Abstract

Aim: Repeat breeding syndrome (RBS) is a reproductive disorder in cattle characterized by failure to conceive after three or more inseminations with fertile semen in the absence of detectable abnormalities. Delayed ovulation is a major underlying cause. Conventional therapy using synthetic gonadotropins is constrained by cost, regulatory restrictions, and concerns about hormone residues in animal products. Therefore, this study aimed to evaluate the effectiveness of bovine pituitary extract (BPE), a natural source of gonadotropins derived from anterior pituitary glands, in managing RBS associated with delayed ovulation.
Methods: An experimental study with a Completely Randomized Design was conducted using Bali cattle diagnosed with RBS, divided into control (n = 16) and treatment (n = 16) groups. Estrus was monitored and follicle diameter measured ultrasonographically at estrus and prior to artificial insemination (AI). Twelve hours after estrus detection, the control group received 5 mL aqua bi-distillations, while the treatment group received 2 mL BPE diluted in 3 mL aqua bi-distillations. Follicle diameter data were analyzed using ANOVA and independent t-tests, and conception rates were compared using chi-square analysis (p < 0.05).
Results: Mean follicle diameters at estrus did not differ significantly between groups (p > 0.05). At AI, follicle size remained unchanged in controls but decreased significantly in the treatment group (p < 0.05), indicating ovulation induction.
Conclusion: BPE effectively induces ovulation in Bali cattle with RBS caused by delayed ovulation and represents a promising, biologically based alternative to synthetic hormonal therapy.

Key words: Cattle, infertility, ovulation, pituitary gland extracts, reproductive techniques