Fecal trimethylamine, lactate and volatile fatty acid concentrations and their relationships with diarrhea in newborn dairy calves.

To clarify the significance of fecal trimethylamine, lactate and volatile fatty acids (VFAs) in fermentative development of the hindgut in neonatal calves and the occurrence of diarrhea, 143 fecal samples (47 diarrheic, 93 normal and 3 meconium) were collected from 58 dairy calves fed milk. An additional 20 fecal samples were obtained from 10 weaned calves aged 13 to 18 weeks. Fecal pH, trimethylamine, ammonia, lactate and VFAs were analyzed. Compared with weaned calves, the trimethylamine level was higher in milk-fed calves and was associated with a large number of cases of diarrhea, but it had little relationship with the fecal ammonia level. Feces collected from the youngest (<2 weeks age) calves were more acidic and were associated with a higher lactate concentration. Lactic fermentation and fecal acidity were tremendously accelerated, particularly in diarrhea. Despite large fluctuations, the VFA concentrations were lower in diarrheic than in normal feces. In diarrheic feces at the youngest stage, the lower proportion of n-butyrate in the VFAs was accompanied by the elevated proportion of acetate. However, the fermentative differences between the diarrheic and normal feces were less apparent with advancing age. Thus, the fecal lactate and VFA profiles revealed marked changes with advancing age and suffering from diarrhea. Upon comparison with weaned calves, the trimethylamine level was clearly higher in the milk-fed calves and showed huge elevations in diarrheic cases.