Monday, July 11, 2011

Picking breeding stock: Making the cut for 2012

Culling criteria for sows

One of the regular tasks that I face is to look at my pig herd and make the call as to who stays, and who goes.  My list for sows goes something like this: 

Number of piglets weaned
Her condition and general health

Temperament is how easy she is to work with.  This is pretty high on my list because sows that are gentle natured and not aggressive are safer and easier to work with.  They're a joy to work with, and at 400+ pounds, you really don't want them to be mean. 

Fertility is the number of piglets produced live; weaned is the number who survive to weaning.  Some sows are better than others, and I consider all the circumstances, but the bottom line is that they need to produce and wean at least 20 piglets a year to make economic sense. 

Condition is noted based on where she is in; she'll be skinny if she's just weaning her pigs; she'll be a little plump when she's gestating -- but I want a pig who bounces back from pregnancy well, and takes care of herself with as little input from me as I can manage.  In particular, I'll look at their feet for any sign of problems or weakness.  They're already carrying 400lbs -- a litter of pigs adds another 100lbs to that, and if they are limping, it won't have a chance to get better. 

Criteria for potential gilts - picking good piglets
Having decided how many sows that I want to replace, I'll also consider how many sows I'd like to run next year.  I have to think about this about a year in advance.  So here's my gilt selection list: 

Condition at age
Number of nipples
Definition of muscles
Bow of back

Temperament is how the pig is fitting into my farm.  Is it having a good time, and friendly?
Condition at age is how this pig compares to others at the same age.  I want a piglet to be noticeably bigger and more robust than her litter mates. 
Stance:  looking at the front legs of the piglet, does it have a wide stance?  Means better musculature.
Number of nipples:  I want a minimum of 14 nipples.  16 or 18 is better. 
Definition of muscles:  At this age, I want to see the loins down the back, and I want to see good conformation of hams and hocks.  
Finally, I want her back to have a good, upward bow that is even and uninterrupted.

  So I look through each group of piglets for good gilt potential.  Here's 7 piglets all lined up.  The one 4th from the left, the biggest one, is my first choice from this group.   Compared to the others, she's managed to put on more weight and I can see more definition of muscles between her shoulders and at the base of the tail.   My second choice from this view would by the one 2nd from the left, and my third would be split between the one all the way to the right, or the one that is 5th from the left.  Click on the picture for a bigger version.   
  I find this lineup to be very good at showing me relatively small differences in growth and body shape.  Of this group, the only one that I chose to look at further for breeding was my #1 pick. 

The little girl that is at the left front is one that is showing bad posture.  Now she might be stretching, so I'll watch to make sure that it wasn't just a momentary thing - piglets will do that if they get sunburned, this little downward wiggle, but a drop between hams and shoulders is an automatic disqualify for breeding for me.  Fine as a meat pig, but she won't have a good time carrying a litter.   There are three pigs there that have good posture.  Which ones? 

Temperament is a bit more subjective.  My preference is to get to pigs that haven't been stressed; pick them out at the farm of origin if I'm buying from someone else, or quietly evaluate them while they're on the sow at my farm.  I want the little pigs to be curious and active; I want them to approach me.  I want bright eyes and an active and speedy piglet.  I want them to approach me when I get into the pen.  They may shy away if I try to touch them.  This little girl is curious about my boot.  Good sign. 

Which of these four would you pick, and why? 

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