How ultrasound technologies have expanded and revolutionized research in reproduction in large animals

Inter-software reliability and agreement for follicular and luteal morphometric and echotextural ultrasonographic parameters in beef cattle

This study aimed to compare the inter-software and inter-observer reliability and agreement for the assessment of follicular and luteal morphometry and echotexture parameters in beef crossbreed females (3/8 Bos taurus indicus and 5/8 Bos taurus taurus). B-mode and color Doppler ultrasonographic ovarian images were obtained at specific time points of estradiol-progesterone-based protocols for timed artificial insemination (TAI). Sonograms were analyzed by two observers using a licensed (IASP1) and an open access (IASP2) software package. A total of 292 snap-shot sonograms were analyzed for morphometric parameters and 504 for echotexture parameters. inter-software reliability was judged moderate to excellent (ICC or CCC=0.73-0.98), whereas inter-observer reliability for morphometric parameters was deemed good to excellent (ICC or CCC=0.82-0.98). A small percentage (up to 10.95 %) of measured parameters fell outside the limits of inter-software and inter-observer agreement. For echotexture parameters, inter-software reliability varied widely (ICC or CCC=0.16-0.95) based on the size of regions of interest (ROI), while inter-observer reliability ranged from moderate to excellent (ICC or CCC= 0.71-0.97). The highest inter-software reliability for pixel value and heterogeneity value was observed for the corpus luteum (ICCs=0.81-0.95; P>0.05), followed by the peripheral follicular antrum (ICCs=0.75-0.78; P<0.05). However, lower reliability was determined for the follicular wall (ICCs=0.08-0.33; P<0.0001) and perifollicular stroma (ICCs=0.16-0.46; P<0.05). In conclusion, both software packages showed high reproducibility for morphometric measurements, while echotexture measurements were more challenging to replicate based on ROI sizes. Caution is advised when selecting ROI sizes for echotexture measurements in bovine ovaries.

Unveiling the Role of IGF-I in Fertility: Effect of Long-Acting Bovine Somatotropin (bST) on Terminal Follicular Development and Fertility during an Annual Reproductive Cycle in Sheep

The study aimed to assess the effect of long-acting bST treatment, in a dose that only increases IGF-I plasma concentrations, on ovarian and fertility markers of estrous synchronized ewes that were fed to keep their bodyweight. Three experiments were designed to evaluate this effect: in Experiment 1, 18 ewes were distributed in groups (bST 0, 30, 50 mg) to measure plasma IGF-I and insulin for 15 days; in Experiment 2, 92 ewes (5 replicates) in two groups (0 and 30 mg bST) were synchronized using a 6-day progesterone protocol during the breeding season to assess the effect of bST on follicular and luteal performances, estrous and ovulation, and fertility after mating. In Experiment 3, 50 ewes (3 replicates) were used to repeat the study before but during anestrus. Results indicate that 50 mg bST increased IGF-I and insulin plasma concentrations, but 30 mg bST only increased IGF-I concentrations; and that only during the breeding season did 30 mg bST increase the number of lambs born and the reproductive success of ovulatory-sized follicles compared to controls. This occurred without it affecting any other reproductive marker. In conclusion, 30 mg bST treatment may improve oocyte competence for fertility during the breeding season.

Luteal tissue blood flow and side effects of horse-recommended luteolytic doses of dinoprost and cloprostenol in donkeys

This study assessed luteolysis and side effects in jennies receiving standard horse-recommended doses of cloprostenol and dinoprost. Sixteen cycles of eight jennies were randomly assigned in a sequential crossover design to receive dinoprost (5 mg, i.m.) and cloprostenol (0.25 mg, i.m.) at 5-d post-ovulation. B-mode and Doppler ultrasonography were employed to assess luteal tissue size and blood flow before (-15 min and 0h) and after (0.5, 1, 2, 3, 4, 5, 6, 7, 8, 12, 24, and 48h) administering PGF2α. Immunoreactive progesterone concentrations were assayed at similar timepoints via RIA. Side effects such as sweating, abdominal discomfort, and diarrhea were scored at 15-min-intervals for 1h after PGF2α. Data normality was assessed with the Shapiro-Wilk's test. Luteal tissue size and blood flow were analyzed using PROC-MIXED and post-hoc by Tukey. Non-parametric tests analyzed side effect variables. The luteal blood flow increased overtime by 27% at 45 min and peaked by 49% at 3 h for dinoprost, and conversely, it increased by 14% at 30 min and peaked at 39% at 5h for cloprostenol (P<0.05). Luteal blood flow was reduced by 50%, 25%, and 10% on both groups at 8, 12, and 24h (P<0.05). Immunoreactive progesterone concentrations decreased in 0.5h for dinoprost and 1h for cloprostenol and gradually decreased by 48h (P<0.05). Dinoprost induced greater sudoresis scores, while cloprostenol resulted in greater abdominal discomfort and diarrhea scores (P<0.05). In conclusion, dinoprost and cloprostenol effectively induced luteolysis with distinct side effects; this could guide practitioners' case selection to use one or another PGF2α.

Age-Related Differences in Testosterone Concentration and Its Relation to Testicular Biometrics, Hemodynamics, and Fertility in Alpacas (Vicugna pacos)

The goal of this study was to investigate the age-related differences in testosterone concentration and its relation to testicular biometrics, testicular blood flow, and fertility in alpacas (Vicugna pacos). Fifteen alpaca males with different ages (young (YM; ~12-14 mo.), n = 5; intermediate (IM; ~24 mo.), n = 5; and old (OM; ≥36 mo.), n = 5) were enrolled in the study. Blood samples were taken from each alpaca male and the circulating plasmatic testosterone concentration (TC; ng/mL) was determined using ELISA analysis. The testicular traits related to bio-morphometric parameters (the length (L), width (W), area (A), and volume (TV)) were assessed using B-mode ultrasonography. Pulse-wave/power Doppler ultrasonography was used to obtain the circulatory dynamic values (testicular hemodynamics) before the beginning of natural service mating. Significant differences were observed in TC among the age groups, increasing as the age of the males increased (2.47 ± 0.31, 8.45 ± 1.53, and 22.66 ± 2.15 for YM, IM, and OM, respectively; p < 0.05); however, no differences were observed regarding the testicular B-mode ultrasonographic parameters (L, W, and A) (p > 0.05). Positive correlations were observed between TV and testicular L, W, and A (r = 0.96, r = 0.95, and r = 0.96, respectively; p ≤ 0.001). Pulse-wave-Doppler-derived parameters such as the pulsatility index (PI) and the resistive index (RI), as well as the total vascularity area (TVA) assessed by power Doppler, were similar in all of the age groups studied (p > 0.05). General linear model (GLM) analysis showed a relationship between TC and TV (OR = 0.95; p = 0.04), as well as between TC and TVA (OR = 0.99; p= 0.02). Finally, no differences were observed regarding the pregnancy rate among the different age groups (p > 0.05). In conclusion, TC increased as the age of the alpaca males increased. Although TC was related to TV and TVA, the pregnancy rates obtained from individuals belonging to the different age groups were similar, indicating that TC, TV, and TVA were not determining factors in assessing the potential age-related fertility differences in alpaca males.

