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One of the biggest challenges is find good feeding strategies for rearing of gilts to ensure a high level of weaned pigs during the sows’ reproductive life. The aim of this study was to investigate the development of gilts when offered the commercial recommendations for dietary energy levels during rearing and mid-gestation compared to higher dietary energy levels, and to evaluate how these different gilt development strategies would affect productive and reproductive performance. A total of 500 Norwegian Landrace x Yorkshire gilts were followed from 25 kg live weight (LW) in their first reproductive cycle 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, back fat, 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<0.001) 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, this study showed that dietary energy level during rearing affect the age of attainment of puberty and the backfat thickness of gilts at selection for mating. Considering the four gilt development strategies investigated in this paper, increasing the dietary energy level during rearing and mid-gestation was the preferred strategy for this genotype. Although productive and reproductive performance was not affected by gilt development strategy, more gilts from the HH group made the transition from first to second parity, which is of high economical value for the pig producer.
Thingnes, S. L., Hallenstvedt, E., Sandberg, E. And Framstad, T. 2015. The effect of different dietary energy levels during rearing and mid-gestation on gilt performance and culling rate. Livestock Science 172; 33–42. http://dx.doi.org/10.1016/j.livsci.2014.11.012
