15AGRITECHCAT3 Evaluating a potential proxy test for Feed Conversion Efficiency in beef cattle.

The project targets the large feed costs savings that could be achieved by selection for feed conversion efficiency (FCE) in
the UK beef industry. It will deliver a new tool to identify feed efficient cattle - without the need for expensive recording of
feed intake and growth rates. The cost of recording has been the main factor limiting the incorporation of FCE into ruminant
breeding programmes. The project will also provide preliminary information about genetic variation and correlations - to
help with incorporation of the new tool into breeding programmes. The scientific basis for the project is the relationship
between FCE and the phenomenon of N isotopic fractionation. N isotopic fractionation has been measured using blood
samples in previous work, and is low when FCE is high. This project will explore a new approach to measure N isotopic
fractionation using hair samples. Hair samples are attractive because they accumulate information from an extended period
of time and are easy to obtain from cattle undergoing on-farm recording for other traits. Commercially, this is both an
opportunity for breeders to produce more valuable stock (sales of bulls, semen and embryos) and for all beef producers to
reduce feeding costs. The early-stage project will gather key information needed to make decisions about the choice of
proxy tool and the way that it will be used in breeding programmes:
(i) Verification of the relationship between the proxy (Delta-15N) based on plasma or hair samples and N-use efficiency.
(ii) Evaluation of the suitability of hair as a representative sample for measuring Delta-15N.
(iii) Investigation of the relationship between proxy measurements and other farm-recorded traits.
(iv) Preliminary analysis of genetic variation in FCE based on the proxy (Delta-15N).
We will use samples of plasma and hair taken at the end of the recording period of groups of cattle (n=100 in total) on a full
feed conversion efficiency protocol (60-day recording of feed intake, live-weight, and body composition (by ultrasound
scanning)) as part of another study. Hair samples will be sectioned to ensure that the portion to be analysed was produced
during the recording period (the basal 4.5 cm representing growth in the last two months; Zazzo et al. 2007). Samples of
plasma, hair and feed will be analysed for Delta-15N and relationships between Delta-15N and FCE explored, with and
without inclusion of information about body composition. We will (i) investigate the relationship between the hair 15N proxy
measurement and other farm-recorded traits (400-day weights and ultrasound scans) and (ii) conduct a preliminary
analysis of genetic variation in FCE based on the proxy, using 2,000 pedigree Aberdeen Angus animals (approx. 100-150
herds) currently being recorded through the Aberdeen Angus Cattle Society (AACS) on-farm recording scheme.

The project targets the large feed costs savings that could be achieved by selection for feed conversion efficiency (FCE) in the UK beef industry. It will deliver a new tool to identify feed efficient cattle - without the need for expensive recording of feed intake and growth rates. The project will also provide preliminary information about genetic variation and correlations - to help with incorporation of the new tool into breeding programmes. The scientific basis for the project is the relationship between FCE and N isotopic fractionation. N isotopic fractionation has been measured using blood samples in previous work, and is low when FCE is high. This project will explore a new approach to measure N isotopic fractionation using hair samples. The project will gather key information needed to make decisions about the choice of proxy tool and the way that it will be used in breeding programmes. We will use samples of plasma and hair taken at the end of the recording period of groups of cattle on a full FCE protocol (60-day recording of feed intake, live-weight, and body composition). Hair samples will be sectioned to ensure that the portion to be analysed was produced during the recording period (the basal 4.5 cm representing growth in the last 2 months). Samples of plasma, hair and feed will be analysed for Delta-15N and relationships between Delta-15N and FCE explored, with and without inclusion of information about body composition. We will (i) investigate the relationship between the hair 15N proxy measurement and other farm-recorded traits (400-day weights and ultrasound scans) and (ii) conduct a preliminary analysis of genetic variation in FCE based on the proxy, using 2,000 pedigree Aberdeen Angus animals currently being recorded through the Aberdeen Angus Cattle Society recording scheme.

The project will deliver knowledge and experience to implement a proxy for feed conversion efficiency (FCE) based on 15N
analysis of hair samples taken from contemporary groups of growing cattle. The test will address the urgent need for tools
to reduce production (particularly feed) costs in UK beef production and allow the UK to compete more effectively in the
global beef cattle breeding industry, where a number of countries (notably Australia and Canada) have well-established
testing facilities for FCE. UK beef production (885,000 tonnes per annum represents just over 1% of global beef production.
Global demand for beef is increasing as world population expands and people in developing countries seek more meat in
their diets (FAO projections of 1.2% annual growth until 2050). So, there are good market opportunities both for beef and
for beef genetics - provided that the major challenge to reduce production costs can be addressed. Without such as stepchange,
the steady decline of the UK beef breeding and production industries will continue.
The UK has realised the need to breed for FCE much later than leading beef breeding countries, with major negative
implications for the relative efficiency of its beef production as well as the international competitiveness of its beef breeding
industry. We believe that the low-cost FCE proxy approach proposed for this project will allow UK beef breeders to leapfrog
countries that have adopted the expensive testing station approach to FCE breeding, and provide a sustainable approach
that can be implemented over many decades. The FCE proxy will be used to develop testing schemes for FCE, alongside
existing on-farm recording. It is anticipated that these schemes will be used by pedigree breeders, breed societies and
other breeding organisations to develop and provide Breeding Values for FCE. The project will provide the base of
knowledge and experience for implementation of the new analysis in breeding programmes, initially within the Aberdeen
Angus breed. Once the format of the test and its implementation are clear (outcomes from the current project), we will seek
additional partners (using licence agreements) to develop the necessary sampling and analytical services and capture the
larger market with other breeds. A potential further development would be to link the analysis to DNA analysis based on
DNA extracted from the opposite end of the same hair sample (i.e. hair follicles) - either to verify pedigree information or to
explore genomic associations. This is highly complementary to existing activity of the AACS, which is taking ear tissue
samples from all pedigree calves for future genotyping in a partnership with Caisley Eartags).
The potential £200+ million reduction in feed costs for the UK beef industry (~ 2 million cattle x £100 potential saving per
animal) defines the potential financial benefits that could be delivered to UK beef industry in its broadest sense. Savings in
feed costs of up to £100 per animal could be achieved (this is the difference between the current top 20% and bottom 20%
of animals) and this would represent £10,000 extra net margin for a unit finishing 100 cattle. In fact QMS (2014) data show
average net losses for forage-based finishing of 100 cattle in Scotland in the range (-) £1,200 to (-) £4,800, so this would
bring many more producers to make a profit before subsidy. In addition to the increased viability of beef enterprises, this
provides a strong driver for farmers to invest in the breeding and evaluation industry, providing for:
1. Leading breeders marketing bulls and semen from High Feed Efficiency bulls, as well as High Feed Efficiency embryos,
within the UK and internationally.
2. Development of a commercial sampling and testing service - either through enhancement of existing BreedPlan recording
services or through establishment of a new company.
3. Growth in membership and engagement with breed societies.