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Improving Piglet Survival Through Breeding

by 5m Editor
13 March 2009, at 12:00am

Analysis of the records of separate sire and dam lines of one breed has shown up genetic links between piglet survival, litter size and production traits, offering the hope of improving survival through breeding. The results were presented by Dagmar Kapell at a special event prior to the latest JSR Technical Conference, and reported here by ThePigSite editor, Jackie Linden.

JSR Genetics introduced its first ever Student Press Release Competition last year, offering students the opportunity to present their work at a special event linked to the company's 19th Technical Conference, entitled '50 Years of Excellence in Breeding'.

The initiative was set up to help talented, skilled individuals to enter the pig industry. The competition brought two winners, one of whom was Dagmar Kapell. She studied animal science at the Wageningen University and Research Centre in the Netherlands, and is now in her third year of PhD studies at the Scottish Agricultural College. She presented her paper on the genetic improvement of piglet survival.

"My ambition in the pig industry is to improve piglet survival in current production systems," Ms Kapell said. "Piglet survival has a large influence on both economics and welfare. Also consumers have become increasingly aware of animal welfare, so I feel that traits related to animal welfare will play an important role in future breeding programmes. My goal is to contribute to the development of pig breeding programmes that focus on both production and piglet survival traits."

In her paper entitled 'Genetic associations between piglet survival, litter size and production traits', she explained that the average of 13 per cent of pigs born alive that die before weaning represent both an economic loss and lost potential. Piglet survival may play a more important role in future pig breeding programmes, said Ms Kapell.

However, unfavourable associations may exist between piglet survival and other reproductive or production traits, she warned.

Her work aimed to estimate the genetic influence on piglet survival as well as genetic associations of piglet survival with litter size traits such as number born alive, and with production traits such as growth rate and backfat thickness. Overall, the aim was to achieve maximum overall genetic improvement.

Ms Kapell looked at two lines within the LArge White breed: the sire line selected for production traits and the dam line selected mainly for reproductive traits. The lines were separated about 25 years ago. She looked at the data from 1991 to 2007.

For each line, there were two data sets: reproductive performance (including piglets born alive and weaned, and parity) and production performance (including average daily gain, backfat thickness and muscle depth). In total, there were more than 63,000 records for the sire line and 123,000 records for the dam line.

The main results are shown in the following tables.


Table 1. Comparison of traits between sire line and dam line

Table 2. Genetic influence on survival and reproduction traits

Table 3. Genetic influence on production traits

Table 4. Genetic association between survival and litter size
(figures in red are unfavourable)

Table 5. Genetic associations between production and reproduction traits
(figures in red are unfavourable)

Conclusions

The data shows that selection pressure on the different traits has altered the means for the different lines. For example, the number born alive is 9.7 for the sire line and 11.1 for the dam line, and backfat thickness is 8.8 and 10.5 for the sire and dam lines, respectively.

The study distinguishes between with sire and dam lines within one breed, the Large White. The heritability of percentage pigs stillborn is three per cent for the sire line and six per cent for the dam line. Heritabilities for backfat thickness are 50 per cent and 42 per cent for the sire and dam lines, respectively.

Heritabilities for survival and reproduction traits were found to be low. Furthermore, some correlations were found to be unfavourable, for example, between backfat and stillborns in the sire line, and between growth and stillborns in the dam line.

However, simultaneous improvement of the sire and dam lines is possible, concluded Ms Kapell from her work.

March 2009