Document Type

Thesis - University Access Only

Award Date

2011

Degree Name

Master of Science (MS)

Department / School

Animal Science

Abstract

A nursery pig feeding study was conducted to determine the effect of feeding increased dietary concentrations of amino acids on nursery pigs which were heavy and medium weight at weaning compared to the average of the weaning group. A subsequent finishing trial was conducted to determine the effect of amino acid treatments during the nursery period on finishing performance and carcass quality. A total of 144 (N = 144) crossbred, mixed sex pigs (21 ± 1 days-of-age) were stratified by weight and randomly allotted to pens within a defined weight group. Four dietary treatments were randomly assigned to 24 pens within a defined weight group of medium weight pigs and heavy weight pigs. Phase one diets were fed on d 1- 7 after weaning, phase two diets were fed on d 8-14 after weaning, and phase three diets were fed on d 15-35 after weaning. Treatments consisted of nursery diets formulated to increased concentrations of lysine, methionine, threonine and tryptophan. Amino acid concentrations were increased above the control (Control; n = 12) diet by 10% (Ctrl+ 10; n = 12), 20% (Ctrl+20; n = 12), and 30% (Ctrl+30; n = 12) using synthetic amino acids. However, post-trial biochemical analysis of dietary treatments revealed no clear or consistent amino acid titration among the dietary treatments. Pigs were allotted to pen by body weight (7.87 and 5.88 kg; SEM=0.06) at weaning. Heavy pigs were defined as pigs with a body weight greater than one standard deviation above the mean of a farrowing group. Medium pigs were defined as pigs with a body weight within one standard deviation of the mean of a farrowing group. Pigs were weighed at trial initiation and at each diet change; feed disappearance was determined during each phase. All pigs were bled on d 4, 11, and 28 after initiation of the trial for determination of plasma urea nitrogen (PUN) levels. After a five week nursery period, pigs were placed in a finishing facility. Pigs remained within the same treatment and pen groups when moved into the finishing facility. In the finishing period, pigs were phase fed a common com-soybean meal diet. Pig performance and carcass measurements subsequently were recorded. Heavy weight pigs displayed significantly improved average daily gain (ADG; 0.50 vs. 0.46 kg/d; SE= 0.011; P < 0.05) and average daily feed disappearance (ADFD; 0.72 vs. 0.65 kg/d; SE= 0.016; P < 0.05) compared with medium weight pigs during the overall nursery period. Medium wean pigs exhibited improved gain to feed ratio (G:F; 0. 71 vs. 0.69; SE = 0.004; P < 0.05) compared with heavy weaned pigs during nursery period. Pigs receiving the Ctrl+ 10 treatment displayed improved feed efficiency (G:F; 0.72 vs. 0.70, 0.69, 0.68; Ctrl+l0, Ctrl+30, Ctrl+20, Control; respectively; SE= 0.005; P < 0.05). Plasma urea nitrogen concentrations were significantly affected by weaning weight, dietary treatment, and day. Heavy weight nursery pigs had significantly increased PUN concentrations (14.73 vs. 12.70 mg/dL; SE= 0.678; P < 0.01) compared to medium weight nursery pigs. Ctrl+IO had decreased PUN levels when compared to the Control and Ctrl+20 treatments (12.21 vs. 15.00, 14.34 mg/dL; Ctrl+IO, Control, Ctrl+20; respectively; SE= 0.833 P < 0.05). During the finishing trial, there was a significant difference in ADG between dietary treatments but no differences in ADFD and G:F were observed. Pigs fed the Ctrl+ 30 diet had increased in ADG (0.95 vs. 0.90, 0.90 kg/d; Ctrl+ 30, Ctrl+ 10, Ctrl+20; respectively; SE = 0.049; P < 0.05). Medium weight pigs displayed increased total finishing trial G:F (0.38 vs. 0.37 kg/d; medium, heavy; respectively; SE= 0.004; P < 0.05). The effect of dietary treatment and weaning weight showed no significant difference in carcass characteristics. These results indicate that heavy weaned nursery pigs displayed improved ADG and ADFD during the nursery period while medium weaned pigs were more efficient during the nursery period. Medium weaned pig also displayed improved feed efficiency over the total trial. The effects of dietary treatments suggest an amino acid imbalance had occurred during diet formulation resulting in valine becoming the first limiting amino within all treatments. Increased G:F observed in pigs receiving Ctrl+ 10 treatment during the nursery period could be the result of increased g/d intake of valine.

Library of Congress Subject Headings

Swine -- Feeding and feeds

Amino acids in animal nutrition

Format

application/pdf

Number of Pages

73

Publisher

South Dakota State University

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