Is it possible to breed better mothers for free farrowing conditions? Jenelle Dunkelberger, global health and behavior platform lead for Topigs Norsvin, says the global trend to explore alternative housing systems for pig production prompted her company to look for solutions.
“Behavior is a great example of a trait that we are still learning how to define,” Dunkelberger said during a seminar at the American Association of Swine Veterinarians annual meeting on March 2. “For example, how do you define good maternal behavior? What type of behavior are you really looking for?”
The use of camera technology and sensors can help generate data that can be used to study traits like behavior, among other things, she points out. But researchers still need to have a sense of what to look for that’s indicative of good behavior.
“What we do know is that a good mother should check her surroundings and exercise care when lying or changing positions,” she says. “But it goes so much deeper than that. For example, pigs are smart, and we don’t yet fully understand how sows communicate with their piglets.”
Pork producers want to know how important these complex traits will be in the future of pig production, especially now that the industry has access to tools that can capture data which has never been captured before.
What is Best for the Sow and Her Piglets?
“For some, removing farrowing crates is thought to translate to better sow welfare,” she says. “But of course, the reason we have farrowing crates in the first place is to protect the welfare of the piglets. Therefore, if farrowing crates are removed, novel management strategies will be required to ensure that we protect the welfare of the piglets. We have to maximize both sow and piglet welfare.”
Results from our research trial showed that piglet crushing was 8% higher for the free farrowing versus crated group, Dunkelberger says.
This highlights the need to develop strategies to mitigate piglet losses in such housing systems. For this reason, another objective of this research was to investigate the potential of genetic selection for enhanced mothering ability as a potential solution to this issue.
Topigs Norsvin has been selecting for enhanced mothering ability as part of its breeding program for over two decades. Dunkelberger says they do this by collecting data in a crated environment because that’s been the structure of the industry. Data is collected in that environment and used to calculate a sow’s genetic merit for mothering ability.
“We calculate breeding values for mothering ability as the maternal effect on piglet survival. In other words, the impact of the mother’s genes on the ability to keep her piglets alive,” she says.
In the study that Dunkelberger referenced, Topigs Norsvin wanted to evaluate whether genetic selection for improved maternal behavior validates in a free farrowing environment. Large White x Landrace sows were group-housed during gestation and transported to the farrowing unit at approximately 109 days of gestation. In the farrowing unit, half of the sows were assigned to the free farrowing group, and the remaining half to the crated group, where parity structure was balanced across groups. Sows and piglets were monitored throughout the duration of the study using cameras mounted above each pen or crate.
Overall piglet mortality was significantly higher in the free farrowing group (14.2%) versus 5.9% in the crated group. Consistent with this finding, mortality due to crushing was also significantly higher for free farrowing (11.8%) versus crated litters (1.1%).
“The majority of piglet death loss was due to crushing,” she says. “But when you look at the effect of breeding value for mothering ability, we observed that sows with a better breeding value for mothering ability had lower overall piglet mortality, including lower mortality due to crushing. We observed this result regardless of housing type (crated or free farrowing environment).”
The takeaway is that genetic selection for better mothering ability validates in a crated environment, but also in a free farrowing environment, Dunkelberger points out.
“We’re encouraged by this finding,” she says. “Results from this study show that our current approach of breeding for enhanced mothering ability reduces piglet losses in a crated environment, but also in a free farrowing environment. This means that genetic selection for better maternal behavior can be part of a strategy to reduce piglet death loss, if and where these alternative housing systems are being used.”
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