Agriculture Reference
In-Depth Information
highest ranked individual being the 'fittest' or
most profitable according to the BO and there-
fore a desirable parent for a given production
system. With classical index selection, the BO
determines the targeted direction of genetic
change for the traits, weighted by their respec-
tive market values (MV). This MV is the eco-
nomic value per unit increment in the trait
(e.g. $ kg
−1
, $ per egg). The breeding goal (H) or
aggregate genotype can be represented in the
following equation:
H=MV
1
EBV
1
+MV
2
EBV
2
+ . . . +MV
n
EBV
n
where EBV
i
is the additive genetic value of trait
i
,
and MV
i
is the MV (also known as economic
value) of trait
i
, defined by the change in profit of
a unit change in the trait
i
(Hazel, 1943). The
values for EBV
i
are derived using a multi-trait
best linear unbiased prediction (BLUP) computer
program that takes into account genetic and
environmental correlations among traits as well
as pedigree relationships (Lynch and Walsh,
1998). Clearly animals that have the highest
EBV for traits with a high MV will have the high-
est index value (i.e. will be the 'fittest' in this
selection scenario) and will be most likely to
become parents of the next generation.
Genetic improvements in efficiency have
been most pronounced in those industries
that have a highly structured breeding sector
(e.g. dairy, pig and poultry) and well defined,
profit-maximizing BO. These gains have largely
come about because improved efficiency is
directly associated with improved profitability.
A small number of animal breeding companies
control the genetics of these vertically integra-
ted industries. For example, over 90% of global
poultry breeding stock is managed by three com-
panies selling to a worldwide market (Flint and
Woolliams, 2008). Industries that have less ver-
tical integration (e.g. beef and sheep) have made
less progress. Animal breeding in these indus-
tries tends to be driven by breed associations,
and because the MV of traits differs among
industry sectors (e.g. breeder, farmer, feeder,
processor), it is difficult to develop a single,
industry-wide BO that is economically rational
for all sectors. This leads to an important con-
cept in animal breeding, the role of the 'decision
maker' in animal breeding (Olesen
et al
., 2000).
In the absence of vertical integration, breeding
goals will be developed based on the individual
producer's financial interests. The producer is
the one investing in breeding stock and in a
competitive market their decision will be based
on the ways they perceive that animals contrib-
ute to farm profit. If there is market failure in
terms of attributes of sustainability (e.g. there
is no price incentive associated with the inclu-
sion of improved animal welfare in BO), then
alternative approaches will need to be imple-
mented to incentivize the inclusion of such
considerations into BO in less vertically inte-
grated industries. These incentives may take
the form of subsidized breeding, regulations,
fines for poor welfare or increased prices for
products labelled according to specific welfare
grades (Nielsen
et al
., 2011).
Sustainable Animal Breeding
Key words characterizing sustainable animal
breeding are
product quality, genetic diversity, effi-
ciency, environment
and
animal health and welfare
(Nielsen
et al
., 2006). The traditional methods
used to derive MV in the BO with the objective of
maximizing the profit of the farmer have focused
on production traits such as milk yield, growth
rate and meat yield. Key social goals such as food
safety, food quality, environmental protection
and animal welfare have often not been overtly
included in BO. Torp-Donner and Juga (1997)
reviewed studies that used different criteria to
describe sustainable livestock production from
the perspective of animal breeding. Their review
suggested that under low and intermediate pro-
duction levels, increased yield and efficiency
will be more environmentally sustainable than
goals associated with extensive production. How-
ever, intensive systems are associated with their
own environmental concerns. Other stakeholders
would like to see more selection emphasis placed
on secondary or functional traits that are not
directly associated with production outputs or
even economic return, including traits that could
lead to improved animal welfare and reduced GHG
emissions. Several authors have discussed app-
roaches to incorporate 'sustainability traits' into BO.
As might be predicted from the rather broad defi-
nitions of sustainable animal breeding above,
approaches vary depending upon which compo-
nents of sustainability are under discussion.
