Table 1.

Experiment A: time course of Megasphaera elsdenii colonization of newborn pigs

Animal groupa	Day after birth	Day from weaning	M. elsdenii fecal concnb
			Range	Avg (no. of pigs)	SD
Group 1	11	−10	<LOD	Und (6)	NA
	18	−3	<LOD	Und (6)	NA
	25	+4	<LOD to 3.5 × 106	1.4 × 106 (3)	1.8 × 106
	32	+11	1 × 107 to 2.1 × 108	1.3 × 107 (6)	106
	46	+25	5.2 × 107 to 2 × 108	1.4 × 108 (6)	6 × 107
	70	+49	4 × 105 to 1 × 108	2.4 × 107 (6)	107
Group 2	32	+11	4.6 × 106 to 1.2 × 107	1.2 × 107 (4)	3.7 × 106
	70	+49	4 × 105 to 1.4 × 106	8.5 × 105 (4)	4.4 × 105

^aAll pigs were littermates weaned at 21 days after birth. At weaning, group 1 pigs (six) were removed to a separate pen in the same room as the mother sow and group 2 pigs (four) were removed to a pen in a separate room.

^bConcentrations (CFU/g [wet weight] of feces) were determined by plating serial dilutions of fecal suspensions onto Me109M agar medium selective for M. elsdenii growth. SD, sample standard deviation for average fecal counts; Und, no M. elsdenii colonies were obtained; NA, not applicable, insufficient data; <LOD, beneath limit of detection and estimated to be <8,000 CFU/g (wet weight) of feces for loop samples (0.3 g) taken at 11, 18, and 25 days after birth and <5,000 CFU/g (wet weight) of feces for whole fecal (5-g) samples taken at 32, 46, and 70 days after birth.