EFFECT OF DIETARY FAT ON OVARIAN AND METABOLIC RESPONSE OF HEIFERS SUFFERING FROM OVARIAN INACTIVITY

Eleven Holstein Friesian heifers suffering from ovarian inactivity were allocated according to their age and weight to either a normal lipid (NL; n=6, 2.3% ether extract) or high lipid (HL; n=5, 5.8% ether extract) diet. Diets were fed for 55 days and formulated to be almost isonitrogenous. The number and percentage of heifers that showed regular changes in progesterone concentrations consistent with normal cyclic ovarian activity were 1/5 (20%), 2/5 (40%) and 4/5 (80%) up to 10, 20 and 55 days of the treatment period, respectively, in non-cycling heifers receiving HL diet. The comparable results in NL-fed heifers were 0/6 (0%), 1/6 (16.6%) and 2/6 (33.3%), respectively. The differences between the two groups were significant (p< 0.1-0.6). Three heifers in HL (60%) and no heifer (0%) in NL showed continuously elevated serum progesterone for at least 35 days after the last recorded estrus and confirmed to be pregnant by rectal palpation 45 days post service. The difference in pregnancy rate between the two groups was highly significant (p<0.01).  Concentrations of serum total lipids, triglycerides, total cholesterol and high density lipoprotein- cholesterol were 1.26 (10.64±0.79 Vs 8.42±0.41 g/dl; p<0.03), 2.12 (218.90±18.53 Vs 103.23±9.3mg/dl; p<0.001), 1.66 (141±11.20 “Vs 85.60±4.61 mg/dl; p<0.06) and 1.27 (38.10±3.71 Vs 29.96±1.16 mg/dl; p<0.06) times greater in HL when compared to NL-fed heifers. Moreover, serum progesterone levels during the mid-lutealphase of oestrous cycle tended to be higher (P<0.19) in HL than NL (4.97±0.819 Vs 3.61±0.728 ng/ml). Insulin concentration was significantly (p<0.03) elevated in heifers receiving HL (14.70±1.75 µµ/ml) than those receiving NL (4.07±1.27 µµ/ml). However, increasing dietary lipids (HL) in the diets did not significantly (P<0.05) affect serum concentrations albumin (3.03±0.16 Vs 2.77±0.19 g/dl), urea (43.30±2.47 Vs 40.93±4.38 mg/dl), Ca (7.17±0.90 Vs 6.33±0.86mg/dl), Mg (2.22±0.08 Vs 2.02±0.18meg/dl), Zinc (0.61±0.11 Vs 0.91±0.14mg/l) Cu (0.73±0.04 Vs 0.61±0.1mg/I) or selenium (1.42±0.07 mg/l Vs 1.64+0.12 mg/l). From this study, it can be recommended that dietary fat can be sucessively used as a non hormonal treatment for inactive ovarian in heifers and to improvize their pregnancy rate.