Relationships between follicle and corpus luteum diameter, blood flow, and progesterone production in beef cows and heifers: preliminary results

The aim of the present study in beef cattle was to investigate potential differences in follicle size and follicle wall-blood flow between cows and heifers and to compare follicle wall-blood flow between smaller and larger follicles. Cows and heifers were treated with a synchronization protocol and follicles and CLs were measured and evaluated for blood flow. Pregnancy diagnosis was performed on day 50 of the protocol. Cows had larger (P 0.05) in CL diameter, CL blood flow, and plasma progesterone concentrations. Moderate correlations between follicle diameter and follicle blood flow were observed for cows (r = 0.51; P 0.05) among all follicle diameter categories. In conclusion, synchronized beef cows and pregnant cows had larger follicles and greater blood flow than heifers and non-pregnant cows, and follicle wall blood flow was closely associated with increasing follicle diameter.

Relationships between follicle and corpus luteum diameter, blood flow, and progesterone production in beef cows and heifers: preliminary results

The aim of the present study in beef cattle was to investigate potential differences in follicle size and follicle wall-blood flow between cows and heifers and to compare follicle wall-blood flow between smaller and larger follicles. Cows and heifers were treated with a synchronization protocol and follicles and CLs were measured and evaluated for blood flow. Pregnancy diagnosis was performed on day 50 of the protocol. Cows had larger (P < 0.008) follicles than heifers. Cows, heifers, and pregnant and non-pregnant cows did not differ (P > 0.05) in CL diameter, CL blood flow, and plasma progesterone concentrations. Moderate correlations between follicle diameter and follicle blood flow were observed for cows (r = 0.51; P < 0.002) and heifers (r = 0.61; P < 0.0001). Pregnant cows tended (P < 0.1) to have larger follicles between 12 to 60 h before ovulation, and had larger (P < 0.05) follicles than non-pregnant cows at hour 24 before ovulation and at hour 12 before maximum values. Pregnant cows had greater (P < 0.05) follicle blood flow than non-pregnant cows at hours −36 and −24 before maximum values. Follicle blood flow was greater (P < 0.002) in the large follicles compared with the small follicles, and tended (P < 0.06) to be greater than in medium follicles. Moderate to strong correlations were found between follicle blood flow and diameter of small (r = 0.59; P < 0.002), medium (r = 0.50; P < 0.02), and large (r = 0.71; P < 0.0001) follicles. Pregnancy rates were similar (P > 0.05) among all follicle diameter categories. In conclusion, synchronized beef cows and pregnant cows had larger follicles and greater blood flow than heifers and non-pregnant cows, and follicle wall blood flow was closely associated with increasing follicle diameter.(AU)

Novel prospects for evaluation of follicle wall blood flow using color-Dopplerultrasonography

The goal of this study was to develop anobjective method for evaluation of ovarian follicle wallblood flow in cattle. Two subjective methods were used:(I) real-time ultrasound evaluations performed by oneoperator in the barn and (II) video clip evaluationsperformed by four operators in the laboratory. Thefollowing objective methods evaluated in the laboratorywere used for comparison: (I) percentage of follicle wallcircumference under blood flow (WUF) and (II) pixelarea of color-Doppler signals. Cows (n = 21) weresubmitted to a synchronization protocol, follicles ≥7 mmwere measured, and blood flow was evaluated every 12 huntil ovulation using color-Doppler ultrasonography. Nodifference (P > 0.05) was observed among laboratoryoperators from day 2 of training onwards. Therefore,an average score of all operators was used forcomparisons among different methods. Both subjectiveand objective methods of evaluation showed anincrease (P < 0.0001) in follicle blood flow over time.Higher (P < 0.001) correlations were obtained betweenWUF and subjective laboratory evaluation thanbetween WUF and pixel area or WUF and subjectivebarn data. Higher (P < 0.0003) correlation coefficientswere observed for WUF than for the pixel area whencompared with the barn (r = 0.70 vs. r = 0.42) orlaboratory (r = 0.84 vs. r = 0.62) data. Subjectiveevaluations at the laboratory and barn producedstronger correlations with WUF (P < 0.0008) than withpixel area (P < 0.01). In conclusion, WUF is aneffective and reliable method for objective evaluationof follicle wall blood flow in cows.

