Effect of freezing colostrum on resistance of neonatal lambs to experimental infection with Escherichia coli

Abstract

Effects of freezing and thawing colostrum on resistance of neonatal lambs to experimental infection with Escherichia coli were evaluated using 16 newborn lambs. Eight sets of twins were fed colostrum from the ewe at 3.3 and 15.4 h of age. Colostrum was obtained from the ewe and divided into two equal portions. One portion was frozen in liquid nitrogen and then thawed in a water bath prior to feeding. The second portion was held at approximately 39°C in a water bath. Four sets of twins were orally inoculated with 3 × 108 to 1011 cfu of enterotoxigenic E. coli at 24 h of age. Blood was sampled at 0 and 24 h for IgG and differential leukocyte counts. Freezing and thawing reduced cell viability in colostrum from 43.1 to 10.1%. Neither freezing and thawing colostrum nor E. coli inoculation affected plasma IgG or total or differential leukocyte counts, fecal scores, respiration rates, rectal temperatures, fecal coliform excretion or intake. Shedding of K99 + E. coli was increased and body weight gain from 7 to 14 d was decreased when lambs were inoculated with E. coli. Results of this study suggest that freezing and thawing colostrum does not destroy components that provide resistance to E. coli challenge in newborn lambs.