keep peace…
Mix at weaning and
keep peace…
How to improve pig breeding
and feeding management to
stem falling margins are key
issues covered in this Pig
Special.First Simon Wragg
details latest MAFFresearch
on how to reduce aggression
and bullying in loose housing
PIG producers should consider mixing sows at weaning and allowing them extra space to do so for one day before moving them into loose housed accommodation.
Mixing at weaning compared with after service – and allowing extra space – will reduce stress and maximise reproductive performance.
So says ADAS research consultant, Roger Kay, of ADAS Terrington, where MAFF-funded research is now getting close to finding the ideal mixing pen design.
"Poor layout and space allocation can restrict normal sow behaviour and increases stress – a potential cause of poor reproductive performance," he says.
Although inconclusive, recent research suggests grouped sows kept in a low-stress environment have 1.7 piglets a litter more than sows remixed during implantation – about two to three weeks after service, says Mr Kay.
"Sows need to establish a hierarchy when mixed. This causes stress, especially when space is at a premium. Potentially this stress can be reduced if sows are allowed to express normal submissive behaviour in response to aggression."
At Terrington, eight groups of six sows each were housed in a large 18m x 10.5m (59ft x 34ft) loose housed straw yards. This allowed them to display normal patterns of fight and flight which were recorded during the hierarchy building period.
Sows may run in excess of 20m (66ft) when challenged by an aggressor – an indication of space required in mixing situations, says Mr Kay.
"This is especially important in the first two hours after mixing, when a third of all interactions take place. In the next two-hour period, the number of interactions is reduced by 50%."
Interactions were monitored over a 28-hour period using visual and video observation. Walls are grid-marked at 1.5m (5ft) intervals to allow accurate distances to be recorded.
Three groups
According to trial consultant, Hans Spoolder, interactions could be divided into three groups: Brief threats, where dominant sow knocks, snaps or bites submissive sows; one-sided fights, where dominant sow chases, but with no reprisal; and two-sided fights, where both sows are aggressive. All had different responses in terms of flight and chase distances (see the table).
"Having found average chase and flight distances, the next stage is to establish what this means for the size and design of a mixing pen," says Mr Spoolder.
Research using different pen shapes and stocking density started in late February and will be completed later this year. "The introduction of boars to the mixing pen will also be investigated," adds Mr Spoolder.
However, immediate improvements to reduce aggression are possible even in smaller size mixing pens, adds Mr Kay. "Big bales or vertically suspended conveyor belting could be used to create escape areas and reduce interactions."
Fight and Flight distances (m)
Chase Flight
Number of cases 50% 95% 50% 95%
Brief threat 0 3.5 4 10*
One-sided fight 3 11.5 9 15.5
Two-sided fight 3.5 13.5 8.5 16.5
Average distance 0 7 5 14
For example, allow 10m* flight distance to accommodate 95% of all responses to brief threats.
Improve sow output by reducing mixing stress
• Mix groups at weaning.
• Avoid further mixing into small groups.
• Use bales or belting as barriers.
• Maximise space during the first day after mixing.
Mixing sows at weaning will reduce aggression later on, according to research at ADASTerrington. Inset:Researcher Hans Spoolder… improvements to cut aggression are possible even in smaller mixing pens.
LESS STRESS AT MIXING
• Mix groups at weaning.
• Avoid further mixing into small groups.
• Use bales or belting as barriers.
• Maximise space during the first day after mixing.
Fight and flight distances
Chase (m) Flight (m)
Number of cases 50% 95% 50% 95%
Brief threat 0 3.5 4 10*
One-sided fight 3 11.5 9 15.5
Two-sided fight 3.5 13.5 8.5 16.5
Average distance 0 7 5 14
For example, consider allowing a 10m* flight distance to accommodate 95% of all responses to brief threats.