Effects of pig sexing and the period of restricted feed supply on growth performance

The effect of pig sexing on growth performance and carcass composition was investigated under two feeding strategies.Feeding restriction was applied either at the beginning or at the end of the fattening period. In RALIB treatment, initial feed supply averaged 4% of initial body weight and increased by 25 g/d/pig afterwards. In LIBRA treatment, pigs were fed ad libitum up to 2.5 kg/d. Pigs were group-housed by 6 and slaughtered on three separate days over three weeks. No significant difference of overall average daily feed intake, average daily gain (ADG) and feed conversion ratio (FCR) was observed at slaughter between both feeding strategies. However, restricted feed supply at the end of the fattening period (LIBRA) improved significantly carcass leanness. Feed allowance to RALIB pigs averaged 79% ad libitum over the first 48 fattening days and resulted in a 15% decrease of ADG over this period. After the 73rd day, feed supply to RALIB pigs exceeded their ingestion capacity and a higher ADG was then observed (+73 g/d when compared to LIBRA pigs). However, the initial growth delay was not completely compensated. Thus, RALIB pigs were lighter before the first slaughtering than the LIBRA (-3 kg, P