Utilization of distillers dried grains with solubles and phytase in sow lactation diets to meet the sow's P requirement and reduce fecal P concentration

¹ Michigan State University, East Lansing 48824
² Dakota Gold Research Association, Sioux Falls 57059

^* To whom correspondence should be addressed. E-mail: hillgre{at}msu.edu.

	Abstract

Two experiments were completed to determine the potential for using distillers dried grains with solubles (DDGS) in diets with or without phytase to provide available P, energy, and protein to highly-productive lactating sows without increasing fecal P. In Exp. 1, the dietary treatments were: (1) corn and soybean meal with 5% beet pulp (BP), or (2) corn and soybean meal with 15% DDGS (DDGS). Besides containing similar amounts of fiber, diets were iso-nitrogenous (21% CP, 1.2% Lys), and iso-phosphorus (0.8% P). Sixty-one sows were allotted to dietary treatments at approximately 110 d of gestation (when they were placed in farrowing crates) based on genetics, parity, and date of farrowing. Sows were gradually transitioned to their lactation diet. On d 2 of lactation, litters were cross-fostered to achieve 11 pigs/litter. Sows and litters were weighed on d 2 and 18. Fecal grab samples were collected on d 7, 14, and 18 of lactation. Dietary treatment did not affect number of pigs weaned (10.9 vs. 10.8) or litter weaning weight. On d 14, DDGS sows had less fecal P concentration than BP sows (28.3 vs. 32.8 mg/g; P = 0.04). Fecal Ca of sows fed DDGS decreased for d 7, 14, and 18 (55.6, 51.4, and 47.1 mg/g DM, respectively; P = 0.05) but not for BP sows. In Exp. 2, the dietary treatments were: (1) corn and soybean meal (CON), (2) CON + 500 phytase units (FTU) Natuphos/kg diet (CON + Phy), (3) corn and soybean meal with 15 % DDGS and no phytase (DDGS), or (4) DDGS + 500 FTU Natuphos/kg diet (DDGS + Phy). Sows (n = 87) were managed as described for Exp 1. Litter weight gain (46.0, 46.3, 42.1, and 42.2 kg; P = 0.25) and sow weight loss (8.1, 7.2, 7.4, and 6.3 kg for CON, CON + Phy, DDGS, and DDGS + Phy, respectively; P = 0.97) were not affected by dietary treatment. Fecal P concentration did not differ among dietary treatments, but was reduced at d 14 and 18 compared with d 7 regardless of treatment (P = 0.001). However, fecal phytate P concentration was decreased by the addition of DDGS when DDGS and DDGS + P were compared with the CON sows except on d 7 (P < 0.05). Sows fed CON diet had greater fecal phytate P than sows fed DDGS, and sows fed DDGS + P had less fecal phytate P than sows fed DDGS with no phytase (P = 0.001). While these experiments were only carried out for one lactation, these results indicate that highly-productive sows can sustain lactation performance with reduced fecal phytate P when fed DDGS and phytase in lactation diets.

Key Words: distillers dried grains and solubles, lactation, P excretion, phytase, sow