Goat Genetics 101

I get a lot of questions about genetics. As in, "what will this buck / doe produce?" Sometimes, genetics are a guessing game, but the more you know, the easier it is to make purposeful decisions about breeding. without detailed dna tests, we don't know what genes are being carried by the goat, only what is expressed (seen). I'm going to explain the basics as best I can.

The first thing you need to know is the difference between dominant and recessive genes. I've met a lot of people who think that if a goat possesses a dominant gene, it means it will always produce that trait in its kids. This is NOT true. Dominant means that IF this gene is passed on to the young, it will be expressed. For example, let's talk about blue eyes, which is a common vanity trait in goats. I'm a sucker for those baby blues myself, but as a lot of breeders say, "You can't milk eyes."

In goats, blue eyes are a dominant gene (unlike humans, where it's recessive). Brown eyes (all shades of brown) are recessive. So each goat carries two genes for eye color, and they can pass on either one to their offspring. Let's call the blue eyed gene capital B and the brown eyed lowercase b. So the different eye color gene combinations they could have are:

BB- blue eyes expressed, can only pass on the blue eyed gene.

Bb- blue eyes expressed, can pass on B or b.

bb- brown eyes expressed, can pass on only b.

Each parent passes on ONE of their genes. So let's say you breed a bb to a Bb. One brown-eyed goat to one blue-eyed goat. The possible eye color gene combinations you have are:

Bb or bb. SO, each baby goat has about a 50/50 chance of having blue eyes. That doesn't mean half of the babies born will have blue eyes. I've seen litters all with blue eyes from this type of breeding, and I've seen litters all with brown eyes. There are no rules. You flip a coin 100 times, and in theory, you have a 50/50 chance of heads or tails, but in practice, you could get many more of one or the other.

Let's try two blue-eyed goats: Bb to Bb. The possible combinations are:

BB

Bb

Bb

bb

So for this breeding, you have a higher chance of getting blue eyes, but you can still get brown eyed goats from two blue eyed goats.

The BB is homozygous for blue eyes. That means that you'll get blue eyes no matter who you breed to, even a bb, since B is dominant. That does NOT mean that the offspring will also be homozygous. BB to bb creates all Bb, so the offspring can pass on brown eyes.

with a recessive gene, a goat can pass something on that is NOT expressed. The black coat color, for example, is recessive. You could breed a red goat to a buckskin goat, and ba-boom, you get a black goat and wonder where on earth that came from. Probably grandma.

But with a dominant gene, it has to be present in order to be passed on. Blue eyes, moonspots, and polled heads (no horns) are all dominant traits. So if someone tries to tell you that a brown-eyed goat can produce blue eyes because both his parents had blue eyes, your leg is being pulled.

Genetics are not just for flash, obviously, but those are the easiest traits to talk about. Breeding can be a lot of guesswork, but it's encouraging. Say you have a doe with excellent body capacity, nice width and depth, but less than ideal teats or udder attachments. You don't need to throw her away if you like her. You can breed her to a buck whose dam excelled in teats and udder attachments, and you can improve on your doe. Sometimes it's trial and error. I have a gorgeous buck with a nice topline and width, but if I breed him to does with already widely spaced teats, we end up with what my husband affectionately calls "derp tits". If I breed him to a doe with a narrow udder, he fills out the daughter perfectly. He has a nice, level rump, but it doesn't generally improve on a doe with a steep rump. That could be because maybe his sire had a steep rump (I don't know a lot about his sire) so those genes are hiding in there and can't wait to make friends with your steep-rumped doe. But if a doe is already relatively level, she's safe to breed with him because the kid will look like both of them. That's why it's important to consider both the sire and dam of any animal you are purchasing. Nothing wrong with the occasional derp tits, but it's a good idea to know what's behind them. I have traits that I tolerate more than others. Others have different things they look for. But I don't like to breed willy nilly.

This is another case of "breed what you like". Don't let anyone shame you for appreciating blue eyes! But make sure you're looking at other traits as well.