Ovarian follicular response to different hormonal stimulation treatments in Canindé goats

In vitro embryo production in small ruminants: what is still missing?

In vitro embryo production (IVEP) is an extremely important tool for genetic improvement in livestock and it is the biotechnology that has grown the most recently. However, multiple ovulation followed by embryo transfer is still considered the leading biotechnology for embryo production in small ruminants. This review aimed to identify what is still missing for more efficient diffusion of IVEP in small ruminants, going through the IVEP steps and highlighting the main factors affecting the outcomes. Oocyte quality is essential for the success of IVEP and an aspect to be considered in small ruminants is their reproductive seasonality and strategies to mitigate the effect of season. The logistics for oocyte collection from live females is more complex than in cattle, and tools to simplify this collection system and/or to promote an alternative way of recovering oocytes may be an important point in this scenario. The heterogeneity of oocytes collected from growing follicles in live females or from ovaries collected from abattoirs remains a challenge, and there is a demand to standardize/homogenize the hormonal stimulatory protocols and IVM protocols for each source of oocytes. The use of sexed semen is technically possible, however the low market demand associated with the high costs of the sexing process prevents the routine use of this technique, but its higher availability is an important aspect aiming for greater dissemination of IVEP. New noninvasive approaches for embryo selection are key factors since the selection for transfer or cryopreservation is another difficulty faced among laboratories. Embryo selection is based on morphological traits, although these are not necessarily reliable in predicting pregnancy. Several issues described in this review must be considered by researchers in other to promote the diffusion of IVEP in small ruminants.

Dose and administration protocol for FSH used for ovarian stimulation affect gene expression in sheep cumulus–oocyte complexes

The present study evaluated the effect of four ovarian stimulation protocols on the follicular population and molecular status of cumulus–oocyte complexes (COCs). Twelve Santa Inês ewes (in a cross-over design) received 80 or 120 mg FSH alone in a multiple-dose (MD80 and MD120) regimen or in combination with 300 IU equine chorionic gonadotrophin (eCG) in a one-shot (OS80 and OS120) protocol. The follicular population, COC recovery rate, mean COCs per ewe and the rate of brilliant Cresyl blue-positive (BCB+) COCs were similar among treatments (P > 0.05). The expression of markers of oocyte competence (ZAR1, zygote arrest 1; MATER, maternal antigen that embryo requires; GDF9, growth differentiation factor 9; BMP15, bone morphogenetic protein 15; Bcl-2, B-cell lymphoma 2; BAX, Bcl-2 associated X protein) and the steroidogenic pathway (ERα, oestrogen receptor α; LHr, LH receptor; FSHr, FSH receptor; STAR, steroidogenic acute regulatory protein) was affected by stimulation. Specifically, the expression of markers of the steroidogenic pathway was reduced with increasing FSH dose in the OS protocol. FSH at a dose of 80 mg reduced the expression of FSHr and ERα in the OS versus MD protocol. Conversely, in MD protocol, only LHr was affected by increasing FSH dose. In conclusion, 80 mg FSH in the MD or OS protocol was sufficient to promote the development of multiple follicles and obtain fully grown (BCB+) oocytes. The MD protocol may be more appropriate for the production of better-quality oocytes.

MAMMARY BIOPSY IN INDUCED LACTATING GOATS: ASSESSMENT OF POST-BIOPSY MILK PROPERTIES AND ULTRASONOGRAPHIC APPEARANCE

Abstract The aim of this study was to evaluate the effects of mammary biopsy procedures on gland function of goats submitted to hormonal lactation. Ten female Caninde goats, at the age of around 3 years, were used, and lactation was induced by using estrogen, progesterone, and prednisolone. Ultrasonographic examinations of mammary gland, milking, and analysis of physicochemical properties of milk were performed immediately before (0 h) and 24, 48, and 72 h after each biopsy procedure. Surgical mammary gland biopsies were obtained at days 5 and 26 of the lactation. Even after drying initiation, all animals produced milk for five months. No abnormalities were observed on the ultrasonographic appearance of biopsied glands. All 20 biopsies were technically successful and any inflammation or infection was associated with biopsy procedures. Regarding the physicochemical properties and volumes of milk produced, no significant differences (P > 0.05) were observed between right and left glands nor in the comparison of the results from time 0 with 24, 48, and 72 h for biopsied teats. The mammary biopsy did not induce neither severe changes in production and physicochemical properties of the milk nor in ultrasonographic appearance of mammary gland of goats in hormonal lactation.