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Selection for Piglet Vitality Pays Off

by 5m Editor
18 July 2008, at 12:00am

Breeding effort since 2002 shows more piglets and less mortality, writes Jackie Linden, ThePigSite Editor.

Piglet Vitality a Hot Issue

Reducing the mortality of piglets with the sow is a hot issue. Due to the increase in litter size and the changing circumstances in the swine industry it is more important than ever to ensure good maternal characteristics and strong and vigorous piglets. TOPIGS has successfully paid attention to these aspects in its breeding policy in various years.

Less Labour for More Piglets

Over the past ten years the amount of time each piglet receives has decreased due to high labour costs and increasing automation. Based on the standards in the Dutch Piglet Prices Scheme it can be concluded that between 1997 and 2007 the employment effort per weaned piglet has halved: from more than 40 minutes per piglet to 20 minutes per piglet. At the same time the selection for litter size and leaner growth had put growing pressure on piglet vitality since the mid-1990s.

Energy Level at Birth the Key Factor

Research carried out in the mid-1990s by IPG and Wageningen University demonstrated that it was possible to select for piglet vitality. For this it was necessary to introduce the piglet weighing protocol in which newborn piglets were weighed and mortality and cross fostering were recorded. Research carried out in the mid-1990s by IPG and Wageningen University into the underlying biological mechanisms revealed that genetic differences in vitality were mainly related to higher energy reserves at birth rather than a higher birth weight.

Selection for Piglet Survival since 2002

By applying this knowledge in the breeding objective of all TOPIGS dam lines since 2002, the accuracy of selection for survival has increased considerably. The result can be seen in the figure below (under heading ‘The results are clear and impressive’): since 2002 the genetic trend for litter loss has been falling, whereas the trend for litter size has continued to increase.

Also Important: Mothering Abilities

Since 2004, our understanding of the biological backgrounds and the behaviour of the sow that underlie the differences in genetic predisposition for nurturing ability has increased. This insight was included in the breeding programme under the name nurturing ability. Genetically good mothers ensure that piglets take up colostrum faster because they are quieter in the nursing pen, lie more often in the feeding position and are more alert in responding to the piglets.

Extra Focus in Breeding Goal TOPIGS

In 2006, the breeding objective was adapted once again to focus even more on piglet vitality, nurturing ability and maternal characteristics. At the same time, there has been a considerable increase in the number of sows available for the collection of data according to the piglet weighing protocol. The figure below (under heading ‘The results are clear and impressive’):shows that these adaptations have led to a clear decrease in the genetic trend for litter mortality.

New Technology Makes More Possible

Despite the visible effect of efforts over the past few years, we are not there yet. TOPIGS and IPG are continuing to look for even better methods to allow even more piglets to survive. For example, this year TOPIGS will deploy a new breeding estimation programme that will allow breeding values for survival to be estimated even more accurately. This will make it possible to select more specifically still for survival.

The Uterus Effect

Since 2007, research at TOPIGS and IPG has also focused on the development of unborn piglets in the uterus, as this affects the performances after birth. For example, if too many embryos are implanted in relation to the capacity of the uterus (uterine crowding) then birth weight, litter uniformity and growth can be negatively affected during the fattening process. The knowledge from this type of research contributes to a more balanced selection.

The TOPIGS Way: Interaction between Practice and Research

The developments described above illustrate how TOPIGS develops knowledge and subsequently applies this in its breeding programme. Feedback from breeding practice is processed in a well-considered and scientific manner. Thanks to this approach the TOPIGS pig remains in balance: the increasingly larger number of piglets born can also be raised.

Results Both Clear and Impressive

This graph shows the genetic improvement in the pure lines of TOPIGS and, albeit with a small delay, the same improvement can be seen in the production sows as well. A value of 1.2 in 2007 for the total number of births indicates that the sow has the genetic predisposition to produce 1.2 piglets more per litter than a sow in 2001. A value for litter loss of -0.35% in 2007 means that the litter loss is 0.35% lower than in 2001.

A global calculation example based on the genetic predisposition of the combined effect of both trends: assuming an average litter size of 12.2 of which 0.9 stillborn piglets and a litter loss of 11.5% in 2001. In 2001 a sow weaned 10 piglets per litter. In 2007 the number of piglets per litter had increased to 13.4 piglets (12.2+1.2). The number of stillborn piglets per litter was 0.8. For the period 2001-2007, the genetic trend for this characteristic was -0.08. The litter loss was 11.65% (12-0.35). This means that in 2007 the sow weaned about 11.1 piglets per litter. An increase of about 1.1 weaned piglets per litter.

July 2008