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Post-Cervical AI Makes A Comeback For Swine

Bernie Peet is president of Pork Chain Consulting Ltd. of Lacombe, Alberta, and editor of Western Hog Journal. His columns will run every second week in the Manitoba Co-operator.

About 10 years ago, when the technique of post-cervical AI (PCAI) was introduced, a series of trials in Europe showed placing semen directly into the uterine body resulted in excellent fertility with just half the normal number of sperm cells. However, while the method showed great promise, it was not widely used commercially and most production operations around the world continued to use conventional AI.

But now a number of companies in Canada and the U.S. have revisited PCAI and are getting excellent results.

Julie Ménard from integrated production company F. Ménard Inc. in Quebec and John Sonderman, technical services manager with Danbred North America, explained the benefits of the technique to delegates at the recent Swine Breeding Management Workshop held in Edmonton.

Using less sperm per semen dose (typically 1.5 billion rather than three billion) means fewer boars are required. While this doesn’t reduce the genetic cost component of the semen, it saves money on other inputs such as extender, according to Sonderman.

“The biggest benefit is that using fewer sperm per dose allows producers to spread the use of the highest indexing boars over more sows,” he said.

The financial advantage of an “Elite AI boar” over a regular AI boar in the Danbred system is just over $2 per market hog, he noted. In addition, there are significant labour savings when PCAI is used.

“It takes about half the time to inseminate a sow compared to the standard technique,” said Ménard. “Time is also saved in semen preparation because there is no need to warm the semen dose prior to use.”

In conventional AI, semen is placed in the cervix and has to be transported through the body of the uterus and eventually to the top of the two uterine horns. A key part of the AI process is to provide strong boar stimulation, which results in rhythmic contractions of the uterus, moving semen from the cervix up into the uterine horns. With PCAI, the semen is deposited at the top of the uterine body at the junction of the two uterine horns using a thin cannula, which passes through the catheter tube and extends from its foam or plastic tip. In this case, boar stimulation is not required and insemination takes place about 30 minutes after heat detection.

Sonderman described the PCAI routine used at a large production system in the U.S. Midwest that uses only 1.2 billion sperm per dose in an extender volume of 34 ml compared to the normal 80 ml.

“First, sows in heat are identified using teaser boars and then the boars are removed for a minimum of 20 minutes,” said Sonderman. “Then the vulva is cleaned and the catheter-cannula removed from its sterile container. The tip of the catheter is lubricated and inserted as with normal AI, but then the cannula is pushed carefully through the cervix and up to the uterine wall.

“When resistance is felt the cannula is pulled back slightly and the semen dose is squeezed in over a period of 10 seconds. Then the cannula is partly withdrawn and cervical stimulation carried out for about 10 seconds by manipulating the catheter.”

EXCELLENT HEAT DETECTION

Spanish research suggests this technique leads to improved results.

Heat detection has to be excellent where PCAI is used, Ménard stressed.

“If the technician tries to introduce the post-cervical catheter too early or too late during oestrus, the cannula will bend and potentially cause damage to the cervix, with possible bleeding or infection,” she said.

She also pointed out that while boar presence is essential for good heat detection, his absence during insemination is essential.

“If the boar is present when insemination takes place, this causes the cervix to close up tightly, making it difficult to introduce the cannula,” she explained.

Ménard also noted the PCAI technique is not suitable for gilts because of their smaller genital tract. This requires two separate AI techniques and sets of equipment to be used, making PCAI more suitable for larger production systems.

F. Ménard Inc. carried out an initial trial on PCAI in 2006, then gradually introduced it into more farms and by the end of 2007 was using it throughout its 26,500- sow system. The company was originally cautious about reducing the sperm dose and semen volume too much, but a recent trial showed that it could get similar results using a 1.5-billionsperm/ 50-ml dose as using a 2.0-billion/80-ml dose (Table 1).

Ménard said the benefit of using PCAI has been a reduction in boar inventory of 25 per cent, even with a cautious approach to sperm numbers per dose. This has led to savings of $150,000 per year, excluding the additional benefits of using higher index boars. She emphasized that the success of PCIA is very dependent on the ability of the technicians involved.

Sonderman stressed the time savings.

“The breeding team on a 5,200- sow unit using PCAI has been reduced from five to two,” he notes. “On a good day it is possible to inseminate 100 sows in 30 minutes.”

He also pointed out that the 53,000-sow system he works with has gone from 120 sows per boar to 400 as a result of using fewer sperm per semen dose.

“Fewer boars means less variation in the progeny in addition to the benefits of using boars of higher genetic merit,” he said.

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Table 1: Preliminary results of breeding with 1.5-billionsperm and 50-ml versus 2.0-billion-sperm and 80-ml dose

No. sows bred

No. sows with results

No. farrowing

Farrowing rate (%)

Adjusted farrowing rate (%)

Total born/litter

1.5 Bn/50 ml 2.0 Bn/80 ml

157

145

89.5

92.4

14.14

264

153

142

91.0

92.8

14.2

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