Nearly all of our litters are a result of AI as we have no boars, and so far we have found it very easy to do and had almost 100% positive results first attempt. We also inseminate only once a year for spring litters, so each sow has a dry period of about 6 months. Nevertheless, I check vulvas daily from weaning onwards to check heat dates and whether they are happening at regular 3 week intervals. Our 18 month old Tamworth sow Mango who had her first litter without problems at 13 months old has been having extremely regular heats - or so I thought. Every third Tuesday, Wednesday and Thursday she shows an increasingly red, swollen vulva, followed by less redness and the swelling disappearing completely by the following Monday. Then in the intervening period a pale pink, small neat vulva, very different indeed.
We have now gone through 2 such cycles with the semen ordered on time from Deerpark and attempted AI on her, but something has gone completely wrong. Usually, with a combination of stroking, back pressure, mucus at the vulva entrance, strange ear movements and boar mate, we have been able to pin-point which was the peak day and deliver the three doses just when needed. With Mango there has nothing but intense hostility and disinterest over every single day she might/should have been on heat. Barking at us, leaping around, zero response to boar mate - sort of, just go away and leave me alone.
On each occasion we have tried to get some semen in, I have been allowed to wipe her vulva clean, insert the catheter and get a lock. That doesn't seem to bother her particularly or cause her any discomfort. But standing around at her back end makes her very cross, she runs off again and again, and eventually lies down so her vulva is stuck in the mud. All these shenanigans succeed in expelling the catheter.
What is so mystifying is she appears to be on heat (red swollen vulva every 3 weeks), yet appears to be not on heat (complete disinterest), simultaneously, and we are at a loss to explain what on earth is the problem, and whether she is or isn't. The only two things we can think of are, firstly, her hatred of injections, and possibly her thinking we are trying to get a jab in. Secondly, this was one of the few pigs who had a natural service for her first litter, so this is her first experience of AI, and she definitely does not like it. Could she be pining for a real live boar? Do you suppose it is possible for psychological factors to over-ride pig hormones? I would have thought not, most of our sows are absolutely gagging for it on a deliberately dry month, but am wondering whether anyone else has ever experienced anything like this before.
By the way, she is well in every other respect, eating, pooing, weeing, and quite civil to us when we don't have catheters and suspicious buckets in view. Took her temperature the other day which was quite normal, and all regular jabs are up to date.
Would really appreciate hearing from anyone who has any thoughts or ideas as to what could be going on. I do know that leaving a sow too long can result in infertility, but it is only 6 months since she weaned, and since then has had an unbroken set of 3 weekly swollen red vulvas, which would seem to me very unlikely if she wasn't coming into heat every 3 weeks as she should. Hope someone can throw some light on this - Tamsaddle