Which is better? Passive or more active and confident pigs?

Monday, February 3, 2014

When selecting livestock for intensive production, 'we have inadvertently been selecting for more aggressive animals,' says a Prairie Swine Centre ethologist. But will screening out that trait necessarily be beneficial? Some farmers remain skeptical

by DON STONEMAN

The movement away from gestation stalls and towards group housing has been a challenge for some producers. Sow interaction has always been a huge concern and the reason some producers so strongly resist the change. While much focus has been on management in the barn, there is also relatively new and ongoing research into selection of sows that are most suited for group housing.
In selecting for livestock raised in confinement, "we have inadvertently been selecting for more and more aggressive animals," says ethologist Jennifer Brown, who studies animal behaviour at the Prairie Swine Centre (PSC) in Saskatoon, Sask.

Aggression, in particular, leads to problems when livestock is managed in groups. Brown says a two-pronged approach may be necessary to make the best of group housing. Pens need to be set up to reduce competition between individual sows, and perhaps aggressive sows need to be banished from loose-housed barns.

The Canadian Centre for Swine Improvement, headquartered in Ottawa, isn't using suitability to group housing as a selection criterion for sows yet, says CEO Brian Sullivan, "but it is on the radar, though, for sure." He thinks there is likely potential to select for better social behaviour. "It is tricky because most sows (in Canada) aren't housed that way. You can't evaluate traits."

Brown has been working with sows that have been screened and categorized using four different personality types. The types and tests were developed by now-retired PSC ethologist Harold Gonyou. The temperament testing involves "simple" behavioural tests, including measuring how long it takes individual pigs to go through an newly opened door, how they respond to an approaching human, how long it takes a pig to approach a human and also pigs' response to novel objects in a pen. The categories are as follows:

• "Active and fearful" pigs which have a fight or flight response.
• "Passive and fearful" animals which "will try to hide in a corner."
• "Passive and confident" animals which will be calm but not active, and
• "Active and confident" animals which are as described.

According to Brown, the open door test and the novel object test both evaluate a pig's willingness to explore unknown territory, thus measuring active/passive temperaments. The human approach test and the pig approaching human test are considered a better indicator of confident/fearful temperaments. Brown notes that individual pig's temperaments are made up of overlapping characteristics.

Pigs that make a fast exit from a pen with an open door are considered to be active pigs, as are pigs that make contact quickly with novel objects. Slower exiting pigs are considered to be passive, as are pigs slower to contact new objects.

It is complicated to explore temperament traits in pigs, Brown allows. There is variability in the genetics in current pig populations, therefore genetic progress can be made and the personality trait is heritable, "but not highly so." What Brown finds most important in a group setting at the PSC, however, is that the passive trait was linked to economically important traits. Passive sows in unbedded systems had lower injury scores, more piglets born and born alive, and better body condition during gestation than "active" sows.

"Confident" sows were found to have a higher injury score in a bedded electronic feeder system. In a partially slatted system, they had a greater improvement in body condition scoring during gestation. Pigs with confident traits tended to have higher lesion scores following mixing. In unbedded systems, fearful sows produced a greater number of piglets born and born alive than confident sows.

However, research conducted elsewhere isn't necessarily consistent with PSC findings. (Brown points out that other research conducted in 2003 revealed that sows with strong fear responses had a greater number of stillborn piglets and higher piglet mortality than confident sows. She notes that pigs at PSC are very used to human contact and that this may be a factor in how they are categorized.)

Aggressive sows, Brown found, had better body condition scores than fearful sows, but were more likely to be injured and bore fewer babies. (Brown says information from a parallel study at the University of Manitoba's barns could not be analyzed for production data.) "There is still a long way to go in using temperament to select pigs for loose-housed systems," Brown says. While "aggression is something we definitely don't want to see in grouped animals . . . we need to know how the traits interact before we begin selection or we will end up with problems in other areas."

There are concerns that screening out that trait, for example, will make some other aspects of commercial pig management difficult. How does selection for passive animals affect how their offspring handle in the barn? Brown asks. Will it be difficult to get passive animals to exit pens? Will passive animals have poorer maternal characteristics, even though they bore more babies? Will passive mothers be aware of their offspring and be protective?

Pigs don't react the same way in all systems, Brown notes. Straw-based pigs exit pens more quickly than pigs on slatted floors. Pigs in both systems had the same genetics and the barn design was the same, with the floor the only difference. She did caution, however, that the pigs in the research barn were very accustomed to a human in the pen and may not respond to a human entering the pen "because of indifference."

Brown noted "very distinct differences" in the temperaments of purebred and crossbred lines. There were also differences depending upon the age of the sow. Middle parity sows are calmer; older sows even more so. "My hypothesis is that younger sows are more fearful," Brown says.

On concrete-floored, electronic sow-feeder systems, aggressive sows had higher injury scores. More confident sows had better body condition scores during gestation. Brown believes the confident sows have a higher social status and get first access to the feeder, and also have a better opportunity to clean up after other sows. Another hypothesis is that more confident sows are more efficient at maintaining body weight.

