|Raeth-Knight, M - UNIVERSITY OF MINNESOTA|
|Linn, J - UNIVERSITY OF MINNESOTA|
|Jung, Hans Joachim|
Submitted to: Journal of Dairy Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 18, 2006
Publication Date: April 1, 2007
Repository URL: http://hdl.handle.net/10113/16608
Citation: Raeth-Knight, M.L., Linn, J.G., Jung, H.G. 2007. Effect of direct-fed microbials on performance, diet digestibility, and rumen characteristics of Holstein dairy cows. Journal of Dairy Science. 90:1802-1809. Interpretive Summary: Because of concern about the use of antibiotics as feed ingredients for livestock production, farmers are looking for natural alternative feed additives that will provide the same performance benefits. Several types of microorganisms have been proposed for inclusion in dairy cow diets as such beneficial feed additives. A study was conducted to evaluate the impact of feeding two strains of one bacteria (Lactobacillus acidophilus) in combination with a second bacteria (Propionibacteria freudenreichii) on performance of dairy cows. None of the bacterial combinations altered milk production or composition by the cows, and feed consumption was also not changed. Health of the rumen of these cows was not impacted and feed digestibility was the same for all cows. While some other microbial feed additives have been shown to improve milk production, these bacterial combinations did not improve cow performance under the conditions of this study. These results will be of value to farmers as they evaluate alternative microbial products as feed additives for dairy cows.
Technical Abstract: The objective of this study was to determine the effect of feeding bacterial direct fed microbial (DFM) products containing Lactobacillus acidophilus (LA) and Propionibacteria freudenreichii (PF) on the performance, nutrient digestibility, and rumen fermentation of Holstein dairy cows in mid-lactation. Cows were fed one of three dietary treatments: 1) 1 x 10**9 colony forming units (cfu)/d live LA strain LA747 and 2 x 10**9 cfu/d live PF strain PF24 (DFM1), 2) 1 x 10**9 cfu/d live LA strain LA747, 2 x 10**9 cfu/d live PF strain PF24, and 5 x 10**8 cfu/d LA strain LA45 (DFM2), or 3) lactose (Control). In Study 1 (lactation study), 57 Holstein cows were blocked by parity and randomly assigned to treatments for 84 d. A rumen fermentation study (Study 2) was conducted concurrently with the lactation study. Three rumen fistulated, multiparous Holstein cows were randomly assigned to dietary treatments DFM1, DFM2, and Control in a 3 x 3 Latin square design with 28-d periods. In Study 1, there was no difference (P>0.10) in average dry matter (DM) intake (23.9, 23.6, and 24.2 kg/d) or 4% fat corrected milk (36.8, 35.3, and 36.2 kg/d) for treatments DFM1, DFM2, and Control. Milk components also did not differ (P>0.10) among treatments. Feed efficiency averaged 1.52 kg 4% FCM per kg of DM intake and did not differ (P>0.10) among treatments. There were no differences (P>0.10) in apparent DM, CP, NDF, or starch digestibility among treatments. In Study 2, there was no difference (P>0.10) in rumen pH and concentrations of ammonia or total volatile fatty acids measured at 0-, 1-, 3-, and 6-h post feeding. In these studies, supplementing mid-lactation cows with DFM products containing LA and PF did not affect cow performance, diet digestibility, or rumen fermentation.