The effect of different dietary energy levels during rearing and mid-gestation on gilt performance and culling rate

In an effective pig production, proper feeding management during rearing and first gestation is important to ensure a good lifetime performance in terms of a high number of weaned pigs per sow lifetime. Dietary energy levels offered during these periods may effect the body compositional development of gilts and their productive and reproductive performance. The aim of the current study was to compare the development and productive performance of gilts when fed the commercial recommendations of dietary energy levels during rearing and mid-gestation with an increased dietary energy level. A total of 500 Norwegian Landrace×Yorkshire (LY) gilts were followed from 25 kg live weight (LW) and until rebreeding or culling after weaning of their first litter. The gilts were offered two dietary energy levels during rearing; 13.2-29.0 MJ NE/d (High) or 10.6-22.9 MJ NE/d (Norm), and two dietary energy levels during mid-gestation (day 42-94); 27.3 MJ NE/d (High) or 22.3 MJ NE/d (Norm). This gave four gilt development strategies, High/High (HH), High/Norm (HN), Norm/High (NH), and Norm/Norm (NN). Data collection included individual gilt weight, age, backfat, number of piglets born and weaned, litter weights at birth and weaning, and weaning-to-service interval (WSI). At selection for mating (110 kg LW), gilts reared on the higher energy diet were younger (P<0.001) and had more fat reserves (P<0.0001) compared to the norm energy reared gilts. Three weeks before expected parturition the NN gilts were older (P<0.001), lighter (P=0.075) and leaner (P=0.013) compared to the HH gilts, with the HN and NH gilts at intermediate levels. The productive and reproductive performance was not affected by gilt development strategy. Removal reasons did not differ between dietary treatments, but the probability of removal tended to be higher among the norm energy reared gilts compared to the higher energy reared gilts (P=0.056), and lower among the HH gilts compared to the other three gilt development strategies (P=0.033). In conclusion, although maternal performance was not affected, gilt development strategy affected both development and survival probability.