ULTRASONOGRAPHIC AND COMPUTED TOMOGRAPHIC CHARACTERISTICS OF THE REPRODUCTIVE CYCLE IN FEMALE VEILED CHAMELEONS (CHAMAELEO CALYPTRATUS)

Female veiled chameleons, Chamaeleo calyptratus, have a high fecundity and fast maturation, which makes them a suitable model species for squamate reproduction. The authors investigated the morphological follicular development of a group of 20 healthy adult animals over a 12-mon period using ultrasonography (US) and CT. Four stages of follicular development could be distinguished by imaging diagnostics and were confirmed by histology: previtellogenesis, vitellogenesis, gravidity, and atresia. Using a linear ultrasound transducer (18 MHz), previtellogenic follicles could be visualized as small, round, hypoechoic structures. Identification of this stage was unreliable on CT. On US, vitellogenic follicles remained round and showed increasing echogenicity from the hypoechoic center outwards, displaying vinyl-like hyperechoic banding in later stages. On CT, early vitellogenic follicles were round, hyperdense structures, which reduced in density as they grew. A hyperdense inner ring with a hypodense central point characterized late vitellogenesis. Following ovulation, eggs became distinctly oval on both CT and US, with formation of a hyperdense or hyperechoic outer ring, respectively. Atresia followed in cases where no ovulation occurred, and was divided into yolky and cystic atresia. Sonographically, early yolky atretic follicles became unevenly shaped, packed against one another, and developed heterogenous content. Late atretic follicles were homogenous and reduced in size. Reduction of density and uneven shape were also observed on CT. Cystic atretic follicles developed an anechoic cavity with a dense peripheral accumulation of content. In many animals 2-3 generations of atretic follicles were observed without indication of impairment to the development of the newest batch of follicles. Thus, follicular atresia need not necessarily lead to a pathological condition in veiled chameleons, at least not within a few consecutive cycles.

Comparison between transrectal palpation, B-mode and Doppler ultrasonography to assess luteal function in Holstein cattle

Introduction

Over the years, the most common methods for monitoring reproductive health in cattle have varied from transrectal palpation to B-mode ultrasonography. Nowadays, some portable ultrasound equipment includes the Doppler mode. Therefore, the aim of this study was to compare the accuracy of the different methods to assess corpus luteum (CL) functionality.

Methods

In Experiment 1, 53 Holstein lactating cows undergoing a synchronization protocol were examined via transrectal palpation and B-mode scanning. Measurements for the largest diameter (LAD) and subjective size of CL (SCLS) were collected. Data were analyzed using correlation analysis and ROC Curves. In Experiment 2, 30 Holstein non-lactating cows with a CL were administered PGF2α and examined several times after injection, first in B-mode and then with Power Doppler. Measurements for LAD, CL area (CLA) and subjective and objective CL blood flow were collected. Blood samples were taken in both experiments to determine P4 concentration. Data were analyzed using correlation analysis and the GLM repeated measures test.

Results

Results for Experiment 1 showed that LAD was more accurate than SCLS. In Experiment 2, CLA was the best measurement to assess CL function, although both subjective and objective CL blood flow offer accurate information 24 h after PGF2α administration.

Discussion

Consequently, ultrasonography provides more accurate information about CL function than transrectal palpation. Although CLA seems to be an earlier indicator of luteal function than blood flow, 24 h after the onset of luteolysis, both parameters are valid.

Review: Non-surgical artificial insemination and embryo recovery as safe tools for genetic preservation in small ruminants

Artificial insemination (AI) and in vivo embryo production (or multiple ovulation and embryo transfer, MOET) programs are both instrumental in accelerating the propagation of genetically and economically superior goats and sheep. The aim of this review was to present the current gestalt of non-surgical AI and embryo recovery (NSER) procedures in small ruminants. Small body size, precluding rectal palpation, and highly limited penetrability of the uterine cervix in ewes are the major reasons for the scarce use of non-surgical assisted reproduction techniques in this species. As a result, AI and embryo recovery techniques in sheep mainly involve laparoscopy or laparotomy (LAP). In does, however, the Embrapa method of AI allows for successful intrauterine deposition of semen, resulting in pregnancy rates from 50 to 80% under field conditions (>3 000 goats inseminated) when frozen-thawed semen is used. After the administration of prostaglandin F2α (PGF2α), non-surgical (transcervical) embryo recovery is also feasible in goats, with the cervical penetration rate approaching 100%. There is a paucity of information on the efficacy of non-surgical AI using frozen semen in sheep, but the results are satisfactory with fresh, cooled, or chilled ram semen. An application of the NSER technique in ewes has greatly improved over the last decade, and cervical penetration rates of ∼90% can be achieved when a hormonal cervical dilation protocol using PGF2α, oxytocin, and/or estradiol ester (e.g., estradiol benzoate) is applied. In some genotypes of sheep, sufficient cervical dilation can be induced without estradiol ester included in the protocol. Several studies indicated that recovery of transferable quality ovine embryos using NSER is comparable to that employing a ventral midline laparotomy, and NSER is evidently a method of choice when animal welfare is concerned. Considering both the number of retrievable embryos and animal well-being, the NSER is a viable alternative for surgical procedures. With further developments, it has the makings of a primary, if not exclusive, embryo recovery technique in small ruminants worldwide.

Ovarian and uterine two-dimensional and Doppler ultrasonographic changes in the feline peri-estrus period

OBJECTIVES

The aim of this study was to evaluate two-dimensional and Doppler ultrasonographic changes of the ovary and uterus during estrus and the early post-estrus period in domestic cats.

