The Clock is ticking … … … Part 1

In late June and early July 2017, two UK newspapers published articles on the Suffolk Horse which created discussion on social media, particularly the FaceBook 1 page of Jason Rutledge with its 4000+ (and growing) followers.  

The Daily Telegraph’s headline read:  “Revealed:  Why Britain’s oldest horse breed is veering towards extinction”2 and the Daily Mail’s proclaimed: “Four-legged magic: Britain’s majestic Suffolk Punch horses are dying out because too few fillies are being born – which makes the arrival of Lilly Rose so special…  “3

When pondering the various points made in these articles, there is one overriding consideration which often gets buried in all the hype of “rarity”:  the present day UK population of the Suffolk horse is tiny, and has been over six decades.   Gone are the halcyon days of Stud Books recording registration of 112 Horses and Mares 502 (a total of 612 ) as it did in the Stud Book  1919 which covered the two years 1917-1918..   Transfers (the sale of horses) listed in that volume were 443, of which 54 were horses, and mares 3894.  Volume 41 published in 1938 and covering 1937 recorded the registrations on 855 entries (113 horses, 722 mares).5 

The List of Suffolk Stallions, licensed by the Ministry of Agriculture and Fisheries for the licensing year 1 November 1936 to 31 October 1937, listed 240 stallions.    Compare this number to the 2017 current Stallion List, licensed by the Suffolk Horse Society, of 23 stallions.6  

And the overall health of the Suffolk herd in the 1930’s was reflected in foaling percentages   Keith Chivers records figures of 68.1%, 67.2% and 66.0% for the years 1934, 1935, and 1936.  These foaling percentages were higher than for the Shire and Clydesdales across those three years.7    It is not known what the foaling percentages are in recent years, since the Suffolk Horse Society stopped printing its Stallion Covering Tables with the last one published in the Suffolk Horse Magazine several years ago.   Foaling percentages from around the years 2000-2008 varied between the mid to late thirties, to early forties.8

Some might say that the Daily Telegraph’s headline, was extreme in asserting that the Suffolk Horse is veering towards extinction,    Yet the person suggesting things might be terribly wrong with the continuing preservation of the iconic draught horse, is the one genetic researcher in the UK who has been studying the population dynamics and genetics of the Suffolk Punch since at least 2009 – Dr Sarah Blott. 

In 2009 the Animal Health Trust, announced:

The Suffolk Horse Society ask equine geneticists at the AHT to assess the genetic diversity of the Suffolk Horse, an iconic local breed but now listed as critically endangered.   Our work will enable breeders to minimise the risk of health problems associated with a lack of genetic diversity.

In November 2009, BBC Suffolk interviewed Dr Blott at the Animal Health Trust on the genetic research involving the Suffolk Horse:

“The sequencing of the horse gene in 2007 has radically altered the way we can do research into equine genetics,” said Dr Sarah Blott, who’s an equine quantitative geneticist.  We can sample 60,000 points in the genome whereas before we would only have done around 2-300. Our aim is to help breeders develop breeding strategies that will ensure their long-term future,” said Dr Blott.

One of the trust’s projects involves looking at genetic diversity in the Suffolk Horse (aka Suffolk Punch) breed.

“Because it’s a rare breed, it’s at potential risk of inherited disease becoming a problem in the future and we’re looking at breeding strategies to prevent that,” said Dr Blott.

“… … … so over time all individuals become more inbred so that’s a risk factor for inherited disease. What we’re doing is surveying the current genetic diversity. We’re using computer modelling to ask what happens if we use different breeding strategies.”

In April 2010, Dr Blott presented initial findings at a seminar organized by Rossdale & Partners at Newmarket.  Among the points she raised were:

  • Too much dependency on popular sires -> small genetic population
  • Rate of inbreeding has gone up from 5% in 1978 to between 7-8% (as at 2010)
  • To maintain a viable breeding population, there needs an introduction of new bloodlines.
  • Hair sampling kits were to be sent out through April – June of 2010; genotyping work was to be carried out during July and August and the report finalised by November 2010.  

