Page 47 - NZ Hereford Magazine 2023

Breeding for

environmental efficiency

Words: Edited from an original article by any potential livestock carbon taxes into its models and adjust
Southern Beef Technology Services (SBTS) breeding objectives appropriately.
While the correlation between dry matter intake and
While the concept of breeding livestock that have a reduced methane production gives breeders the opportunity to improve
environmental footprint may not be something that all breeders productivity without compromising their environmental
have considered and/or think is valuable, consumers are already footprint, this approach is limited by the low levels of net feed
demanding more environmentally friendly protein sources. intake (NFI) recording, which requires the measurement of
This is only likely to increase and the beef industry risks losing growth rate and the feed consumed to support this growth.
further market share if it does not respond satisfactorily. Specialist equipment is required to identify the quantity of dry
Already we are seeing beef processors offering certified carbon matter consumed by each individual animal, and has limited
neutral product into markets. The aim of this article is to discuss widespread adoption due to cost and availability. Until recently,
the options that cattle breeders have when selecting animals for this technology has only been available for use in feedlots
greater environmental efficiency and the relationship between due to the difficulty in quantifying the amount of dry matter
environmental and production efficiency; the two categories consumed by an individual animal when grazing pasture in a
might not be as different as one might first think. mob situation. However, new technologies that aim to capture
Achieving carbon neutrality may sound daunting, but there NFI on pasture are currently being trialled in several Australian
are already breeding practices and management decisions research projects. This may allow the nutritional requirements
beef producers routinely make to reduce the environmental of mature cows on pasture to be recorded – an important
footprint of their enterprises. Genetics is not the only solution step forward because cows are responsible for most of the
to reducing carbon emissions. Other practices, such as carbon nutritional requirements of a beef production system.
sinks (e.g. pastures, soils and trees) and dietary changes (e.g.
novel feeds and supplements), will also play a part in allowing Summary
the red meat industry to achieve total carbon neutrality.
From a breeding perspective, selecting for a reduced As this article has outlined, breeding for environmental
environmental footprint is similar to selecting for profitable efficiency and breeding for economic efficiency are highly
cattle. The underlying reason for this is the positive relationship complementary. In both cases, fertility is paramount; after all,
between dry matter intake and methane emissions as shown a cow in the breeding herd should raise a live calf each year
in Figure 1. An animal efficiently converting dry matter to and failure to do so makes her a drain on resources. Faster
product is likely to be the animal emitting the least methane age to turnoff, achieved through selection on a combination
per kilo of production. When you break this relationship down of growth and carcass traits, reduces both the amount of feed
to component traits it becomes clearer. For example, faster required and the amount of methane emitted because the
growth to market specifications reduces both the amount of animal is younger when marketed. With feed being the biggest
feed required and the amount of methane emitted because the cost in any beef production system, maintaining production
animal will be younger when marketed. Equally, a cow that fails levels while minimising required feed input will also improve
to rear a calf not only consumes feed but also emits greenhouse both economic and environmental efficiency.
gas without producing saleable progeny. As methane is a waste
product that costs energy to produce, a more methane-efficient
animal will better utilise the nutritional energy it consumes
over its lifetime. One producer recently summarised the link
between production and environmental efficiency perfectly:
“Being carbon neutral is complementary with the way we run
our beef enterprise because our objective is productivity. It’s
much easier to be green when the enterprise is in the black.”
Breeding for environmental efficiency still has its challenges.
The gold standard for recording individual animal greenhouse
gas (GHG) emissions requires sealed climate chambers to
measure the emissions of each animal. Some Hereford genetics
(with linkage to New Zealand) utilised in the Southern Multi
Breed project currently under way in New South Wales will be
tested in climate chambers. Other methods of measuring GHG
emissions in cattle are also under investigation. Once enough
data has been collected to produce GHG EBVs, these have
the potential to be included in existing beef cattle selection Figure 1. The combined relationship between methane production
indexes. Utilising the relationships described in the previous and dry matter intake for dairy (triangles), southern beef (circles) and
paragraph, the existing BreedObject software can be used to tropical beef (squares) cattle. Source: Charmley et al. 2016.
create the selection indexes used in Breedplan that incorporate http://www.publish.csiro.au/an/Fulltext/AN15365.

Year 2023 HEREFORD MAGAZINE 45