METHODS

Two-dimensional and Doppler ultrasonographic evaluations of the ovaries and uterus were performed in seven queens on days 1, 3 and 5 of estrus, and 5 days after estrus (AE5).

RESULTS

On day 1, 5.4 ± 0.5 follicles of 2.1 ± 0.1 mm were detected progressively increasing in number and size up to day 5 and then decreased on AE5 (P <0.05). A maximum follicular diameter of 4.1 ± 0.1 mm was achieved on day 5. Both during and after estrus, the uterus was generally hypoechoic compared with the surrounding tissues and delineated by a thin hyperechoic line corresponding to the serosa. In some animals, the uterine layers were distinguished during and after estrus. The blood flow waveforms of the intraovarian and uterine arteries were characterized by a systolic peak and diastolic flow extending throughout the remainder of the cardiac cycle to the next systole. In the uterine artery waveforms, the early diastolic notch was mild or absent during most estrous observations. The resistance index of the intraovarian arteries decreased up to day 5, and then increased on AE5 (P <0.05). The resistance index of the uterine arteries was lower during estrus than in the post-estrus period (P <0.05).

CONCLUSIONS AND RELEVANCE

It is concluded that in the domestic cat, follicular number and diameter as well as ovarian and uterine blood flow changed during and immediately after estrus. Doppler ultrasound proved suitable to evaluate the hemodynamic changes involved in the cyclic remodeling of ovarian and uterine tissues that occurs during and after follicular growth in domestic cats.

Advances in the ultrasound diagnosis in equine reproductive medicine: New approaches

Ultrasound technology has led to new lines of research in equine reproduction, and it has helped to greatly improve clinical diagnosis and reproductive outcomes in equine practice. This review aims to discuss the potential clinical uses and new approaches of ultrasonography in equine reproduction. Doppler modalities are usually used to evaluate the vascularization of the follicles, corpus luteum (CL), and the uterus in the mare for diagnostic purposes. Inclusion of Doppler ultrasound in artificial insemination and embryo transfer programs could improve the reproductive outcome of these techniques. Better selection of recipients based on CL functionality, early pregnancy diagnosis 7-8 days postovulation of the donor before flushing or diagnosis of mares with endometritis with pathological increases of blood flow are examples of clinical applications in the mare. In the stallion, colour Doppler ultrasound has improved the diagnostic potential of B-mode ultrasound, improving the differential diagnosis of pathologies such as testicular torsion (decrease or absence of blood flow in the cord) and orchitis (increased blood flow in the cord). The incorporation of pulsed Doppler ultrasound into the reproductive evaluation of the stallion has enabled early identification of stallions with testicular dysfunction, thus allowing administration of timely treatment and subsequent improvements of the fertility prognosis for these animals. In addition, this technique has been used in the monitoring of patients undergoing medical and surgical treatments, thus verifying their efficacy. Recently, computer-assisted pixel analysis using specific software has been performed in research work in order to semi-quantitatively evaluate the vascularization (colour and power Doppler) and echotexture of different organs. These softwares are now being developed for clinical purposes, as is the case with Ecotext, a computer program developed for the evaluation of testicular echotexture, providing information on testicular functionality.

Doppler Ultrasound in the Reproduction of Mares

Doppler ultrasonographic (US) is a method that provides real-time information on vascular architecture and hemodynamic aspects of blood vessels. It can determine the presence, direction, and speed of blood flow, being subdivided into the categories of color Doppler (color flow and power flow) and pulsed Doppler. The objective of this chapter was to compile data from several studies addressing the use of US Doppler correlated with pathophysiological phenomena of equine reproduction. Initially we decided to describe the technique, advantages, and disadvantages of each Doppler mode. Then the applicability of US Doppler in mares related to equine reproduction. Thus, within this chapter, you will find the form of use and descriptions of studies carried out on vascular perfusion of the follicular dynamics, the corpus luteum, the uterine segments, which we have divided into post-insemination evaluation, endometritis diagnosis and pregnancy diagnosis. So, we hope that this chapter will expand the knowledge about US Doppler and increase the number of veterinarians who will introduce the technique into their practical routine.

The impact of the cavitary corpus luteum on the blood progesterone concentration and pregnancy rate of embryo recipient heifers

In cattle there are two types of the corpus luteum (CL): homogeneous (CL_hom) and cavitary (CL_cav). Although they are considered equal in their hormonal activity, the function of the CL_cav is questioned by many veterinarians. In consequence, females with the CL_cav are considered less valuable for assisted reproductive techniques such as embryo transfer (ET), where recipients with the CL_hom are preferred. The aim of our study was to compare the two types of CLs regarding morphological endpoints, serum progesterone (P4) concentrations and final pregnancy rate (PR) in recipient heifers after ET. The morphological type of the CL and the final PR after ET of 432 Holstein Friesian heifers were analyzed. Oestrus was synchronized with two i.m. inj. of 0.5 μg cloprostenol 14 days apart. The ET took place on the day 7 of the estrous cycle, only animals with visible oestrum were chosen for the procedure. Clinical and transrectal US examinations of ovaries were performed on the day of ET. The presence of the CL_hom or CL_cav was determined, and the CL diameter and cross-sectional area were measured. If present, measurements of the cavities were also taken. Only embryos recovered immediately prior to the ET at the morula or blastocyst stage were transferred to the randomly chosen recipient that underwent initial selection regardless of the CL morphology. Additionally, from randomly selected heifers (N = 53, CL_hom = 33; CL_cav = 20) blood samples for serum P4 concentration analysis were collected. Pregnancy was determined by transrectal palpation 2 months after ET. The medium-sized CL_cav was larger in diameter (P < 0.001) and cross-sectional area (P < 0.01) than the CL_hom (mean ± SD) - 23.29 ± 3.6 mm and 419.57 ± 135.01 mm² compared to 21.87 ± 3.57 mm and 384.73 ± 145.46 mm², respectively. The mean diameter and cross-sectional area of the cavity were 10.2 ± 4.36 mm and 97.59 ± 71.13 mm², respectively. The volume of both types of CLs was similar (P = 0.3). The mean serum P4 concentration was 8.84 ng/ml, higher (P < 0.0001) for females with the CL_cav (11.31 ng/ml) than for those with the CL_hom (7.15 ng/ml). The PR was 36.1%, higher (P < 0.05) for recipients with the CL_cav (47.7%) compared to the CL_hom (29.9%). The presence of a CL_cav in the recipient heifers did not negatively affect the potential of the CL to maintain pregnancy. On the contrary, the CL_cav may give the embryo better chances of surviving the time of pregnancy recognition and in consequence, may have a positive effect on PR in heifers.

