Polled livestock are

livestock Livestock are the domesticated animals raised in an agricultural setting to provide labor and produce diversified products for consumption such as meat, eggs, milk, fur, leather, and wool. The term is sometimes used to refer solely to ani ...

without horns in species which are normally horned. The term refers to both

breed A breed is a specific group of domestic animals having homogeneous appearance (phenotype), homogeneous behavior, and/or other characteristics that distinguish it from other organisms of the same species. In literature, there exist several slig ...

s and strains that are naturally polled through

selective breeding Selective breeding (also called artificial selection) is the process by which humans use animal breeding and plant breeding to selectively develop particular phenotypic traits (characteristics) by choosing which typically animal or plant ...

and also to naturally horned animals that have been disbudded. Natural polling occurs in

cattle Cattle (''Bos taurus'') are large, domesticated, cloven-hooved, herbivores. They are a prominent modern member of the subfamily Bovinae and the most widespread species of the genus '' Bos''. Adult females are referred to as cows and adult ...

yak The domestic yak (''Bos grunniens''), also known as the Tartary ox, grunting ox or hairy cattle, is a species of long-haired domesticated cattle found throughout the Himalayan region of the Indian subcontinent, the Tibetan Plateau, Kachin S ...

water buffalo The water buffalo (''Bubalus bubalis''), also called the domestic water buffalo or Asian water buffalo, is a large bovid originating in the Indian subcontinent and Southeast Asia. Today, it is also found in Europe, Australia, North America, So ...

, and

goats The goat or domestic goat (''Capra hircus'') is a domesticated species of goat-antelope typically kept as livestock. It was domesticated from the wild goat (''C. aegagrus'') of Southwest Asia and Eastern Europe. The goat is a member of th ...

, and in these animals it affects both sexes equally; in

sheep Sheep or domestic sheep (''Ovis aries'') are domesticated, ruminant mammals typically kept as livestock. Although the term ''sheep'' can apply to other species in the genus '' Ovis'', in everyday usage it almost always refers to domesticate ...

, by contrast, both sexes may be horned, both polled, or only the females polled. The history of breeding polled livestock starts about 6000 years BC.

Terminology

The archaic term or is sometimes used to refer to hornless livestock (especially cattle) in folk songs, folk tales, and

poetry Poetry (derived from the Greek '' poiesis'', "making"), also called verse, is a form of literature that uses aesthetic and often rhythmic qualities of language − such as phonaesthetics, sound symbolism, and metre − to evoke meani ...

, and in the name of the polled Irish Moiled cattle breed. "Muley" derives from Irish and

Scottish Gaelic Scottish Gaelic ( gd, Gàidhlig ), also known as Scots Gaelic and Gaelic, is a Goidelic language (in the Celtic branch of the Indo-European language family) native to the Gaels of Scotland. As a Goidelic language, Scottish Gaelic, as well as ...

''maol'', and

Welsh Welsh may refer to: Related to Wales * Welsh, referring or related to Wales * Welsh language, a Brittonic Celtic language spoken in Wales * Welsh people People * Welsh (surname) * Sometimes used as a synonym for the ancient Britons (Celtic peopl ...

''moel''.

Genetics

, the polled

allele An allele (, ; ; modern formation from Greek ἄλλος ''állos'', "other") is a variation of the same sequence of nucleotides at the same place on a long DNA molecule, as described in leading textbooks on genetics and evolution. ::"The chrom ...

is genetically dominant to that for horns. The polled trait is far more common in beef breeds than in dairy breeds.

CRISPR CRISPR () (an acronym for clustered regularly interspaced short palindromic repeats) is a family of DNA sequences found in the genomes of prokaryotic organisms such as bacteria and archaea. These sequences are derived from DNA fragments of bact ...

technology is being developed to create polled versions of dairy breeds. In

, the

for horns in both sexes is partially dominant to the allele for being polled in both sexes, and both of these are dominant to that for polling in the female only. The development of true breeding polled

goat The goat or domestic goat (''Capra hircus'') is a domesticated species of goat-antelope typically kept as livestock. It was domesticated from the wild goat (''C. aegagrus'') of Southwest Asia and Eastern Europe. The goat is a member of the a ...

s is discouraged as the polled locus is strongly associated with Polled Intersex Syndrome (PIS). Naturally polled

also have genital defects.

Scurs

Naturally polled animals may have scurs – small, loose, horny growths in the skin where their horns would be. In cattle, this trait has been traced to a separate

gene In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a b ...

(on a different

chromosome A chromosome is a long DNA molecule with part or all of the genetic material of an organism. In most chromosomes the very long thin DNA fibers are coated with packaging proteins; in eukaryotic cells the most important of these proteins ar ...

) from that responsible for polling. However, the presence of the allele for scurs in cattle can only be seen in a polled animal, because horns replace the scurs in horned animals. Similar scurs may also occur where disbudding of a naturally horned animal has been incomplete.

Reasons for polling

Polled livestock are preferred by many

farmer A farmer is a person engaged in agriculture, raising living organisms for food or raw materials. The term usually applies to people who do some combination of raising field crops, orchards, vineyards, poultry, or other livestock. A farmer m ...

s for a variety of reasons, the foremost being that horns can pose a physical danger to humans, other livestock and equipment. Horns may also interfere with equipment used with livestock (such as a cattle crush), or they may become damaged during handling. In other circumstances, horned animals may be preferred, for example, to help the animal defend itself against

predator Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill t ...

s, to allow the attachment of head

yoke A yoke is a wooden beam sometimes used between a pair of oxen or other animals to enable them to pull together on a load when working in pairs, as oxen usually do; some yokes are fitted to individual animals. There are several types of yoke, u ...

s to draught oxen, to provide a hand-hold on smaller animals such as sheep, or for aesthetic reasons – in some breeds the retention of horns is required for showing. In the US no show requires horns to be left on. Most shows require at a minimum blunting of the horns to a minimum diameter of inch. Boer Goat Shows allow disbudded goats. Dairy breeds of goats are required to be naturally hornless or disbudded. 4H and FFA show goats must be hornless or blunted so as not to be sharp and dangerous.

Development of polled strains

Polled strains have been developed of many cattle breeds which were originally horned. This has usually been done by crossing with naturally polled breeds, most commonly Angus and

Galloway Galloway ( ; sco, Gallowa; la, Gallovidia) is a region in southwestern Scotland comprising the historic counties of Wigtownshire and Kirkcudbrightshire. It is administered as part of the council area of Dumfries and Galloway. A native or ...

cattle. For example, polled Jersey cattle originated in

Ohio Ohio () is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. Of the List of states and territories of the United States, fifty U.S. states, it is the List of U.S. states and territories by area, 34th-l ...

sometime prior to 1895. Two strains were developed, the first to appear being founded by crosses of registered Jersey bulls (the standard) on common muley (hornless) cows. These were graded up by the continued use of purebred Jersey sires, selection being made of the polled offspring of each generation, the horned progeny being discarded. Thus originated what was later known as the single-standard strain. As in the case of the Polled Shorthorns and Polled Herefords, the development of the single-standard strain was soon followed by the appearance of a double-standard strain, founded by a few naturally hornless

sports Sport pertains to any form of competitive physical activity or game that aims to use, maintain, or improve physical ability and skills while providing enjoyment to participants and, in some cases, entertainment to spectators. Sports can, ...

that were discovered in registered herds of horned Jersey cattle. These standards were bred among themselves or crossed with registered horned Jerseys, followed by selection for the polled head, and the strain was developed in this way.

References