Effect of pretreatment with insulin on the response of buffaloes with inactive ovaries to gonadotrophin-releasing hormone agonist treatment in summer.

The aim of the present study was to evaluate the effect of a pretreatment with insulin on the response of buffalo cows with inactive ovaries to gonadotrophin-releasing hormone agonist (GnRHa) treatment during hot summer months (July and August). Thirty-six Egyptian buffalo cows with inactive ovaries were randomly allocated into three groups: (1) group treated with GnRHa (G1, n = 16) in which each buffalo received an intramuscular injection of 250 mg of GnRHa (Day 0; gonadorelin, Fertagyl); (2) group treated with insulin before the GnRHa injection (G2, n = 8) in which each buffalo received a subcutaneous injection of biphasic insulin at a dose of 0.25 IU kg(-1) bodyweight once daily starting at Day -3 for 3 consecutive days, followed by an intramuscular injection of 250 mg of GnRHa on Day 0; and (3) the control group (G3, n = 12) in which each buffalo cow received an intramuscular injection of 2.