Ultrasound Characteristics of the Cavitary Corpus Luteum after Oestrus Synchronization in Heifers in Relation to the Results of Embryo Transfer

Simple Summary

In cattle there are physiologically two morphological forms of the corpus luteum: compact and with cavity. During ultrasound examination a fluid filled cavity is clearly visible. Routine ultrasound examination is performed—as a part of preselection—in embryo-recipient heifers/cows. Some vets eliminate recipients with cavitary corpus luteum from embryo transfer, considering them to be less suitable for an embryo to develop. In our research, we showed that the level of progesterone in the blood of recipients on Embryo Transfer day was higher in the case of cavitary corpus luteum than in the case of compact ones. Similarly, the pregnancy rate of recipients with a cavitary corpus luteum was higher. The presence of cavity inside the corpus luteum should not be a reason for the elimination of recipients from embryo transfer. Moreover, cavitary corpus luteum may be a valuable indicator of the recipient’s reproductive potential.

Abstract

The aim of the study was to conduct an ultrasound analysis of quantitative parameters of the corpus luteum (CL) in recipient heifers on days 6–8 after oestrus, and to compare reproduction potential of both types of CL in those females. Analyses were performed on 300 heifers, synchronized with two injections of cloprostenol. Clinical and ultrasound examinations of ovaries were performed and measurements of the CL were recorded. The blood samples were taken to determine progesterone level. Pregnancy examination was conducted after 6–8 weeks from the ET. Cavitary CL was found in 32.7% heifers In 48.0% of the cavitary CL, its luteal tissue area was reduced by 14.3% compared to the compact CL, while 16.3% of the CL had luteal tissue reduced by more than 33.8%. Progesterone level in blood serum was higher in heifers with the cavitary CL (p < 0.001). Pregnancy rate was higher for females with a cavitary CL (52%) than those with compact ones (33%, p < 0.05). The ultrasound assessment of luteal tissue should be included in the evaluation of the functional status of the CL in ET-recipient heifers. The cavitary CL presence may indicate a higher potential of the recipient in maintaining the pregnancy.

Assessment of the accuracy of testicular dysfunction detection in male donkey (Equus asinus) with the aid of colour-spectral Doppler in relation to plasma testosterone and serum nitric oxide levels

This study aimed to determine the usefulness of colour and pulsed Doppler modes for the accurate diagnosis of donkeys suffering from subfertility to determine whether testicular vascularity assessment could be an indicator for sperm functionality. The study sample was composed of 10 male donkeys with normospermia (control group) and 10 donkeys with hypospermia. Animals underwent scrotal circumference measurement, testicular Doppler examination, seminal evaluation, blood sampling and hormonal assay. Semen volume and concentration were significantly (p ≤ .05) lower in the subfertile group (30.25 ± 1.22 ml and 89.44 ± 2.55 × 10⁶ /ml) as compared with the control group (82.76 ± 1.65 ml and 452.78 ± 1.25 × 10⁶ /ml), and total sperm/ejaculation was significantly (p ≤ .05) higher in the normal donkeys (28.30 ± 2.32 × 10⁹ /total ejaculated) as compared with the subfertile group. Intratesticular coloured area showed a marked decline in the hypospermic males. There was no significant difference between the two groups in testosterone level, although the normal group showed an increase in nitric oxide metabolites. Both Doppler indices of the three branches of the testicular artery were elevated significantly (p ≤ .05) in abnormal donkeys, whereas Doppler peak systolic and end-diastolic velocities were increased in the normal group. Male donkeys with subfertility demonstrated lower arterial vascularity parameters in the form of intratesticular coloured area and blood flow rate; therefore, the most optimal parameters for differentiating subfertile hypospermic from normospermic donkeys were found to be the two Doppler indices, velocities parameters, testicular blood flow rate and nitric oxide levels.

Postpartum Uterine Involution and Embryonic Development Pattern in Chinese Holstein Dairy Cows

Understanding the postpartum uterine involution pattern and embryonic development could facilitate bovine reproduction management, improve reproductive efficiency, and diagnosis of the reproductive disorder, which would contribute to the success of the dairy business. This study aimed to investigate postpartum uterine involution and embryonic developmental patterns or postconceptional marks of embryonic fetal development in Chinese Holstein dairy cows using B-mode ultrasonography. The results revealed a significant decline in the involution period with an increase of parity and age. The uterine involution period was shorter in multiparous cows when compared with cows with lower parities. Consistently, cows over 4 years old recovered faster than younger cows (2 or 3 years). Besides, the elder cows (over 4 years) had a relatively larger size of resumed cervix uteri and horns. Postpartum uterine involution pattern analysis revealed that the reproductive tract recovered very fast during the first 16 days postpartum for all the parity. Results of postconceptional marks of embryo development revealed a slow increase in diameter of the gravid uterine horn and crown-rump length (CRL) before day 60. In contrast, this increase was dramatic and rapid after the 60th day. We also established two models to estimate gestational age based on gravid uterine horn diameter or CRL. A formula was established to determine the gravid uterine horn size during postconceptional on day 30th–day 90th (r = 0.8714, P < 0.01). In addition, a significant positive correlation between CRL and gestational age (r = 0.98151, P < 0.01) was built. In conclusion, these results illustrated that parity and calving age had significant effects on uterine involution in Chinese Holstein cows. Crown-rump length and gravid uterine horn diameter are both efficient for evaluating the embryo growth. These current findings broaden the understanding of basic reproductive pattern in Chinese Holstein cows and could benefit bovine reproductive management primarily in postpartum and early pregnant cows to reduce the calving interval and avoid periparturient metabolic diseases.

