Supernumerary Teats

Why Breed Them Out?

Multiple teats on San Clemente Island doeThe breed standard created by the International Dairy Goat Registry in 2002 states that supernumerary teats on San Clemente Island goats constitute faults (of varying degrees). Such teats are prevalent with this breed, and were common on San Clemente Island. They do not make a goat unsound. San Clemente Island goats not only exhibit supernumerary teats, but some may possibly have more than two cisterns per udder. We are eager to find the results as more people report on their findings.

In the meantime, the breed standard as put forth by the IDGR shows itself to be contrary to the preservation of genetic diversity of San Clemente Island goats, which then puts the breed at a higher risk of extinction. The San Clemente Island Goat Association focuses on preserving the genetic diversity of purebred San Clemente Island goats. We're trying to save a genepool that was not shaped by industrialized farming practices: we don't need to hone them into show-goats, we need to salvage every hardy, sound goat left, even if it may look 'different' from a 21st-century dairy show-goat.

Teats on the Island
Dr. Phyllis H. Larsen was present on San Clemente Island in 1980. She studied the goat population and their diseases. Her focus was preventative veterinary medicine. Larsen studied 163 does, and documented that "many" of them had supernumerary teats. In a recent communication with Larsen, she said that she believes about 75% of the does and bucks had supernumerary teats. For a peek at a brief tabulated summary of her findings on San Clemente Island, you may wish to view a one-page tabulation summary by Dr. Phyllis H. Larsen. Needless to say, her paper goes into greater and fascinating detail, but is not published in entirety on this site.
Dawn Seward examined 105 does on San Clemente Island between June 1989 and April 1991. She worked under Dr. Bruce Coblentz and was studying the effectiveness of the Judas goat program. Her focus was in Wildlife Science. Seward did not document the presence or absence of supernumerary teats, but stated in recent communication that although she came across one case of mastitis and one deformed teat, she did not see any supernumerary teats, and believes that she would have noticed if they had been present.

The reason for the discrepancy in accounts of the presence of supernumerary teats in the larger sampling in 1980 and the smaller sampling in 1990 is unknown. Owners of mainland goats today indicate that supernumerary teats on San Clemente Island goats are extremely prevalent, but one owner states that she has goats showing single pairs of teats.

Effects of the Current Standard
There are an abundance of registries that will register your goat, but the International Dairy Goat Registry is effectively the only registry that has a history of registering San Clemente Island goats. Many purebred San Clemente Island goats are not registered for various reasons. The IDGR keeps accurate records, so if you need this service, they're there for you.

You will need to abide by the IDGR breed standard if you would like your goat to be registered by the IDGR. Many purebred San Clemente Island goats do not meet this breed standard. The breed standard counts supernumerary teats, which are the norm for San Clemente Island goats, to be serious faults. It is unclear why, but it is clear that the standard seeks to streamline the breed into one that mostly reflects mainland dairy breeds, not to conserve the avialable genes that we presently have.

The San Clemente Island Goat Association seeks to proactively promote responsible stewardship of San Clemente Island goats. Part of this involves increasing public awareness of the breed. As the 4-H has many members who are highly involved in the careful breeding and showing of livestock on both local and national levels, we would like to invite their participation in helping save San Clemente Island goats from extinction. However, because the breed standard put forth by the IDGR faults traits that are natural to this breed, the current standard strongly reduces the ability of 4-H members to successfully bring San Clemente Island goats into the show ring, and therefore discourages 4-H members from becoming involved in breed stewardship. Youth education and participation are important, and we would like to facilitate their involvement as they help us achieve our goals.

Please also visit the whitegoats page.

Let's see what the American Livestock Breeds Conservancy thinks about all this. . .

Feral Endangered Animals and Breed Standards

From Donald E. Bixby, DVM, American Livestock Breeds Conservancy:

Feral animals are domesticated animals that have escaped domesticated settings and have returned to a free-living state. Even though some feral animals do indeed approach the wild ancestral type of the species, the truly wild type and genetic strain are never fully regained by feral populations. Still feral animals are interesting due to their being returned to a selection environment where nature, rather than humans, decides which ones survive and reproduce.