Farmers can't wait to see how this research turns out. They are already going ahead with loose-sow housing with mixed results.  

Wide personality differences
At Sebringville, Doug Ahrens has converted his 600-sow unit to loose housing with electronic feeders. He started putting females into the new loose housing barn in the spring. He's seeing a wide variety of personality differences among the pigs that he uses, which are based on Topig genetics. The transition to loose housing "is not as smooth as I thought it was going to go, but it could have been a whole lot worse." He predicts it will take "a minimum of two years" to transition what he calls "a working herd" into a loose-housing system.

In the fall, he had more problems getting gilts to adapt to the system than before and he doesn't know why. As many as 20 to 30 per cent would not go through the feeders and had to be returned to gestation crates. His goal is to have 90 to 95 per cent of sows in loose pens. "There are so many things that change on a bi-weekly basis  . . .  and it all has to do with the temperament of the sows," Ahrens says. He believes "a full moon has a great deal to do with temperament, too," with the week they are brought into the loose barn being critical.

"You take a group of sows (to the loose pen barn) on the week of a full moon and it's a whole different game than on a week that isn't. You can say what you want, but a full moon plays a big part with temperament, too."

Ahrens has his own terminology for sows with different personalities, referring to some animals as "high strung. We see that (trait in pigs) walking down the hall. We have learned not to put them out there because they won't work in that system. But they will work in a stall." He notes that "passive" animals will use the feeders once they learn and "they will eat at the end of the day" when other pigs are through the system.

Ahrens says he has been unable to be selective about the gilts placed into his barn because he is still short of stock after a PRRS outbreak two years ago. "I am using everything I can get my hands on."

He says moving loose-housed sows is easier than moving sows kept in stalls. They are not so "afraid of a shadow" as gestation-crated sows are when they are moved, and most loose-housed sows will go directly from the loose-sow pens into a gestation stall without encouragement or herding.

But Ahrens is skeptical about deliberately selecting for "passive" sows in his electronic feeding system. "They will run through a feeder and stand and gawk all over the place. Some sows are like puppy dogs," he adds. "They will follow you around. But they are the ones that eat last."

This year, Ahrens plans to put a feeder into the gilt barn and start training 180-day-old gilts to use it so they will be more comfortable in the gestation barn.

Focus on marketing
Oliver Haan and his wife Renate direct-market pork from their 85-90-sow, farrow-to-finish operation between Belleville and Napanee. The Haan herd is raised on straw, crate-free, and "has been loose housed all along." The focus is on marketing rather than on using top genetics to get the highest production.

"We tried to bring modern genetics into the herd and then we just raised from our crossbred program," Oliver Haan says. "Definitely our crossbred animals that were raised together in large groups are the ones that respond the best in group housing."

Haan runs 100 to 125 pigs in a stable in a large group and selects the best from those groups. "They spend a lifetime being in that environment," he says. "They seem to do the best." He also keeps a boar in each group pen and he thinks that helps.  

Haan found that by bringing in new genetics "you get what I would call 'high-maintenance-type' females; they either are one extreme or the other. They are too passive or too aggressive and both have negative results in group housing. We have gone back to 100 per cent raising our own animals from within our own herd and then doing a good job with the boars. That is what we found works."

Haan isn't sure he wants "passive" sows in his barn. "The passive sow is the one who won't get up to eat enough. She will stay back at feeding time and she will generally go up and see if there is anything left over after everyone else is full.

"Her condition suffers and then you have to start segregating her. When you start segregating sows on a regular basis, they never adapt to the group. When you segregate them once, you are sort of in a position where that is what you have to continue to do with them. And that defeats the purpose" of group housing.

"They are not going to produce you the strong healthy piglets. They are not going to produce you as many piglets. And the sow is not going to be a real contributor to her herd."

Two aggressive sows in the same pen isn't a good situation either. "There's going to be a loser. And that is going to be a real problem, too."

Reid Wilson of Milverton has been raising sows in group housing for 40 years. He thinks the selection studies are nonsense and the real issue with aggressive pigs is the way they are handled.
"I still believe in stockmanship, treating animals with respect, and they are never as aggressive then either. Pigs are not stupid animals. They remember."

Wilson floor feeds one group of sows in a partially slatted-floor barn (one-third slats, two-thirds solid concrete) five to six times a day. Another group of sows are floor fed once a day in an old-style bank barn bedded with straw and cleaned out with a skid steer loader. "It is low cost, but there is a little more labour involved," he allows. He doesn't think much feed is wasted by floor feeding.

Wilson says he used electronic feeders for a while, "but I was never crazy about them." A year ago he did a depopulation and repopulation, introducing genetics from Vista Villa, and he had no problems. But no one is going to promote his style of production, Wilson says, because "there is no money to be made from it," such as by selling electronic feeders. He doesn't mind heaping more fuel on the group-housing, gestation stall controversy. "I'm sure there are some aggressive pigs out there, but I don't think it's as big an issue as some of them would like to make you believe."  BP