Novel prospects for evaluation of follicle wall blood flow using color-Dopplerultrasonography

The goal of this study was to develop anobjective method for evaluation of ovarian follicle wallblood flow in cattle. Two subjective methods were used:(I) real-time ultrasound evaluations performed by oneoperator in the barn and (II) video clip evaluationsperformed by four operators in the laboratory. Thefollowing objective methods evaluated in the laboratorywere used for comparison: (I) percentage of follicle wallcircumference under blood flow (WUF) and (II) pixelarea of color-Doppler signals. Cows (n = 21) weresubmitted to a synchronization protocol, follicles ≥7 mmwere measured, and blood flow was evaluated every 12 huntil ovulation using color-Doppler ultrasonography. Nodifference (P > 0.05) was observed among laboratoryoperators from day 2 of training onwards. Therefore,an average score of all operators was used forcomparisons among different methods. Both subjectiveand objective methods of evaluation showed anincrease (P < 0.0001) in follicle blood flow over time.Higher (P < 0.001) correlations were obtained betweenWUF and subjective laboratory evaluation thanbetween WUF and pixel area or WUF and subjectivebarn data. Higher (P < 0.0003) correlation coefficientswere observed for WUF than for the pixel area whencompared with the barn (r = 0.70 vs. r = 0.42) orlaboratory (r = 0.84 vs. r = 0.62) data. Subjectiveevaluations at the laboratory and barn producedstronger correlations with WUF (P < 0.0008) than withpixel area (P < 0.01). In conclusion, WUF is aneffective and reliable method for objective evaluationof follicle wall blood flow in cows.(AU)

Effects of a-MEM and TCM-199 culture media and epidermal growth factor on survival and growth of goat and sheep preantral follicles cultured in vitro

The aim of this study was to evaluate the effect of culture media (Alpha Minimum Essential Medium, α-MEM; and Tissue Culture Medium-199, TCM-199) in the absence or presence of Epidermal Growth Factor (EGF) on an in vitro culture of goat and sheep preantral follicles enclosed in ovarian tissue. The fragments of ovarian cortex from both species were immediately analyzed after collection (non-cultured control group) or cultured for 1 or 7 days in α-MEM+ or TCM-199+in the absence or presence of EGF (10 ng/ml). Before and after the culture, the fragments of ovarian cortex were analyzed by classical histology and fluorescence microscopy. After 1 day of culture, all treatments decreased the percentage of morphologically normal follicles when compared to non-cultured control in both species (P 0.05). Regarding follicle activation, an increase in the percentage of growing follicles was observed in all treatments after 7 days of culture when compared to the control group in both species. However, in sheep, after 7 days, only the treatments α-MEM+/EGF and TCM-199+showed larger(P < 0.05) oocytes than the control group. In conclusion, the TCM-199+ Preserved goat preantral follicle viability after in vitro culture. Furthermore, the media α-MEM+/EGF and TCM-199+ increased the oocyte diameter after 7 days of culture in sheep. Therefore, it isrecommended to use TCM-199+ In the culture of preantral follicles in both species.

Effects of a-MEM and TCM-199 culture media and epidermal growth factor on survival and growth of goat and sheep preantral follicles cultured in vitro

