Breed of the Week #8 - Merino
Image: A Delaine Merino ram looks at you with a very sweet expression. Note the fluffy fleece, impressive horns, and kind face. Photo credit: Richard Bailey http://www.richardbaileyphotography.co.uk/ (from an article on the Modern Farmer website)
This week on Breed of the Week, we move from dairy sheep to the foundation of the modern wool industry, the Merino!
The Merino originated as a Spanish breed in the early 12th century, and helped contribute to the rise and historic success of the Spanish fine wool industry. In fact, these sheep were so economically important that until the early 1765, exporting Merino sheep was punishable by death! Things eased up in the 1700s, where Merinos were exported to royal allies in other countries and helped improve other sheep breeds, such as the Rambouillet, which is also known as the French Merino.
Image: Painting of a child with shepherding tools, petting a sheep - one of the earliest artistic depictions of Merino sheep. Image credit: El Buen Pastor, by Bartolomé Esteban Murillo
There are >10 sub-breeds of Merino, and Merino sheep have contributed genetics to multiple breeds in countries such as China, the US, Russia, Italy, and Germany. Today the Merino is the most common sheep in the world! Merinos can breed out of season compared to other sheep breeds and have long reproductive lives, making them popular as sires for crossbreeds. One variant, the Booroola Merino, is the most fertile type of sheep in the world! Due to a genetic mutation leading to especially high twinning rates, the average ewe produces 2.4 lambs per pregnancy but a Booroola ewe can have as many as six lambs at a time!
Merino sheep made their way to Australia in the late 1797 where wool pioneers such as John & Elizabeth Macarthur, and Eliza Furlong helped grow the Australian sheep industry until by the late 1800’s, wool was Australia’s major export. Australian breeders worked hard to find the best Merino lines to cross to create large, robust sheep with wool yields up to 10x higher than the original Spanish stock, and with the finer, more elastic wool that was prized by textile manufacturers. Merino wool is a major industry in Australia, and the major sheep breed, farmed primarily for wool but also for market lambs. Despite a decline in the past 25 years due to decreased wool demand, the Merino wool industry in Australia is so important that they produce >90% of the world’s supply of fine Merino wool.
Image: Merino ram, showing off how fluffy and woolly he is. Note the wooled forehead and the sheer amount of wool he has. Impressive! Photo credit: https://milligansganderhillfarm.wordpress.com
But why are Merinos so popular and valuable that Spanish kings were willing to kill to protect their monopoly? The answer lies in their wool! While the specific quality and best use of their wool depends on the sub-breed, Merino sheep have been bred over centuries to produce large quantities of fine, soft wool. Merinos produce a dense coat of wool that is less than half the diameter of a human hair, and ultrafine Merino wool can have a diameter ¼ that of a human hair! This ultrafine wool makes for luxurious, soft yarn that is prized for clothing.
Image: Merino wool, still on the sheep. Note the high density of fibers in the exposed section of fleece! Photo credit: XTM Australia.
Merino sheep can produce a lot of wool - the Peppin Merino, a Merino sub breed popular in Australia, can produce over 22 lb of wool per year! In the US, Delaine Merinos are the most common type of Merino, and a 125-180lb ewe can produce 12-20 lbs of wool in a year! In comparison, that’s more than twice what a Targhee would produce, and finer quality.
Image: A medium wool Merino being shorn. Notice how much fleece is coming off one sheep! Photo credit: Charles Esson, Wikimedia Commons https://en.wikipedia.org/wiki/User:Charles_Esson
One of the major differences between these common Merino types is that Delaine Merino sheep like those found in the US have been bred specifically for smooth skin, while many Australian Merino sheep have wrinkly skin. Because wool production is a function of skin surface area, wrinkly-skinned Merinos could have a higher fleece weight. But the wrinkly skin can cause its own problems - the wool around the rump can get contaminated with waste, attracting flies and increasing the risk of flystrike - a disease where blowflies lay their eggs in wool or open wounds. (WARNING: DO NOT GOOGLE IMAGE SEARCH BLOW FLIES OR FLYSTRIKE. It is a horrific disease and very gory. You have been warned. I am not kidding. Blowflies are #1 on the very short list of things I find incredibly disgusting, and I do not get squeamish easily. They are that bad.) When the eggs hatch, the larvae cause serious damage and pain to the animal. Flystrike can be lethal to sheep, as the ammonia produced by the larvae poisons the animal.
