Fertility By Design

Artificial insemination allows easy movement of desirable genetics in a container that doesn’t eat, poop, or experience suffering when transport times are excessive. That’s great news, so long as you are willing to take on all the work done by a healthy sire!

In this article we’ll explore basic artificial insemination processes, challenges and benefits, and keys to success.

 

Collection and storage

Semen is collected from ruminants through an artificial vagina, electro-ejaculation, or internal massage through the rectal wall. Collection from pigs and poultry is generally by massage. As you can imagine, rectal massage and electrical stimulation come with obvious comfort concerns. The artificial vagina is considered safest for sires and their human handlers.

Collected semen is usually pooled and diluted with an extender, with glycerol added to protect it from freezing. Artificial color may be added to distinguish breeds.

Chicken and turkey semen begins to lose fertilizing ability if stored for over an hour, while fresh bull semen can be successfully stored for a few days. (Poultry semen can be frozen, but reduced fertility limits its utility, so artificial insemination is not commonly used except for special breeding projects and the turkey industry.)

Frozen ruminant semen, however, can be stored indefinitely if it is maintained constantly (and I mean constantly!) at temperatures below -112°F. With liquid nitrogen storage (-320°F), viability can be maintained for years without any decrease in fertility.

 

Application

For all methods of artificial insemination, the objective is to deposit sperm in the cervix (the passage between the vagina and uterus) or directly into the uterus. In a typical approach, a speculum is placed in the vagina, and the inseminating tube is passed through the speculum to deposit semen in the cervix. Successful vaginal artificial insemination requires precise know-how and dexterity to achieve correct placement, as well as basic technique and hygiene practices to prevent injury or infection. In addition, animals must be conditioned to restraint—artificial insemination is not appropriate for range herds that are handled infrequently.

Surgical approaches, in which semen is deposited directly into the uterus, can require less handling. However, they also come with surgery’s full suite of medical risks, pain, and wound management.

Risks and management concerns prevent widespread use of surgical artificial insemination across livestock operations, but it is sometimes employed to increase artificial insemination conception rates in small ruminants.

 

Pros and cons

Studs excel at storing semen for maximum viability, identifying each female’s optimal breeding window, and placing sperm at the proper location at the ideal time. For a good return on an investment in artificial insemination, you—as well as the bull—have to succeed in doing all of these things.

Pros

• Rapid herd-level improvement in traits like disease resistance, milk production, foot health, meat quality, fertility, and many more.
• Access to geographically inaccessible sires.
• More information about a sire’s previous outcomes (rapid increase in number of offspring means more data is available sooner).
• Reduces or eliminates the cost and challenges of maintaining breeding males.
• Eliminates quarantine and biosecurity concerns associated with moving animals.
• Virtually eliminates injury to breeding stock (non-surgical methods only).
• Simplifies recordkeeping.
• Reduces inbreeding.
• Minimizes risk of venereal disease.
• Sires who are past their natural breeding lifespan (aged, injured, or dead).
• Fine-tunes timing to align production with labor, facilities, and markets.

 

Cons

• Risk of amplifying undesirable genetics, including unwanted traits or genetic disease.
• Infectious disease spread by poor hygiene.
• Injury due to poor technique.
• Initial investment.
• Cost (ongoing).
• Lost opportunity cost if not as successful as natural service.
• May not be preferred by producers or customers who aim to closely model natural systems.

 

Additional challenges for small ruminants

• Small available pool of sires.
• Lower success rates.
• Individual variation in estrus cycle timing (does).

 

Remember: the genetic improvements to your herd are only as good as the whole genome of your selected sires. Whether desirable, undesirable, or masked, all traits are amplified when one sire is used for many offspring. Choose the wrong sires and you could be left with less adaptive diversity in your herd than you started with. While artificial insemination offers the potential to fine-tune production and improve financial performance, it also carries the risk of poor outcomes at high cost.

 

Intact males

Many herds will experience weaker estrus cycles if male breeding animals are entirely absent. Although freedom from managing intact males is considered a benefit of artificial insemination, exposure to males can actually improve artificial insemination conception rates. Ram and boar exposure, in particular, can improve artificial insemination results for sheep and pigs, respectively.

