New Breeders

Prospective New Member/Breeder Information

There are many questions you will have as you think about becoming a new GOS pig owner and breeder. This will be a brief overview of what to expect. Check with the FAQ page to see if there is an answer for any questions you still have after reading this introduction. You can also visit our blog for the latest news. Our website has all sorts of useful information, feel free to take a look through all of the menu items and pages. One important stop is the Code of Ethics we expect our members to follow, these should help give you some peace of mind when you buy your stock. If you want to know more of the history of the breed then click here or use the New Breeders/About the Breed menu option above.

If you want to join our organization you can do so by clicking here or selecting the menu option New Breeders/Become a Member above.


Thinking about buying GOS breeding stock?

The Gloucestershire Old Spots Pig is a truly remarkable animal. The breed, as a general rule, has a very sane, calm temperament. They are excellent mothers, and do very well in all types of climate situations. Take the time to read all you can about Old Spots. Learn about the different family lines here in the US, and how the GOSPBU can assist you in finding compatible breeding animals. You can look in the classified area of the GOSPBU website, call breeders that are listed on our breeder list, or even use a search engine to find stock.

There are basically four family lines of GOS pigs in the US. Someday, this will change, as more genetics are brought in from the UK. Family lines are designated by color; which is each subdivided by name for example: “Green Group Princess”. All pigs are white with black spots, but have a color as their Group distinction. The color of the Dam, or sow, will determine the color group of all of her offspring; they are the same as the sow. When a Green group sow has a litter, all of her piglets are said to be of the Green group. The three other Color Groups are the Red, Blue and Black. This naming system is the result of a unique breeding regiment known as the color wheel. It was developed in the UK by George Styles, a GOS breeder that held the largest herd of GOS in the world. He developed this system to prevent inbreeding in boars of his herd. This system is also referred to as cyclic breeding.

The color wheel is simple to use, but not practical unless you have an accessible herd that is extremely large, and supports multiple animals in the color group with different family subdivisions. Most farms in the US and the UK only use this system if it is practical. In most instances the color wheel cannot be utilized without a significant likelihood of inbreeding. It is therefore recommended to use the color wheel only as a tool, and to also use the CI calculator on the GOSPBU website. The CI or coefficient of inbreeding, tells how closely related two pigs are. The lower the number, the less related the pigs are. It is a general rule to keep the number as low as possible, and try to produce litters that are 5% or less of a CI. Coefficients significantly higher than this are not generally recommended. Some people that have been pig breeders for many years, may use a practice known as line breeding. This has the potential to bolster certain traits that are targeted, but can also fail, resulting in poor results in offspring.

If you are considering buying multiple GOS pigs, please consider buying a boar and gilts that are not related too closely. Often a breeder will produce piglets from their farm where all the sows are sisters. This creates a gene pool issue by flooding the market with almost identical genetics. Please read the Definitions and Recommendations for Breeding section.

Make sure you consider driving versus shipping costs into the price of your pigs. Air shipping might be possible with certain breeders, but not offered by everyone. Trucking is another consideration. Weather conditions are important in determining shipping feasibility. Too hot or too cold may affect transportation requirements depending on the carrier. Many breeders in our GOSPBU network work together to help share costs of transportation when possible.

Find out if the breeder you are buying pigs from has wormed your pigs. It is a common request by the buyer, to have the seller worm pigs before transport to their new farm. This is a common practice, which could help prevent the spread of parasites from farm to farm. You will find articles on farm bio-security in our news letter.

The stress of shipping can cause loose stools in pigs. Try to get a few pounds of feed from the breeder you acquired your pig from. This will help reduce stress on your pig. A word of caution. Ask the breeder to hold back feed for at least 12 hours before shipping your pigs. This will reduce the likelihood that your pigs will soil their crate, or stink up the cargo area of a plane, the back of a truck, or the front seat of your new minivan.


My Pigs are Home

After you purchase your breeding stock, you must transfer the registrations so that you are listed as the new owner. Expect it to take a few weeks to receive your registration papers. The papers will list the generational pedigree, and have the registration number of your pig. The pedigree will be printed on a paper that represents the color group of your pig. For example, red group pigs will have their pedigree on a red certificate. The registration number of each pig will be recorded into the database of the GOSPBU. Someday, when your pigs have a litter, you will need the number of the dam and sire to register the litter of piglets. It will be your responsibility as a breeder to only sell and transfer pigs that are of the breed standard. Pigs that do not meet the standard should not be registered or bred. The gene pool is very shallow for this breed; it is our duty to follow the code of ethics.

When you bring your pigs home, you have to settle them in. GOS pigs are easy to train to electric fencing. If they are trained to fencing already, then you can pen them in a contained area for a few days to let them get used to the sounds and smells of your farm. They will need to feel safe, before you turn them loose. After a few days of getting to know you, you can let them venture out. They will invariably find the edge of their pen, and walk the entire perimeter. Make sure there is a strand of electric at or near the high nose and low nose positions of you pigs. A few tests of the fencing will convince them to stay in their pen. They need to feel safe inside their fencing, and quite afraid of anything on the other side of the fence. Electric fencing is a psychological barrier, and needs to be properly installed and maintained to make sure your pigs stay in.

Moving pigs around the farm is a common chore. Rotational grazing is common with GOS pigs, and can be difficult with certain pigs. Just remember to be fair, and calm. Do not chase a pig, they will always outrun you, and sometimes out think you! If a pig is out, hold a bucket of feed, and get him to follow you into the pen he belongs in. When all else fails, use your head. The use of a hog panel, a pig box, or bucket over the pigs head, can all help get the pig to where it belongs.


Definitions and Recommendations for Breeding


Line-breeding is the mating together of related animals. That is, the two animals mated have ancestors that are the same. The strength of line-breeding is that it makes animals more uniform, so that they are more predictable as to looks and performance. Too much of it, though, can lead to depression of growth, immune function, and reproductive traits.


Inbreeding is also the mating together of related animals.

The question then becomes, what is the difference between line-breeding and inbreeding? In most cases, inbreeding can be considered to be the mating together of first degree relatives, such as parent to offspring, or brother to sister. Line-breeding is more distant than this. In general, inbreeding comes with more risk of depression than does line-breeding, but there is no absolutely magical threshold.


Line-crossing is a mating between two unrelated lines of a single breed. The results counteract the depression of inbreeding or line-breeding, but likewise produce animals that are a bit more difficult to predict as to productive ability.


Crossbreeding is the mating of animals of two different breeds.

Coefficient of inbreeding

The Coefficient of Inbreeding is a useful figure. It is the probability that any two genes in an animal are identical because they came from the same ancestor. So, automatically, all line-crossed animals have a coefficient of inbreeding of zero, because the ancestors are all different. In contrast, the coefficient of a close inbred animal may be 25% or greater. Parent to offspring matings produce offspring with a coefficient of inbreeding of 25%. The higher the coefficient, the more likely depression will set in. Safe levels are usually around the 5% range, but individual animals and families vary in their resistance to inbreeding depression so that absolute figures are difficult to pin down.

D. Phillip Sponenberg, DVM, PhD
Professor, Pathology and Genetics
205 Duck Pond Drive
Virginia-Maryland Regional College of Veterinary Medicine
Virginia Tech
Blacksburg, VA  24061