title: Hypophagic effects of propionic acid are not attenuated during a 3-day infusion in the early postpartum period in Holstein cows.
abstract: We previously showed that propionic acid was more hypophagic than acetic acid when infused intraruminally in cows in the postpartum period and that the degree of hypophagia from short-term propionic acid infusion (18 h) was related to the acetyl coenzyme A (CoA) concentration in the liver. The objective of this experiment was to evaluate adaptation over time with longer-term infusions over 3 d. Twelve multiparous cows (2-13 d postpartum) were blocked by calving date and assigned randomly to treatment sequence in a crossover design experiment. The experiment was 12 d long with covariate periods preceding each 3-d infusion period. Treatments were 1.0 M propionic acid or 1.0 M acetic acid, infused intraruminally at 0.5 mol of volatile fatty acids/h beginning 6 h before feeding and continuing for 78 h with 3 d between infusions. Propionic acid decreased dry matter intake (DMI) relative to acetic acid (15.9 vs. 17.0 kg/d). However, a period-by- treatment interaction was detected for DMI. During period 1, propionic acid decreased DMI relative to acetic acid (14.3 vs. 17.5 kg/d) because of a reduction in meal size (1.30 vs. 1.65 kg), with no effect on intermeal interval. Propionic acid decreased DMI over the first 4 h following feeding (5.86 vs. 8.23 kg) but did not affect DMI 4 to 24 h after feeding. The depression in DMI in period 1 was positively related to hepatic acetyl-CoA concentration during the covariate period. Propionic acid was increasingly more hypophagic than acetic acid as hepatic acetyl-CoA concentration was elevated. No treatment-by-day interaction for DMI was observed, suggesting little or no measurable adaptation to treatment over the 3-d infusion period. These results suggest that hypophagia from propionic acid is enhanced when hepatic acetyl-CoA concentrations are elevated, such as when cows are in a lipolytic state.
authors.affiliation: Department of Animal Science, Michigan State University, East Lansing MI 48824-1225, USA.
authors.forename: S E
authors.initials: SE
authors.lastname: Stocks
authors.forename: M S
authors.initials: MS
authors.lastname: Allen
mesh_terms: D000105:Acetyl Coenzyme A / Q000032:analysis; D000818:Animals; D002417:Cattle / Q000502:physiology*; D004435:Eating / Q000187:drug effects*; D005232:Fatty Acids, Volatile / Q000032:analysis; D005247:Feeding Behavior / Q000187:drug effects; D005260:Female; D005285:Fermentation; D006863:Hydrogen-Ion Concentration; D007774:Lactation / Q000502:physiology*; D008066:Lipolysis; D008099:Liver / Q000737:chemistry; D049590:Postpartum Period / Q000502:physiology*; D011422:Propionates / Q000008:administration & dosage* / Q000378:metabolism; D012417:Rumen / Q000737:chemistry / Q000187:drug effects* / Q000378:metabolism; D013213:Starch / Q000378:metabolism
chemical_list: D005232:Fatty Acids, Volatile; D011422:Propionates; D000105:Acetyl Coenzyme A; D013213:Starch; C029658:propionic acid