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C9a. Animal genetic resources – effective population size of Native Breeds at Risk

Type: State / Benefit Indicator

Indicator Description

Genetic diversity is an important component of biological diversity. Rare and native breeds of farm animals are part of our cultural heritage, are often associated with traditional land management required to conserve important habitats, and may have genetic traits of value to future agriculture. 

The genetic diversity in UK breeds can be assessed by the effective population size (Ne), which accounts for the total number of animals in a population and the relative numbers of sires and dams (male and female parents). A low effective population size signifies a greater likelihood of in-breeding and risk of loss of genetic diversity. 

This indicator shows the change in the average effective population sizes for breeds of goats, pigs, horses, sheep and cattle classified by the UK Farm Animal Genetic Resources Committee as Native Breeds at Risk (NBAR).

Contents

  1. Summary
  2. Downloads

Summary

The average effective population size of the native breeds at risk included in this indicator:

 for pigs decreased from 176 in 2000 to 174 in 2013 and to 152 in 2018;

 for horses decreased from 178 in 2000 to 128 in 2013 and to 117 in 2018;

 for sheep increased from 245 in 2000 to 380 in 2013 and to 403 in 2018;

 for cattle increased from 88 in 2000 to 181 in 2013 and to 295 in 2018;

 for goats the dataset starts in 2004 when it was 62, increasing to 80 in 2013 and increasing to 100 in 2018; prior to 2004, effective population size could only be calculated for one breed. 

The average effective population sizes calculated between 2000 and 2018 for the native breeds at risk of goats, pigs, horses, sheep and cattle were each above 50, the figure set by the United Nations Food and Agriculture Organisation as a threshold for concern. However, in 2018, of the Native Breeds at Risk, one breed of goat (Toggenburg), three breeds of horse (Cleveland Bay Horse, Eriskay Pony, and Suffolk Punch), and one breed of cattle (Vaynol), had a Ne less than 50. No breeds of sheep or pig had effective population sizes below the threshold in 2018.

There has been no reported UK extinction of any breeds of goats, pigs, horses, sheep or cattle since 1973. 

Figure C9ai. Average effective population size (Ne) of Native Breeds at Risk, 2000 to 2018

A line graph showing the effective population size of native breeds at risk for goats, pigs, horses, sheep and cattle from 2000 to 2018 in the UK. Data for goat breeds are only available from 2004. The threshold for the effective population size of native breeds at risk is set at 50 (dotted line on the graph) by the United Nations Food and Agriculture Organisation as a threshold for concern. The average effective population sizes calculated between 2000 and 2018 for the native breeds at risk of goats, pigs, horses, sheep and cattle were each above the threshold of 50.

Notes:

  1. The number of breeds included in the indicator varies year by year as a result of data availability for both sires and dams (data for both are needed to calculate effective population size). The maximum number of breeds included in each measure is shown in brackets after the species name in the legend. The annual data collection for the 2018 data only relates to a third of the total breeds and these are for 4 goat breeds, 11 pig breeds, 13 horse breeds, 30 sheep breeds, and 18 cattle breeds. Further details of how many breeds are included in each year can be found in the technical background document and the datasheet.
  2. Data for 2015, 2016 and 2017 in the previous publication of this indicator was provisional. However two thirds of the breeds data has now been collected through the three yearly survey in October 2018. Data for 2018 are provisional, hence the last part of the lines are showed as ‘dashed’. It is expected that the 2018 data can be confirmed in late 2021 when the next triennial exercise has taken place.
  3. Based on data in the UK Farm Animal Genetic Resources Breed Inventory published on 8 May 2019.
  4. Historic data for some breeds have been revised. As a result, this indicator is not directly comparable with the previous publication. The Breed Inventory Results published on 8 May 2019 can be accessed through the following link: https://www.gov.uk/government/statistics/uk-farm-animal-genetic-resources-fangr-breed-inventory-results. The Excel dataset provides information on revisions.   
  5. The dotted black line shows effective population size (Ne) equal to 50; the level set by the United Nations Food and Agriculture Organisation as a threshold for concern. The dark grey line is an average of all 86 Native Breeds at Risk for which Ne could be calculated; this is included to provide context, but is not assessed.

Source: British Pig Association, Defra, Grassroots Systems Ltd., Rare Breeds Survival Trust, and participating breed societies.

Assessment of change in effective population size of Native Breeds at Risk

 

Long term

Short term

Latest year

Goat breeds


2004–2018


2013–2018

Decreased (2018)

Pig breeds


2000–2018


2013–2018

Decreased (2018)

Horse breeds

2000–2018


2013–2018

Increased (2018)

Sheep breeds

2000–2018


2013–2018

Increased (2018)

Cattle breeds


2000–2018


2013–2018

Increased (2018)

Note: Long- and short-term assessments are based on a 5% rule of thumb. Where possible, the base years for these assessments use a 3-year average. See Assessing Indicators.

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Downloads

Download the Fiche, Datasheet and Technical background document from the JNCC Resource Hub

Last updated: September 2019

Latest data available: 2014 and 2017

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Categories:

UK Biodiversity Indicators 2019

Published: .

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