Sow welfare research update: Solving the problem of hunger and aggression in gestating sows
Simon Turner (left), Sandra Edwards (center), and Yuzhi Li (right) at the 2014 Animal Science Annual Joint Meeting in Kansas City, MO.
The Animal Science Annual Joint Meeting was held in Kansas City, MO. during July 21 to 24, 2014. This year two world-renowned swine scientists were invited to speak at the meeting. British scientists Dr. Sandra Edwards, professor of the University of Newcastle, and Dr. Simon Turner, senior researcher of the Scotland's Rural College, discussed recent discoveries in sow welfare research.
Dr. Edwards spoke about feeding behavior, productivity and welfare of sows. Her speech focused on how to feed gestating and lactating sows to meet their production and welfare needs. The challenges of feeding sows come from the contrast between nutrient requirements during gestation and lactation. For optimal reproductive performance, sows should eat less during gestation and eat more during lactation. During gestation, sows are fed enough to maintain body condition and support reproduction, but not enough to reach appetite satiety. Limited-feeding induces chronic hunger, which is a major welfare issue for gestating sows.
In confinement gestation stalls, hungry sows develop stereotypic behaviors such as bar biting, sham chewing. In addition, hungry sows are aggressive. In group-housing systems, limited-fed sows sustained more injuries caused by fighting than sows that were fed to their appetite satiety. One solution to hunger is to enhance satiation of gestating sows. From the research conducted over the last 20 years, Dr. Edwards concluded that feeding high fiber diets to fill the gut is an effective way to enhance satiation while maintaining the body condition and reproductive performance of gestating sows.
There is evidence that feeding appropriate fermentable dietary fibers such as sugar beet pulp during gestation can increase the voluntary feed intake during lactation, which may be the carry-over effect of gut fill during gestation. So, the take home message is that feeding high fiber diets to gestating sows may enhance sow welfare during both gestation and lactation.
Dr. Turner's speech focused on his research of controlling aggression among group-housed gestating sows, with emphasis on genetic selection against aggression. Aggression in pigs is heritable, with a heritability of 0.31. Aggression among sows is difficult to measure. However, Dr. Turner's group found that aggression can be assessed by skin lesion scoring. This is because there is a strong genetic correlation between aggressiveness and skin lesions in sows. Thus, selecting against skin lesions at mixing can result in reduced aggressiveness among sows. Genetic selection can be a solution to minimize aggression among group-housed sows.
Reviewed by Wayne Martin