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

Residual 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)

We want to acknowledge the

collaborating / funding institutions