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Introducing New Genetics to the Pig Unit

by 5m Editor
1 May 2003, at 12:00am

By Livestock Knowledge Transfer, UK - This aticle looks at the methods and advantages of bringing in new genetics to your stock.

Genetic improvement and your pig farm

Replacing breeding stock with home produced animals may be successful in large herds where the variation in commercially important traits can be identified. But it could reduce performance and cost more than it saves.
A reputable breeding company will sell you a package of stock in which the terminal sire complements the parent female to maximise profit from each sow.

Boar lines are typically selected for growth and carcass traits, including meat quality, whilst sow lines are selected for a combination of reproductive output and finishing performance. Interfering with this balance can be detrimental.

Also, modern breeding companies use sophisticated selection methods not generally available on farm, and include traits that the individual farmer would find difficult or costly to measure.

What do you get out of buying improved genetics?

  • Hybrid vigour = piglets born, better survival, higher growth rates, greater disease resistance
  • Improved economic performance - through extra piglets born, better growth and improved FCR.
    Other traits such as meat quality, longevity and survival are also being improved genetically

Do'd and don'ts of replacement stock:

  • Make sure you use F1 Parent gilts – i.e. a cross between two completely different lines
  • Use of a third breed boar (as opposed to a backcross) will maximise hybrid vigour in the piglets and lead to better survival
  • Don’t try to produce your own replacement gilts unless you have a large herd (over 500 sows). This reduces overall herd performance
  • Use tested boars that are above the average of the tested population on index score. If in doubt ask your supplier what the average was for the contemporary group tested
  • You don’t have to buy the most expensive boars or semen to get good results. A good average is all that is needed

Relative advantage of crossbreeding














Estimated Breeding Value's for ADG



















  • Always look at the EBV (Estimated Breeding Value) of the trait. This should always be above average. As genetic improvement increases over time, the average EBVs improve, so it is again important to ask what the average of contemporaries is. The graph shows the frequency of pigs with EBVs for lifetime gain. The average EBV is +2.5 grams, and over 50% of the pigs in this population have an EBV greater than this. Consider only these boars when purchasing
  • Half the breeding value of a boar is passed on to its offspring. If you buy a boar with an EBV of + 40g, expect his offspring to be 20g better than the average of progeny from all boars in the population

Integrating stock into your herd

Once the type of breeding stock has been agreed the practical requirements of receiving and integrating the stock onto your unit must be addressed.

Herd health is the most important issue. Ask your vet to assess the compatibility of your herd health with that of the supplying unit. You need to be sure that you aren’t bringing new diseases onto your unit or buying in stock that will be adversely affected by your own herd’s health problems.

Make sure you have isolation facilities away from your herd where you can keep new stock entirely separate - if possible with non-unit staff looking after them - for a period of about 2 months. If unit staff have to look after the stock, tasks should be undertaken at the end of the day and separate clothing/boots and rigorous cleansing and disinfection procedures should be used.

The policy may entail buying in two batches of gilts, one a month younger than the other. New stock must not be mixed in with gilts which are just about to leave isolation to go into the herd.

To help acclimatise stock to your herd’s own disease profile, you might consider mixing some cull stock into the isolation premises prior to sale or possibly giving the new stock access to manure from the grower section of the herd. You should discuss this with your vet.

Some producers have opted to breed their own replacements to improve herd health. The principles of the breeding policy discussed above still apply - a nucleus of grandparent stock needs to be set up in the herd and Artificial Insemination (AI) will be used to bring in the majority of the genetic improvement. As discussed above this is usually only applicable to larger herds. A rigorous breeding programme needs to be set up.
This is not simply a matter of retaining gilts from the slaughter generation.

If in doubt, get help. Ask your supplier to explain the figures to your satisfaction, or look for independent advice, from ADAS or the MLC.



Source: Livestock Knowledge Transfer - First published 2001. Added to this site 2003.