Over the last 10 to 15 years, genetic selection for litter size has boosted the total number of pigs born per litter. There are now commercial herds that consistently achieve 14 or more, which brings with it the challenge of rearing pigs that are surplus to the sows’ rearing capacity.
I recently had the opportunity to review the production data for two very high-performing breeding herds, both producing around 30 pigs weaned per sow. That set me wondering about the approach each unit takes to rearing piglets from very large litters and whether it differed from Danish producers, who have been dealing with high litter size for many years.
Greenwald Colony, 15 miles north of Beausejour, Manitoba, is a 1,300-sow farrow-to-finish operation, using Danbred genetics, that has the distinction of being the highest-performing breeding herd in the Nebraska-based Swine Management Services benchmarking comparison. With 1.1 million sows in the SMS database, that is no mean achievement, especially when the herd weaned 31 pigs per sow in the 12 months to March 2009 (see table).
With a litter size of 13.8 born alive, keeping piglets alive could be a challenge, but pre-wean mortality is only 10 per cent. Their approach to maximizing survival is to leave 11-12 piglets on each sow and rear surplus piglets off the sow.
“We wean a good litter at seven days old and place it in a supplementary rearing unit in the overflow nursery room,” explains hog boss Calvin Hofer. “The piglets are fed with milk and creep for another six to seven days and then weaned into the nursery, where they do very well, despite being younger than older piglets weaned off the sow.”
The sow that the piglets are taken off is used as a foster mother for surplus newly weaned pigs.
“We reduce the sow’s feed from around 15 lbs per day down to 10 lbs for a couple of days and that seems to avoid the younger piglets scouring,” says Hofer. Sows in their first three parities, with good teats, are used as foster mothers.
If sows keep their own litters they are weaned at 21 to 24 days, although the average age of pigs weaned is around 20 days (increased from the 18.5 shown in the table) due to the number of piglets that are early weaned into the supplementary rearing pens. “We typically remove piglets from about 10 or 11 sows out of the 54 that farrow each week,” Hofer says.
Another unit with outstanding litter size is Hartland Colony, located just west of Bashaw, Alberta, which is a new 775-sow operation using breeding stock from Fast Genetics. The first gilts entered the barn at the end of February 2008, so the herd is currently farrowing third litters, which are averaging over 16 total born and nearly 15 born alive.
This herd also uses supplementary rearing, but in a slightly different way. Each farrowing room contains two rows of nine crates and at the end of each row is an additional creep area with a heated mat, which is used to rear surplus piglets.
“We take a litter of large piglets at seven days of age and put them in this area,” explains Martin Waldner, the colony’s hog boss. “They have access to milk in trays and creep feed when they go in, then the milk is removed seven days before the room of sows is weaned at 24 days.”
Piglets that are too small may be moved back to the previous room and weaned a week later. The sow that has had the piglets removed is used as a foster mother and given surplus newborn piglets. “It’s important to use a sow that is very calm and has good teats,” Waldner stresses.
Both Greenwald and Hartland take a similar approach, but piglets are placed in the nursery at different ages. Supplementary rearing means that the average lactation length is not extended too much, which helps to maximize litters/ sow/year. Both these herds average 2.47 for this parameter.
However, in Denmark, the figure is 2.2 to 2.3 due to their average weaning age of over 30 days and the fact that they are not allowed to use supplementary rearing and wean piglets at less than 21 days of age.
The Danish approach is to use a two-stage fostering technique, which involves using gilts and second litter sows as foster mothers. A full litter of large piglets is weaned at 21 days and then that sow has a litter of seven-day old piglets fostered on. The sow that is seven days after farrowing has surplus newly weaned piglets placed on her. By using gilts as foster mothers, their lactation length is extended to around 35 days. This has been shown to result in a shorter weaning to service interval, improved farrowing rate and higher second litter size.
Achieving very high litter size is a challenge in itself, but keeping piglets alive is potentially a bigger hurdle to achieving the coveted 30 pigs per sow. These two units clearly do a remarkable job in maximizing survival rate through the use of supplementary rearing.