Tuesday, 1 August 2017

Inseminating a pig

Early in May I inseminated a pig. I think one of our British Saddleback sows is now pregnant. If she is, then this will be the second time I have been successful with artificial insemination (AI). The problem is that pigs often do not show signs of pregnancy until relatively late in their gestation. But I should expect to know for sure fairly soon.

One of our British Saddleback sows

Basically there are three options available if you want to breed pigs. The first is to  keep your own boar. He is then readily available to mate with your sows, and possessing instinctive expertise in this area normally means he will do a good job and when precisely to go about it. Keeping a boar can be quite an expense because of the additional feed and vet bills, and he will need his own separate accommodation at times. The other thing to bear in mind is that if you only have two or three sows then that might be insufficient to keep a boar busy enough.

The second option, therefore, is to borrow or hire a boar for a few weeks at a time when the need arises. A variation of this is to send your sow away to spend some time with a friendly boar. This saves on costs but will involve movement licences, attending to bio-security arrangements and adhering to standstill requirements. There is also the problem of finding the right boar within reasonable travel distance, especially if you are breeding pedigree stock. This arrangement might work for some but I found it problematic. As a result I pursued the third option of AI.

AI has its own challenges. For me the primary difficulty is the issue of timing. Sows come into season every 21 days, but there is only a two, or at most three, day window of opportunity when she is fertile and receptive. This means recognising the signs that the sow is in season. The two main signs are an enlarged vulva and a reddening of the vulva. However, with black pigs (or largely black, in the case of our saddlebacks) reddening of the vulva is not apparent and often, especially with first time mums, there is little sign of the vulva swelling up either. You have to be vigilant to notice any changes. Some recommend using a tape measure to measure the distance between the anus and the vulva each day and identifying when the gap is at its smallest. As it is, I am in the habit of checking daily the look of each sow's vulva in the hope of becoming as acquainted as I can with their cycles. There was an additional sign I noticed which was a slight trickle of fluid from the vulva around the time I thought she was in season. The other thing to try is to press down on the sow's back (mimicking a boar) and if she stands still for you then that could be a further sign she is ready for you. That has worked quite well for me in corroborating my suspicions.

The actual process of AI  is relatively straightforward. You can send off for the supply of semen from specialist providers. I use a company called Deerpark Pedigree Pigs based in the north of Ireland who I have found very helpful. They supply three 'doses' which are administered morning, afternoon and finally the next morning. After that it is a matter of waiting for signs that the sow is 'in pig'. The abdomen will eventually show signs of expanding but for me previously it was the undercarriage dropping that confirmed the pregnancy. 

The length of gestation is traditionally cited as three months, three weeks and three days. That is 115 days. The piglets invariably arrive within a day or two of that period. With the sow I AI'd, we are now on day 86. All being well, 29 days to go.

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