD.
b
Requirements for growth and maintenance.
c
Based on a dressing percentage of 50.
E .P.C. Koenen et al. Livestock Production Science 66 2000 235 –250
237
the effect of genetic improvement using a model that exceeded marginal beef returns when increasing LW.
described traits during the life cycle of a dairy cow. Estimated EVs for LW were more negative when
Steverink et al. 1994a and Visscher et al. 1994 roughage input was restricted Dempfle, 1989;
modelled the production system at farm level. The Groen, 1989c; Visscher et al., 1994. With a fixed
study of Van der Werf et al. 1998 modelled beef roughage input per farm, increased maintenance feed
production at sector level and simultaneously evalu- requirements per cow resulted in a reduction of the
ated the effect of increased LW in dairy cows on number of cows and consequently in a lower milk
costs and revenues from veal calves, fattening bulls output per farm. Also in situations with restrictions
and culled cows. on nutrient surpluses, EVs for LW were more nega-
Model elements that were considered in estimating tive as a result of higher marginal feed costs
EVs varied among studies. Most studies included Steverink et al., 1994a.
energy requirements and beef production. VanRaden Most studies that derived EVs for DMIC Table 2
1988 also considered higher costs for housing and defined DMIC as the maximum daily ad libitum feed
fertility problems associated with a higher LW. intake in kg dry-matter DM of a reference feed
Steverink et al. 1994a defined a model at farm level e.g. pasture grass cut at the grazing stage of first
that also included grass and maize production. growth; Jarrige et al., 1986. Other elements in the
Different restrictions on input or output of the models were energy and protein requirements, avail-
production system have been imposed. Milk output ability of feeds and their corresponding costs. Most
was restricted by the milk quota system for European studies included two different feed stuffs Groen and
situations Groen, 1989c; Steverink et al., 1994a. Korver, 1989; Veerkamp, 1996 or more Berentsen
Feed input at farm level was restricted for pasture- and Giessen, 1996.
based production systems in New Zealand Dempfle, Estimated EVs for DMIC ranged from 0 to 164
1989 and Australia Visscher et al., 1994. An kg day cow year Table 2. The large variation
example of environmental restrictions is the inclu- might be related to assumed milk production levels
sion of levies for nutrient surpluses above acceptable and marginal feed costs. In the study of Steverink et
levels Steverink et al., 1994a. al. 1994a, EVs for DMIC were mostly zero as
Estimated EVs for LW ranged from 2 1.28 to 0.02
DMIC was not limiting the formulation of the kg cow year. In most studies, marginal feed costs
cheapest diet at a milk production level of 6000 kg.
Table 2 Model characteristics and estimates for the economic value for dry-matter intake capacity
Source Level
Elements Restrictions
Economic value
a
kg day cow year
b
Groen and Korver, 1989 Animal
Energy requirements 2–17
Feed alternatives Zeddies, 1992
Animal Energy requirements
77–164 Feed alternatives
Steverink et al., 1994a Farm
Energy requirements Milk output
0–3 Protein requirements
Nitrogen use Feed alternatives
Phosphate use Crop production
Berentsen and Giessen, 1996 Farm
Energy requirements Milk output
7–37 Protein requirements
Nitrogen surplus Feed alternatives
Phosphate surplus Crop production
Veerkamp, 1996 Animal
Energy requirements 5–27
Feed alternatives
a
1.00 50.51 DM50.68 GBP50.45 NLG.
b
Requirements for growth and maintenance.
238 E
.P.C. Koenen et al. Livestock Production Science 66 2000 235 –250
At higher production levels, Berentsen and Giessen techniques were then used to maximise labour
1996 found positive EVs as DMIC became limit- income under all defined production circumstances.
ing. The EV of DMIC was highly sensitive to the price
3.1. Scenarios difference
between roughage
and concentrates
Groen and Korver, 1989. Some studies assumed Production circumstances for 1998 1998 – Actu-
feed costs to be fixed e.g. Groen and Korver, 1989; al are based on actual data Table 3. The first
Veerkamp, 1996,
whereas in
other studies
scenario for the situation in 2008 2008 – Trend Steverink et al., 1994a; Berentsen and Giessen,
includes a moderate market liberalisation within the 1996 marginal feed costs varied with specific pro-
European Union EU. The second scenario 2008 – duction circumstances.
Liberal includes a complete market liberalisation At lower production intensities
, 12 000 kg policy; i.e. abolition of milk quotas and price inter-
milk ha marginal costs for roughage are generally vention. The third scenario 2008 – LTO is in line
lower than at higher production intensity 16 000 kg with the 2008 – Trend scenario but includes two
milk ha which
results in
increased EVs
for additional environmental restrictions. First, present
roughage, whereas an opposite trend can be seen plans of the Dutch farmers organisation LTO LTO,
when restrictions on nutrient surpluses are imposed 1998 promote a ground-based production system in
Steverink et al., 1994a. which input of roughages at farm level is excluded.
Second, a more severe restriction on stocking density is included in order to comply with the European
3. Material and methods nitrate directive European Commission, 1991.
