Vaccinerad hangris : optimal lysinhalt?

Abstract: Vaccination against boar taint with Improvac® is one of the alternatives to surgical castration. It was not until 2009 the use of Improvac® was approved within EU. There is a lack of Swedish studies concerning the requirement of protein and lysine to vaccinated male pigs. Therefore, the aim of this study was to examine if the protein and feed efficiency of vaccinated male pigs differ from that of female pigs. The study included 4 treatments: low and high lysine level to vaccinated entire male and female pigs assigned to a pen with animals of the same sex. The pigs were randomly allocated to one of the treatments at weaning depending on litter and live weight. The pigs were moved into the slaughter stable at an average age of 9 weeks. The vaccinated male pigs and females were raised in separate pens in two batches. Two feeds with different lysine content (8.3 and 9.8 g lysine/kg) were used and the pigs were single fed. The male pigs were vaccinated at 9 and 13 weeks of age. The pigs were weighed at the start of the experiment and thereafter every second week and finally the day before slaughter. The results showed no interactions between lysine level and sex. However, female pigs grew faster from a live weight of 60 kg to slaughter than vaccinated pigs. Pigs fed 9.8 g lysine/kg had a higher daily weight gain in the interval from start to 60 kg than pigs fed 8,3 g lysine/kg. The pigs fed the low lysine level compensated totally during the following period and consequently daily weight gain for the total raising period did not differ between pigs fed the low and the high lysine level. Furthermore, the result showed that the lysine content did not have any significant impact on feed efficiency, slaughter weight and lean meat content. A lower lysine content resulted in a price reduction for feed with 9% per pig and 25% lower nitrogen emission.