Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)


Animal Science

First Advisor

Crystal Levesque


growth performance, Lysine:energy, piglet robustness, sow productivity


Across 4 breeding groups, 63 primiparous and multiparous females were blocked by parity, balanced by weight, then randomly assigned to one of 3 gestation feeding regimens: Control (CON), 1.50 g SID Lys/Mcal ME from d2-110 of gestation; Phase Feeding 1 (PF1), 1.50 g SID Lys/Mcal ME from d2-89 and 2.11 g SID Lys/Mcal ME from d 90-110 of gestation; Phase Feeding 2 (PF2), 1.25, 1.07, and 0.88g SID Lys/Mcal ME from d2-89 for gilts, parity 1, and parity 2+, respectively and 2.11 g SID Lys/Mcal ME from d90-110 of gestation over 2 reproductive cycles. During lactation, all sows received a common lactation diet. Measures of sow productivity included maternal backfat, BW, litter characteristics at birth, colostrum nutrient content, and lactation feed intake. Piglet robustness was measured through analysis of cord blood cortisol, liver and muscle glycogen, Intestinal Alkaline Phosphatase activity, and small intestinal morphology at birth. Other markers of piglet quality and robustness included serum immunocrit at 2 days of age along with BW at d7 and weaning. To assess post-weaning performance, all piglets were weaned to an on-site wean-to-finish facility and raised in group pens according to maternal treatment. Pen feed disappearance and individual pig weights were determined at least once each month until market. Data were analyzed using both Mixed and Correlation procedures of SAS in a randomized complete block design with means separation using Scheffe’s adjustment. Altering Lys:energy ratio had minimal impacts on variables of sow productivity. Piglets born from PF1 litters during the first gestation/lactation cycle were heavier at birth (P < 0.01) compared to PF2 offspring, however no differences were detected in other litter characteristic parameters at birth. Though no differences were detected for ADG, ADFI, of G:F during the post-wean period, PF1 and PF2 offspring were heavier (P = 0.02) at adjusted d130 than CON pigs. PF1 offspring also and spent 4 days fewer on feed (P = 0.002) than CON offspring. During the second reproductive cycle, PF1 sows weighed less than PF2 females at d110 (P = 0.01) and less than CON sows at weaning (P = 0.02). Again, no differences were detected in litter characteristics other than BW at birth where PF1 piglets weighed more than offspring of both other treatments (P < 0.01). Second gestation/lactation offspring displayed minimal differences in BW, ADG, ADFI, and G:F post-weaning. However, though not statistically significant, PF1 offspring from block 3 were able to maintain the heavier birth and wean weights until market and weighed more than both other treatments. When data from all piglets was analyzed together, this advantage seems to be not detectable. During both reproductive cycles there were few detectable differences in biological markers of sow nutrient utilization although colostral fat content was greater for PF2 females compared to both CON and PF1 (P = 0.02) during the first lactation. Biological indicators of piglet robustness and performance potential also demonstrated few differences. Muscle samples from PF2 piglets tended to contain greater levels of glycogen than both other treatments (P = 0.08) and piglets born in the first half of the birth order tended to have higher (P = 0.08) serum immunocrit values. From these findings it seems there may be a benefit to altering the Lys:energy ratio during gestation on piglet growth performance during the suckling period and late finisher stages. Additional expenses associated with excess AA excreted as waste during gestation and maintaining market hogs for a longer period of time may also be decreased by implementing a phase-feeding program.



Number of Pages



South Dakota State University


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