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

Effects of freezing and thawing colostrum on resistance of neonatal lambs t o experimental infection with Escherichia coli were evaluated using 16 newb orn lambs. Eight sets of twins were fed colostrum from the ewe at 3.3 and 1 5.4 h of age. Colostrum was obtained from the ewe and divided into two equa l 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 3 9 degreesC in a water bath. Four sets of twins were orally inoculated with 3 x 10(8) to 10(11) cfu of enterotoxigenic E. coli at 24 h of age. Blood wa s sampled at 0 and 24 h for Ige and differential leukocyte counts. Freezing and thawing reduced cell viability in colostrum from 43.1 to 10.1%. Neithe r freezing and thawing colostrum nor E. coli inoculation affected plasma Ig e or total or differential leukocyte counts, fecal scores, respiration rate s, 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 re sistance to E. coli challenge in newborn lambs.