03046naa a2200385 a 450000100080000000500110000800800410001902400410006010000220010124501610012326000090028452018400029365000270213365000330216065000170219365000100221065000190222065300260223965300220226565300220228765300220230965300250233165300230235670000210237970000310240070000200243170000170245170000210246870000250248970000270251470000220254170000180256370000200258177300590260121721452025-01-30       2025    bl uuuu     u00u1 u    #d7 ahttps://doi.org/10.1071/AN243682DOI1 aRIBEIRO, A. C. S.  aReducing one third the dose of porcine follicle-stimulating hormone did not affect the in vivo embryo production in Santa Inês ewes.h[electronic resource]  c2025  aAbstract: Context - Superovulation is still a main limitation of multiple ovulation and embryo transfer programs because of its high cost and the variability in the responses to the hormonal protocols used. Aims - This study aimed to compare the effect of two doses of porcine follicle-stimulating hormone (pFSH) on follicular growth, superovulatory response, and in vivo embryo production of Santa Inês ewes. Methods - A total of 40 multiparous ewes received a Day 0 estrus synchronization protocol and were superovulated with either 333 IU (G333, n = 20) or 500 IU (G500, n = 20) of pFSH. Ultrasonographic evaluations of ovaries were performed every 12 h, from the first pFSH dose until 60 h after the last dose. Ewes were naturally mated and submitted to non-surgical embryo recovery. A subsample of viable blastocysts (G333: n = 10; G500: n = 8) was stained with Nile Red to quantify lipid droplets. Key results - The number of small, medium, and large follicles, and the size of the largest follicle, varied over time (P &lt 0.0001), even though there was no difference between the treatments. The pFSH dose also did not affect estrous behavior rate (95% vs 100%), superovulatory response (75% vs 70%), recovery rate (52.4% vs 56.4%), viability rate (73.8% vs 62.3%), recovered structures (5.9 vs 5.3), viable embryos (4.9 vs 3.7), and lipid accumulation in embryos (132.9 vs 129.4 arbitrary fluorescence units), for G333 and G500 respectively. Four ewes (10%) had premature luteal regression. It should be noted that all viable embryos recovered were Grade 1 or 2, that is, freezable embryos. Conclusions - In conclusion, 333 IU of pFSH is enough to reach a similar superovulatory response as obtained from 500 IU of pFSH in Santa Inês ewes. Implications - The use of lower doses of pFSH could reduce costs per embryo produced.  aEstrus synchronization  aFollicle-stimulating hormone  aReproduction  aSheep  aSuperovulation  aCrescimento folicular  aEmbryo collection  aEmbryonic quality  aFollicular growth  aLipid quantification  aMultiple ovulation1 aSANTOS, J. D. R.1 aGUERRERO-GUTIÉRREZ, M. M.1 aCUNHA, C. C. C.1 aSILVA, S. R.1 aBALARO, M. F. A.1 aBATISTA, R. I. T. P.1 aSOUZA-FABJAN, J. M. G.1 aFONSECA, J. F. da1 aUNGERFELD, R.1 aBRANDÃO, F. Z.  tAnimal Production Sciencegv. 65, n. 2, AN24368, 2025.