There are six points largely being overlooked that can lead the way to achieving better sow fertility and labor efficiency in artificial insemination (AI) programs.
The data compiled by veterinarian Brad Thacker of Iowa State University is based on farms grappling with AI mating problems. He provided details on these common reproductive problems at a management seminar hosted by Intervet Inc.
Sows are stimulated too soon before you're ready to breed them, so they are no longer in heat when you're ready to inseminate them. There is no element of surprise.
“In our old, hand-mating/natural-mating systems, we typically keep the sow and boar separate,” says Thacker. “Then, when it is time to mate, we usually put them together in a breeding pen or sometimes take the sow to the boar pen, achieving what we call the ‘bedroom effect.’”
The bedroom effect is needed with AI matings too, he asserts. But often when we want to breed a group of sows in a row, we stimulate them with a teaser boar long before it's their chance to be bred. When it's their turn, they are past being receptive to stimulation.
“Females start to become stimulated, and then start to lock up. If it takes us 15-20 min. to get there, by that time she is no longer interested in mating,” he says. Sows only stay in heat 7-12 min. at a time.
Thacker suggests adding some solid dividers in adjacent crates so sows down the line can't see what's going on. “They can hear some things, maybe smell a little bit, but they are not stimulated until we get that boar in front of them, creating the bedroom effect.”
The boar is not close enough to the sow during heat detection and stimulation. For proper nose-to-nose contact, the boar's head should be within 2-3 ft. of the sow. The boar's pheromones that stimulate the female are secreted in his saliva.
Too much noise and commotion distracts sows during mating. A common distraction is trying to get sows that are not in heat to show signs of heat by aggressively applying back pressure, causing the sow to make a lot of noise. The same individualized attention that applies during heat detection should also apply during mating, he says.
The operator becomes irritated from holding the AI bottle while the sow draws up the semen. “This can be one of the worst 3- to 5-min. jobs on the farm,” admits Thacker. Most people don't like to stand still for that long.
Consider switching to bags/flat packs or flexible tubes along with hands-free breeding belts or saddle bags to help “automate” insemination.
“One-minute matings need to be eliminated,” he stresses. “The problem is as soon as the semen goes in, the operator leaves that sow. The sow doesn't really know whether the semen is in or not, so that's why she needs continued stimulation for up to 15-20 min.” Sperm don't swim. Rather, semen is deposited into the cervix and contractions move it through the uterus and into the oviducts for fertilization.
“With the use of flat packs, a properly stimulated sow will easily draw in the semen within a minute. However, additional stimulation time is needed,” Thacker emphasizes.
Maintaining a boar in front of the artificially inseminated sow for another 15-20 min. is one aspect of this stimulation, he points out. In addition, Thacker is a big proponent of the breeding belt for providing constant back pressure on the sow. Belts can be cinched to achieve the proper pressure.
“What I also like about the belt is if the sow is not really in standing heat, she will not tolerate wearing the belt. We can spend a lot of time trying to understand estrus behavior, and we need to know that,” he says. “But if we've got a new person coming into an operation, basically all the person needs to be told is to stimulate the sows a little bit and try and put the belt on. If she stands for the belt, she is probably going to be in standing heat.” Saddle bags and other devices can be used to provide stimulation as well.
Avoid late matings. The uterus can't quickly clear semen which contains many nasty things, including bacteria. The cleaning mechanisms are less effective as the female goes out of estrus, Thacker observes. Also, time for cleanup is reduced before the embryos arrive, which in the pig is only 48 hours after ovulation. The cleanup mechanisms involve white blood cells entering the uterus and digesting the sperm and other debris. If these pus cells are still present in the uterus when the fertilized egg arrives from the oviduct, the process can be compromised.