Expert opinion

3 commentslast update:Apr 25, 2009

Mixing growing pigs

Try to mix pigs as little as possible. Varley (2001) showed that litters kept together grew 110g/day faster to 20 days post-weaning.

My own work (2003) into justifying 'big pens' showed that pigs split into 4 pens rather than into one big one grew 13.5% slower from 10 – 92 kg., their feed intake fell by 7.2% and food conversion worsened by 7.2%. Stocking density, feed and water allowances were all up to par. But we all have to mix pigs at one time or another…….

*The big error is to fail to allow sufficient space for submissives to avoid dominants and for dominants to get their challenges over with minimal damage to either party.

* Try to allow 20% more ground plan to that from which they came. Young pigs will grow into it and everyone tends to overstock these days.

*Feeder space and drinking space. The majority of aggressive incidents occur close to the feeder and this is why an extra feeder or hopper for a while after mixing is advisable.

*We have all learned now that two drinkers are advisable in every pen including those with wet/dry feed hoppers as these are only food-moistening/better feed-intake devices, not adequate water sources. And one drinker is essential even in pipeline-fed layouts.

*If possible reduce the feed allowance by a quarter from the morning of mixing day.

*Introduce the pigs just before dusk, certainly not by mid-afternoon.

*Allow ample food once the pigs are moved.

*Spray the pigs with lavatory freshener aerosol once they are mixed.

* If using bedding, re-bed amply just before mixing.

*Place some of the to-be-mixed pig's faeces in the voiding area.

*Do not batch too evenly, especially young pigs out of the nursery. A  4 kg range in an 30-35 weight band is better than identical weights (Lean, 1985) and at 21 to 28 day weaning, a 1 to 1.5kg range difference may be best for groups of 20 to be grouped together. This allows dominance to be established quicker.

*In larger 'big pen' groups now gaining favour, once the group size reaches 50 to 100 animals the reduction in weight gain after weaning begins to disappear – one of the several reasons for its popularity.

* Watch stocking density in relation to pen shape. Pigs in long, narrow pens need more space to allow the submissives to escape. Fairly squarish oblongs are best.

* That first night's rest together is important, when 'stranger scents' get rubbed-off and mingled by dawn. Allow ample resting space and in winter a temporary cover placed over the sleeping area makes for cosiness in a strange place, discouraging nervous  'sleeping out' by the submissives which can cause tail biting later on.

 If any of you have any tips on mixing which you find work - please share them.

Mixing sows is another skill which I will deal with next time.



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    this is a great idea spraying them with lavatory aerosol. I also like the idea of trying to keep the weights much the same. We often mix pigs and as long as the weights are with in the limit then you will get away with a few scuffles. I do not spray any of my pigs and I mix right through the day. I find a good wallow filled with cool water is also a distraction, along with a little clean dirt in the pen. Really anything to distract them is important for the first few days. Also feed them in more than one place and slowly take the spots away. Or feed in the evening/late afternoon. They will have a feed and then find a place to camp for the night.

    Sows and boars on the other hand are a little different. I find that mixing sows is relatively easy, as long as they are about the same weight. I observe the day before I wean. When I have made a decision I put them all in one pen and their will be enough boars in the pen, if not I add more. But the important issue is that the sows are all a similar weight otherwise there is too much damage to skin during their scuffles. Skinny sows should not be put in a pen with fatter sows, they should be put in a pen on their own for a week or two to put on some weight before they are mated. You obviously lose 3 weeks, but sometimes that is the way it is, otherwise you can cull these sows.

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    p. fairclough

    as always, informative and interesting, i learn something new every time! thankyou

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