Follicle Ablation Improves the Ovarian Response and the Number of Collected Embryos in Superovulated Cows During the Early Stages of Lactation

Abstract

A field study was designed to compare ovarian response and embryo yield in cows during early lactation when gonadotropin administration followed one of four treatments. In group 1A (n = 19) and 1B (n = 9), the estrouses were synchronized by two prostaglandin F2alpha (PG) injections given 11 days apart, and starting from day 9 of the synchronized cycle superovulation was conducted with eight decreasing dose of FSH. In group 1B, ablation of all follicles >3 mm was carried out on day 8. In group 2A and 2B (each n = 9), a progesterone plus oestradiol intravaginal device (PRID) was inserted for 11 days and gonadotropin administration started on day 9, while cows from group 2B had a follicle ablation on day 8. In all groups, two PG injections were given along with the sixth and the seventh dose of FSH, and the cows were twice inseminated 12 and 24 h after estrus detection. Embryos were collected on day 7. In cumulative results from aspirated and non-aspirated cows, follicular ablation significantly improved: the ovarian response (10 +/- 1.23 vs 6.69 +/- 0.60 corpora lutea per donor), the mean collected embryos (6.57 +/- 0.94 vs 2.46 +/- 0.53) and the mean transferable embryos (4.43 +/- 0.89 vs 2.18 +/- 0.47). Group 1B and 2B cows had better ovarian response than 1A (6.44 +/- 0.81, 12.25 +/- 4.11 and 9.44 +/- 0.93, for groups 1A, 1B and 2B, respectively, p < 0.05). Similarly, from groups 1B and 2B more (p < 0.05) embryos were collected in comparison with their respective group, while the mean transferable embryos from group 2B (5.22 +/- 1.13) was greater (p < 0.05) than that of group 1A (1.67 +/- 0.35), and tented to be greater than those of groups 2A (3.44 +/- 1.19, p = 0.062) and 1B (3.00 +/- 1.78, p = 0.066). The highest (p < 0.05) transferable embryo collection rate was recorded in group 2B (55.29%), followed by that of group 1B (41.33%). In summary, early in lactation, an acceptable number of transferable embryos can be collected from high producing dairy cows, when follicle ablation prior to superovulation is combined with progesterone and oestradiol administration.

Effects of Superovulation with oFSH and Norgestomet/GnRH‐Controlled Release of the LH Surge on Hormone Concentrations, and Yield of Oocytes and Embryos at Specific Developmental Stages

“…Merton et al., showed that dominant follicle ablation increased the number of ovulations and viable embryos, especially in cows (Merton et al. 2003; Amiridis et al. 2006).…”

Respuesta superovulatoria en vacas donantes Brahman usando ablación folicular previo a protocolos de superovulación

“…Particularmente, hembras bovinas de origen Bos indicus presentan elevados concentraciones circulantes de factor de crecimiento similar a insulina (IGF) en comparación a animales Bos Taurus, esta característica ha sido relacionada con una población folicular elevada propia de hembras de esta subespecie (21), por consiguiente, al trabajar con vacas de la raza Brahman, una considerable cantidad de folículos se encuentran disponibles y con posibilidad de responder adecuadamente a los tratamientos de SPO (13,22) Al comparar las dos metodologías, fue observado que el uso de la ablación folicular aumentó el porcentaje de embriones de calidad 1. Ha sido ampliamente demostrado que la ausencia de un folículo dominante al inicio de la estimulación del crecimiento folicular con FSH exógena, es uno los factores que mayor influencia tienen en la respuesta superovulatoria, no solamente en lo referente al número de ovulaciones, sino además en la calidad de las estructuras recuperadas (4,23).…”

No-CL Superstimulatory Protocol: Developing a New Superovulation Treatment Initiated in the Absence of Corpus Luteum (CL) and Compared with D1 and Traditional Superovulation in Cattle

“…Empirical evidence suggested that elimination of the dominant follicle prior to superovulation induced a new follicular wave emergence which improved the ovarian response to gonadotrophic stimulation [3,4,[13][14][15]. However, D1 protocol had the same merit of absence of the dominant follicle (D.F) after spontaneous ovulation however; the number of emerged follicles was significantly lower than the no-CL protocol.…”

“…For instance, the initiation of the FSH treatment at the time of wave emergence elicited a high superovulation response [2]. Furthermore, removal of the dominant follicle by ablation [3,4] or injection of GnRH [5] increased the number of recruited follicles and synchronized the follicular wave emergence [4]. Some researchers have focused on starting the superovulation protocol at the first wave in which the wave emergence occurred at a consistent point (after ovulation) and in the absence of dominant follicle.…”