While any animal can get flystrike, it can be a particular issue for sheep production, especially in wet weather. Many producers trim the wool around the rump and between the hind legs to prevent this and to help keep the sheep hygenic in general. For many wooled breeds, this kind of sanitary haircut is considered best practice and not any more stressful than being sheared. But for wrinkly-skinned Merinos, sometimes a procedure called mulesing is used. This procedure was invented in the 1930’s after the accidental introduction of blowflies in the early 1900’s led to devastating effects to Australian sheep production and animal wellbeing. Mulesing is now commonly performed with pain relief, and removes a loose fold of skin from each side of the sheep’s rear/tail area. The area heals, leaving a smooth scar that will not produce wool and which will be less likely to be affected by flystrike.
Photo: Two shorn Merino ewes, one wrinkly-skinned, one “plain-bodied” (less wrinkled). The wrinkly-skinned one is at higher risk of flystrike. Photo credit: Dr. Jim Watts, SRS Genetics https://www.linkedin.com/pulse/changing-wrinkly-merino-sheep-plain-bodied-productive-dr-jim-watts
However, this procedure has been subject to a great deal of ethical debate. Some people feel that it was cruel to the animals, while others felt that the risk of pain and death due to flystrike was more cruel. Many companies have chosen to buy wool only from non-mulesed sheep, leading to difficult decisions for producers, especially in areas where blowflies are common. Commercial treatments are expensive, but the price premium from non-mulesed wool can help alleviate some of the increased costs. While commercial insecticides exist, as do skin treatments that can make the skin less attractive to blowflies, there is still much work to be done. The Australian government has even created a help site to help producers figure out the best way to prevent this severe health issue. Research has shown that mulesing leads to stress that lasts longer than what occurs from common health procedures such as shearing or castration, but on the other hand, stress from flystrike can last longer and be fatal.
Most researchers and producers agree that the long-term goal for the breed is to breed for flystrike resistance so that Merinos have less wool around their rear ends, and more bare skin, which is less likely to be affected by flystrike. Australian Wool Innovation has even released a scoring guide for breeders so they can choose sheep with the most resistance for their breeding programs. Breeders can also choose to introduce “plain-bodied” (less wrinkled) animals into their flocks as breeding stock, while still trying to maintain high wool production. I am hopeful that improved genetics will continue to show great progress in reducing the risk of this serious health issue, and in the meantime, I hope that continued research into non-surgical alternatives as well as increased use of pain relief will help producers figure out the best plan for the continued health of their sheep. Flystrike is a nasty, terrible disease and they are in a difficult situation. I know that producers have the best interests of their sheep at heart, and for the moment, I hope they will do research and consult with experts to figure out the best options for their flocks.
Image: I think we all need some cute after that.Here is a Booroola Merino ewe and her quadruplet lambs. Photo credit: http://animaladay.blogspot.com/
Merinos are the foundation of the modern wool industry, and have been a large part of the history of wool. From their origins as a Spanish state secret to their domination of the Australian sheep industry, these sheep have shown time and again that they are the world champions of wool, and an important part of meat sheep production in Australia as well Their unique genetics bring with them both triumph (#1 for wool!) and heartache (high flystrike risk!) but producers and researchers are working hard to make the best Merinos possible so that this long heritage of success can continue. If you ever have a chance to feel just how soft and comfortable Merino wool can be, you may understand why this breed is so popular.
Photo: Two balls of superfine Merino yarn. Note how smooth and soft the yarn looks. Photo credit: http://handmadebystefanie.blogspot.com
Five Fast Facts About Merinos
Merino wool was so important to the Spanish economy that until 1765 exporting Merino sheep was punishable by death
Merino sheep are the most common breed of sheep in the world
The Booroola Merino is the most fertile type of sheep in the world, with an average of 2.4 lambs per ewe per pregnancy!
Merinos are known for producing large quantities of fine-quality wool
Australia produces >90% of the world’s superfine wool, primarily from Merinos and their crosses
Image: Two Merino lambs. Photo credit: http://www.mooseyscountrygarden.com
Further reading: http://www.nma.gov.au/online_features/defining_moments/featured/merino-sheep-introduced , https://gsejournal.biomedcentral.com/articles/10.1186/s12711-015-0139-z , http://www.countrylovin.com/ADMRA/breed.html
http://www.animalwelfarestandards.net.au/files/2011/05/Sheep-Mulesing-discussion-paper-5.3.13.pdf
Welfare Consequences of Mulesing of Sheep (C. Lee & A.D. Fisher, requires academic access) http://onlinelibrary.wiley.com/doi/10.1111/j.1751-0813.2007.00114.x/abstract;jsessionid=A1521BD9C4D7462990D4F150E17E40DB.f03t04
