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Impact of reduced crude protein diets on lactating sow nitrogen utilization and piglet performance

Monday, March 17, 2014: 2:30 PM
312-313 (Community Choice Credit Union Convention Center)
Lee Anne Huber , University of Guelph, Guelph, ON, Canada
Cornelis F.M. de Lange , Department of Animal and Poultry Science, University of Guelph, Guelph, ON, Canada
Uffe Krogh , Aarhus University, Foulum, Denmark
David Chamberlin , Michigan State University, East Lansing, MI
Nathalie L. Trottier , Michigan State University, East Lansing, MI
Abstract Text:

Forty lactating multiparous Yorkshire sows were used to determine if reducing dietary crude protein (CP) and supplementing with crystalline amino acids (CAA) increases piglet performance and maternal N utilization during early and peak lactation. Sows were assigned to 1 of 4 diets: [1] 16.0% CP (as-fed; analyzed contents; HCP); [2] 15.7% CP (MHCP); [3] 14.3% CP (MLCP); [4] 13.2% CP (LCP); diet HCP was formulated using soybean meal and corn as the only Lys sources. Across diets standardized ileal digestible (SID) content of Lys was 0.86%, based on analyzed content and estimated SID. Other essential AA were included to exceed requirements. Sow and piglet BW were measured on d 1, 3, 7, 14, 18 and 21 of lactation. Sow N balances were conducted between d 3 and 7 (early) and d 14 and 18 (peak). Milk N output was calculated from estimated milk yield and analyzed true protein concentration. Sow BW change and litter ADG did not differ between diets (mean: −248 and 2259 g/d, respectively), nor did sow average daily DM intake (mean: 4.05 and 6.12 kg/d; early and peak lactation, respectively) or fecal N digestibility (mean: 88.6%). Nitrogen intake decreased as dietary CP decreased (114.3, 106.0, 107.4, and 99.0±5.29 g/d and 169.5, 168.3, 161.2, and 145.1±5.29 g/d for HCP, MHCP, MLCP, and LCP in early and peak lactation, respectively; Linear (L) P<0.05 and quadratic (Q) effects of diet CP content: P>0.10). In early lactation, N retention (N intake – N excretion with feces and urine) and milk N output were not affected by diet (P>0.10), and N retained as percentage of N intake tended to increase as dietary CP decreased (L: P=0.09). In peak lactation, N retention decreased (122.5, 123.8, 121.2, and 109.0±4.88 g/d for HCP, MHCP, MLCP, and LCP, respectively; L: P<0.05 and Q:  P=0.16), N retained as percentage of intake tended to increase (L: P=0.11), and estimated efficiency of using retained N for milk N output increased (51.0, 55.2, 57.1, and 66.3±8.43 % for HCP, MHCP, MLCP, and LCP, respectively; L: P<0.05). Feeding lactating diets reduced in CP from 16.0 to 14.3% with CAA inclusion as partial replacement for limiting AA maintains piglet performance and improves N utilization efficiency, but at the lowest dietary CP N retention during peak lactation was reduced.    

Keywords: amino acid intake, lactating sows, nitrogen retention