The Breeding Tool

by Ed and Chris Null

Artificial insemination is not new. It’s been around in one form or another since the late 1700’s. Whatever ideas or prejudices you may have come from over two hundred years of practice. AI is a tool. Nothing more, nothing less. You can use it to improve your herd, or misuse and damage it. You may not need it at all. The purpose of this article is to provide the information you need to decide whether AI has a place in your livestock operation.

The first hard records on artificial breeding come from the late 1780’s, when Lazzaro Spallanzani impregnated a bitch by injecting fresh semen into the uterus. He also demonstrated that spermatozoa were directly involved in fertilization, a fact that had evidently been overlooked before. Spallanzani was the first to introduce the possibility of freezing semen for storage.

AI was first used on a large scale by E.I. Ivanov, who employed the technique to improve breeding performance on Russian government horse farms in the late 1800’s. After the Bolsheviks came to power, Ivanov worked in Moscow improving collection and dilution methods for cattle, sheep, and horses. He also did important work on cooling and transporting semen. It is estimated that in 1938 there were 40,000 mares, 1.2 million cows, and fifteen million sheep serviced by AI in Russia.

The research boom in the U.S. began around 1937, when agricultural colleges began using AI on University herds. The Cooperative Artificial Breeding Association No. 1 was formed in New Jersey in 1938 – the first organization of its kind in the country – with 102 members and slightly more than a thousand cows. 1976 estimates suggest that up to 8 million cows are serviced by AI each year, made up of 55-60% of the dairy cows and 3-5% of the beef cows in the U.S. That doesn’t include other classes of stock. It has been pointed out that this adds up to more potential than demand.

Why use AI? Well, it gives the small producer access to sires which would be priced way out of his or her league. With Al, you can throw calves out of a bull costing tens of thousands of dollars for, say, sixty bucks a shot (prices vary widely – sometimes wildly – depending on breed, parentage, performance, politics, etc). No small stockman can afford a really world-class sire, and the prices on some of them would make J .R. Ewing raise his eyebrows. AI gives you the capability to add fine bloodlines to your herd at a nominal cost, compared to buying the animal, or even having it shipped for natural breeding.

A bull, for example, has the potential to breed half a million cows in his lifetime – and after – through the use of frozen semen. If you come up with a good performer, you might have a source of income other than steaks and hamburger. Of course, he’d have to be tested and documented. You can sire more calves with AI than the bull could ever father naturally, and slash the time you need to get those breeding records.

AI also sidesteps problems of incompatibility between sire and dam, such as a large, potentially dangerous difference in size.

If you do all your breeding artificially, you avoid the too-often overlooked danger of a bull or stallion – nobody ever got trampled by a catheter.

The risk of disease is also reduced. Aside from the danger of a bull having a high time spreading infection through your herd, you have the assurance that semen isn’t processed from diseased bulls (by reputable dealers, that is). This eliminates the chances of venereal disease, among other things.

AI can make managing your herd much simpler by allowing you to time calving (or foaling, or lambing) for when it is best for you. For instance, if you wanted your cows to calve in early spring to take advantage of the best forage, you’d have to keep the bull away from them from the last birth until the first of June, feeding and caring for the big galoot the whole time. With Al, you breed the cows in June as they come into estrus, and don’t even worry about a bull the other eleven months of the year. Subtracting the yearly cost of keeping a sire lowers the cost of AI considerably.

Maybe you need a new herd bull. Raising your own is the cheapest way to go, but doing that continually raises the specter of inbreeding and reduced calf performance. Piece of cake. AI your best cows, save the best bull, and sell his mother. You have just injected new blood into your herd at a fraction of the cost of an outside bull. (Be aware that any heifers thrown will be the bull’s half-sisters, and should not be kept for breeding purposes).

It sounds so great, why isn’t every stockman using AI? Every story has two sides, and artificial breeding is no exception.

The first and biggest problem is ESTRUS DETECTION! If you ain’t on time, you might as well inseminate the pot-bellied stove. Successful AI depends on the stockman knowing his herd, keeping records, and just generally paying attention. If each new calf is a surprise, AI is not for you.

The number of sires available to you may be limited by which method you are set up for.

