Large-scale trials make case for longer sow lactations

The Pipestone System in Minnesota recently conducted at their research facilities two large-scale trials to study the effects of lactation length on sows and growing-pig performance.¹

Increasingly, hog operations consider later weaning and long lactation to improve piglet and sow health.

In the first trial at a 3,000-sow farm, investigators used five lactation groups from 21 days to 30 days weaning with 2 days in each group. They identified sows by parity 1 (P1) and parity 2+ (P2) and evenly divided them into each lactation group. Sows were weighed and body condition scores taken as they entered the farrowing house and again when sows moved to gestation.

Heavier pigs

All piglets received vaccines for mycoplasma and circovirus, as well as a porcine reproductive and respiratory syndrome vaccine at 21 days. Creep feeding started at 18 days, 1 pound two times a day. At weaning, pigs moved to the research barn into pens designed for 27 pigs in each with 7 square feet per pig. They were split by gender. Personnel weighed pigs when diets changed, about every three weeks. The pigs were followed to processing for carcass data.

After analysis, researchers found a longer lactation did not significantly affect sows overall. The P1 sows did lose significant weight compared to P2 sows, which is expected. The 29-30 days’ lactation caused the least sow-weight loss of the groups.

Later weaning produced heavier pigs that grew faster. But when measured from birth through lifetime, later weaning did not improve average daily gain. Later weaning reduced wean-to-finish mortality, culls and removal rates. The 25-26 days’ weaning slightly increased carcass yield.

The second trial used 1 year of farrowing records from 100,000 sows to evaluate how lactation length affected sow performance and total born. Investigators excluded health-challenged farms and sows with less than five and more than 25 total pigs born per year.

The data showed longer lactation increases subsequent total born per sow (between 0.5 to one pig per litter). Researchers concluded longer lactation lengths and later weaning (between 22 and 25 days) benefit both sows and piglets.

1 Schmitt C. Our Thought Process and a Field Trial, Allen D. Leman Swine Conference, 2017.