Salmon oil supplementation in dogs affects the blood flow of testicular arteries

The administration of fish oils is known to cause changes in several reproductive parameters of domestic animals. The ingestion of polyunsaturated fatty acids (PUFAs) of the omega-3 family, such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), has been described and correlated with changes in the semen quality, testosterone levels and male fertility. Nevertheless, few studies monitored and registered effects after ceasing supplementation. In the present study, we monitored the Doppler velocimetric and ultrasonographic parameters of nine dogs' testis for 90 days (D90) checking the effect of salmon oil supplementation, and monitoring continued for 60 days more, after ceasing supplementation (D150). Ultrasonographic evaluations comprised determining the Doppler velocimetric parameters, testicular and epididymal volume, and testicular echotexture. Peak systolic velocity (PSV) as well as final diastolic velocity (EDV) in the supratesticular arteries (STA), and marginal artery (MA) increased during the period of treatment and kept that level up to D150. There was no difference between the fish-oil supplementation period and the unsupplemented one regarding the testicular and epididymal volume and echogenicity and heterogeneity characteristics. A negative correlation was found between heterogeneity of testis and sperm production (r = -.41, p = .008). Doppler velocimetry indices were affected by the supplementation, leading to an increase in testicular blood flow.

Placentation in Equids

This chapter focuses on the early stages of placental development in horses and their relatives in the genus Equus and highlights unique features of equid reproductive biology. The equine placenta is classified as a noninvasive, epitheliochorial type. However, equids have evolved a minor component of invasive trophoblast, the chorionic girdle and endometrial cups, which links the equine placenta with the highly invasive hemochorial placentae of rodents and, particularly, with the primate placenta. Two types of fetus-to-mother signaling in equine pregnancy are mediated by the invasive equine trophoblast cells. First, endocrinological signaling mediated by equine chorionic gonadotrophin (eCG) drives maternal progesterone production to support the equine conceptus between days 40 and 100 of gestation. Only in primates and equids does the placenta produce a gonadotrophin, but the evolutionary paths taken by these two groups of mammals to produce this placental signal were very different. Second, florid expression of paternal major histocompatibility complex (MHC) class I molecules by invading chorionic girdle cells stimulates strong maternal anti-fetal antibody responses that may play a role in the development of immunological tolerance that protects the conceptus from destruction by the maternal immune system. In humans, invasive extravillous trophoblasts also express MHC class I molecules, but the loci involved, and their likely function, are different from those of the horse. Comparison of the cellular and molecular events in these disparate species provides outstanding examples of convergent evolution and co-option in mammalian pregnancy and highlights how studies of the equine placenta have produced new insights into reproductive strategies.

Uterine and Corpus Luteum Blood Flow Evaluation Prior to Uterine Flushing in Llama Embryo Donors

The aim of this study was to assess the uterine blood flow (UBF) and corpus luteum blood flow (CLBF) in llamas 8 days post-mating, using color-Doppler ultrasonography (CDU), to determine the possible relationship between vascularization and the presence of an embryo. Adult females (n = 25) were used to monitor ovarian dynamics by palpation and transrectal ultrasonography until detection of a ≥6 mm growing follicle. Females were randomly assigned to one of two groups: Group I (n = 19), were mated and ovulation was induced by a single dose of buserelin (GnRH analog) that same day (Day 0); and Group II (n = 6), only ovulation was induced (control). On Day 8, UBF and CLBF were evaluated transrectally in both groups. The color-flow images obtained were analyzed with Image J1.52a software to determine the vascularization area and the percentage of corpus luteum with blood flow emission (CLBF%) together with the percentage for each uterine horn (UBF%). Statistical analysis was performed using an ANOVA test. In Group I, uterine flushing was performed to obtain the embryos, thus dividing the females into Group I+ (n = 10), when an embryo was recovered and Group I- (n = 9), when no embryo was recovered. Embryo recovery rate was 52.63% (10/19). In Group I+, UBF% was significantly higher compared to Group I- and Group II (P <0.05). UBF appears to be a good predictor for embryo presence, with an area under the curve (AUC) of 0.9 and an optimal cut-off value of 9.37% (with a sensitivity of 90% and specificity of 88.9%). The CLBF% did not differ between groups (P > 0.05). In conclusion, it is possible to detect a local increase of UBF in the presence of an embryo on day 8 post-mating in llamas. This could be useful to achieve an early pregnancy diagnosis or to decide whether to carry out the uterine flushing in a llama embryo transfer program.

Outcome prediction from the first examination in clinical mastitis using ultrasonography in dairy cows

The aim of this study was to examine whether ultrasonography can be used to predict the outcome of clinical mastitis in dairy cows. Forty-seven mastitic quarters of Holstein-Friesian cows were examined using ultrasonography at the time of the first examination. In mastitic mammary tissue, three sonographic signs indicating tissue abnormality were found: a hyperechoic spot in the parenchyma area, structural changes to the milk duct, and non-homogeneous parenchyma. Logistic regression was used to evaluate whether the abnormal findings in the sonographic images can be used to predict the outcome of clinical mastitis. The outcomes of clinical mastitis were defined by the return, or failure to return, to marketable milk production. The sonogram finding of non-homogeneous parenchyma in the first examination did predict the outcome of clinical mastitis, whereas the type of systemic symptoms (severe or moderate) was not a predictor in this regression model. Therefore, ultrasound examinations of mammary glands in the first examination could be a useful method for predicting outcome of clinical mastitis. There is an economic benefit if ultrasound examination in first examination helps in the decision of whether or not to treat the mastitic cows.

Spectral Doppler ultrasound in selecting an equine embryo receiver

The aim of this study was to evaluate whether the RI and PI values would help in choosing the best embryo recipient, and observe whether CL vascularization would influence P4 production. During the breeding season 2018/2019, the study was conducted using 35 mares, which is used for reference to collect data for the project on the day of embryo transfer. The utilized mares were divided into five groups followed by the day after ovulation, with D0 being the day of ovulation. Therefore, the five groups are as follows: D4-mares that were on the 4th post-ovulation day; D5-mares that were on the 5th post-ovulation day; and doing so successively for D6, D7 and D8. On the day of embryo transfer, the CL of the mares that selected as recipients was evaluated by B-mode and power flow mode ultrasonography and the right and left dorsal branches of the uterine arteries by spectral Doppler ultrasonography. Blood samples were taken on the day of the embryo transfer for a dosage of P4 concentration by radioimmunoassay. No statistical difference was found between the variables when the mares were separated into pregnant and non-pregnant mares, or when they were separated by age groups. When the groups of mares were compared by the day of embryo transfer, the statistical difference was found between the groups D5 × D6 (p = .0053) and D6 × D8 (p = .0036) in RI variable. In PI variable, the statistical difference was found between the groups D4 × D8 (p = .049), D5 × D6 (p = .0446) and D6 × D8 (p = .0024). We conclude that the mares with RI measurement of uterine arteries near 1.0 are correlated to mares with high CL vascularization and elevated P4 concentration.

