What is Dual Sire?
Let’s talk about the birds and the bees…and puppies! We want to talk about the ins and outs of dual siring here, and the first question is - what is dual sire? When a litter is dual sired, it means that in one litter with one mama, there are two (possibly more) sires/papas within that litter.
How does dual siring work?
When a dam ovulates during her heat cycle, she releases multiple eggs. The number of eggs released is different every time for every dam, and each egg needs a separate sperm to fertilize it. Typically, the number of eggs released is the biggest factor in determining litter sizes. The most fertile period for a dam is the 48-72 hours after she ovulates, so any sperm introduced then, or the couple days prior that are still viable, all have chances to reach the eggs. When a litter is dual sired, it means that multiple studs were introduced during this fertile period and two or more studs’ sperm fertilized the dam’s different eggs and puppies will have different fathers.
Dogs are not like humans, but if a version of this metaphor helps, a litter of puppies are similar to when a woman has fraternal twins, triplets, etc, because she releases 2 or 3 eggs instead of 1. A litter of puppies does not come from one fertilized egg and sperm that are divided multiple times, creating the litter like when a woman has identical twins or triplets, coming from only one egg of hers.
It is important to note, there’s no way to predict how many eggs each stud’s sperm fertilizes. It’s like throwing genetic dice every time. You could get close to a 50/50 outcome, but you could also get a 0/100 outcome. The latter result can happen more commonly.
Here is an example of how the genetic dice fell in my Elsa’s spring 2021 litter of 15:
How does dual sire happen?
In the breeding world, dual siring can happen a couple different ways. The first is simply by accident. During the days when a dam is fertile, she is very motivated to get as fertilized as possible, and the boys in the surrounding areas become very motivated to get to her - they seem to get extra smart and quick during these days. In best breeding practice, breeders want to keep the female very securely separate from any unaltered males, but sometimes accidents happen and an unwanted stud finds the female.
Dual siring can be the intended outcome as well. When a breeder decides to use this strategy, there are a couple different ways this can be accomplished. They can do live breedings with the 2 different studs over the days when she is most fertile. They can perform artificial insemination and even combine the two collected sperm samples into one procedure over her fertile days. It is also important to note, whether through live breedings or AI, generally fewer litters are produced with 2 sires actually both being successful. Here is a blog that describes the results of a study done with different dual sire strategies.
When you dual sire, it is best to genetic test the litter and determine parentage. If you are producing an AKC litter, AKC requires you to use their genetic testing and for the results to be complete before the puppies are registered. If you are producing a non-AKC, and/or doodle litter, there are many genetic labs you can use. Embark will tell you the sire of puppies at no additional cost once you get the puppies’ embark results back.
Why dual sire?
There are a couple good reasons breeders may choose to dual sire. You can get more genetic diversity in your breeding program using this strategy. You can also help prove a younger male and give him the chance to become proven, but also cover with a more experienced stud and know you can still produce puppies.
Here at Daisy Mountain Doodles, we love this strategy and will use this often. We are able to do this because we embark all puppies produced by us anyway, so it is very easy to work with and ask embark for parentage.