Quantifying the effect of monensin dose on the rumen volatile fatty acid profile in high-grain-fed beef cattle.
Monensin is a common feed additive used in various countries, where 1 of the associated benefits for use in beef cattle is improved efficiency of energy metabolism by the rumen bacteria, the animal, or both. Modeling fermentation-altering supplements is of interest, and thus, it is the purpose of this paper to quantify the change in VFA profile caused by monensin dose in high-grain-fed beef cattle. The developmental database used for meta-analysis included 58 treatment means from 16 studies from the published literature, and the proportional change in molar acetate, propionate, and butyrate (mol/100 mol) as well as total VFA (mM) with monensin feeding dose (mg/kg DM, concentration in the feed) was evaluated using the MIXED procedure (SAS Inst. Inc., Cary, NC) with the study treated as a random effect. The mean monensin dose in the literature database was 30.9 ± 3.70 mg/kg DM and ranged from 0.0 to 88.0 mg/kg DM. Mean DMI was 7.8 ± 0.26 kg DM/d, mean concentrate proportion of the diet was 0.87 ± 0.01, and mean treatment period was 42 ± 5.6 d. Results produced the following equations: proportional change in acetate (mol/100 mol) = -0.0634 (± 0.0323) × monensin (mg/kg DM)/100 (P = 0.068), proportional change in propionate (mol/100 mol) = 0.260 (± 0.0735) × monensin (mg/kg DM)/100 (P = 0.003), and proportional change in butyrate (mol/100 mol) = -0.335 (± 0.0916) × monensin (mg/kg DM)/100 (P = 0.002). The change in total VFA was not significantly related to monensin dose (P = 0.93). The results presented here indicate that the shift in VFA profile may be dose dependent, with increasing propionate and decreasing acetate and butyrate proportions (mol/100 mol). These equations could be applied within mechanistic models of rumen fermentation to represent the effect of monensin dose on the VFA profile in high-grain-fed beef cattle.
Animal Nutrition Group, Wageningen University, Wageningen 6708 WD, the Netherlands. jennifer.st-pierre@wur.nl
J L
JL
Ellis
J
J
Dijkstra
A
A
Bannink
E
E
Kebreab
S E
SE
Hook
S
S
Archibeque
J
J
France
D000821:Animal Feed / Q000032:analysis*; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D002417:Cattle / Q000502:physiology*; D004032:Diet / Q000662:veterinary; D004305:Dose-Response Relationship, Drug; D002523:Edible Grain; D005232:Fatty Acids, Volatile / Q000737:chemistry / Q000378:metabolism*; D008985:Monensin / Q000008:administration & dosage / Q000494:pharmacology*; D061209:Proton Ionophores / Q000008:administration & dosage / Q000494:pharmacology; D012417:Rumen / Q000378:metabolism*
D005232:Fatty Acids, Volatile; D061209:Proton Ionophores; D008985:Monensin