Estimated Breeding Values FAQ

EBV stands for estimated breeding value. If you are familiar with the cattle industry, they use EPDs. EPDs show the breeding value of an individual animal’s progeny whereas EBVs denote the value of the individual animal. An EBV helps a producer to use objective data to make culling and purchasing decisions, rather than subjective visual appraisals.

Each animal's performance is based on two things; it’s genetic potential and its environment. A quick example may suffice to explain. If I tell you Goat A weaned at 56 lbs and Goat B weaned at 65 lbs, which would you rather buy? Now, what if I told you, Goat A was a triplet and Goat B was a single? And what if I told you, Goat A was raised on pasture and weeds, and Goat B was creep fed and had unlimited access to high quality alfalfa hay? Now what if I told you Goat A was born and raised in a cold harsh climate and Goat B was in a much milder climate? As you can see through this exercise, raw data is definitely better than nothing, but it only tells part of the story. This is where EBVs have the ability to add so much value.

Yes, is the short answer. I asked the National Sheep Improvement Program director this once, and this was his response:

“The EBV analysis accounts for [different management practices] like creep feeding and other environmental differences. That is really the power of EBVs because they eliminate those sources of environmental variation and truly represent the just the genetic potential of that animal. Yes, creep feeding can increase the growth rates of young goat kids, however, it cannot increase their genetic potential for weight gain. Another way to look at it is that by creep feeding, you are allowing those kids to express their full genetic potential by providing them with all the nutrients they need through the creep feed. For producers who do not creep feed for whatever reason, those kids may not be performing to their full genetic potential. That is not a bad thing, as everyone needs to match genetic potential with the environment/nutrient level you can adequately [and economically] supply to your animals. Also, creep feeding doesn’t necessarily mean animals will perform better. If they have a poor genetic potential for growth, it doesn’t matter how well you feed them, that poor genetic potential will limit their performance.

There are oftentimes a disconnect between what commercial producers want and what breeding stock producers are providing. This gets a little tricky because oftentimes a commercial producer will say they want an animal that is grass fed or with limited grain inputs but when they go to buy breeding stock, they wind up choosing the heavy grain fed animal that looks nice and healthy over the greener, grass fed only buck.”

EBVs help to put data in the decision making process, rather than again, just visual appraisals. In our opinion this data backed decision making is critical. For this reason, as outlined in our production practices article, we cannot economically creep feed animals at this point in time. As such, we want our livestock to be high performers on primarily grass pastures, as that is how we can most economically raise our commercial herd animals. As such, we raise our breeding stock the same way.

Until you share a genetic linkage with another herd, the EBV is calculated solely off your own herd in their own contemporary group (more on this later). It based around the average performance of that kid crop, in short, unless you have a genetic linkage with another herd. Once you can establish that link, then the accuracy and ability to compare across herds and breeders increases. You use genetics from my herd, I use genetics from your herd, and if we both submit our data to receive EBVs, then that algorithm can take into account and REMOVE the environmental differences and compare truly genetic potential of the animals.

I think the answer to this one is obvious, but still worth answering. No. You can have an amazingly fast growing buck, but if he has weak pasterns, a huge cleft in his scrotum, and a hunchback you probably shouldn’t buy him. Furthermore, there are breed standards and preferences to take into account, such as pigment, hair color, etc. So there is still very much a visual aspect to making your purchasing decision.

There are a couple things to remember. You should look as much at the spread sometimes as the individual number. One great real life example was twin doelings we had. Coal's BWT result was -0.13, and a WWT of 0.04. Her sister Ash was BW of -0.22 and a WWT of 0.00. If you look solely at the WWT number, you would think Coal is the better animal. However, looking at the actual numbers, Ash weighed less at birth and more at weaning. So how come she isn't the better animal? Well, she is. You just have to look at the spread. Coal's spread is 0.17. Ash's is 0.22. So seeing the whole picture now, Ash is the better choice. Lower birth weight, with a net better gain.

No. EBVs are constantly changing each time you add more data. Because each data point is correlated with other measures (e.g. higher birth weight is highly correclated to higher wean weight), each time you add data, it changes the EBV results. Also, as more and more gentic linkages are created, this will also adjust EBV results, as the algorithim is more accurately able to remove environmental factors from the results.

