Piglet vitality is a hot issue as is reducing pre-weaning the mortality. Due to the increase in litter size and the changing circumstances in the swine industry it is critically important to ensure good maternal characteristics and strong and vigorous piglets. TOPIGS has successfully addressed these aspects in its breeding policy a and says that it is now reaping the rewards.

Less labour for more piglets

During 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. Further research carried out around the same time revealed that the underlying biological mechanisms had genetic differences in vitality. These were mainly related to higher energy reserves at birth rather than a higher birth weight.

By applying this knowledge within the dam line breeding programme TOPIGS has improved the accuracy of selection for survival and seen considerable benefits. Results care shown in the graph. Since 2002 the genetic trend for litter loss has been falling, whereas the trend for litter size has continued to increase.

Key Factor: mothering abilities

Since 2004, TOPIGS says that its understanding of the biological backgrounds and the behaviour of the sow post-partum and during lactation has increased. This insight has also been integrated into the in the breeding programme under the term 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' needs.

Increased Focus, New Technology
In 2006, the breeding objective was adapted to focus more attention 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 graph below also illustrates the trends associated with these adaptations. TIt shows a clear decrease in the genetic trend for litter mortality.

In spite of the visible effect of these efforts the improvement programme continues. 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.

Uterine Effect
Research at TOPIGS and IPG has been looking at the development of unborn piglets in the uterus. The iinter-uterineenvironment has been found to affect 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 developments described here illustrates how TOPIGS uses research-based knowledge within its breeding programme. Feedback from breeding practice is processed in a well-considered and scientific manner and the results are 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 per cent in 2007 means that the litter loss is 0.35 per cent 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.