Regulation of AMH, AMHR-II, and BMPs (2,6) Genes of Bovine Granulosa Cells Treated with Exogenous FSH and Their Association with Protein Hormones

Anti-Mullerian hormone (AMH) is an important reproductive marker of ovarian reserve produced by granulosa cells (GCs) of pre-antral and early-antral ovarian follicles in several species, including cattle. This hormone plays a vital role during the recruitment of primordial follicles and follicle stimulating hormone (FSH)-dependent follicular growth. However, the regulatory mechanism of AMH expression in follicles is still unclear. In this study, we compared the expression of AMH, AMHR-II, BMP2, BMP6, FSHR, and LHCGR genes during follicular development. In-vitro expression study was performed with and without FSH for AMH, AMHR-II, BMP2, and BMP6 genes in bovine GCs which were isolated from 3–8 mm follicles. Association among the mRNA expression and hormone level was estimated. GCs were collected from small (3–8 mm), medium (9–12 mm) and large size (13 to 24 mm) follicles before, during onset, and after deviation, respectively. Further, mRNA expression, hormones (AMH, FSH, and LH), apoptosis of GCs, and cell viability were detected by qRT-PCR, ELISA, flow cytometry, and spectrophotometry. AMH, AMHR-II, BMP2, and FSHR genes were highly expressed in small and medium follicles as compared to large ones. In addition, the highest level of AMH protein (84.14 ± 5.41 ng/mL) was found in medium-size follicles. Lower doses of FSH increased the viability of bovine GCs while higher doses repressed them. In-vitro cultured GCs treated with FSH significantly increased the AMH, AMHR-II, and BMP2 expression levels at lower doses, while expression levels decreased at higher doses. We found an optimum level of FSH (25 ng/mL) which can significantly enhance AMH and BMP2 abundance (p < 0.05). In summary, AMH, AMHR-II, and BMP2 genes showed a higher expression in follicles developed in the presence of FSH. However, lower doses of FSH demonstrated a stimulatory effect on AMH and BMP2 expression, while expression started to decline at the maximum dose. In this study, we have provided a better understanding of the mechanisms regulating AMH, AMHR II, and BMP2 signaling in GCs during folliculogenesis, which would improve the outcomes of conventional assisted reproductive technologies (ARTs), such as superovulation and oestrus synchronization in bovines.

Consideration of breed specific fetal trunk diameter for the estimation of gestation age using trans-abdominal ultrasonography in sheep

The study aim was to estimate gestational age (GA), expected parturition date (EPD) and growth rate by determining fetal trunk diameter (TD). Effects of fetal-dam pelvis alignment and in utero fetal position at time of ultrasonography (UG) on fetal numbers and sex determination were also studied. Trans-abdominal UG (3-6.5 MHz) was conducted on 37 ewes with known breeding dates from Days 25-120 of pregnancy. Errors in GA and EPD were studied using an equation in the same ewes at their successive breeding when date of breeding was unknown. There were four equations, Y = 1.28861X+32.656 (R² = 0.92), for Indigenous; Y = 1.2603X+38.075 (R² = 0.85), for Indigenous × Garole; and Y = 0.8932X+45.916 (R² = 0.99), for Garole fetuses; and the equation, Y = 1.3565X + 32.604 (R² = 0.94), independent of breed were computed to estimate GA and the relationship between GA and TD of different breeds. The error in estimated GA and EPD using these four equations was determined and there was comparison with the data collected using US and the previously described equations. Results indicate there was the greatest (P <  0.01) error for GA and EPD values using the US TD equation for all breeds. There was the least error in estimated EPD using the breed specific equations. Error in the sex determination was 4.8 % and fetal number determination was 16.7 % with singleton and 7.7 % twin fetuses. The results indicate there is a breed specific fetal TD that is useful for predicting GA in sheep.

Uterine hemodynamics during a short-term progesterone synchronization protocol in ewes

Twenty-eight pluriparous and non-lactating Santa Inês sheep were synchronized with vaginal sponge and an intramuscular (IM) injection of 37.5 μg of cloprostenol on random days of the estrous cycle (D0); day 6 (D6), at 7:00 am, the devices were removed, and after 24 h (D7), GnRH analog (25 μg of lecirelin) was administrated. Fixed-time artificial insemination (FTAI) with cervical traction by the transcervical route was performed 52 to 58 h after sponge removal. Doppler velocimetry of both uterine arteries was performed on D0, D2, D4, and the morning of D6 (every 48 h), and then every 12 h from D6 to D8 (7:00 a.m. and 7:00 p.m.). We analyzed the peak systolic velocity (PSV), end-diastolic velocity (EVD), time-averaged maximum and mean velocity (TAMAX, TAMEAN), pulsatility index (PI), resistance index (RI), systolic/diastolic ratio (S/D), arterial diameter (AD), and blood flow volume (BFV), with the objective of evaluating the hemodynamic behavior of blood flow velocity parameters of the uterine artery during a short-term progesterone synchronization protocol in ewes. With respect to phases, we noted increases in the means of TAMAX and TAMEAN and decreases of EDV, PI, and RI (P < 0.05). S/D, EDV, TAMEAN, PI, RI, SD, AD, and BFV showed differences between the time of progesterone insertion and the estimated time of ovulation (which was considered the last evaluation) (P < 0.05). The PI and RI values were different when comparing the times of insertion and withdrawal of the progesterone device (PI 2.53-1.54 and RI 0.76-0.68) (P < 0.05). The PI was different with respect to side (P < 0.001), but no side effect was seen in the RI. In conclusion, the two uterine arteries behave differently under the effect of progesterone (intravaginal sponges) and the effect of estradiol during the follicular phase, and estrous phase was responsible for increasing uterine blood flow.