A scale and some animals is about all you need. That being said, to get the best accuracy, and the most value out of your EBVs it goes back to statistics. The larger the sample size, the better and more accurate the results. So the more animals you have the better. Also, ideally you need a minimum of two different bucks, to separate the genetic value from the environment better. They say ideally, there would be 15 does to each buck, and a minimum of two bucks. Once you have that base, it is a matter of collecting data.

A contemporary group is simply a group of animals that have all been born and raised the same way in the same general time frame. This again goes back to the idea behind EBVs, to remove the effects of their environment and isolate performance based upon genetic potential. According to NSIP, a contemporary group must have no more than 42 days difference in age. This is to assure the animals have been raised in a similar manner, with similar environmental conditions, and it happens to line up with two heat cycles for the animals.

A good contemporary group is ideally a minimum of 15 does per buck, bred and kids born within 42 days, and two bucks (with their associated does) per contemporary group. This is obviously the ideal, as outlined by NSIP. It doesn't mean you can't do less or modify as needed and still get EBVs.

This is one of the coolest parts to me about EBVs in goats, is that there is so much you can measure. There are carcass traits that can be measured, such as birth weight, wean weight, post wean weight, yearling weight, etc. There are fertility measurements for both male and females; scrotal circumference (bigger tends to mean higher fertility) and quantity of kids per kidding for females. You can measure mothering ability with an EBV that calculates the mothers ability to wean live kids. Also, it can measure the mothers ability to produce large volumes of milk for the kids, through the additional pounds gained by the kids. There are EBVs that measure parasite resistance through egg counts. There are even EBVs that can measure fat depth and loin eye muscle size to hone in even more on producing the best yielding meat animals.

Of all the goat breeds in the USA right now, I strongly feel that the Savanna industry has the greatest opportunity in front of it to become the leader in data backed performance. The main reason is that cross herd EBVs are more accurate and more powerful the more genetic linkages that exist between herds. Right now, the youngest animals are probably only a few generations away from the original animals that were imported. Pedigree International said in 2020 there were only 3,500 animals that were 10 years old or younger registered. Many of those tie back to the same sires and dams in some form or another. Thus, genetic potential could actually relatively quickly be determined with high levels of accuracy.

Embryo Transfers (ET) and Artificial Insemination (AI) can be very valuable tools to regenerate old bloodlines and broaden the genetic pool, as well as allow individual producers access to high powered bucks without the cost of the buck themselves. But how does ET and AI affect EBVs?

All ET animals are automatically divided into a separate contemporary group. Results are limited, as all you can measure is the kid’s personal performance. In other words, it doesn’t give you any data on the dam, her performance in rearing, weaning, birthing, etc. Also, it would be best to keep these animals for a much longer period (like 9 months to a year), to make sure you pull out the effect on performance of the recip. For example, if one recip is a dairy goat and one is a scraggly crossbreed goat, a kid might perform really well under a dairy goat with unlimited supply essentially to milk, while the other may struggle, but not because of its own genetic flaws. Time helps even some of these results out. Again, ET are an incredible tool and technology available to the industry, but because of the difficulties of getting accurate data on them, we typically avoid ET within our own herd.

AI is quite different. Where you are using the bucks semen (their only contribution is genetics and rearing) and the doe is carrying, birthing, and rearing the kids, it has no effect upon the accuracies, value, and available data that can be gathered from the animals.

Trick question. Yes and no. Can they be helpful? Yes. Should they be the only method of making breeding and culling decisions? No, especially early on. Value of EBVs will increase over time as you are able to create a large sample size, and as you are able to compare the same genetics over multiple seasons, environmental factors, and so forth. So don't give up after, one, two, or even three years. It's going to take time and effort to get there. Remember, cattle have been doing this for 30+ years to get to where they are today.

This one is not straightforward. The challenge is the system cannot currently differentiate between fullblood and cross-bred. Thus, if you combined all in one submission, or even have animals that cross over between the two, it could decrease the values on your fullblood stock, because the commercial animals may have the benefit of hybrid vigor that the fullblood obviously do not. Thus, our suggestion is that if you desire to run EBV's on your non-fullblood breeding stock, that is great, go for it, but don't have animals that cross over between the two. And if you do have animals that cross over between the two, use a different ID number so the system will not correlate them to each other.