In the magazine Heavy Horse World, Summer 2011 issue (pp46-47),9 Dr Blott pointed out the Critical status of the Suffolk horse (less than 300 breeding females) and stated: 

“While low numbers are an indicator of vulnerability, it is also important to consider the genetic structure of the populations and how this may be impacting on genetic diversity.   Conservation is about ensuring that these breeds continue to exist in a healthy state.   This means not only working to make sure they remain in reasonable numbers, but managing their genetic health by monitoring within breed diversity and preventing rapid rises in inbreeding.”

Dr Blott goes on to state: 

“Certain events such as genetic bottlenecks and selection can, however, accelerate the rate of inbreeding.   Bottlenecks occur when a limited number of individuals contribute to future generations …  popular sires will have more offspring than other individuals and will consequently have a higher chance of contributing their genes to subsequent generations.”

And on 12th August 2016, Dr Blott of the University of Nottingham, School of Veterinary Medicine & Science gave the following presentation – 

How genetic science can help conserve and sustain the Exmoor pony“…. an introduction to DNA, genes and genomics, along with description of a project being developed to fully characterise the genetic profile of the Exmoor pony”

(http://www.exmoor-nationalpark.gov.uk/Whats-Special/wildlife/exmoor-ponies/exmoor-pony-action-plan-update)

As an example inbreeding in other breeds, Dr Blott presented the following diagram. 

Screen Shot 2017-07-31 at 6.39.25 am

 

Genetic bottlenecks have been an ongoing problem with the Suffolk Horse in the UK since the overall population rapidly declined from the mid to late 1950s.     Table 1 below shows ten popular sires covering the years 1954 -2011, together with their resultant progeny.  A total of 394 foals was produced over 63 years.   Note that Stallion E (although deceased) standing since 1996 is still producing foals via AI.    Potentially, and of course depending on how much harvested semen remains, he could go on adding his genetics for some time.

Table 1:  Ten Popular Sires with Total Numbers of Progeny

Another problem is the close relationships between these ten popular sires. Popular sires frequently produce popular and sought after progeny.    Stallion I, is a direct descendent to six of the other popular sires in the table, with one stallion appearing twice, in five generations (Stallion I being the fifth).   Also contributing to the potential bottlenecks is the appearance in the dams’ pedigrees of the same popular sires.    The dam of Stallion I has five of the popular sires in Table 1 in her pedigree of five generations, with two stallions appearing twice.10

The website Understanding Evolution, explains further another confronting problem of low populations. 

“Without genetic variation, a population cannot evolve in response to changing environmental variables and, as a result, may face an increased risk of extinction. For example, if a population is exposed to a new disease, selection will act on genes for resistance to the disease if they exist in the population. But if they do not exist — if the right genetic variation is not present — the population will not evolve and could be wiped out by the disease.

As an endangered species dwindles, it loses genetic variation — and even if the species rebounds, its level of genetic variation will not. Genetic variation will only slowly be restored through the accumulation of mutations over many generations. For this reason, an endangered species with low genetic variation may risk extinction long after its population size has recovered.”(http://evolution.berkeley.edu/evolibrary/article/conservation_04)

 

Population diversity is also seriously compromised when overall Stallion List numbers fall below the minimum optimum.    Professor Twink Allen proposed a minimum of 25, Professor John Bowman in 1969 proposed a minimum of 30.11

Figure 1 shows these two optima over two decades of actual stallions used compared to total number of stallions on the Stallion List.  It will be seen that there was only a brief couple of years when the Stallion List achieved the optimum of 25 offered, but no years when the actual number of stallions covering mares achieved either optima. 12

By contrast Figure 2 can only show the total numbers of foals produced between 2006-2017 with the two optima, as the Stallion Breeding Tables have not been published for a number of years.    Those tables were very useful sources of information.  Against each stallion on the Stallion List (for the previous year), were the totals of: 

Mares covered for the year,

Mares NOT in Foal,

Mares died in Foal, Aborted,

Foals born Dead,

Live Foal (current year),

Unregistered Live Foal.

