POSTPARTUM OVARIAN ACTIVITY RESUMPTION AND PLASMA CONCENTRATION OF LIPID METABOLITES AND PROGESTERONE IN INDOBRASIL COWS IN THE DRY TROPICS OF MICHOACAN SUPPLEMENTED WITH BYPASS FAT

Abstract

The aim of this work was to evaluate the effect of supplementation with bypass fat on plasma concentrations of cholesterol (COL), tryglicerides (TG), high density lipoproteins (HDL), low density lipoproteins (LDL) and progesterone (P4), during the early postpartum period in Indobrasil cows in the dry tropics. Thirty five anestrous cows with 62.91±20.87 days postpartum, 3.24±0.43 body condition score and 486.17±72.54 kg liveweight, multiparous (four and six calvings) were used. Both groups of cows were given isoenergetic and isoproteic feed supplements and were divided in two groups, without supplementation (GC, n=17) and with supplementation with bypass fat (GG, n=18), equivalent to 4% of ration DM for 35 days. Plasma concentrations of COL, TG, HDL and LDL were assayed by enzymatic-colorimetric methods and concentrations of P4 by solid phase radioinmunoassay. Cows in group GG showed increased plasma concentration of COL (216.80±6.36 vs 168.32±7.46 mg/dl; P<0.001), LAD (104.97±2.07 vs 88.15±2.4, mg/dl, P<0.001), LBD (48.02±2.66 vs 38.88±3.12 mg/dl; P<0.05) and P4 (3.02±0.18 vs 0.49±0.22 ng/ml P<0.001). No differences were observed in plasma concentration of TG among treatments. Supplementation with bypass fat had a positive effect on re-initiation of ovarian activity, changing positively plasma concentrations of COL, HDL, LDL and P4.