Distinctive feral populations usually arise from a few founders and long isolated periods of survival under natural selection. Most feral populations, however, have broad genetic variation due to constant infusion of new recruits from a wide variety of genetic sources. These populations are unimportant as genetic resources or as targets of conservation. Only a very few feral populations qualify as genetically distinct breeds with limited variability. The San Clemente goat is one of those breeds and it is indeed fascinating for its adaptation and survival traits.

Conservation of genetically distinct feral livestock populations is problematic. Once these animals are removed from their original selection environment into a domesticated state, selection pressure changes dramatically. It is inevitable that conservation breeders want to establish a breed standard to identify and define the population as nearly an assumed underpinning by much of the breed community. Applying a breed standard to a formerly feral population such as San Clemente goats can be fraught with problems, since the new breed standard has little in common with the "standard" of nature.

Standards for the most established breeds are "prescriptive." In contrast, the best standards for formerly feral populations are "descriptive." These describe, rather than prescribe, what the animals actually are. This is subtly different from a prescriptive standard, but understanding this difference is essential if feral breeds are to be successfully conserved. Making a descriptive standard is more difficult than a prescriptive one, especially as most breeders are interested in some degree of uniformity and production superiority. The San Clemente standard must allow more variation than standards for established breeds. It is important to realize that feral populations such as the San Clemente goat were successful in their environment before a breed standard was derived for them. This is an essential detail if important variants are not to be lost for future generations.

The goal of any breed standard is to help breeders visualize characters and traits that should be included as typical of a breed. The standard guides observers (especially breeders and judges) as to what should be ideal for the breed, what is marginal for the breed, and what is outside of breed parameters. The level of specificity of a breed standard varies from breed to breed. For established breeds it is common to have a fairly narrow breed standard that is based on an ideal that may or may not have been achieved—or may not even be achievable! In many established breeds it is common for the standard to specifically penalize certain variants that may well be produced in the breed from time to time. This is especially true of color traits (red in Angus cattle, body spots in many horse breeds). Such exclusion can also be for physical traits such as a split scrotum in many goat and sheep breeds, or polledness or horns in many breeds of several species. Other breeds fault other traits considered by the association to be defects, such as supernumerary teats in goats. This is a huge issue with dairy goats, but a minor blip in meat or other goats. In the case of San Clemente goats, the incidence of supernumerary teats seems to be quite high. Since natural selection has not considered this a serious fault, it can logically be dismissed as a soundness fault in the breed standard.

Restrictive breed standards can have the unintended, and potentially dangerous side effect of narrowing genetic variation because certain variants are excluded from the breed. For numerous breeds with great genetic breadth this narrowing is probably of little or no significance. For rare breeds such as San Clemente goats whose population sizes are barely viable the standard must be a part of breed conservation strategy, which focuses on the larger issues of breed survival and less on the presence of incidental variation. This does not hold for fitness traits (lethal or debilitating conditions, for example) but certainly does hold true for more trivial cosmetic traits. ALBC encourages the change of the San Clemente breed standard to eliminate supernumerary teats as soundness fault.

Donald E. Bixby, DVM
Technical Programs Manager
American Livestock Breeds Conservancy
P.O. Box 477
Pittsboro. NC 27312;

To open a printable copy (pdf format) of the San Clemente Island Goat Breed Standard as written and published by the IDGR in January 2007, please select this text.

Types of Teats

Goats can have different types of teats:

Functional teat: a working teat with one orifice.
Multiple teats: more than one teat per half of the udder.
Fish teat: a single teat that flattens and splits near the end, and has two separate orifices on opposite sides of the teat.
Split teat: a single teat that splits into two separate teats with two separate orifices.
Double-orifaced teat: more than one orifice per teat.

It appears that the majority of San Clemente Island goats have multiple teats. Some teats are functional, some are not. Some are non-functional until you really work them, but on breeder says it's probably best to leave those alone. Another breeder believes that the milk on one side of her doe's udder is seperated into two cisterns, each with its own teat. . .

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San Clemente Island Goat Association