To take one year, 2003 Breeding Results, there were 21 stallions on the Stallion List, but six of these covered no mares.    A  total of 74 mares were covered by the remaining 15, to produce 31 foals.   It should be noted however that eight popular sires covered 55 of the total 74 mares, with the most popular for the 2003 breeding year, covering 11 mares, another covered 10.    Seven stallions covered between one to four mares, eight stallions covered between five to eleven.13

Figure 1:  Two Decades of Foal Production
Showing Actual Stallions Used 1988-2008
Compared to Total Stallions on Stallion List
Against Two Optima for Genetic Diversity

Figure 2:  2006-2017 Total Foals Produced 
with Totals of Colts and Fillies
No published data available to Show Actual Stallions Used

Over the past few years, little by little tangible information seems to be disappearing, as the Stallion Breeding Results mentioned above.    The latest Stud Book available according to the SHS website is Volume 91 covering the registration year 2014, and yet in the Report to the Charities’ Commission, dated 31 December 2016, it states that the SHS has achieved an Objective in 2016 by the publication of Volume 92 of the Stud Book.   Promotion of its availability is yet to show up on the SHS website.

Stallion Lists for the year used to give the number of progeny produced by numbers of colts and foals. And although “Foal Watch” on the SHS is a delight, consistent information for each foal:  dam, sire and Registration Number would be the added bonus which seems to have disappeared.  

The back of the SHS Magazine previously carried useful information, such as the names and positions of the Officers and Council of the Suffolk Horse Society, together with the various Committees.    It also gave the total of SHS Members and Friends.

 

 The Genetically Healthy Herd

For a genetically healthy population it is not enough to have a minimum number of sires available; if possible all available sires should be used, which will mean that the concept of elite sires must be diminished, if the conservation aim, rather than commercial success, is to be achieved.

The DEFRA Research Project GC0146 by Dr Stephen J.G. Hall, Conservation of Farm Animal Genetic Resources:  implementation Guidance14, suggests

“… have as many active sires as practicable, all siring much the same number of young

.….have at least 25 sires in each generation, each siring similar numbers of offspring.”

And of course, the female side of the equation has to be considered and ranked equally importantly.   The Guide goes on:

  1. How many dams are there on average for each sire?   This will probably be 5 or more for cattle, 5 for sheep and goats, 3 for horses and poultry, 2 for pigs.   There is no need to try and change this.

Deduce how many breeding offspring (sexes combined) the average female produces during her lifetime. For all species, this will probably be between 4 and 12.

  1. Are there at least the following numbers of males siring registered stock in the current year:
  2. For a lifetime production of 4, 21 bulls, rams or bucks; 24 stallions or male birds, 25 boars
  3. For a lifetime production of 12, 25 bulls, rams or bucks; 28 stallions or male birds, 43 boars.   …

The target is to have at least the number of sires given in (3) above for your species.

Some Questions to be Considered

There are some questions question which naturally follow.  

  1.  Are there sufficient numbers of both Suffolk stallions and mares in the UK herd to ensure a viable genetically diverse population?

The short answer is – probably No.

The UK National Inventory of Farm Animal Genetic Resources “helps Defra monitor breed populations and identify breeds that may be at risk, the updated inventory shows the current breed data … Equines (horses) … as at 10 August 2016.” 15

Using the 2017 Stallion List of those registered and licensed stallions, there are 23 available for covering mares, just one short of the 24 stallions suggested by Dr Hall, then 23 x 4 = 92.     This is 20 less than the estimated pedigree registered breeding females in 2015.   

Table 2 Suffolk Horse Mares Inventory as at 10 August 2016

Table 3:  Statistics for Suffolk Horses at the year-end 2012-2016 has been derived from various sources, viz:

http://apps.charitycommission.gov.uk/Accounts/Ends56/0000220756_AC_20151231_E_C.pd

fhttp://apps.charitycommission.gov.uk/Accounts/Ends56/0000220756_AC_20141231_E_C.pd 

http://apps.charitycommission.gov.uk/Accounts/Ends56/0000220756_AC_20161231_E_C.pdf

Despite the 541 herd size for 2016, and 280 mares holding SHS passports, the actual breeding herd is estimated at 93 of mares and registered licensed stallions.   This is an important point because confusion can arise with the statement “Critically endangered” meaning less than 300.

Table 3: Statistics for Suffolk Horses at the year-end 2012-201616

 

Figure 3: Total Colts, Fillies and full Foal Production 2006-2017 is the same as Figure 2 without the two optima.   What it does show is that overall foal production is down from the high of 50 in 2010, beginning with a decrease of 10 foals in 2011 to 40, then hitting 39, 36, 32 through 2012-2014, and two years at 27, then 28 through 2015-2016, and dropping again in 2017 to only 23 foals.