The aim of this study was to evaluate the effect of culture media (Alpha Minimum Essential Medium, α-MEM; and Tissue Culture Medium-199, TCM-199) in the absence or presence of Epidermal Growth Factor (EGF) on an in vitro culture of goat and sheep preantral follicles enclosed in ovarian tissue. The fragments of ovarian cortex from both species were immediately analyzed after collection (non-cultured control group) or cultured for 1 or 7 days in α-MEM+ or TCM-199+in the absence or presence of EGF (10 ng/ml). Before and after the culture, the fragments of ovarian cortex were analyzed by classical histology and fluorescence microscopy. After 1 day of culture, all treatments decreased the percentage of morphologically normal follicles when compared to non-cultured control in both species (P < 0.05). In fluorescence microscopy, viable sheep follicles were observed to decrease in all treatments after 7 days of culture when compared to non-cultured controls. However, in goats, the culture with TCM-199+maintained follicle viability after 7 days of culture, similar to fresh tissue (P > 0.05). Regarding follicle activation, an increase in the percentage of growing follicles was observed in all treatments after 7 days of culture when compared to the control group in both species. However, in sheep, after 7 days, only the treatments α-MEM+/EGF and TCM-199+showed larger(P < 0.05) oocytes than the control group. In conclusion, the TCM-199+ Preserved goat preantral follicle viability after in vitro culture. Furthermore, the media α-MEM+/EGF and TCM-199+ increased the oocyte diameter after 7 days of culture in sheep. Therefore, it isrecommended to use TCM-199+ In the culture of preantral follicles in both species.(AU)

Equine preantral follicle harvesting, processing, and in vitro culture: the journey has already started

Preantral follicles are of great abundance in mammalian ovaries and the vast majority (>99.9%) never become ovulatory; therefore, the ability to rescue these otherwise wasted follicles seems very aooealing. Considering there are striking similarities in antral follicle dynamics between mares and women, the mare might become a good model to study early (preantral and antral) folliculogenesis in women, with several advantages related to using an animal model. Studies in our laboratory recently validated the use of a transvaginal ultrasound-guided ovarian. Biopsy Pick-Up (BPU) method to harvest preantral follicles using the mare as a model to study early folliculogenesis (Haag et al., 2013a, b, c). This article will review some of the important findings of our recent studies related to the harvesting, processing, and culture of equine preantral follicles and discuss those with the limited information availeble in the literature.

Equine preantral follicle harvesting, processing, and in vitro culture: the journey has already started

Preantral follicles are of great abundance in mammalian ovaries and the vast majority (>99.9%) never become ovulatory; therefore, the ability to rescue these otherwise wasted follicles seems very aooealing. Considering there are striking similarities in antral follicle dynamics between mares and women, the mare might become a good model to study early (preantral and antral) folliculogenesis in women, with several advantages related to using an animal model. Studies in our laboratory recently validated the use of a transvaginal ultrasound-guided ovarian. Biopsy Pick-Up (BPU) method to harvest preantral follicles using the mare as a model to study early folliculogenesis (Haag et al., 2013a, b, c). This article will review some of the important findings of our recent studies related to the harvesting, processing, and culture of equine preantral follicles and discuss those with the limited information availeble in the literature.(AU)

Equine preovulatory follicle: blood flow changes, prediction of ovulation and fertility / Folículo pré-ovulatório equino: mudanças circulatórias, predição de ovulação e fertilidade

This review will focus on the main findings of our experiments that used B-mode and color-Doppler ultrasonography during the preovulatory period to study the morphological and blood flow/perfusion changes of the preovulatory follicle in mares. The topics to be addressed herein will be: ultrasonographic characteristics of the preovulatory follicle; B-mode echotextural changes of the follicle wall; blood flow and perfusion changes of the follicle wall; signs of impending ovulation; prediction of impending ovulation; types of preovulatory follicle outcomes such as ovulation, septated evacuation, hemorrhagic anovulatory follicle, and atresia; follicle blood flow during evacuation; early corpus luteum blood flow; and vascularity of the preovulatory follicle versus fertility.(AU)

This review will focus on the main findings of our experiments that used B-mode and color-Doppler ultrasonography during the preovulatory period to study the morphological and blood flow/perfusion changes of the preovulatory follicle in mares. The topics to be addressed herein will be: ultrasonographic characteristics of the preovulatory follicle; B-mode echotextural changes of the follicle wall; blood flow and perfusion changes of the follicle wall; signs of impending ovulation; prediction of impending ovulation; types of preovulatory follicle outcomes such as ovulation, septated evacuation, hemorrhagic anovulatory follicle, and atresia; follicle blood flow during evacuation; early corpus luteum blood flow; and vascularity of the preovulatory follicle versus fertility.(AU)

