C9. Genetic resources for food and agriculture

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

i. Goat breeds

ii. Pig breeds

iii. Horse breeds

iv. Sheep breeds

v. Cattle breeds


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).




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

for pigs increased from 176 in 2000 to 192 in 2012, but decreased to 156 in 2017;

for horses decreased from 178 in 2000 to 130 in 2012 and to 127 in 2017;

 for sheep increased from 246 in 2000 to 378 in 2012 and to 411 in 2017;

 for cattle increased from 89 in 2000 to 206 in 2012 and to 251 in 2017;   

for goats the dataset starts in 2004 when it was 62, decreasing to 59 in 2012 and increasing to 101 in 2017; prior to 2004, effective population size could only be calculated for one breed

The average effective population sizes calculated between 2000 and 2017 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 2017, of the Native Breeds at Risk, one breed of goat (Toggenburg), three breeds of horse (Cleveland Bay Horse, Eriskay Pony, and Suffolk Punch), and three breeds of cattle (Dairy Shorthorn (original population), Northern Dairy Shorthorn, and Vaynol), had a Ne less than 50.  No breeds of sheep or pig had effective population sizes below the threshold in 2017.

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 2017.




  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 2017 values are based on four goat breeds, 11 pig breeds, 14 horse breeds, 34 sheep breeds, and 25 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 are provisional, hence the last part of the lines are shown as ‘dashed’.  It is expected that the provisional data can be confirmed later in 2018 (see the technical document for details).
  3. Based on data in the UK Farm Animal Genetic Resources Breed Inventory published on 3 May 2018.  
  4.  Historic data for some breeds of sheep and cattle are now available in the inventory published in 2017 and again in 2018, affecting the series for these species.  There have been some minor revisions to previously published data, some going back to 2000.  As a result, this indicator is not directly comparable with the previous publication.  The Breed Inventory Results published on 3 May 2018 can be accessed through the following link:  https://www.gov.uk/government/statistics/uk-farm-animal-genetic-resources-fangr-breed-inventory-results.
  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 pale grey line is an average of all 88 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, 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



Increased (2017)

Pig breeds




Increased (2017)


Horse breeds



Increased (2017)


Sheep breeds



Increased (2017)

Cattle breeds



Decreased  (2017)


Download Fiche

Download Datasheet 

Download Technical background document


Last updated: July 2018

Latest data: 2017

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