Document Type

Dissertation - Open Access

Award Date


Degree Name

Doctor of Philosophy (PhD)

Department / School

Animal Science

First Advisor

Richard C. Wahlstrom


It has been estimated that of the potential ova shed by the sow on1y about 55% result in live pigs born. Reproductive inefficiency can occur as a result of oversupplying or undersupplying energy. Since 1959, the National Research Council has reduced its listed energy requirements for the gravid sow considerably. The studies reported herein were conducted to evaluate metabolizable energy (ME) levels for gestating sows at and below the recommended levels and measure their effect on sow productivity as well as sow hematology at various stages of reproduction. Two experiments, each consisting of three trials, were conducted. Experiment 1, two winter tria1s and one summer trial, consisted of 60 gilt matings and 110 sow matings and metabolizable energy treatments of 3,000, 4,000, 5,000 am 6,000 kcal per day. Experiment 2, two summer trials and one winter trial, utilized 124 sow matings and metabolizable energy levels of 4,000, 5,000, 6,000 and 7,000 kcal daily. In the second experiment, blood sample were taken from sows approximately 30 days after breeding, 30 days before parturition and after 21 days of lactation. Blood values for hematocrit, hemoglobin, red blood cells, white blood cells, white blood cell differentiation, blood urea nitrogen, calcium, phosphorus, sodium and potassium were determined. In trial 1 of experiment 1, a winter trial, none of the energy levels were adequate under the conditions of the experiment. Two gilts and two sows receiving 3,000 kcal of ME and one sow receiving 5,000 kcal of ME died of emaciation. In trial 3, also a winter trial, all sows receiving less than 5,000 kcal of ME had to be removed from test and sows on all treatments lost weight during gestation. Environmental conditions of extreme cold, the use of no bedding and ice build-up in housing units must be credited with sane of the poor performance. Blood samples from sows which were taken off test showed marked increases in blood urea nitrogen with the most emaciated sows exhibiting the highest blood urea nitrogen levels. In the summer trial little difference was observed among dietary energy treatments. All sows gained weight during gestation and pig production was approximately equal among treatments, indicating all energy levels were adequate under these conditions. In the second experiment all three trials were combined for statistical analysis. Gestation weight gains were approximately twice as great for the summer trials as for the winter trial and a linear response due to treatment was observed with 6,000 kcal of ME producing the largest gain. It appeared that 4,000 kcal was inadequate during the winter and only marginal during the summer from the standpoint of gestation weight gain. Sows that gained more during gestation lost more or gained less during lactation. Significant negative correlations were observed between gestation gain and 14- and 21-day lactation gain. A significant linear decrease in number of live pigs born due to treatment was observed and number of stillborn pigs was highly correlated with gestation weight gain. The heaviest litter birth weight was produced by sows receiving 6,000 kcal of ME and a linear treatment effect on average pig birth weight resulted in the heaviest pigs from litters from sows receiving 6,000 and 7,000 kcal. of ME daily. No differences in number of pigs weaned were observed. A significant quadratic effect due to treatment was seen for litter weaning weight and for average pig weaning weight with the 6,000 kcal group of sows producing the heaviest pigs. Hematology variables were different among treatments and samples, but all fell into expected ranges for the reproducing sow.

Library of Congress Subject Headings

Swine -- Breeding




South Dakota State University