Abstract:
Thirty calves were randomly assigned to 2 treatments and fed until weaning (42 days (d) of age).
Treatments were a control group (n=15), which did not receive Megasphaera elsdenii (Me0) and
a M. elsdenii group, which received a 50-mL oral dose of M. elsdenii NCIMB 41125 (108
CFU/mL) at d 14 d of age (Me14). Calves were given colostrum for the first 3 d followed by
limited whole milk feeding. A commercial calf starter was offered ad libitum starting at d 4 until
the end of the study. Fresh water was available throughout the study. Feed intake and growth
were measured. Blood samples were collected via jugular venipuncture to determine β-
hydroxybutyrate (BHBA) concentrations. Fourteen male calves (7 per group) were euthanized
on d 42 and digestive tracts harvested. Reticulo-rumen weight was determined and rumen tissue
samples collected from the cranial and caudal sacs of the ventral and dorsal portions of the rumen for measurements of papillae length, papillae width, and rumen wall thickness. Dosing
with M. elsdenii NCIMB 41125 improved starter dry matter intake (DMI), weaning body weight
(BW), and tended to improve average daily gain. Calves in Me14 group had greater plasma
BHBA concentration than Me0-calves during the last 3 weeks of the trial, and had at d 42 greater
reticulo-rumen weight, papillae width and papillae density compared to Me0. No differences in
rumen wall thickness or papillae length were observed between the two groups. Total volatile
fatty acids, acetate, and propionate production did not differ between treatments, but butyrate
production was greater in Me14 than Me0. Dosing M. elsdenii NCIMB 41125 showed benefit for
calves with improved feed intake and rumen development suggesting increased epithelium
metabolism and improved absorption of digestive end products.
