A wether is a castrated male sheep or goat. They lack the breeding drive of rams (male sheep) and bucks (male goats), and thus are less aggressive and are generally easier to manage for farmers and ranchers. Only a small percentage of males are needed for breeding duty; many of the rest are thus castrated for ease of control. Wethers have been used as pets, guides, pack animals, and flock leaders. When these are not needed, they are raised for their meat.

The word wether originates before the 12th century, and was probably spelled weþer or wæþer in Old English with a thorn character (þ, pronounced th). In Middle English, a wether could refer to any male sheep (both castrated and uncastrated), but its meaning gradually narrowed to just castrated sheep and goats.^[1]

The related term 'bellwether' originated somewhat later, in the 15th century. Middle English's belle-wether referred to the practice of placing a bell around the neck of the lead wether. A shepherd could then note the movements of the animals by hearing the bell, even when the flock was not in sight.^[2] This could substitute for the presence of a guard dog watching a flock.^[3]

The equivalent for castrated male cattle is a steer, although large ruminants like cattle are generally raised and treated differently than small ruminants like sheep and goats. An incompletely or 'late' castrated ram or buck is sometimes called a "stag", not to be confused with a male deer.^[4]

In general, there is not a great demand for male sheep and goats, as a single male can breed with many female ewes and does. One guide writes that "not one in a hundred [males] can be kept, profitably, as a herd sire."^[6]

The most prominent use of raising males is for lamb and mutton meat, and goat meat.^[6] Rams have more muscle and less fat than ewes and wethers, and are sometimes believed to have a more "intense" flavor, making ram meat worth slightly less than wether meat.^[7] While long-lived rams can become heavier than long-lived wethers, wethers can actually be heavier when slaughtered at younger ages; one study suggested around 10 pounds more market weight per head for wethers than rams.^[8] If a lamb or goat is intended to be slaughtered very young (e.g. around 5-6 months age), there is no need for castration. However, ones raised longer (e.g. to an age of 6-12 months) will generally be castrated. Slaughterhouses prefer handling castrated males and will usually pay more for them. And for goats, this avoids a "buck odor" to the goat meat.^[9][10]

When raising sheep for wool, wethers are commonly used. This is because rams produce more wool than ewes, but will fight each other and reduce their lifespan if left intact but not carefully managed.^[11] Sometimes entire wool flocks are wethers. A full wether flock makes the most sense in eras and locations with high wool prices, such as medieval England or the Carolingian Empire, and is reported as far back as the Bronze Age Minoan civilization.^[12] Even when wool prices are depressed, this is still sometimes done in areas with dry climates such as modern Australia.^[12][11]

Especially in pre-modern eras, sheep wethers could be used to guide flocks, as "bellwethers" above (regardless of if an actual bell was used). Aristotle's book History of Animals reports that in the 4th century BCE, a wether would be trained in every flock to lead it and answer to its name. Wethers also tended to live longer, spared from the lambing and milking duties of ewes, or the in-fighting of rams; Aristotle reports wethers living fifteen years if well-kept, compared to just ten for ewes.^[13] Goat wethers can also be used to lead sheep flocks.^[14]

A use for wethers is as pack goats, beasts of burden used to transport in tough terrain. Goats remain a viable option for moving cargo, especially in hilly and untamed regions. Wethers are the most standard choice for this role, as they are stronger and larger than does, yet more pliable than bucks. Similarly, wethers can work for weed control, where goats are used to graze in regions difficult for other ruminants to reach and eat forage others won't touch.^[15]

When keeping goats as pets, wethers are generally preferred due to the ease in raising them.^[6] Intact male bucks are notoriously smelly to humans during the rut, and will urinate on nearby objects and themselves. Wethers avoid these issues.^[16]

There are two different common ways to create a wether. Surgical castration simply uses a scalpel or emasculator to cut out the testicles. The other style is elastration, where tight rubber bands are placed over the scrotum and above the testes, until eventually the testicles atrophy and fall off weeks later.^[9]

Castration can increase the risk of tetanus due to creating a wound for Clostridium tetani to enter.^[17][18] Tetanus vaccines are recommended. Similarly, parasites such as screwworms are a greater risk immediately after castration as well.^[17] Castrated sheep run the risk of flystrike and maggots getting in on the wound, especially in warm weather. Fly repellant or simply avoiding warm weather months for the procedure can mitigate the issue.^[19]

If a ram is castrated at less than 4 weeks of age, this can increase the risk of urinary calculi ("water belly", urolithiasis), as the urethra does not grow to its intended size. This leaves the wether more vulnerable if stones form in the urinary tract, e.g. due to a diet overly high in calcium or phosphates.^[18][20]

Older practice would sometimes perform both the castration process and docking (tail-shortening) of a lamb at the same time, although given that docking is usually done to lambs only a week or two old, this contrasts with later advice to wait somewhat longer before castrating.^[8]

Teaser rams can be used to better control the estrus cycle in female sheep. They are usually not wethers, but are rather fully intact males who've been vasectomized. Wethers can still be used for their purpose, albeit generally after treating them with a sex hormone injection.^[21] Releasing a 'teaser ram' among the flock three weeks before planned breeding can speed up the cycle and synchronize upcoming planned pregnancies. This can ensure all or most of the females are in estrus (heat) by the time the real rams are released.^[22][23]

Among goats, teaser bucks are similarly usually intact males who've been vasectomized. They retain the same sex drive as males intended for breeding, but can't actually get any does pregnant. They are used in speeding up and controlling the estrus cycle, as does will enter estrus more quickly in the presence of eager males. They are also be used to detect females who didn't successfully get pregnant, as they'll continue trying to mate with them.^[24] Similar to sheep, giving goat wethers an injection of sex hormones such as estrogen and testosterone activates futile mating behaviors that allow them to be used in the role of teaser buck.^[24] While castration removes the breeding drive, goat wethers will still occasionally mount females, even when not hormone-treated.^[25]

• Abbott, Kym (2018). The Practice of Sheep Veterinary Medicine (PDF). University of Adelaide Press.
• Belanger, Jerry; Bredesen, Sara Thomson (2018). Storey's Guide to Raising Dairy Goats (5th ed.). Storey Publishing. ISBN 9781612129334.
• Ryder, Michael Lawson (2007) [1983]. Sheep & Man. Duckworth. ISBN 978-0-7156-3647-3.
• Simmons, Paula; Ekarius, Carol (2009). Storey's Guide to Raising Sheep (4th ed.). Storey Publishing. ISBN 978-1-60342-459-2.
• Sheep Production Handbook (8th ed.). American Sheep Industry Association. 2015. ISBN 978-0-9742857-6-4.