Breeding strategies to lower the carbon footprint of livestock
51st SASAS CONGRESS
10 - 12 June 2019 Bloemfontein, South Africa
M.M. Scholtz, M.C. Chadyiwa, F.J. Jordaan, G.M. Pyoos, A Theunissen, N.P. Bareki, M.D. MacNeil & F.W.C. Neser
ARC-Animal Production, University of the Free State, Northern Cape DALRRD, North West DREAD & Delta G
LAY OUT
Background
• Perspective on greenhouse gases from livestock
• Reducing the carbon footprint
Approaches
• Selection for parent-offspring efficiency
• Selection for alternative post weaning efficiency
traits
• Alternative production systems (crossbreeding)
• Seasonal forecasts
• Landscape genomics
Take home messages
PERSPECTIVE ON GREENHOUSE GASES
FROM LIVESTOCK The most important Greenhouse Gases are:
• Carbon dioxide – 49%
• Methane – 18%
• Nitrate gases – 6%
PERSPECTIVE ON GREENHOSE GASES
FROM LIVESTOCK
Natural sources of methane production
• Wetlands – 22%
• Termites – 4%
• Oceans – 3%
Anthropogenic sources of methane production
• Gas & coal mining / Natural gas – 19%
• Enteric fermentation (ruminants) – 16%
• Rice cultivation – 12%
• Biomass burning (veld fires) – 8%
• Land fills (dumping sites) – 6%
• Animal waste (including manure) – 5%
• Sewage treatment – 5%
PERSPECTIVE ON GREENHOUSE GASES
FROM LIVESTOCK
Natural sources of methane production
• Wetlands – 22%
• Termites – 4%
• Oceans – 3%
Anthropogenic sources of methane production
• Gas & coal mining / Natural gas – 19%
• Enteric fermentation (ruminants) – 16%
• Rice cultivation – 12%
• Biomass burning (veld fires) – 8%
• Land fills (dumping sites) – 6%
• Animal waste (including manure) – 5%
• Sewage treatment – 5%
SIMPLE ARITHMETICS
Atmospheric concentration of methane
(CH4) is 18 %
Enteric fermentation responsible for 16% &
animal waste for 5% of global CH4 = 21%
21% of 18% = ??
SIMPLE ARITHMETICS
Atmospheric concentration of methane
(CH4) is 18 %
Enteric fermentation responsible for 16% &
animal waste for 5% of global CH4 = 21%
21% of 18% = 4%
Livestock responsible for 4% of global
GHG’s
REDUCING THE CARBON FOOTPRINT
An effective way to reduce the carbon footprint is
to reduce animal numbers and increase the
production per animal unit.
Increased productivity generates less greenhouse
gas (GHG) emission per unit of product.
Goal: improve production efficiency and revenue
and not merely genetic change or higher
production.
Selection for many of the traditional traits may
increase production, but not necessarily
productivity or efficiency of production.
Approach 1: Selection for parent-
offspring efficiency
• The parent-offspring production cycle is
responsible for most of the energy consumed
(in beef cattle - approximately 72% of the energy
consumed from conception to slaughter)
• In mature cow maintenance requirements
represent 70% of her feed expenses, & average
feed cost per cow is 42% of the total annual
production cost
• If parent maintenance requirements per unit
product can be reduced, it will decrease the
carbon footprint.
Approach 1: Selection for parent-
offspring efficiency
Sheep:
Total weight of lamb weaned per ewe joined
(TWW) has been used with success in
recent years.
h2 = 0.19 – 0.21
Suitable selection criterion for improving
reproductive performance in flocks with a
high reproduction rate where an increase in
the number of lambs would be undesirable.
Approach 1: Selection for parent-
offspring efficiency
Beef cattle:
• Calf weaning weight/cow weight ratio
• Calf weaning weight/cow weight0.75
• Kg of calf weaned per Large Stock Unit
The use of ratio traits as selection criteria has
theoretical defects, since it places inconsistent
emphasis on the component traits.