There also exists the possibility of spreading disease at wildfire pace through your herd through the use of untested sires, but that’s the fault of the producer, not the tool.

You have to be trained to perform Al, or hire trained technicians. This is not a problem if you are willing to take a couple of days and learn the process.

One major objection to AI is the bottom line. It takes some bucks to set up the system. The big-ticket item is the semen tank, and that sucker can set you back $500 even if you don’t get fancy. One solution might be to band together with your neighbors and share the costs and responsibilities of caring for the equipage.

A remaining point, and the one sure to cause a ruckus in many circles, is the potential shrinkage of our livestock gene pool. Note that we said “potential.” It is conceivable that we could get so involved in a few sires of good quality that we destroyed the genetic diversity of our herds, but it’s not very likely. In the first place, AI is not for every producer. Most producers don’t use AI as their sole means of breeding. Artificial breeding as a means of introducing new blood into a herd can serve to enhance genetic diversity. Just look at the number of crossbreeds in cattle that are now considered distinct breeds. Santa Gertrudis and Brangus come to mind. That looks like a net increase in diversity. Many crosses are easier to do with AI, because it eliminates sire-dam incompatibility (such as a large sire mounting a more delicate dam), and insures that the right sire gets to the right dam.

That, and it’s still easier to pack around a relatively cheap and harmless tank of semen than it is to get the original container on the trailer. On that note, let’s look at the screws and washers of this business.

AI equipment is geared for three major methods – straws, ampules, and pellets. We’ll discuss them in order of popularity.

Straws are used by many newer operations. They are just what the name suggests, plastic straws. Most are 13.5 cm long and 3 mm in diameter, with a volume of ½ ml. They offer the advantages of quick thawing (important for sperm viability), economy, less semen waste, and a slightly better conception rate than ampules. They are used by thawing, cutting the end of the straw off (which was plugged with a powder that forms a stopper when dipped in water), loading into a straw gun, and injecting.

Due to their small size, time is of the essence when using straws. That same quick thawing that gives good sperm viability will damage them if handled too long before using. Also, care must be taken to get a clean cut to prevent backflow in the gun, wasting semen.

Ampules are like tiny soda bottles. The necks, flame sealed after filling, are scored so you can break them open. The semen is drawn into a pipette and injected. Ampules don’t thaw as fast as straws, so you have a little more time. One important advantage of this method is that many outstanding sires are already collected and stored. Some of the donors have been dead for years, and are still passing their prime genes to new generations.

One problem with ampules is that it’s almost impossible to get all the semen out, and some is wasted. There is also a higher sperm mortality rate during handling. If the ampule was improperly sealed after filling, nitrogen may leak in during storage, and explode on thawing. Always wrap ampules in toweling while handling, just in case. If you are collecting your own bull, pay special attention to the seal. Nitrogen-propelled shrapnel can be wicked.

Pellets are a quick and simple “on farm” technique. They can be made by dropping a semen/diluter mix into depressions carved in a block of dry ice. They freeze quickly, and can be stacked in a storage cane for the nitrogen tank. To use, simply drop the pellet into a warm extender, draw into a pipette, and inject. It’s easy, cheap, and gives good live sperm recovery.

The disadvantages include a greater risk of bacterial contamination, fast thawing, and difficultly in using pellets for large numbers of animals at once. Also, if you store pellets from more than one male in a cane, chips may relocate and spoil your records. Better to store one sire per cane. and label the cane clearly.

The equipment necessary to start your own AI operation needn’t be complex or expensive – except the exception. The main things you need are lubricant, shoulder-length gloves (rather obvious), insemination gun (for straws) or bulbed pipette (for ampules or pellets), paper towels, wide-mouth thermos for a warming bath, and a straw cutter if you go that route.

The semen tank is expensive, but necessary. Frozen semen must be kept extremely cold to retain its viability. These tanks store the semen above liquid nitrogen. The straws, ampules or pellets are placed in storage canes, and the canes are hung inside the tank. Depending on how much you want to spend, a semen tank will hold at liquid nitrogen temperatures for 10 to 32 weeks – important if you have a large herd to service. It’s also a major factor in the cost.

