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)

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.