Grant Walling, director of UK pig genetics company JSR Genetics, said bigger animals from larger litter sizes was not a straightforward way to make pig production more sustainable, and could result in products that consumers don’t want to eat.

Speaking at the European Federation of Animal Science conference in Belfast, Ireland, Dr Walling said farmers were under pressure to increase their output in a bid to be profitable and meet growing demand for pork.

But attempting to tackle the problem by producing heavier animals from larger litters would make pig farms more complicated to manage and potentially less profitable, he said.

“Elite sows currently produce 3.13 tons of carcasses a year,” he told delegates during a session on the biological and commercial likelihoods of producing a five-ton sow.

“Increasing litter size traditionally led to increased productivity, but we know now that mortality increases in larger litters. We also know that larger litters mean lighter pigs, which are less likely to reach their full value.”

Considerable work for minimal gain

Dr Walling said breeders could focus on traits that shorten the production cycle, such as reduced gestation, but warned it would be a considerable amount of work for minimal gain.

To have the most significant impact on production, farmers could raise larger pigs, but that might not necessarily lead to greater profits, he said.

“Consumer demand for pork is based on weight. There’s a reason why we see conformed sizes of pork chops in our supermarkets, and if we increase chop size then we would fail to meet retail demand.”

Aiming to produce a larger sow would also lead to a reduction of efficiencies on-farm, with growth curves slowing as pigs get bigger, he added.

“The average farm needs 130 days accommodation post-slaughter to get to 110 kg (243 lbs) live-weight. If we say tomorrow we have to get up to a 130 kg (287 lbs) carcass we need 206 days of accommodation, or we need to grow 462 g (0.5 lbs) per day faster — a 58 per cent increase on today’s rate.

“The challenge of achieving that equates to 39 years of genetic progress. It’s clearly not something we can implement straight away.”

However, while producing a 5-ton sow was commercially and biologically unlikely, Dr Walling said making on-farm improvements to achieve 3.5-ton sows was ‘very achievable’.

“The emphasis going forward has to be on piglets,” he said. “We shouldn’t simply be striving for more piglets and then dealing with them afterwards. We need as many animals born to reach their full weight and be reared in a way that consumers find acceptable.”

Taken from Voice of Sustainable Pork