Procedures: Four hundred one sows that farrowed 904 litters over three parities were used in this experiment. Females were assigned to treatments as parity 0 (n=311) or parity 1 (n=90) sows and maintained on their assigned treatments for three reproductive cycles or until they were culled, whichever occurred earlier. Sows were assigned randomly to one of four experimental treatments in a 2 x 2 arrangement. Dietary treatments included a control diet composed of corn and soybean meal (CON) fed during gestation and lactation or similar diets containing 40% DDGS in gestation and 20% DDGS in lactation (DDGS). Within dietary treatment, sows were housed in either individual stalls or group pens (50 sows/pen) with an electronic sow feeder during gestation. Behavior of sows was recorded by video cameras for 24 hours using 40 focal sows in pens and 27 focal sows in stalls. Group-housed sows were recorded immediately after mixing in the pens. Stalled sows were recorded 7 to 10 days after placement in stalls. Total collection of feces and urine were performed on 19 gestating sows fed CON and 21 gestating sows fed DDGS to determine effects of diet on slurry output by sows.
Findings: Sows fed DDGS or CON began the experiment with equal body weight. However, at the end of the first reproductive cycle, DDGS-fed sows were 4 kg lighter than CON-fed sows and at the end of the second reproductive cycle they were 8 kg lighter than CON-fed sows. This difference in body weight stabilized (7 kg) at the end of the third reproductive cycle. These differences in body weight suggest that young sows were less able to derive energy and nutrients for body growth from DDGS diets than older sows. Live born litter size was 0.5 pigs less for DDGS-fed compared with CON-fed sows which translated into 0.4 fewer pigs per litter at weaning. The smaller litters nursing DDGS-fed sows gained less weight than litters nursing CON-fed sows. The smaller weight gain of litters from DDGS sows was most evident during the first reproductive cycle lending support to the idea that young sows had more difficulty digesting diets containing DDGS. Sows housed in pens during gestation and fed DDGS supported the lowest litter weight gain compared with sows assigned to the remaining three treatments. Daily feed intake during lactation and wean-to-estrus intervals were not influenced by diet. The percentage of sows completing three parities in this experiment (CON/stall: 71.8%; CON/pen: 56.0%; DDGS/stall: 66.0%; DDGS/pen: 55.5%) was not statistically different among diet and housing treatments. Over the entire experiment, feeding DDGS reduced the total number of pigs weaned by 0.8 while housing sows in pens of 50 sows during gestation reduced total number of pigs weaned by 2.1. Sows fed DDGS were more aggressive in pens as they were involved in longer and more aggressive fights with pen-mates compared with CON-fed sows. In contrast, DDGS-fed sows in stalls spent more time resting and less time engaged in stereotypic behaviors than sows assigned to CON which suggests sows were more satiated and content. As expected, feeding DDGS to sows did reduce dry matter digestibility of the diet but, contrary to expectations, did not affect output of slurry. This suggests that feeding DDGS to sows will not decrease residence time in slurry storage pits. Nutrient composition of slurry was not affected by inclusion of DDGS in the diet of pregnant sows.
Conclusions: It appears that feeding high levels of DDGS to reproducing sows may result in marginal depressions in production of weaned pigs. These reductions are more likely in young sows (parity 0 and 1) compared with older sows. In this study, gestation housing system had a larger effect on reproductive performance than did diet. Longevity of sows was not affected by inclusion of DDGS in the diet. Slurry output from pregnant sows and nutrient composition of slurry was not influenced by inclusion of DDGS in the diet.