Differential expression of LHCGR and its isoforms is associated to the variability in superovulation responses of Gir cattle

The aim of this study was to evaluate the pattern of expression of LHCGR isoforms in Gir heifers characterized as good (10.3 ± 1.2 ova/embryos per flush, n = 5) or poor responders (1.1 ± 0.3 ova/embryos per flush, n = 5) to superovulation protocols. In both groups, an adapted ultrasound-guided follicular aspiration system was used to collect granulosa cells from 8 mm follicles formed either during a synchronized, non-stimulated follicular wave (no stimulation control, NS) or on the fourth day of a superovulation protocol (SOV) induced with 200 IU of pFSH. The recovered follicular fluid was centrifuged and granulosa cells were washed with NaCl 0.9% and kept in RNAlater^®. RNA extraction was performed using a commercial RNeasy Micro Kit and eluted samples were quantified and reverse transcribed using the commercial Superscript III kit. cDNA samples were amplified by real-time PCR using a primer to target LH/hCG receptor gene - not selective for LHCGR isoforms (total LHCGR) - and four sets of isoforms selective primers (S1, S10, S10 + 11, and S11). Analyses were performed using the REST software and expression levels are shown as mean ± SEM. Under physiological conditions (NS), poor responders had a higher expression of total LHCGR (4.9 ± 1.7 fold-change, P < 0.01) as well as isoforms S10, S11 and S10 + 11, compared to good responders. In both phenotypes, superovulation down-regulated total LHCGR expression (-0.5 ± 0.2 and -0.9 ± 0.0 for good and poor responders, respectively; P < 0.05). However, in poor responders the exogenous FSH treatment up-regulated the S10 (2.4 ± 2.0; P < 0.05), S10 + 11 (3.8 ± 3.2; P < 0.01), and S1 isoforms (1.8 ± 1.3; P < 0.05), compared to good responders We conclude that down-regulation of total LHCGR, associated to up-regulation of their inactive isoforms, may have compromised follicle development and thus contributed to the low efficiency of superovulation in heifers with a poor responder phenotype.

Reproduction in domestic ruminants during the past 50 yr: discovery to application

The study of reproductive physiology in domestic ruminants has progressed from the whole animal to the molecular level in an amazingly short period of time. The volume of information on this subject is enormous; therefore, we have focused on domestic ruminants, with an emphasis on cattle. To date, artificial insemination (AI) is perhaps the most powerful technique that reproductive physiologists and geneticists have provided the livestock industry for genetic improvement. Early efforts to establish AI as a tool were initiated in Russia around 1899 and since that time major advances in methods of semen collection, evaluation of male fertility, cryopreservation of sperm, sex-sorted semen, and estrous cycle control have occurred. The preceding advances not only led to the widespread use of AI, but also contributed to our fundamental understanding of ovulation control, timing of insemination, gamete biology, and cryopreservation. In regards to anestrus, our understanding of the concept of neuroendocrine control of the pituitary gland and the role of steroid feedback led to the Gonadostat Theory, which proposes that onset of puberty is due to a decrease in the negative feedback of gonadal steroids over time. Subsequent studies in prepuberal and postpartum sheep and cattle established that a short luteal phase frequently precedes the first normal length cycle that is accompanied by estrous expression. This observation led to the common practice of treating prepuberal heifers and anestrous postpartum cows with a short-term progestin treatment (e.g., Controlled Internal Drug Release) to induce normal estrous cycles. In domestic ruminants, fertilization rate is high (85% to 95%); however, significant embryonic mortality before or around the time of maternal recognition of pregnancy (MRP) reduces the pregnancy rate to a single breeding. Significant effort has been directed at determining the time of MRP, the signal for MRP, as well as elucidating the physiological, cellular, and molecular dialogue between the conceptus and uterine environment. Advancements have now led us to the ability to edit the genome to alleviate disease and possibly improve production traits. In summary, major advancements in our understanding of reproductive biology have stemmed from efforts to establish the AI and embryo transfer technique and reduce the negative impact of anestrus and embryonic mortality in domestic ruminants.

Using ultrasound to derive new reproductive traits in tropical beef breeds: implications for genetic evaluation

Key components of female fertility in tropically adapted beef breeds are age at puberty and interval from calving to conception. Presence of an ovarian corpus luteum or stage of pregnancy were recorded using trans-rectal ultrasonography in 4649 heifers and 2925 first-lactation cows in seven herds of either Brahman, Droughtmaster or Santa Gertrudis tropical beef cattle breeds in northern Australia. The traits derived from a single ultrasonographic examination were incidence of corpus luteum at ~600 days of age in heifers, and weeks pregnant 5 weeks post-mating in heifers at ~2.5 years of age and in first-lactation cows at either 2.5 or 3.5 years of age. At 600 days of age, the bodyweight of heifers averaged 340 kg and 40% had a corpus luteum. At 2.5 years of age bodyweight of heifers averaged 452 kg and 80% were pregnant. First-lactation cows averaged 473 kg and 64% were pregnant. Considerable between-herd variation in traits reflected differences in climate and management at each site. However, estimates of heritability of incidence of corpus luteum at 600 days (0.18–0.32) and weeks pregnant in lactating cows (0.11–0.20) suggested that a significant proportion of the variation was due to additive gene action. Small to moderate genetic correlations with other economically important traits and the range in estimated breeding values indicate substantial opportunity for genetic improvement of the traits. The study provided evidence to accept the hypothesis that strategically timed ultrasound examinations can be adopted to derive useful traits for genetic evaluation.

Monitoring and controlling ovarian function in the rhinoceros

Despite their size and potentially dangerous demeanor, the rhinoceros has been a preferred subject of wildlife reproductive scientists. Several factors contribute to this taxon's popularity including the ability to utilize insightful tools like non-invasive hormone metabolite monitoring and transrectal ultrasonography, the necessity for mate introductions to coincide with the female's estrus when breeding certain species or individuals, and the desire to develop assisted reproductive technologies to facilitate the genetic management and ultimate sustainability of small, managed populations in human care. The resulting profusion of rhinoceros reproductive studies has revealed significant species-specific characteristics and exposed the prevalence of aberrant reproductive activity within this taxon. Of equal importance, it has guided necessary intervention and enhanced our success in overcoming challenges associated with breeding rhinoceroses.

