Impact of Metabolizable Energy (ME) or Lactation ADFI on Sow and Litter Performance

Abstract Modern genetics push sows to produce a greater number of pigs/litter with heavier birth and wean weights while maintaining their own nutrient requirements for subsequent conception. Previous United Animal Health data (2018) showed that primiparous sows fed 3,332 ME kcal/kg lactation diets had piglets with increased average wean weight by 0.27 kg/pig compared to primiparous sows fed 3,188 ME kcal/kg. The objective of this study was to evaluate the impact of ME in relation to ADFI in lactation on sow and litter performance. A total of 428 DNA 241 F1 or PIC 1050 females (parity = 2.02 ± 1.04) were randomly allotted within farrowing group, genetics, and lactation entry weight to one of four dietary treatments. Treatments were arranged in a 2 × 2 factorial with ME (3,148 and 3,245 kcal/kg) and ADFI (4.54 and 6.35 kg/day). Feed was delivered daily and recorded via a computerized feeding system and daily intake measured by individual feeder weights. All sows assigned to the experiment were weighed upon entry and exit of the farrowing room. Litters were standardized within 24 h of birth within treatment and individual birth and wean weights were recorded via the LeeO RFID system. Wean-to-estrus interval was recorded from d-1 to d-9 post-weaning and conception rate was evaluated on day 35 post-breeding. Data were analyzed as a randomized complete block design with main effects of ME and ADFI, the interaction, and random effect of replicate. Regardless of energy level, sows assigned to 6.35 vs. 4.54 kg/d ADFI had increased (P 0.001) overall litter wean weight by 5.58% (77.72 vs. 73.80 kg/litter, respectively), which resulted in a 5.82% increase (P 0.001) in average piglet wean weight (5.86 vs. 5.53 kg/pig, respectively). Although there was no interaction observed between energy and ADFI for total weight loss, sows assigned to 3,245 vs. 3,148 ME kcal/kg had reduced (P = 0.016) total weight loss by 7.94% (-26.3 vs. -28.6 kg, respectively), and sows assigned 6.25 vs. 4.54 kg/d ADFI had reduced (P 0.001) total weight loss by 43.67% (-19.8 vs. -35.1 kg). Regardless of energy level, there was a 16.79% improvement (P 0.001) in sows expressing estrus by day 5-post weaning with high compared to low ADFI (85.59 vs. 68.80%, respectively). Sows fed high ADFI had improved conception rate (P 0.001) by 18.34% compared to low ADFI sows (90.35 vs. 72.01%, respectively). These data show increased ADFI to 6.35 kg/d improved piglet wean weight, sow weight loss, wean-to-estrus interval, and conception rate, whereas increased energy to 3,245 ME kcal/kg has limited impact on performance metrics in lactation and is unable to overcome the negative impact of low feed intake.