How to select breeding boar for your herd

Farming Issues Mhlupheki Dube
THIS week we will look at factors that a pig producer needs to consider when selecting a breeding boar. The performance level of a swine herd is determined by two things namely genetics and environment.  The genetic contribution is determined by the quality of boars and gilts selected and the crossbreeding programme used. The environment which includes aspects such as weather, housing, feeding, management, will enhance or hinder the genetic expression of performance traits.

Age of boar is an important selection factor. Farmers should purchase boars at six to seven months of age for use.
Don’t just use young boars because they appear to be large enough. Boars used at too early an age may have their working life considerably shortened and their breeding ability impaired. Replacement boars should be purchased at least two months prior to the breeding season.

This allows them to be isolated and checked for health, conditioned to the farm and test-mated or evaluated for reproductive performance.
When selecting a boar for a breeding programme, factors such as origination from a specific disease-free herd, performance, soundness and conformation, age of puberty, and other pertinent parameters related to reproduction should be considered.

Boars from large litters (10 piglets) that reach puberty early (5½–6 months) tend to produce highly productive daughters who also reach puberty at an early age.
Performance parameters such as feed efficiency, backfat, and average daily gain are also highly heritable.

Conformation and physical soundness of the boar is important therefore particular attention should be given to the boar’s legs and feet as they are subjected to considerable strain during mating.

Any sign of weakness at this early age could signal a serious problem at a later date. Make sure that the toes and pasterns are not long, weak or misshapen.
The boar should walk and move freely without any sign of stiffness or lameness. The testes should be normal in shape and size, even, and free from defects. While the width of the testes is directly related to total sperm output, it is not a true indication of the libido or sexual activity of the boar.

It is also important to get boars from producers who have a deliberate and careful selection programme.
This should be supported by consistent and meticulous records. Selection efforts should be based on boars that will sire fast growing, efficient pigs with desirable carcasses.
Maternal boars used to produce replacement gilts should be selected on a balance of reproductive and post weaning performance. The genetic background of the boar should be consistent with the intended use. Selection of boars with heritable defects such as cryptorchidism or rectal prolapse can be avoided by careful analysis of the source herd production records.

A complete history of the boar should be obtained before a decision to purchase is made. This should include the age and origin of the boar, source herd health, immunisations, previous disease problems and treatments.

It should also include, if available, a description of the boar’s previous libido, mating behaviour, conception rates, litter size and performance of relatives and other boars in the herd.

For young boars, observations of sexual behaviour may be useful. Identification of responsible seedstock suppliers is therefore extremely important so that you can get a superior seedstock as a result of proper genetic selection and herd health programmes. When selecting seedstock suppliers, review their genetic improvement programme. A sound genetic improvement programme should include the following features:

• Accurate complete performance records including animal identification, consistent measurement of all boars and gilts.
• Assessment of the genetic merit of economically important traits (growth rate, feed efficiency, carcass merit and reproductive performance) based on the individual’s performance relative to its contemporary group.

In summary a good boar should give you a good growth and performance traits and it should come from a health herd. Some of the important carcass traits include backfat, muscling and length of the carcass. The key production trait is the litter size which can only be inferred from the maternal ancestors of the boar.