Abstract
Background:
Treating beef cattle with estradiol benzoate before ovum pick-up (OPU) increases the number of high-quality follicles and oocytes. L. spinosa Thwaites (L. spinosa Thw.) supplement has been used to replace synthetic estradiol benzoate in food animals to reduce the side effects and meat residue in consumers.

Aim:
This study aimed to evaluate the effects of L. spinosa Thw. feed supplementation on the follicle and oocyte quality of crossbred Brahman.

Methods:
Estrus was induced in 21 crossbred Brahman cows using intravaginal controlled internal drug release (CIDR) and prostaglandin F2α. The cows were divided into Groups 1, 2, and 3, with each group receiving L. spinosa Thw. supplements at daily rates of 0, 15, and 30 g per cow, respectively. Blood samples were collected to measure plasma estradiol (E2) levels. The follicles were evaluated via ultrasonography and categorized according to follicle diameter. Oocytes were collected using OPUs for counting and grading.

Results:
The cows in Groups 2 and 3 produced more medium follicles (Group 2=5.29±1.80, Group 3=7.43±1.72) than those in Group 1 (2.57±1.51) (P<0.05). Cows in Group 3 also produced more combined grade A+B (good-quality) oocytes (9.71±1.89) than Group 1’s (5.14±2.12) (P<0.05). Groups 1 and 2 did not differ significantly in this regard, nor did Group 2 differ from Group 3. In addition, the plasma E2 levels of Groups 2 and 3 were not significantly different, and both groups showed higher levels than those in Group 1 (P<0.05).

Conclusion:
Feeding crossbred Brahman with 30 g/cow/day L. spinosa Thw. was more effective than the control group, resulting in a greater number of high-quality follicles and oocytes.

Key words: Animal feed supplement; Brahman cow; L. spinosa Thw.; Phytoestrogen; OPU.