Artificial insemination, embryo transfer, cloning, transgenic, hybrid…so many terms are confusing to consumers and with misunderstanding comes fear. These practices are things that you might not be involved in but you benefit from. For the purpose of the article here I’m focusing on livestock, although some things apply to plants as well.
In years gone by a farmer had but two options in breeding livestock – you kept breeding animals or you paid someone for the service, or stud fee, of breeding to their male. A farmer might borrow a neighbor’s bull, or have his mare visit a stallion in the next county. The idea of breeding to a bull across the country, or in another country, was unheard of. The availability of a top sire was out of reach of most farmers. Many farmers simply produced their own rams, boars, bulls or, if there was one or two they might use a neighbor’s.
There were problems with this – the female had to be moved at just the right time to insure conception, which wasn’t always convenient. Handling mature breeding males can be dangerous, especially one not raised with respect. Thousands of farmers have been killed when a bull turned on them and crushed them. People see movies like “Babe” and don’t realize that a mature boar might weigh 600 pounds or more – some up to 1,100! Stallions can grab a person and shake you like a rag doll, and equally injure and kill many people. With children around that can be a huge risk. A buck goat can rear up and butt heads with the force to fracture your skull, as can a dangerous ram. All of these animals are also tougher on equipment and fencing. For these reasons many people do not want to maintain a breeding sire on their property.
With technology bringing advances it is now possible to breed your mare in California to a stallion in Virginia without her ever leaving home. A cow might be bred to a good bull who died two years earlier. A goat could be bred to a buck who could never leave his home property any more than the doe could leave hers. There’s so many options that 100 years ago were simply beyond comprehension and many livestock breeders of today must be part scientist and part veterinarian in addition to selecting the best traits and characteristics of his animals.
Artificial insemination is basicly the collection of the semen into a recepticle that allows for splitting the collection amount or processing it. One stallion, for example, might produce enough off of one collection to, with technology, split the amount into four or six amounts and inseminate four or six mares. What this means to the stallion and handlers is less chance of getting hurt with breeding and instead of breeding four or six times he breeds once. For stallions that are heavily used this is a big difference. Other species are similar. Sometimes with horses semen is “cooled” – which is done to transport long distances – or, as with other species, frozen. With frozen technology a tank with liquid nitrogen keeps the semen frozen…which preserves it and thus allows the use of semen from the US in Australia, or for ‘insurance’ of a valued animal’s genetics in case of death.
Similar technology spawned embryo transfer (ET)…in which an animal is bred, then later the eggs are ‘flushed’, separated and implanted in surrogate females, or recipients. This might be of use for a valuable female – allowing from one ‘flush’ perhaps four or five eggs – which would all be full siblings, divided and implanted in four or five females. In this way one cow might have five calves born in one year, all offspring that are full siblings. They carry no genetic material from the recipient, who simply serves as a surrogate – a means to give birth to the embryo.
Cloning, much in the news, involves taking those microscopic eggs flushed from an animal and removing the DNA from them. Cells grown from tissue give DNA to a valuable animal and his/her DNA is inserted into the egg, creating an embryonic ‘twin’ of the donor. If five are produced and born this would not be offspring of the cow but rather sisters to her with identical DNA. There is nothing changed about the animal – it simply reproduces itself. This technology could be of use for endangered livestock breeds, or animals with very outstanding traits. In cases like “Scamper”, a world champion barrel racing gelding, his ability to reproduce was removed when he was neutered. In August of 2006 “Clayton”, his clone, was born – through Clayton Scamper’s abilities as a barrel racer are able to be passed on to breed mares even though Scamper himself was not able to do so. Clones do not necessarily have the same markings – five Ayrshire cows won’t have the same exact spots – but they DO share other traits. Cloning, being a new technology, is still very expensive and difficult. A cow might cost $20,000 to produce – horses are said to be nearer $150,000. You can be assured that a $20,000 calf is not going to be sold for 75cents per pound as hamburger. However, if there are five bulls with superior traits for muscle (which translates to meat) their offspring would be likely to enter the food chain, as would the milk from cloned dairy animals.
Transgenic takes things further still, inserting a gene trait for a specific thing into the egg. For example, a trait might be a protein from humans in the milk that assists with human medical issues. http://www.transgenics.com/products/questions.html provides more detailed answers to how these are used.
Hybrid is another misunderstood term – more commonly in livestock called crossbred. One breed crossed to another is a hybrid as is creatures like the beefalo (produced by crossing bison and cattle) and mule (donkey and horse cross). “Hybrid vigor” is a term when the offspring combine the best qualities from both parents. An example might be crossing a Holstein (for milk production volume) with a Brown Swiss (for protein) to produce a cow who has a higher amount of protein and more milk then the parents.
Each of these methods can have a place in agriculture and livestock production. Some of these methods have been responsible for making US animals among the most productive in the world. It has spread good genetics further than otherwise possible and produced proteins in higher volumes for medical treatments. While the possibility for abuse exists, the probability of advances are good. A balance is important.