This will result in variable responses to selection.
In spite of this the use of calf/cow weight ratios is
still common practice
What is important for cow
productivity? The three traits that influence cow productivity are:
1. Weaning weight of the calf
2. Feed requirements to produce the calf - cow
LSU units were estimated since it is linked to
daily feed intake
3. The frequency at which a calf is produced, ICP
was used to estimate calving percentage.
Cow productivity = (205 day weaning weight of
calf/cow LSU unit) x weaning rate.
The Afrikaner example Relevant equations:
Cow productivity = (Weaning rate [deducted from
ICP] x 205 day weaning weight) / cow large stock
unit (LSU)
Example: 0.85 x 210kg / 1.45 LSU = 123 kg
In South Africa the enteric methane emissions
factor (MEFenteric) of a LSU is approximately 94 kg
methane/year
13
Results The phenotypic changes over 33 years in the three
component traits and cow productivity
Trait Wean
weight
Cow
weight
Inter-
calving
Period
Cow
producti
vity
Trend
(change)
+20.4 kg -8.3 kg -19.7 days +18.3%
14
The Afrikaner example
Using the MEFenteric value of 94 kg/year for a LSU in
beef cattle:
It was estimated that in the case of the Afrikaner
the MEFenteric was 1 kg per kilogram calf
weaned in 1980
It decreased to 0.88 kg MEFenteric in 2013
a reduction of 12%.
Cow productivity can be improved if the
weaning weight of the calf relative to the
weight of the cow can be increased; and the
inter-calving period reduced.
15
Conclusion: cow productivity
Ratio traits have complexities
See poster by Pyoos
A “Cow Productivity index” is a more effective
alternative, with minimal to no defects, and
should include cow weight and calf weight but
restricting cow weight.
A restricted selection index will limit or restrict
improvement of cow weight which is also
associated with high maintenance cost.
Conclusion: cow productivity (cont)
Under investigation:
1. Accumulated productivity (ACP): kg of calf
weaned/year over the cow’s lifetime (h2 = 0.39)
See oral presentation by Bareki (Session 9)
2. Evaluate total contribution of:
• Longevity of a cow
• Fertility (no of calves born over lifetime)
• Size of calves (weight)
• Feed efficiency
• Maintenance cost of the cow
- on the “methane budget/balance” of the cow-calf
production system
Approach 2: Selection for alternative
post weaning efficiency traits
Feed conversion ratio (FCR) –feed intake/growth
Alternative efficiency traits:
Residual feed intake (RFI) or net feed intake
Residual daily gain (RDG)
FCR - improved by better growth or lower intake
or both
RFI - improved by reducing feed intake without
changing growth
RDG - improve growth without affecting feed
intake
Approach 2: Selection for alternative
post weaning efficiency traits (cont)
• Low RFI animals produces less methane
(28%) and eats less than high RFI animals –
more efficient cows
• Correlation between RFI and heat production
~ 0.68
• High RFI animals greater visceral organ
weight
• Low RFI animals have shorter feeding
duration - 25 min/day less
Approach 2: Selection for alternative
post weaning efficiency traits (cont)
• Selection based on RFI and RDG rank animals
differently - alternative measures or both should
be used in a selection programme.
• A selection index is a possible approach for
breaking this antagonism.
• Apply economic weights to the EBV for ADG and
DFI directly is straightforward and more
transparent to farmers, compared residual
measures of efficiency
Approach 2: Selection for alternative
post weaning efficiency traits (cont)
• If magnitude of the economic value for ADG
(kg/d) is 7 times the economic value for feed
intake (kg/d); then: I = 7*EBVADG – EBVDFI
• Bivariate methods to estimate protein (muscle)
and adipose (fat) deposition efficiencies have
been developed – It may be possible to select
animals for efficiency of fat deposition and/or
efficiency of muscle growth
RFI IN DAIRY CATTLE?
