Problems With the Polled Goat
Reading Time: 4 minutes
The genetics in polling can be complicated. Understanding the potential problems with a polled goat can save time, money, and even heartache.
THE SUBJECT OF HORNED GOATS CAN BE a hot one for breeders. Those who run dairy operations, show goats, or have safety concerns often value disbudded goats. Others prioritize the natural functions of horns and the hazards linked to removing them. Full disclosure: All heritage-breed goats and sheep on my homestead are their natural selves, whether horned, polled, or somewhere in-between.
What does polled mean in goats?
For those unfamiliar with goat and sheep horn anatomy, polled sheep and goats are naturally born without the genetic markers to grow horns. This trait is common among ruminants and is bred for in many cattle and sheep breeds. If people want goats without horns, why not just breed for a polled goat?
The genetics in polling can be complicated and differ between cattle, sheep, and goats. In cattle and sheep, breeding for animals without horns has shown no signs of causing other health issues. However, in goats without horns, several decades of studies have shown a strong connection between breeding for the polled trait and intersex syndrome. Intersex condition — formerly hermaphroditism or pseudohermaphrodism— results in sterile animals and isn’t always easily diagnosed.
Hornless goats with this condition are so widely recognized it’s become known as Polled Intersex Syndrome (PIS). The condition is identified primarily in genetically female dairy goats.
Genetic connection between a polled goat and PIS.
The genetic connection between polled goats and PIS is definitive, but it’s still important to note that not all polled goats carry this gene. Breeds that most commonly show PIS need two genes to cause the intersex condition to appear, but only one is required for a goat to be polled. This would mean the polled gene is dominant and the intersex gene is recessive. Specialized breeds with heavy line breeding history, such as Saanen, Alpine, and Toggenburg goats, show significant prevalence.
Regional differences occur even within the same breed because breeders tend to choose dams and sires within their areas. One study reported that the intersex condition in Saanens was between 2% and 15% in dairy goats from the United States while in only 3.82 to 10.63% of tested Chinese dairy goats because of how the Chinese breeders carry out their breeding plans and the lines they work with.
The condition is inconsistent in goats without horns across all breeds. Angora and Nubian goats appear to have different genetic requirements for polling and intersex conditions. Unlike other Oberhasli lines, the Bernese strain is naturally polled while showing no significant signs of intersex conditions.
Symptoms of PIS
Symptoms of intersex conditions in females may vary. Does with PIS may present with normal genitalia but fail to kid. In one study, several of the animals examined appeared female but also exhibited testes. testes. This can result in a loss of resources if breeders can’t identify and cull these goats early on.
In some cases, a doe may have prominent male genitalia. In other cases, detection may require a vet inspection or genetic testing. Though female, affected animals may sometimes present as male, including size, smell, and mounting behavior. In these cases, a genetic test is needed to show that they are, in fact, female. Keeping records to avoid breeding parents with polled genes is the only way to prevent PIS in high-risk breeds.
To read more about hermaphrodism and the genetic link to polled goats, and to see photographic examples, check out: Hermaphroditism and Polled Goats.
With freemartins, which differs from intersex condition, females receive masculinizing hormones from sharing placentas with male twins. Read about genetic tests do identify freemartins at G6-S Testing Labs: Goat Genetic Tests 101.
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SHERRI TALBOT is the co-owner and operator of Saffron and Honey Homestead in Windsor, Maine. She raises endangered, heritage breed livestock and hopes someday to make education and writing on conservation breeding her full-time job. Details can be found at SaffronandHoneyHomestead.com or on Facebook at facebook.com/SaffronandHoneyHomestead.
SOURCES:
- https://onlinelibrary.wiley.com/doi/abs/10.1111/ age.12918
- R.O. Ramadan & A.M. El Hassan (1988) Intersexuality in goats, New Zealand Veterinary Journal, 36:3, 120-124, DOI: 10.1080/00480169 1988.35505
- Smith, Mary C & Sherman, David M. (2023) Goat Medicine, 3rd ed. Hoboken, NJ. John Wiley & Sons, Inc. ISBN-10: 1119382734
- Yang S, Han H, Li J, Zhang Y, Zhao J, Wei H, Hasi T, Lv H, Zhao X, Quan K. 2021 Jan; Transcriptomic analysis of gene expression in normal goat ovary and intersex goat gonad. Reprod Domest Anim. 56(1):12- 25. doi: 10.1111/rda 13844
- Zhang S, Cao X, Li Y, Wang K, Yuan M, Lan X. 2020 Dec; Detection of polled intersex syndrome (PIS) and its effect on phenotypic traits in goats. Anim Biotechnol. 31(6):561-565. doi: 10.1080/10495398.2019 1625782
Originally published in the Spring 2024 issue of Goat Journal and regularly vetted for accuracy.
