Meliora Drents

Note: this was originally posted to our Facebook Page on 11/26/23, and copied here for redundancy.

Huge news for the Drentsche Patrijshond – the report commissioned by three European Drent clubs (VDPH, DPHCN, and SDPK) from Dr. Pieter Oliehoek of Dogs Global, a leading expert in genetic management of rare breeds, is now available to the public. The report analyzes the current state of genetic diversity within the global Drentsche Patrijshond population, and is a fascinating read for anyone interested in the conservation of rare breeds: find it HERE.

While I’m still digesting the 44 page report, some of my major takeaways include:

1. The current genetic diversity that exists within the breed today is the same as if the population was founded by 2.15 animals. While that is very low, it’s actually not as low as many other rare breeds. However, the breed’s genetic diversity is very much at risk of further and rapid decline.
2. Most of the unique genetic diversity in the breed today exists in older animals who are aging out of breeding. Once unique genetic material is lost, it is lost forever. The only way to add genetic diversity back in is through a successful outcross program to unrelated breed(s).
3. Loss of genetic diversity to date can be contributed largely to the Dominant Ancestor effect (in contrast with popular sire syndrome, this considers the impact of a dog’s progeny on the population, whether or not the dog themselves produced many puppies), and heavy selection pressure from breeders and breeding regulations imposed by breed clubs (in terms of conformation, temperament, working ability, and/or health requirements for breeding).
4. What benefits a specific litter (ie heavy selection pressure) does not necessarily benefit the population overall. For example: counterintuitively, avoiding inbreeding in each litter does not alone prevent a small population from becoming more related, and therefore inbred, over time, as more unique genetic material may be lost from both less-related parents than from closer-related parents. However, preserving genetic material across the population should be done in balance with the mitigation of risks passed on to each litter of puppies.
5. The Drent population overall is rapidly declining. Ten years ago there were just under 6000 Drents worldwide, while today there are only around 4000, with only about 250 puppies born annually.
6. The United States has a surprisingly high percentage of Drents with unique and therefore valuable genes to the rest of the worldwide population.

What can be done? The report mentions multiple times that increasing the number of breeding dogs is paramount to maintaining the genetic diversity that remains in the breed. Recommendations in the report include:

• Limiting the number of litters per dog (as long as there are other dogs that are able to be bred instead – the report also states, “from a conservation genetics perspective, breeding […] is favorable over non-breeding”)
• Encouraging “one-time” litters (where dam and/or sire are used once rather than never or multiple times), and
• Reducing selection pressure (ie opening up breeding requirements to make breeding more accessible and/or more dogs “qualified” for breeding).

One of most impactfully counterintuitive quotes in the report for me: “Media often presents dog breeding in a negative light […] such portrayals have led governments, organizations, and certain breeders to amplify measures promoting health-based selection criteria […] (Unwanted genetic dispositions) arise from the loss of genetic diversity, which instigates inbreeding and consequentially breed-specific diseases that are undesirable to all. This situtation is set to deteriorate if selection intensity increases, even when the selection is health-focused.”

The report goes on to provide hope for the future: “…with dedication and perseverance, and thorough scientific guidance it’s entirely feasible to cultivate breeds that will gain a reputation for their robust health and longevity. […] Achieving this balance requires acknowledging and adapting to the considerable differences among breeds. This should go together with a fusion of conservation genetics, quantitative genetics, precise high-quality data, and devoted breeders who deeply care for their breed.”

I encourage all Drent breeders and enthusiasts to read the full report (in Dutch or English) by downloading it from the VDPH website, here: https://drentschepatrijshond.com/…/diversiteit-verbeteren/