Figure 3: Total Colts, Fillies and full Foal Production 2006-2017

 

2. Are the New Breeding Strategies described by Dr Blott in her 2011 article being implemented?

The short answer is, no.

“Changes to the population structure, for example, the use of more males for breeding, could be facilitated by the use of reproductive technologies such as artificial insemination (AI) and embryo transfer.   AI could potentially allow young males to be used in the breeding programme prior to gelding. This would increase the gene pool without increasing the number of stallions that need to be kept, since it must be recognised there may be limited numbers of people with the facilities or experience to keep entire males.” (Page 47, Heavy Horse World, Summer 2011).

To date there have only been two foals born via embryo transfer:  one in the UK in 2013, and the second in Australia in 2016.

The Suffolk Horse Society has long recognised that keeping both mares and stallions does not come cheap.    It offers grants and subsidies to owners and breeders.   Table 3 sets out some of these grants.

Table 3: SUFFOLK HORSE SOCIETY 2017 Grants

It should be noted, however, that there is no grant for the harvesting and storing of semen.     

In summer 2013 reporting on the birth of the pure Suffolk foal using embryo transfer and  frozen semen, the owner made a heartfelt plea: 

 “We would also like to beg stallion owners to see if their horses’ semen is suitable for freezing and if it is, to lay some down with the Society.   In a situation like ours, where we have no easy geographic access to stallions, it is our lifeline and as we all know, the greater the choice the more open the bloodlines.”16

 The 2017 Stallion List on the Suffolk Horse Society Website shows only two horses where frozen semen is available, but enquiry is made to the individual owners, not the Society. Up until last year Colony Edward 8781’s frozen semen was available.   However, the amount of progeny he had produced up to 2015 was 32 (16 colts, 16 fillies).  By 2017 the total number of his progeny has increased to around 36, not presumably by much, but still a concern in terms of genetic diversity.

Another stallion’s semen was also available for AI, with four registered progeny (3 colts, 1 filly) previously described on the 2015 Stallion List.  Neither these two stallions’ semen appears to be available.

Collecting and storing semen to be available for AI is certainly not cheap.

 A few years earlier, the Rare Breeds Survival Trust began to collect and store heavy horses’ frozen semen.  Their Gene Bank web page states:

“RBST is not just collecting from show winners and those considered the best in the breed.  We want the Gene Bank to represent genetic diversity found in each breed.”

As of the January 2017, the Gene Bank of the Rare Breeds Trust, holds only three separate Suffolk Horse frozen semen collections (i.e. collections from three different stallions) (my emphasis).     The Clydesdale and Shires also only have three semen collections each in storage.

“It is our aim to collect semen from at least 25 unrelated stallions from each breed. This is an important number because, if the population was to crash and all stallions were lost, it would be possible to re-establish a population and save approximately 90% of the original genetics. Some of our listed breeds such as the Dales and Exmoor Pony are only represented by two stallions; if a disease epidemic or another situation beyond our control depleted the current population of a breed, there would be no way for us to save any of our listed breeds. The cost per semen collection is extremely high and can only be carried out at certain times of the year, so we need to act quickly and efficiently to ensure that these breeds are safe from extinction.”

The costs associated of each collection is £6,800.  Each 100 doses costs £6,800, (US$8,784.00) with 55 doses for the Gene Bank archive and the remainder for conservation breeding projects.   Total cost then of the 25 unrelated collections is a staggering £170,000 or US$219,627.00.17

In early April 2017, I contacted the Suffolk Horse Society by email pointing out the three solitary semen collections at the Gene Bank, and the costs associated with collection.   I asked if the following questions could be put to the Annual General Meeting under “Any other Business” as a question from the floor.

  • Would the Suffolk Horse Society consider starting a major fund raising enterprise to ensure the survival of the Suffolk Punch by aiming at harvesting 25 different stallions for the Gene Bank?
  • Alternatively, would the Suffolk Horse Society consider grants for Stallion Owners to help harvest and store semen and enable a wider availability that we have at the moment?

The response received said this would be passed to the Breeding Committee who would reply after the AGM.  To this I responded that my queries were for the whole Suffolk Horse Society, all Council members and members of the Society, via the mechanism of a Suggestion/Question from the floor, and I did not understand why this was only to be discussed by the Breeding Committee.

