Effect of 2-methyl-2-phenoxy propionic acid on serum lipid profile and ovarian activity in dairy cows

Abstract

Hepatic lipidosis and ketosis are frequent metabolic disorders in dairy cows during the transition period. The 2-methyl-2-phenoxy propionic acid (MFPA) is an activator of energy metabolism. The objective of this study was to evaluate the effect of administration of MFPA 10 days prepartum to day 36 postpartum on serum lipid profile, ovarian reactivity, and milk yield. Fifty seven multiparous Holstein cows were divided into four groups. The groups 1 (n = 14) and 2 (n = 14) had body condition score (BCS) above 4; BCS of the groups 3 (n = 15) and 4 (n = 14) was between 3.25 and 3.75 at calving. The solution containing 10 mg/kg MFPA was injected intramuscularly (IM) to cows of groups 1 and 3, 10–7 days prepartum and 6 h postpartum. The groups 2 and 4 received 50 ml of 0.9% NaCl as placebo in the same way. Blood samples for serum lipid profile were collected from all cows 10 days before calving without treatment, 2 days after the first administration of MFPA and postpartum at days 2, 10, and 21 after the second administration of MFPA. At days 21, 24, 27, 30, 33, and 36 postpartum, blood samples were obtained for plasma progesterone determination. Milk yield was registered daily during 60 days postpartum. Prepartum free fatty acids (FFA) were mildly increased without difference among all the groups (P > 0.05). b-hydroxybutyrate (BHB) was increased only at day 10 after calving in cows of group 1 treated with MFPA (P < 0.05) due to higher number of postpartum diseases. In cows from groups 3 and 4 (BCS normal), BHB was mildly increased, not indicating subclinical ketosis. The serum concentrations of triacylgycerols, cholesterol, albumin, activities of aspartate aminotransferase and creatine kinase were within the limits of reference values, indicating adequate liver integrity and function. Cows of normal BCS treated with MFPA presented better milk production but without significant difference among four groups (P > 0.05). Ovarian reactivity was present at day 21 in all groups of cows without difference (P > 0.05). The administration of MFPA had no effect on serum lipid profile and ovarian activity in this study.