Submitted to: Research Workers in Animal Diseases Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: November 6, 1996
Publication Date: N/A
Technical Abstract: Periparturient dairy cows have a high incidence of new intramammary infections (IMI). Numbers of bacteria in bedding are directly correlated with IMI rates. Not only does parturition significantly compromise immune defenses, stress can cause the cow to fluctuate feed intake. Previous studies in cattle have shown an association between fluctuations in feed intake and increased shedding of coliform bacteria in feces. We investigated whether fecal coliform shedding in dairy cows changed during the periparturient period. Fecal samples from 5 cows were obtained digitally beginning about 4 wks prepartum through 2 wks postpartum. Each 3-5g wet weight sample was diluted in 12-20 ml of saline (4 ml saline per 1 g feces). Samples were serially diluted and plated on MacConkey's agar to measure the number of coliform bacteria/gm feces. Shedding of coliform bacteria in feces was low to undetectable at 4 wks prior to parturition, yet from -1 wk to +1 wk, coliform numbers increased by 10**5-10**7 cfu/g feces. In another study, we attempted to correlate any changes in coliform shedding with feed intake changes. Again, bacterial shedding increased by 10**5-10**7 cfu/g feces in each of 7 cows, however, no association with feed intake was observed. Random monitoring for Escherichia coli O157:H7 during periods of increased coliform numbers in feces yielded no positive cultures on selective media.