Eighty-eight gilts [initial body weight (BW) 49.8 +/- 0.8 kg] were recruited to determine the effects of moderate energy and protein restriction during the development period on changes in BW and backfat depth (BF) and subsequent lactation performance. Gilts were randomly assigned to one of four feeding programs: 1) standard commercial diet fed ad libitum (CON), 2) standard commercial diet fed 10% or 3) 20% below ad libitum, or 4) a high-fiber diet fed ad libitum [2.5 times more fiber (neutral detergent fiber) than the commercial diet to dilute net energy and crude protein by approximately 20% and 13%, respectively; FIB]. The gilts were housed individually and received the feeding programs between 90 and 190 (breeding) d of age and standard gestation and lactation diets thereafter. Litters were standardized to 12 +/- 1 pigs within 48 h of farrowing; weaning occurred at 20.0 +/- 0.4 d of age. Gilts that received the 20% restricted program had lower overall average daily feed intake (ADFI) during the development period (2.64 +/- 0.04 kg; P < 0.05) versus all other feeding programs and gilts that received the 10% restricted program had lower ADFI than FIB and CON, which were not different (2.96 vs. 3.44 and 3.47 +/- 0.04 kg for 10%, FIB and CON, respectively; P < 0.05). Plasma free fatty acid (FFA) concentrations on day 180 of age were lower for gilts that received the 10% and 20% restricted programs compared to gilts that received the FIB and CON programs, which were not different (97 and 86 vs. 220 and 149 +/- 29 mu Eq/L, respectively; P < 0.05). Plasma concentrations of glucose, urea, prolactin, and IGF-1 were not different among feeding programs on day 180 of age. At breeding, gilts that received the FIB and 10% programs had lower BW and BF versus CON (145.7 and 144.8 vs. 155.2 +/- 0.9 kg and 14.4 and 14.8 vs. 16.5 +/- 0.2 mm for BW and BF, respectively; P < 0.05) but greater BW than gilts that received the 20% restricted program (137.9 kg; P < 0.05). The BW and BF of gilts did not differ at the end of gestation or at weaning. The ADFI of sows during lactation and offspring birth weight and growth rate during lactation and the 5-wk nursery period were not influenced by gilt development feeding program. Therefore, a high-fiber feeding program could be used in group-housing gilt-development scenarios, where feed is offered ad libitum, to control BW and BF prior to breeding without influencing milk production in the subsequent lactation period. Lay Summary Gilt development feeding programs are important to ensure that the female grows at an appropriate rate, without becoming overconditioned or developing locomotion issues. Moreover, between 90 d of age and puberty is the first phase of rapid mammary development, which is necessary to support milk production after farrowing and which can be negatively impacted by reduced energy and protein intakes. Increasing the dietary fiber content is a means to reduce energy intake, to slow growth rates, and to minimize excessive body fat gains. In this study, it was demonstrated that providing a high-fiber feeding program during the gilt development period controlled body weight (BW) and backfat thickness at breeding, while subsequent lactation performance was not impacted. Therefore, a high-fiber feeding program could be used in group-housing gilt-development scenarios where feed is offered ad libitum, in order to control BW and fatness prior to breeding, without influencing milk production in the subsequent lactation period. A high-fiber feeding program for gilt development can be used to control body weight and back fat thickness at breeding, without negatively impacting subsequent lactation performance.