Equine preovulatory follicle: blood flow changes, prediction of ovulation and fertility / Folículo pré-ovulatório equino: mudanças circulatórias, predição de ovulação e fertilidade

This review will focus on the main findings of our experiments that used B-mode and color-Doppler ultrasonography during the preovulatory period to study the morphological and blood flow/perfusion changes of the preovulatory follicle in mares. The topics to be addressed herein will be: ultrasonographic characteristics of the preovulatory follicle; B-mode echotextural changes of the follicle wall; blood flow and perfusion changes of the follicle wall; signs of impending ovulation; prediction of impending ovulation; types of preovulatory follicle outcomes such as ovulation, septated evacuation, hemorrhagic anovulatory follicle, and atresia; follicle blood flow during evacuation; early corpus luteum blood flow; and vascularity of the preovulatory follicle versus fertility.

This review will focus on the main findings of our experiments that used B-mode and color-Doppler ultrasonography during the preovulatory period to study the morphological and blood flow/perfusion changes of the preovulatory follicle in mares. The topics to be addressed herein will be: ultrasonographic characteristics of the preovulatory follicle; B-mode echotextural changes of the follicle wall; blood flow and perfusion changes of the follicle wall; signs of impending ovulation; prediction of impending ovulation; types of preovulatory follicle outcomes such as ovulation, septated evacuation, hemorrhagic anovulatory follicle, and atresia; follicle blood flow during evacuation; early corpus luteum blood flow; and vascularity of the preovulatory follicle versus fertility.

Recent advances and new concepts on follicle and endocrine dynamics during the equine periovulatory period

During the recent years, mares have been shown as relevant follicle-related research comparative model for women because of similarities in the number and nature of ovarian follicular waves, a constant relative diameter of the largest follicle between the two species at definable events throughout the ovulatory wave, and similar ultrasonographic characteristics and changes of the preovulatory follicle. In the mare, as in other monovular species (cattle, women), usually only one dominant follicle develops as a result of the deviation mechanism. However, occasionally two or more dominant follicles may also occur. Few studies in mares have addressed the relationships between periovulatory circulating hormone concentrations and single versus multiple dominant/preovulatory follicles. Temporal and mechanistic studies performed recently (years 2005 to 2008) have contributed to elucidation of intriguing relationships among the dominant follicle and circulating hormones and will be the focus of this review. The main topics discussed herein are: (i) development of one versus two dominant follicles with a single ovulation; (ii) development of one versus multiple ovulatory follicles; (iii) conversion of two dominant follicles to double ovulations; (iv) role of hormones in development of double ovulations; (v) interrelationships of periovulatory reproductive hormones; (vi) repeatability of preovulatory follicle diameter and hormones; and (vii) factors that affect preovulatory follicle diameter and hormones, such as breeds and types of mares, season, body condition, and aging.

Recent advances and new concepts on follicle and endocrine dynamics during the equine periovulatory period

During the recent years, mares have been shown as relevant follicle-related research comparative model for women because of similarities in the number and nature of ovarian follicular waves, a constant relative diameter of the largest follicle between the two species at definable events throughout the ovulatory wave, and similar ultrasonographic characteristics and changes of the preovulatory follicle. In the mare, as in other monovular species (cattle, women), usually only one dominant follicle develops as a result of the deviation mechanism. However, occasionally two or more dominant follicles may also occur. Few studies in mares have addressed the relationships between periovulatory circulating hormone concentrations and single versus multiple dominant/preovulatory follicles. Temporal and mechanistic studies performed recently (years 2005 to 2008) have contributed to elucidation of intriguing relationships among the dominant follicle and circulating hormones and will be the focus of this review. The main topics discussed herein are: (i) development of one versus two dominant follicles with a single ovulation; (ii) development of one versus multiple ovulatory follicles; (iii) conversion of two dominant follicles to double ovulations; (iv) role of hormones in development of double ovulations; (v) interrelationships of periovulatory reproductive hormones; (vi) repeatability of preovulatory follicle diameter and hormones; and (vii) factors that affect preovulatory follicle diameter and hormones, such as breeds and types of mares, season, body condition, and aging.(AU)