Picking the correct genotype for pig herds

Ever wondered whether a Hampshire terminal sire is better than a Large White or if a Pietrain boar pips them both to the post? New research has the answer as Sarah Trickett finds out

Every pig producer knows correct genetics are fundamental to a successful pig herd, but sometimes price and a good sales pitch can direct producers away from the best genotype for them.

Three-way crosses have, however, been on the increase more recently with Hampshire and Pietrain boars more commonly being used as the terminal sire compared to the traditional Large White. But, with research identifying differences between these three commonly used terminal sire breeds, just which one is best for your herd?

Three-way crosses increased in popularity when levels of PMWS went up, with crosses thought to be more robust. But, as levels of PMWS started to decline, it was unclear whether this was due to a switch in sire line or just getter control of the disease, says Leeds University’s Helen Miller, who led the research.

For this reason, a large scale study was initiated at Leeds University farm, looking at how different genotypes affect litter size, robustness and productivity. Large White x Landrace sows were bred using AI with Hampshire, Pietrain and Large White semen.

“This research provides an impartial assessment of how different terminal sire breeds perform; allowing producers to base their terminal sire choices on facts obtained using proper controls,” says Prof Miller.

“We looked at all aspects of production from litter size and pre-weaning to post-weaning, grower and finishing stages, right through to the abattoir to get a break down of the carcass details,” adds Prof miller.

All three genotypes showed different attributes. In pre-weaning, although there were few differences between litter size and piglet weight between different sire lines, the three-way crosses had higher survival rates in the first 24 hours than the Large White.

It also revealed Hampshire-type crosses grew more rapidly, reaching slaughter weight up to seven days before the other two genotypes, with a growth rate of 765g/day compared to 723g/day for the Large White type and 710g/day for the Pietrain type.

“If you want rapid throughput the Hampshire would definitely be a good choice, but it depends on individual priorities and market requirements. Something that may be good for one system, may not be the best for another,” says Prof Miller.

For example, although the Hampshire type had the fastest growth rate, it was actually the Large White types recording the lowest feed intake and also best feed efficiency.

However, robustness in the Large White was not nearly as good as in the Hampshire and Pietrain types, with almost double the number of Large White types having to be removed from the trial compared to the other two types.

“The Large White type may not be as robust as the other two, but they do display some positive attributes such as good carcass composition and a good feed conversion ratio, both important for conventional payment,” adds Prof Miller.

For carcass composition Large White type pigs were the leanest, as assessed by MLC backfat measurements, but Pietrain type carcasses produced the heaviest carcasses and the greatest yield when assessed on the basis of lean meat yield, with Pietrain types also having thicker eye muscles than the Hampshire types.

These results can help producers assess the economic significance of each factor on their own production system, says Prof Miller. “It’s about selecting a breed that suits a system. Look at what you’re doing right now and review herd performance and ask yourself whether there is any area that can be improved,” she says.

But robustness and performance aren’t the only things that need to be considered, as each of the breeds is also slightly different to handle, points out Prof Miller.

“We found Hampshires were the most difficult to manage when driving, because they were reluctant to move. This is compared to the Large White types, which were the most confident when faced with human contact. The Pietrain-type pigs were more jumpy and tended to bolt away from human contact when being driven,” she says.