According to Danish Pig Research Center "Annual Report 2011", the number of live and dead pigs in
nucleus breeding and multiplication herds has shown positive trends since 2004.
Data from purebred sows in nucleus breeding and multiplication herds reveal a steady decrease in mortality since the introduction of the trait live piglets at day 5 (LP5). The reduced piglet mortality results in more surviving pigs, and the number of live piglets at day 5 has, therefore, increased.
In 2004, when LP5 was introduced in the breeding objective, piglet mortality averaged 21% and 23% of all piglets born in the first parity of Landrace and Large White sows, respectively. By 2011, these figures have decreased to averagely 15.4% and 16.9% for newborn piglets of the two breeds. Mortalities are based on the overall number of piglets born, which also includes stillborn piglets.
Analyses of the changes in the total number of piglets born and live piglets at day 5, furthermore, demonstrate that the change in mortality is almost exclusively attributed to an effect of breeding. The current recordings show no indications that this trend will stop. Further analyses reveal that the positive trends in live piglets at day 5 and mortality in nucleus breeding and multiplication herds are attributed to genetic progress. LP5 was included in the breeding objective in the 2004 revision of the objective. The result was a genetic reduction in the number of stillborn piglets in the individual litters, while litter size still underwent genetic progress.
May 2012/ Pig Research Center/ Denmark.