10 Effects of different feeding levels during gestation on gilt reproductive performance during the first lactation
Authors: dos Santos Leticia Moreira , Maiorka Alex , Vier Carine M , Orlando Weasley A , Siqueira Amanda P , Silva Gefferson , Gonsalves Ray Nascimento , Zappani Vanderlei , Beraldin Evandro Cezar , Lu Ning , Dritz Steve 
Published: May 2024

Abstract
Our objective was to determine the effects of different feeding levels for gilts during gestation on reproductive performance during the first lactation. A total of 1,187 PIC Camborough gilts were used. Gilts were randomly allotted in a randomized complete block design based on breeding week, body weight (BW), and age to one of four treatments differing in daily metabolizable energy (ME) intakes per day during gestation. Gilts were housed in stalls throughout the entire gestation and individually fed with a gestation diet containing 2.95 Mcal of ME/kg via feed boxes that were weekly calibrated. Treatments consisted of 1) 5.0 Mcal of ME/d (1.7 kg feed/d) throughout the entire gestation; 2) 5.9 Mcal of ME/d (2.0 kg feed/d) throughout the entire gestation; 3) 6.8 Mcal of ME/d (2.3 kg feed/d) throughout the entire gestation; and 4) 5.0 Mcal of ME/d (1.7 kg feed/d) from breeding until d 90 of gestation, and then 5.9 Mcal of ME/d (2.0 kg feed/d) from d 90 to d 112 of gestation. Gilt was the experimental unit and data were analyzed using generalized linear mixed models with the lmer and glmer functions of R. There was no evidence (P &gt; 0.10) for treatment differences on gilt BW and age at breeding, with gilts averaging 156.7 kg at 210 d of age (Table 1). Gilts receiving 6.8 Mcal of ME/d during gestation were heavier (P &lt; 0.05) at farrowing compared with all other treatments; however, these gilts lost (P &lt; 0.05) more BW during lactation. Gilts receiving 5.0 Mcal ME/d throughout the entire gestation had less (P &lt; 0.05) maternal net BW gain from breeding to weaning compared with gilts receiving 6.8 Mcal ME/d. Gilts receiving 6.8 Mcal of ME/d gained more (P &lt; 0.05) caliper scores (CS) from breeding to d 90 of gestation compared with gilts receiving 5.0 Mcal ME/d. Regardless of feeding level, gilts lost an average of 0.85 CS from d 90 to d 112 of gestation. Overall, gilts receiving 6.8 Mcal of ME/d gained more CS during gestation, but lost more CS during lactation (P &lt; 0.05). There was no evidence for differences in gilt backfat depth measurements (P &gt; 0.10). Gilt feeding levels did not impact (P &gt; 0.10) total piglets born, percentage sillborn, or percentage of mummified fetuses. Gilts receiving 5.0 Mcal of ME/d had greater (P &lt; 0.05) percentage piglets born alive compared with gilts receiving 5.9 Mcal of ME/d, with other treatments intermediate. There was no evidence (P &gt; 0.10) for treatment differences in average piglet BW, average piglet daily gain during lactation, piglet mortality from cross foster to weaning, or wean to estrus interval in the next cycle. In summary, increasing energy intake of gilts during the first gestation did not impact reproductive performance during the first lactation, but gilts receiving 5.0 Mcal of ME/d throughout the entire gestation had less maternal net BW gain.