• No genetic correlation between RFI and milk
production (limited information)
• Weak unfavourable genetic correlations between
RFI and fertility
• Cows with low RFI - digest and metabolize
nutrients more efficiently; overall more efficient
and profitable if they are healthy and fertile
Dairy industry should stop selecting for larger cows
Develop an index: higher milk production &
components, smaller cow size, longer productive
life and negative RFI > Lower carbon footprint
Approach 3: Alternative production
systems (crossbreeding)
Crossbreeding can improve cow
productivity (generally with about 26%)
Benefit of crossbreeding in South
Africa (1)
Increased cow productivity (Kg calf weaned / LSU)
through properly designed crossbreeding systems:
• Simmentaler x Afrikaner = 15%
• Angus x Nguni = 21%
• F1 Afrikaner cow: up to 49%
without additional herd costs through properly
designed crossbreeding systems, thereby
reducing the carbon footprint of beef production.
Benefit of crossbreeding in South
Africa (2) Charolais x Afrikaner
• 26.6% increase in
the value of meat
produced by
crossbred calves.
• calves consumed
26.7% less feed
between weaning
and harvest than
straight bred
Afrikaner calves
Considerations with crossbreeding
• Proper research and simulations needed for
South Africa on different systems
• The use of sexed semen does not have any
benefit due to reduced conception rates.
• Non-traditional inheritance patterns in reciprocal
Bos indicus - Bos Taurus crosses may have a
negative effect on fertility in rotational / criss-
cross systems. It seems that the origin of the X
chromosome (Bos indicus versus Bos Taurus)
and how it is incorporated in the F2 generation
may have an effect.
Approach 4: Seasonal forecasts • Heat stress is a common cause of reproductive
inefficiency. Semen quality decreases when
bulls are exposed to high ambient temperatures.
• Correlation between relative humidity one
month prior to the start of the breeding season
and calving %: -0.95 (Bull fertility?)
• Correlation between minimum temperature and
calving %: -0.35. (Cows were unable to cool
down at night - lower conception rates and
resorptions?)
See Poster by Grobler
Approach 4: Seasonal forecasts
Comparison of the weaning weights of Sanga sired
calves and Angus/Simmentaler sired calves between
the 2015/2016 and 2016/2017 seasons.
Effect of heat waves on post weaning ADG:
Angus and Simmentaler types – 17% decrease
Sanga and Sanga derived types - 9% decrease
Season Sanga sires Angus/
Simmentaler sires
2015/2016 171 171
2016/2017 183 210
Approach 4: Seasonal forecasts The effect of weather patterns on growth of beef
calves in a warm climate
• Correlation between BLUE values (”true
environment”) for weaning weight and maximum
seaonal temperature: -0.65
• Temperature explains 42% of variation in
weaning weight
G X E important in genetic evaluations
See oral presentation by Jordaan (Session 9)
Approach 4: Seasonal forecasts • Heat stress is a common cause of reproductive
inefficiency.
• Temperature may effect weaning weight
• Use multi-sire breeding and/or bulls from
tropical adapted genotypes, to mitigate effect of
heat
Approach 5: Landscape genomics
Landscape genomics correlates genetic variation
patterns with geographic variables (environment
in its widest sense)
How do environmental characteristics /
landscape heterogeneity affect the genetic
structure of populations?
Potential to open up new perspectives to
livestock genomics
Importance of G X E https://www.animalgenome.org/community/angenmap/mail/latest
Take home messages
1. Improve production efficiency (cow-calf
efficiency)
2. Improve post weaning efficiency (don’t
chase maximum production)
3. Crossbreeding can improve both 1 and 2
4. Seasonal forecasts can assist farmers to
mitigate climatic conditions
5. Take note of the effect of the environment
on genetics (GXE, Landscape Genomics)