Intact males can also handle  “cleanup” by breeding females whose artificial insemination did not result in pregnancy. With sheep, a cleanup ram is generally considered necessary, as ovine artificial insemination success rates are often around 50%, compared to 70% for cattle, and 80% or more for pigs.

 

When to breed

Your observations and experience should guide artificial insemination timing. These general guidelines can serve as a starting point.

• Cattle: 12 hours after standing heat ends.
• Sheep: 12–18 hours after the onset of standing heat.
• Goats: 24 hours before the end of that individual’s typical heat period. Ideally, breed again once or twice more at 12-hour intervals. If a doe is still in heat 24 hours after breeding, she is probably not pregnant.
• Pigs: For gilts, 12 and again 24 hours after standing heat begins. For sows, 24 and again 48 hours after standing heat begins.

 

Insemination skill

Following estrus detection, semen placement is the most likely factor influencing artificial insemination outcomes.

Although the process sounds simple, successful artificial insemination breeding outcomes require considerable skill. With artificial insemination technique, as with heat detection, small ruminants present unique challenges.

For example, the ewe’s cervix is long and winds about, with rather inflexible walls, all of which make proper semen deposition especially difficult. Worse, using a speculum and thawed-frozen semen in a maiden ewe is unlikely to result in lambs, but very likely to result in injury.

For all species, professional technicians are significantly more successful at insemination compared to individuals who are inexperienced in this task. When deciding whether to hire an AI technician, consider their fees in relation to the true cost of a reduced conception rate. For sheep and goats in particular, it’s important to find someone experienced at inseminating these species.

 

HEAT DETECTION

To determine which animals are in standing heat, observe for 20 to 30 minutes, twice per day. Nearly half of ruminants will show their strongest heat signs between 12 a.m. and 6 a.m. Could this unusually aggressive and vocal behavior of livestock in the middle of the night be the origin of “the witching hour”?

If you don’t plan to be up stirring the cauldron at this time, make your observations first thing in the morning and again later in the evening. Heat detection aids can be helpful, but tailhead or mounting markers cannot substitute for observation. Watch for these signs—especially the first four:

Standing when other animals try to mount

• Duration of standing heat:
• Cattle: 14-16 hours
• Sheep: 24-40 hours
• Goats: 24-72 hours
• Bison: 36-72 hours
• Pigs: 48-72 hours

Excitement, agitation, increased vocalization: May be restless, nervous, aggressive, more active, noisy

Reduced feed intake and milk production

Vulvar discharge

• Evidence other animals have tried to mount, such as muddy rump or roughened tail head
• Attempts to mount other animals
• Tail raised or flicking; increased pelvic movements
• Increased licking or smelling of herd mates
• Increased frequency of urination
• Vulvar swelling

 

For those who think your laying hens are just asking for scratches when you approach them in the pasture: that squatting behavior is the signal for breeding receptivity in poultry.

 

SHOULD YOU CONSIDER ARTIFICIAL INSEMINATION?

The following questions may help you decide.

Strategy

• What will you gain from utilizing AI?
• How will you obtain the desired benefits?
• Will you use AI on the whole flock, or select certain dams and well-matched sires? Will you keep, or continue to bring in, breeding males?

Animal health

• Are your animals ready to take full advantage of your investment in reproductive assistance?
• In particular, does your nutrition program support reproductive success?

Semen source and storage

• Have you identified specific traits you wish to boost in your herd—and found a source? animal compatible with your breeding females?
• Can you maintain proper storage conditions to preserve semen quality, or will someone else provide storage?

Estrus detection

• Will you be present to observe the necessary time periods, at the right times of day?
• Do you consistently, correctly predict estrus cycles and identify standing heat?

Insemination

• Have you identified an AI professional who understands the species you raise?
• Once estrus is detected, will you be able to schedule and complete insemination by that individual during the breeding window? Success depends on a variety of factors, and many of those are linked to on-farm observation and management. Actual results will vary. If you choose to pursue artificial insemination, it’s worth the time and effort to become adept at heat detection—and worth the cost to work with a skilled technician.

 

 

Author: Jennifer Gravley DMV  is a veterinarian and educator with a special interest in the intersection of food animal medicine and public health

 

 

Originally published in the Summer 2025 issue of AGW’s Sustainable Farming magazine.