The impact of dose of FSH (Folltropin) containing LH (Lutropin) on follicular development, estrus and ovulation responses in prepubertal gilts

Shawn M. Breen, Robert V. Knox

Research output: Contribution to journalArticlepeer-review


FSH is favored over chorionic gonadotropins for induction of estrus in various species, yet little data are available for its effects on follicle development and fertility for use in pigs. For Experiment 1, prepubertal gilts (n= 36) received saline, 100. mg FSH, or FSH with 0.5. mg LH. Treatments were divided into six injections given every 8. h on Days 0 and 1. Proportions of gilts developing medium follicles were increased for FSH and FSH-LH (P< 0.05) compared to saline, but follicles were not sustained and fewer hormone-treated gilts developed large follicles (P< 0.05). No gilts expressed estrus and few ovulated. Experiment 2 tested FSH preparations with greater LH content. Prepubertal gilts (n= 56) received saline, FSH-hCG (100. mg FSH with 200. IU hCG), FSH-LH5 (FSH with 5. mg LH), FSH-LH10 (FSH with 10. mg LH), or FSH-LH20 (FSH with 20. mg LH). FSH-LH was administered as previously described, while 100. IU of hCG was given at 0. h and 24. h. Hormone treated gilts showed increased (P< 0.05) medium and large follicle development, estrus (>70%), ovulation (100%), and ovulation rate (>30 CL) compared to saline. There was an increase (P< 0.05) in the proportion of hormone-treated gilts with follicular cysts at Day 5, but these did not persist to Day 22. These gilts also showed an increase in poorly formed CL (P< 0.05). FSH alone or with small amounts of LH can induce medium follicle growth but greater amounts of LH at the same time is needed to sustain medium follicles, stimulate development of large follicles and induce estrus and ovulation in prepubertal gilts.

Original languageEnglish (US)
Pages (from-to)193-200
Number of pages8
JournalAnimal reproduction science
Issue number3-4
StatePublished - Jun 2012


  • Estrus
  • FSH
  • Gilt
  • LH
  • Ovulation
  • Puberty

ASJC Scopus subject areas

  • Food Animals
  • Animal Science and Zoology
  • Endocrinology


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