Rare Bloodlines Revisited – North American and Dutch Divergence?
/In my 2019 analysis of rare bloodlines in the Fell Pony, nearly 40% of the ponies on the list were born outside the United Kingdom. Most of these were North America-born and the rest were born in The Netherlands. (To read the overview of my 2019 analysis, click here. )
Kimberlake Lady Belle is one of the North American ponies that shows up on the worldwide rare bloodlines list. With both of her parents being North American-born, the question must be asked if our North American herd is diverging from the worldwide population.
My similar study completed a decade ago didn’t have this large non-UK population on the rare bloodlines list, so the obvious question is: are we beginning to see a divergence in bloodlines between the UK and the two other largest populations of Fell Ponies? This question comes to mind because several of the North American ponies on the worldwide rare bloodlines list are not from particularly rare lines within the context of the North American population. For instance, Laurelhighland Jack of Diamonds and his sire Laurelhighland Union Jack appear near the top of the worldwide rare bloodlines list but are near the bottom of the list for North America. Since they were bred at the most prolific of our North American studs, they are related to many of the other ponies on this continent.
Table 1 shows the non-UK sires and dams that show up at the top of the rare bloodlines list based on 2017 and 2018 foal crops. In addition to considering the relative ranking on the local versus worldwide lists, there are two other ways to consider whether the ponies in Table 1 are evidence of diverging bloodlines:
How many of the non-UK ponies’ ancestors were non-UK born? If a particular North American pony, for instance, has one or more North American-born ancestors, then that pony would have fewer ancestors in common with UK ponies and would therefore be computed as being less related to the worldwide population. To determine the number of non-UK ancestors, I looked at the pedigree of each pony and counted the ponies with non-UK names/prefixes. This tally is shown in the column in Table 1 titled “# non-UK ponies behind.” The greatest depth that non-UK ponies reach in a pedigree is 2 (a grandparent.) Wiranda van Nuova, a Dutch-born mare, has a value of 4 in this column, with both her parents being Dutch-born and both her granddams being Dutch-born.
How have the grandparents of these rare bloodline non-UK-born ponies contributed to the modern foal crop? By looking back two generations and seeing if those ponies are common or not in pedigrees of modern day ponies, we can get a better indication of whether the non-UK-ponies truly represent rare bloodlines. This analysis can be completed by looking at what percentage of the 2018 foal crop trace back to the grandsires and granddams of the ponies on the rare bloodline list. By averaging the percentages, it is then possible to compare the rarity of these non-UK ponies to each other. This analysis is shown in the column in Table 1 titled “Sum of Grandparent %.” A lower number indicates less contribution by the four grandparents to the worldwide population, and a higher number indicates more contribution. For instance, Laurelhighland Lyric, with the highest value in that column at more than 10%, has behind her grandsires that are relatively popular: Waverhead Prince II (represented in 20% of the 2018 foal crop) and Townend Samuel (represented in 15% of the 2018 foal crop). By comparison, Angelmeadow Crown Jules has a relatively low value of 1.18% because his grandparents are all resident in North America and have not had broad use.
The results of these two analyses support the hypothesis that UK and non-UK bloodlines are diverging. For a given pony on the list, as more of its ancestors are non-UK born, the less its grandparents are contributing to the worldwide population. For example, the mare Wildhoeve Romy has four foreign-born ancestors, and her grandparents on average are represented in only 1.66% of the 2018 foal crop. By comparison, Olimpia de Knip, who has no foreign-born ancestors, has relatively more relatives in the worldwide population with her grandparents on average being represented in 5.47% of the 2018 foal crop. Nonetheless Olimpia has numerous rare lines, qualifying her for the rare bloodline list.
Here are other key findings:
The late Waverhead Robbie, shown in 2004, is behind the majority of the North American ponies on the rare bloodlines list; his offspring are the only descendants of his dam.
The late Waverhead Robbie, imported to North America in 1994, is behind many of the North American ponies in Table 1. While his sire is somewhat common, Robbie represents the only continuation of his dam’s line in the current worldwide Fell Pony population, resulting in many of his descendants appearing in Table 1.
When a pony is linebred, especially more than twice, the number of its ancestors is reduced so it has fewer opportunities to be related to the rest of the population. If the pony on which it is linebred is relatively common, then while the numbers may say that the pony represents a rare bloodline, in fact it has plenty of relatives in the population. Kimberlake Lady Belle and Maxiem van de Koekoekshof are examples; they are both heavily linebred on the oft-used stallion Heltondale Heather Lad. Because they also have rare outcrosses, they still qualify to be on the rare bloodlines list.
The Dutch ponies in Table 1 have more generations of non-UK ponies (values of 4 and 3) than the North American ponies (values of 2 and 1), reflecting the fact that the Dutch began their Fell Pony program in earnest before North America did.
The divergence between bloodlines in the UK and the two largest foreign populations in North America and The Netherlands isn’t surprising. In fact, this sort of divergence is to be expected over time as relatively fewer ponies are imported and more ponies are born locally. It is important, however, that we know that the divergence is taking place so that worldwide breed management decisions can take it into account. For instance, in time, North American-born ponies may be interesting outcrosses for populations elsewhere, as the Dutch population has been in recent years for UK breeders. Finally, this sort of divergence is not a problem for the breed as long as the ponies born outside the UK are still displaying proper type.
(c) Jenifer Morrissey, 2019
