Reproductive performance linked to live-weight and back-fat gains

Paying closer attention to both sow live weight and back-fat depth could help farmers improve reproductive performance in breeding herds, scientists report.

In a study by researchers from the UK’s Agri-food and Bioscience Institute (Afbi), Teagasc Ireland and the University of Leeds, sows with greater live weight and back fat in late gestation were found to be more likely to produce heavier piglets with higher weaning weights.

Presenting the findings at the British Society of Animal Science conference, Afbi scientist Anna Lavery said the study involved individual sow data collected from 1,058 sows over ten years.

Data included a range of measures, including total born, born alive, piglet birth weight and pre-weaning mortality.

Pre-weaning growth rates per litter, piglets weaned, weaning weight, lactation intake and weaning to service interval were also recorded.

Sow live weight and back fat were measured at service, days 25, 50, 80 and 100 of gestation, and at weaning.

The study found that a 10kg increase in sow live weight led to an increase in litter sizes, the number of piglets born alive, piglet birth weight and pre-weaning growth rate per litter.

However, the gain also led to an increase in pre-weaning mortality, decreased numbers of weaned piglets and lower lactation intake.

Conversely, a 1mm increase in back-fat depth resulted in lower numbers of born-alive piglets, but an increase in birth weights and piglet weaning weight.

“Independent of sow parity, the results showed improved reproductive performance with greater sow live weight and back-fat depth in late gestation,” Lavery said.

“Every 10kg increase in sow live-weight saw piglet weaning weight increase by 0.06kg, with a reduction in lactation intake of 2.60kg.

“Meanwhile every 1mm increase in sow back-fat depth increased piglet weaning weight by 0.02kg, with a reduction in lactation intake of 2.15kg.

“This suggests sows mobilize body reserves to meet the demands of the litter,” she added.

“It highlights the need to consider both live weight and back-fat depth together as important indicators of farrowing and pre-weaning productivity.”