This email was acknowledged, and basically reiterated the previous reply.

I wrote again a few days before the AGM:

“Another potential question from the floor, under Any Other Business.
 
The Rare Breeds Conservation Society of New Zealand is currently trying to raise funds to harvest semen from Capleach Jackson.    Apparently ” initial tests showed his semen to be of good quality”.    See:  https://givealittle.co.nz/cause/savethesuffolks    If successful, the plan is to make the frozen semen available internationally.  (See also:  http://www.stuff.co.nz/the-press/news/90030260/The-mission-to-save-NZs-last-remaining-rare-Suffolk-Punch-horses)
 
Unfortunately fund gathering has only gained some NZ$1,050.00 (some pounds sterling 575.14 at today’s exchange rate) since the page was posted in January 2017.
 
You are probably aware that Capleach Jackson is the least genetically closely related to the current 20 Stallions standing at stud for 2017.     Since the 2017 list contains two pairs of full brothers, this actually reduces the list down to 18 (genetically speaking).   Looking at the 2017 list, if the Sire’s Sire is included in a three generational table, then in pedigrees of the 20 Listed stallions*:
 
One stallion appears eight times, another five times.  Two stallions appear four times each, another two stallions appear three times each, and eleven stallions twice each.**  Jackson is the only living stallion in the three generations who shares one ancestor.
 
My question is:  would the Society consider some form of grant or subsidy to enable the funding to harvest, test and make available for import of Capleach Jackson’s frozen semen, for the UK, USA and Australia?
(* and ** refer to the then Stallion list posted on the SHS website.  In fact, if the Dam’s Sire is added in then the inter-relatedness is even higher)
The fund raising for Capleach Jackson closed mid July, with only something like NZ$1,150.00 donated by 27 donors.    Surely there are SHS funds in reserve that could have made possible the harvesting of semen? 
3. Has the Society responded to the recommendation made by Dr Blott in April 2010 that to maintain a viable breeding population, there needs an introduction of new bloodlines?

No, despite the fact that an exchange of bloodlines between the North American and the UK Suffolks – in both directions – would be of value to both herds, and would certainly buy time while other new breeding strategies are investigated.   This could be achieved by importing and exporting both fillies and foals, and/or frozen semen.   In this latter case, the semen would need to meet the stringent export/import quarantine requirements, not just for UK and North America, but also for Australasia. 

More to follow with Part 2 of this article

References for The Clock is Ticking…Part 1 

  1. https://www.facebook.com/groups/suffolkpunchdrafthorses
  2. http://www.telegraph.co.uk/news/2017/06/26/britains-oldest-horse-breed-veering-towards-extinction-many
  3. http://www.dailymail.co.uk/news/article-4652684/Britain-s-majestic-Suffolk-Punch-horses-dying-out.html
  4. Suffolk Stud Book Volume 22, covering years 1917-1918, published in 1919
  5. Suffolk Stud Book Volume 41 covering year 1937, published in 1938
  6. https://www.suffolkhorsesociety.org.uk/horse-business/stallions-at-stud
  7. The Shire Horse, A History of the breed, the Society & the Men, Keith Chivers, J.A. Allen, London 1976
  8. Suffolk Horse Magazines 2000-2008
  9. Heavy Horse World, Summer 2011, pp46-47
  10. Assorted Suffolk Horse Society Stud Books 1954-2011
  11. Running out of Time Heavy Horse Magazine, Summer 2009
  12. Compilation Stud Book (1960-1985) and Assorted SHS Magazines & Material
  13. SHS Magazine April 2005, 2003 Breeding Results
  14. Defra GC0146, Dr Stephen Hall, Conservation of Farm Animal Genetic Resources: implementation Guidance
  15. UK National Inventory of Farm Animal Genetic Resources Equines https://www.gov.uk/government/publications/uk-country-report-on-farm-animal-genetic-resources-2012, update of the Country Report as at 10 August 2016 https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/547005/fangr-uk-inventory-equines.pdf
  16. SHS Stud Book Volume 30, 2013 Preface 
  17. https://www.rbst.org.uk/content/download/4590/…/Gene+Bank+Pull+Out+2017.pdf