Bernard Peet, Pork Chain Consulting, Lacombe
Every year I look forward to receiving my copy of the Annual Report of the Danish National Committee for Pig Production, which contains information on industry developments and results of research trials carried out. The National Committee is part of the pig producers’ organization Danish Slaughterhouses and has a budget of CDN$20 million per year derived mainly from a check-off from each pig sold by producers. Research and development work is primarily in the areas of breeding, housing and production systems, reproduction, nutrition and health. Over the last few years there has been a focus on increasing piglet survival rate because of the higher litter size that has been achieved as the result of genetic progress.
In the breeding program itself, the emphasis has been changed from selection for total litter size to the number of piglets alive five days after birth or LP5, which is a good measure of survivability. This now forms 69% of the selection index. The report shows that during 2004-5, the first full year of the new program, LP5 increased by 0.33 pigs in Landrace nucleus herds and 0.25 in Large White herds. In addition to this change, research is focussing on how to keep more piglets alive through changes to management. Danish producers now average 12.9 pigs born alive/litter compared to 11.0 ten years ago. The top 25% of producers average 13.4 compared to 11.4 ten years ago (see Table 1). As total litter size has increased, the number of stillborn pigs has also gone up, from 0.78/litter in 1994 to 1.5 in 2004, nearly double. Producers’ ability to control this is limited by the fact that they have to employ a veterinarian to administer prostaglandin and so few producers induce sows to farrow. Similarly, although more pigs are now weaned per litter, the percentage pre-wean loss has increased, from 11% in 1994 to 14% in 2004. However, the research program is now providing some good practical solutions to keeping more pigs alive and improving understanding of the processes involved.
Routine use of nurse sows is required where litter size is high and this is one area that is being looked at. One trial compared the differences between one-step and two-step fostering. A one-step system is where piglets are removed from a sow at, say, 21 days (the minimum weaning age allowed in Denmark) and a new litter of surplus newborn pigs is put on her for a further 21 days. In two-step fostering the sow’s litter is weaned off and replaced with a full litter of 4-7 day old piglets. The 4-7 day farrowed sow is then used as a foster mother for surplus newborn piglets. The results shown in Table 2 show that two-step fostering not only results in a much higher piglet survival rate but also increases weaning weight by nearly 1kg. Another trial compared how sows in different parities performed as foster mothers and this showed that first and second parity sows give better results than older sows.
Click here to view a photo of a sow with her new litter.
Danish producers commonly use gilts as foster mothers in a two-step fostering process to extend their lactation period to 30-35 days. One might think that doing this would deplete the gilt’s body reserves but, in fact, it does the opposite. When the gilt’s first litter is weaned and replaced with smaller pigs, she continues to eat the same high level of feed that she did before but has a much lower nutritional demand because milk production is less. Consequently, she starts to regain some of the condition lost earlier in the lactation period. The longer lactation period also allows the uterus more time to recover from farrowing, a process which takes longer in gilts than in older sows. The end result is that gilts show a significantly shorter wean to estrus period, which leads to a higher farrowing rate and increased second litter size. Danish research shows that nurse sows that have an extended lactation do not lose more weight than those with a normal lactation length.
Video recordings have shown that nurse sows receiving a complete litter of piglets quickly accept them without the need to disguise their smell. However, it takes between 3 and 6 hours before the sow initiates suckling. Therefore it is recommended that litters of large piglets are moved, not the smaller ones, as they can cope better with the period without milk. Where two-step fostering is used, sows accept piglets more readily than in the one-step process, which is probably part of the reason for the lower mortality and higher weaning weights. In fact, piglets fostered in the two-step process performed as well as those that stayed with their own mothers. Another trial showed that non-thriving piglets moved to a nurse sow had a survival rate of 90% whereas if they were left with their own mother this figure was only 66%. This supports the practice of making up a litter of the smallest pigs on one sow rather than leaving them to compete with larger piglets.
With larger litters, colostrum management becomes more critical and split suckling is commonly practiced in Denmark. However, Danish research has shown that the vast majority of piglets receive sufficient colostrum, even in very large litters. It’s probably best to be safe and assume that the little guys need some extra help.
Following some simple rules for fostering will maximize piglet survival:
- Piglets should always have suckled colostrum which, in most cases, will be by 4-6 hours after farrowing.
- The sow’s rearing ability, especially the number of functional teats, should be assessed and noted prior to fostering taking place.
- Plan all moving to be done, taking into account the sow’s rearing ability, number of surplus piglets and piglet size.
- Minimize the amount of movement between sows.
- Always move the larger piglets – they can cope with the stress of movement better and will have consumed sufficient colostrum.
- Re-foster any pigs that fall behind within the next 48 hours.
Danish trials on sow and piglet suckling behaviour and the management practices that increase survival rate is providing some very valuable knowledge that can be applied on every farm. There’s no doubt that Danish producers will continue to increase productivity as a result of their ongoing investment in practical research aimed at maximizing profit potential.
Note: The Annual Report of the National Committee for Pig Production can be viewed at www.danskeslagterier.dk Click on the British flag to go to the English version of the website.
Click here to view a photo of a large litter.
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