Document Type

Thesis - University Access Only

Award Date

1998

Degree Name

Master of Science (MS)

Department / School

Animal Science

Abstract

Performance trials were conducted to determine if increasing amounts of supplemental NaCl or dietary Na above the NRC (1988) recommendation results in improved performance for weanling pigs fed complex diets regardless of whey content. Three experiments using 488 crossbred weanling pigs were arranged in randomized complete block designs. Pigs of Exp. 1 and 2 were weaned at 15 to 28 d of age, divided into young and old groups and further divided into light and heavy pigs within age groups. Experiment 1 (28 d), consisting of six pigs per pen (24 pens), examined a factorial arrangement of NaCl additions (.25 vs .50%) and whey levels (0, 15, and 30%). Similarly, Exp. 2 (27 d), consisting of three pigs per pen (48 pens), examined a factorial arrangement of NaCl additions (.25, .50, and .75%) and whey levels (0, 10, 20, and 30%). Pigs were given ad libitum access to feed and water. Diets contained 1.15% lysine, .80% Ca and .70% P. The basal com, soybean meal, plasma protein, and fishmeal diets (0 to 30% whey) contained .26 to .57% Na and .20 to .80% Cl, respectively. An increase in the whey level resulted in a quadratic effect on average daily gain (ADO) (395, 448, and 452 g/d, P < .05), average daily feed intake (ADFI) (569, 645, and 666 g/d, P < .01), and gain over feed (G/F) (0.695, 0.696, and 0.679, P<.10) in Exp. 1 for the entire 28 d and a linear effect on ADG (402,426,422, and 447 g/d, P < .05) in Exp. 2 for the entire 27 d. A negative effect due to increasing NaCl occurred during the 1 to 14-d period in G/F (0.837 vs 0.813, P < .05), the 15 to 28-d period in ADFI (898 vs 878 g/d, P < .10), and the overall 28-d period in ADFI (628 vs 625 g/d, P<.05) and G/F (0.694 vs 0.685, P < .10) in Exp. 1. Sodium chloride by whey interactions occurred in Exp. 1 with poorer ADG ( P < .10) and ADFI ( P < .01) due to .50% NaCl in the O and 30% whey diets but greater ADG ( P < .05) and ADFI ( P < .01) due to .50% NaCl in the 15% whey diet. No NaCl main effects or NaCl by whey interactions occurred in Exp. 2. Inconsistent NaCl by initial weight interactions were found between Exp. 1 and 2, but the NaCl by initial age interactions between Exp. 1 and 2 were similar. Feed intakes (P < .05) were increased for older pigs but not for younger pigs during the 1 to 14-d period due to higher NaCl levels in Exp. 1. Older pigs had poorer ADFI (P < .05) due to the higher NaCl levels in Exp. 1 during the 15 to 28-d period and the overall 28-d period; similarly, a negative linear response in ADG (P<.10) due to increasing NaCl levels occurred during the 15 to 27-d period in Exp. 2. Experiment 3 (21 d), consisting of five pigs (22 to 28-d old and 7 .34 kg) per pen ( 40 pens), examined a factorial arrangement of total dietary Na levels (.36, .45, .57, .66, and .73%, via NaCl) and whey levels (0 and 15%). Pigs were blocked by weaning date. The basal com, soybean meal, plasma protein, and fishmeal diets (0 and 15% whey) contained 1.23% lysine, .80% Ca, and .70% P. Pigs had ad libiturn access to feed and water. The 15% whey diet produced greater ( P < .01) pig ADG ( 441 vs 483 g/d) and ADFI (560 vs 617 g/d). Sodium levels had a quartic effect on ADG (299, 301, 329, 257, and 321 g/d, P < .05) and ADFI (305,301,327, 256, and 302 g/d, P < . 10) during the 1 to 7-d period, with the peak performance at the .57% Na level. However, a negative cubic effect ( P < . 05) due to increasing Na levels occurred during the 15 to 21-d period for ADG (649,664, 621,603, and 618 g/d) and ADFI (909, 903, 882,824, and 8 72 g/d). Similar negative results due to increasing dietary Na levels occurred during the overall 21-d period with a quartic effect ( P < .05) for ADG (472, 470, 470,439, and 459 g/d). No dietary whey by dietary Na interactions occurred in Exp. 3. The null hypothesis is not rejected based on the negative responses in performance to increasing NaCl in Exp. 1, the lack of response in performance to increasing NaCl in Exp. 2, and the overall greater performance with lesser levels of total dietary Na in Exp. 3. The null hypothesis states that increasing additions of NaCl at greater than the recommended (NRC, 1988) level is not beneficial to the performance of weanling pigs fed complex diets regardless of whey content.

Library of Congress Subject Headings

Swine -- Feeding and feeds Salt in animal nutrition Sodium Whey

Format

application/pdf

Number of Pages

119

Publisher

South Dakota State University

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