Effect of single-sex or mixed rearing and live weight on performance, technological meat quality and sexual maturity in entire male and female pigs fed raw potato starch

Abstract

The aim of our study was to investigate the effect of rearing system (mixed or single-sex) on performance and carcass quality of entire male and female pigs slaughtered at around 90 or 115 kg live weight. We also studied the combined effect of live weight and dietary supplement of raw potato starch (RPS) on technological meat quality for both sexes, and boar taint compounds in entire male pigs. Furthermore, we investigated pre-slaughter routines (pen-wise or mixing with unfamiliar pigs) and sexual maturity. A total of 408 growing/finishing pigs were included in this two-year study. Performance did not differ significantly between entire male and female pigs irrespective of rearing system, except for daily weight gain in the interval from 90 kg to slaughter. Mixed pigs had significantly higher daily weight gain in this interval than single-sex pigs. Entire male pigs had higher carcass lean meat content than female pigs (1.6 percentage units). Technological meat quality differed only slightly between the sexes. Females reared in mixed pens were sexually more mature than female pigs reared in single-sex pens, and mature females had higher growth rate but lower meat content in carcasses than immature females. In contrast, female contact did not influence sexual maturity of entire male pigs. Mixing entire male pigs with unfamiliar pigs at the abattoir resulted in more damaged skin compared with pen-wise keeping whereas female pigs had almost no visible skin damage. We therefore recommend that entire male pigs are not mixed with unfamiliar pigs during transport and at the abattoir, because of fighting and subsequent skin damage. The levels of skatole in fat were significantly lower in high-weight entire male pigs fed RPS compared to high-weight pigs without RPS. Androstenone levels in fat were high in all groups.

Keywords:

• Skatole
• androstenone
• boar taint
• male and female puberty
• pre-slaughter routine

Acknowledgments

This work was supported by grants from The Swedish Board of Agriculture. The authors thank the staff at Funbo-Lövsta Research Station for taking excellent care of the animals and for collecting data. We also thank Ingemar Hansson and Ulla Schmidt for all assistance at the slaughterhouse, Gertrud Andersson for carrying out the meat quality measurements and Marie-Amélie Crochet for help with the glycogen analyses. Lyckeby Culinar AB is gratefully acknowledged for providing raw potato starch.