A semen tank is safer than a bull, but that doesn’t mean you don’t have to show some respect. First off, liquid nitrogen is about minus 196° F, and that will cool you off a lot faster than the old swimmin’ hole. Frostbite, if you get off that lucky, is no more fun in June as January. Also, nitrogen displaces oxygen, so don’t carry the tank in the cab of the truck with you, especially with the windows up.

Semen tanks are nothing more than glorified thermos bottles, and they warm up over time. The cap, which fits rather like the cork in an old-time thermos, will ordinarily let the pressure of the warming gas off gradually. As cold as the nitrogen is, however, it’s possible for moisture to form an ice plug in the neck of the tank, forming a potential bomb. If that happens, use a long drill bit (and a face shield, or at least safety glasses) to bore down through the lid and plug, releasing the pressure. A new lid is a lot cheaper than a hospital bill.

If you decide to get training and start using AI, you will most likely be trained in the recto-cervical method. This was developed in Denmark back in 1937. As the name implies, it involves inserting one hand in the rectum of the animal, and using it to guide the semen tube into the cervix. This was a vast improvement over the older methods, which were mostly “poke and hope”, and resulted in a lot of perforated cervix es.

Once you have your equipment and training, the major concern is estrus detection. There are signs to look for, such as irritability and the mounting of other cows. An estrus cow will seek the companionship of the herd leader, and will stand to be mounted. If you’ve ever watched a cow that didn’t want to be mounted, the distinction becomes clear.

If you want to get technical, there tends to be a variable enlargement of the vulva, and an increase in mucus flow. Clear, stringy mucus that dries on a glass slide in a fern-shaped pattern is an indication of estrus. Cloudy or bloody mucus is a warning flag of infection or other problem.

During estrus, the animal’s body temperature will tend to elevate somewhat less than one degree, and there’ll be a change in the flow of electrical impulses in the vulva. Confused yet? It gets only marginally better.

As alternatives to finding out scientifically which cows are ready to breed, you can use mechanical devices which mark animals which will stand for mounting, or employ altered animals.

The simplest mechanical markers are Kay Mar strips and chin-ball markers. The Kay Mar is a plastic tube containing two chemicals separated by a barrier. It is stuck to the cow in question just above the tail head. If she will stand for mounting, the weight of the mounting animal will break the innards of the strip, causing a readily-spotted color change.

The chin-ball marker is a drum of chalk hung under the chin of the bull or altered animal that will mark the rumps of estrus cows when mounted.

Since the object of all this is to mark estrus cows for artificial breeding, you don’t want them impregnated by a bull. Some stockmen use altered animals to mark breedable dams. Vasectomized bulls lose only breeding ability, not desire, but you lose the advantage of disease control because he can still achieve penetration. This can be avoided by using bulls that have been surgically altered to render penetration impossible. One method is called a penablock, where the penile sheath is blocked to prevent extension of the penis. Another is altering the sheath so that the penis extends at a 45° angle. This has to be bloody frustrating for the bull, and many do lose interest. Aside from that, a lot of stockmen have found that love will find a way, and nothing is impossible.

One method that sidesteps all that is using an androgenized cow. Shoot her full of testosterone and see who salutes. With either chin-ball markers or Kay Mar strips, this male/ cow could mark breedable dams without the possibility of penetration. This might be the best method for a large herd.

When it comes down to the bottom line, though, it doesn’t matter what kind of fancy bells and whistles you hang on a cow to tell you she’s in heat, there’s no substitute for “cow sense”, and a willingness to observe your herd. If you know your animals well enough to spot when they’re acting “odd”, and observe them often enough to see it, you’ll know she’s sick, pregnant, or estrus. You have to pay attention.

Throughout the history of AI, there have been those who decried it as “unnatural”. It is, of course, unnatural. So are steers, hybrid corn, and tractors. We think it is particularly important in these days of “test tube babies” to keep a sense of perspective. Sperm meets egg a little differently, but the result of that union is just as human, bovine, equine, porcine, or whatever as the parents were. Artificial, then, seems to be a more appropriate term than unnatural.

It seems to us that AI has met the test of the centuries. Like any technology, it is a two-edged sword, but it can be a boon to the right stockmen.