Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)

Department / School

Animal Science

First Advisor

Crystal Levesque


Amino Acid, Efficiency of Use, Lysine, Protein Deposition


The total daily amino acid (AA) requirements for pregnant sows are based of Lys which is the first-limiting AA in swine diets. The SID Lys requirements are estimated by the NRC (2012) gestating sow model as the sum of those required for maintenance and protein retention divided by the efficiency of SID Lys utilization. The NRC (2012) gestating sow model assumed AA efficiency is constant across stages of gestation and parities; however, this does not reflect the change in metabolic demand of various age sows at different stages of gestation. Therefore, an experiment was conducted to evaluate the efficiency of SID Lys utilization for whole body protein deposition (kSID Lys WB Pd) in pregnant sows during early, mid and late gestation. Three 12 d N-balance studies were conducted to represent different periods of gestation for gilts, P1 and P2 sows in two blocks. Graded levels of SID Lys below the NRC (2012) requirements were used to estimate the kSID Lys WB Pd within balance periods. The kSID Lys WB Pd was defined as the slope of the linear relationship between SID Lys intake and SID Lys retention. The kSID Lys WB Pd for gilts was 0.71, 0.37 and 0.52 for early, mid and late gestation, respectively; for P1 sows the kSID Lys WB Pd was 0.56, 0.38 and 0.48 for early, mid and late gestation, respectively; for P2 sows the kSID Lys WB PD was 0.44 and 0.65 for early and late gestation, respectively. The kSID Lys WB Pd could not be determined for mid gestation in P2 sows due to data failure to meet statistical assumptions (i.e. normality of residuals). The kSID Lys WB Pd was greatest in early gestation for gilts and late gestation for P2 sows and lowest for all parities in mid gestation. Our present study is important to refine the AA requirement models for gestating sows and suggest the need for parity-segregated phase feeding.

Library of Congress Subject Headings

Sows -- Feeding and feeds.
Swine -- Feeding and feeds.
Lysine in animal nutrition.
Amino acids in animal nutrition.
Proteins in animal nutrition.
Sows -- Pregnancy.



Number of Pages



South Dakota State University



Rights Statement

In Copyright