THE importance of maintaining heavier sows during lactation was reinforced at an Agriculture Department pig science seminar in Perth last week.
Victorian Institute of Animal Science research scientist Dr Ray King said increasing the weight of a sow during pregnancy had a positive economic benefit on progeny at slaughter.
"A heavier weaner makes it easier to grow out," he said.
"As we try to refine pig production and look at ways to improve productivity, we always come back to birth weight and weaning weight.
Dr King said a heavier lactating sow provided a heavier weaning weight which, once known, could also provide a sow's nutrient requirement.
"The weaning weight and birth weight are drivers of growth," he said.
"You should consider anything to increase the feed intake of the sow.
"It's pretty hard to overfeed protein to a lactating sow."
He said the big question was whether the extra cost in feeding the sow was worth a seemingly small response in piglet birthweight.
Dr King said increasing the lysine (amino acid) content of lactating sow diet from 0.85 to 1pc would provide an extra $17.70 per sow, which would also be 10kg heavier.
The gain would be made through saving the sow's lean tissue reserves, which were convertible to milk.
Dr King provided another example where increasing feed intake by 1kg a day would increase piglet growth rate by 12.2g a day, which would translate into a return of $41.60 per sow with nine piglets. Again, the sow would be heavier.
In summary, he said that as the lactating sow's digestible energy increased, the piglet's growth rate also increased. The sow also lost less weight.