What question did this study set out to answer?

The aim is to evaluate the effectiveness of FSH versus FSH/LH regimens for ovarian superstimulation in calves.

May 22, 2026Open Access

Hormonal superstimulation strategies for laparoscopic ovum pick-up (LOPU) in prepubertal Holstein-Friesian calves: a comparison of FSH and FSH/LH regimens

Key Points

The aim is to evaluate the effectiveness of FSH versus FSH/LH regimens for ovarian superstimulation in calves.
Eighteen prepubertal Holstein-Friesian calves aged 2 to 4 months were enrolled.
Calves were split into three groups receiving different hormonal treatments over three days: FSH, FSH/LH, and reduced FSH/LH doses.
Oocytes were retrieved via laparoscopic ovum pick-up and analyzed under a microscope.
The FSH/LH group had an average of 87.7 ovarian follicles, significantly higher than 25.7 in the reduced FSH/LH and 21.2 in the FSH groups (p<0.01).
The number of oocytes retrieved was highest in the FSH/LH group at 32.8, compared to 12.7 and 12.3 in the FSH and reduced FSH/LH groups, respectively (p<0.01).
Oocyte retrieval percentages were 59.4% for FSH, 48.8% for reduced FSH/LH, and 39.9% for FSH/LH, indicating a significant difference (p<0.05).

Abstract

Laparoscopic ovum pick-up (LOPU) combined with IVF allows embryos to be derived from sexually immature heifers as young as 2 months old. An essential step in this procedure is hormonal stimulation to enable the growth of ovarian follicles that can be punctured. Developing the right stimulation protocol is necessary to obtain an adequate, repeatable response of the ovaries to the hormonal stimulation used. The aim of the study was to determine the usefulness of the FSH/LH mixture for ovarian follicle superstimulation in calves. The study was conducted on eighteen calves aged 2 to 4 months, weighing between 62.5 and 112 kg. The animals were divided into 3 groups of 6 individuals and subjected to 3 days of hormonal stimulation via intramuscular injection at 12-hour intervals prior to the procedure: group I with follicle-stimulating hormone FSH (total dose of 168 IU FSH), group II with FSH/LH (total dose of 240 IU FSH/LH), and group III with a reduced dose of FSH/LH (total dose of 165 IU FSH/LH). Simultaneously, progesterone-releasing vaginal inserts were also used. Laparoscopic aspiration of oocytes was performed under general anesthesia. The fluid was evaluated under a stereoscopic microscope to locate oocyte-cumulus complexes. As a result of the use of superstimulation protocols, a statistically significant difference in the number of ovarian follicles was observed, with an average of 87.7 ± 29.2, 25.7 ± 4.1, and 21.2 ± 4.9 for the FSH/LH (total dose 240 IU), reduced FSH/LH, and FSH groups, respectively. The number of oocytes retrieved was 12.7 ± 4.7, 32.8 ± 7.6, 12.3 ± 2.1 for the FSH, FSH/LH, and reduced FSH/LH dose groups, respectively. A statistically significant difference in the % of oocyte retrieval relative to the number of follicles was demonstrated, and it was: 59.4 ± 14.9%, 48.8 ± 8.6%, 39.9 ± 10.1% for the FSH, FSH/LH low dose, and FSH/LH groups, respectively. The FSH/LH-based calf superstimulation protocol, causes a very intense ovarian response. The proposed protocol for hormonal stimulation of calves will increase the possibility of wider application of the LOPU procedure and support early genetic selection in cattle.

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