Hemodynamics of the corpus luteum in mares during experimentally impaired luteogenesis and partial luteolysis

The aim of the current project was to characterize the luteal vascularity and the plasma concentrations of progesterone (P4), prolactin (PRL) and 13,14-dihydro-15-keto-PGF_2α (PGFM) in mares with luteal disturbances during early and mid-diestrus. In Experiment 1, twenty-one mares were treated with 2 mL of 0.9% NaCl, or 1 mg Dinoprost, or 10 mg Dinoprost on day two after ovulation (Control-D2, 1/10PGF-D2 and PGF-D2 groups, respectively; n = 7 mares/group). In Experiment 2, similar treatments were performed eight days post-ovulation using a different cohort of 21 mares (Control-D8, 1/10PGF-D8 and PGF-D8 groups, respectively; n = 7 mares/group). Blood samples were collected hourly and power-Doppler examinations of the corpus luteum (CL) were performed every 6 h from H0 (moment immediately before treatment) to H48. Data collection was also done once a day from D0 (day of ovulation) to D20. In Experiment 1, the PGF-D2 and 1/10PGF-D2 groups had lower increase of plasma concentration of P4 until H48 and reduced maximum P4 concentrations on D8-D11 than mares from the Control-D2 group. However, no differences among groups were detected for luteal vascularity during early and mid-diestrus. In Experiment 2, complete and partial luteolysis were detected in mares from the PGF-D8 and 1/10PGF-D8 groups, respectively. Luteal vascularity and plasma P4 concentrations differed among Control-D8, PGF-D8 and 1/10PGF-D8 groups on H48. Partially regressed CLs (1/10PGF-D8 group) generated more Doppler signals than completed regressed CLs (PGF-D8 group) between D10 and D13. In both experiments, a transient increase in PRL activity was observed in parallel to the PGFM pulse in mares receiving 1 or 10 mg Dinoprost. The use of prostaglandin on D2 at conventional or 1/10 of the dose impaired the luteal development in mares. Moreover, the low dose of prostaglandin lead to partial regression of mature CLs. The blood supply was reduced in partially regressed CLs, but not in CLs undergoing impaired luteogenesis.

Pre-ovulatory follicle affects corpus luteum diameter, blood flow, and progesterone production in mares

Color Doppler ultrasonography was used to study the temporal relationships between pre-ovulatory follicle (POF) and corpus luteum (CL) diameter and blood flow, with systemic progesterone (P4) concentration during two transitional ovulatory seasons in mares. Variables of POF and CL/P4 were evaluated for 6days before and 17days after ovulation, respectively. Evaluations were performed during two consecutive estrous cycles in spring and fall seasons, and during the last estrous cycle of the season. There were significant correlations among POF and CL variables, and P4 concentration that ranged from 0.24 to 0.95, and among the ratios of different variables that ranged from 0.39 to 0.92. There were linear regressions (P<0.01-0.001) for all comparisons among different variables. The POF diameter before the first ovulation of the season was larger (P<0.05), and POF vascularity was less (P<0.05), than in the last estrous cycle during the season. The CL blood flow was less (P<0.01) during the last compared with first pre-ovulatory period of the season. The POF diameters were positively correlated (r=0.67) during the two pre-ovulatory periods of spring and fall. Results provide evidence that the POF affects CL diameter and blood flow, and subsequently P4 production, and that POF diameter is repeatable within the same individual during different seasons.

Pulse Doppler ultrasound as a tool for the diagnosis of chronic testicular dysfunction in stallions

Testicular function is particularly susceptible to vascular insult, resulting in a negative impact on sperm production and quality of the ejaculate. A prompt diagnosis of testicular dysfunction enables implementation of appropriate treatment, hence improving fertility forecasts for stallions. The present research aims to: (1) assess if Doppler ultrasonography is a good tool to diagnose stallions with testicular dysfunction; (2) to study the relationship between Doppler parameters of the testicular artery and those of sperm quality assessed by flow cytometry and (3) to establish cut off values to differentiate fertile stallions from those with pathologies causing testicular dysfunction. A total of 10 stallions (n: 7 healthy stallions and n: 3 sub-fertile stallions) were used in this study. Two ejaculates per stallion were collected and preserved at 5°C in a commercial extender. The semen was evaluated at T0, T24 and T48h by flow cytometry. Integrity and viability of sperm (YoPro®-1/EthD-1), mitochondrial activity (MitoTracker® Deep Red FM) and the DNA fragmentation index (Sperm Chromatin Structure Assay) were assessed. Doppler parameters were measured at three different locations on the testicular artery (Supratesticular artery (SA); Capsular artery (CA) and Intratesticular artery (IA)). The Doppler parameters calculated were: Resistive Index (RI), Pulsatility Index (PI), Peak Systolic Velocity (PSV), End Diastolic Velocity (EDV), Time Average Maximum Velocity (TAMV), Total Arterial Blood Flow (TABF) and TABF rate. The capsular artery was the most reliable location to carry out spectral Doppler assessment, since blood flow parameters of this artery were most closely correlated with sperm quality parameters. Significant differences in all the Doppler parameters studied were observed between fertile and subfertile stallions (p ≤ 0.05). The principal components analysis assay determined that fertile stallions are characterized by high EDV, TAMV, TABF and TABF rate values (high vascular perfusion). In contrast, subfertile stallions tend to present high values of PI and RI (high vascular resistance). The ROC curves revealed that the best Doppler parameters to predict sperm quality in stallions were: Doppler velocities (PSV, EDV and TAMV), the diameter of the capsular artery and TABF parameters (tissue perfusion parameters). Cut off values were established using a Youden´s Index to identify fertile stallions from stallions with testicular dysfunction. Spectral Doppler ultrasound is a good predictive tool for sperm quality since correlations were determined among Doppler parameters and markers of sperm quality. Doppler ultrasonography could be a valuable diagnostic tool for use by clinical practitioners for the diagnosis of stallions with testicular dysfunction and could be a viable alternative to invasive procedures traditionally used for diagnosis of sub-fertility disorders.

Systemic and intrafollicular components of follicle selection in mares

Mares are superb models for study of follicle selection owing to similarities between mares and women in relative follicle diameters at specific events during the follicular wave and follicle accessibility for experimental sampling and manipulation. Usually, only 1 major follicular wave with a dominant follicle (DF) greater than 30 mm develops during the 22 to 24 d of the equine estrous cycle and is termed the primary or ovulatory wave. A major secondary wave occasionally (25%) develops early in the cycle. Follicles of the primary wave emerge at 6 mm on day 10 or 11 (day 0 = ovulation). The 2 largest follicles begin to deviate in diameter on day 16 when the future DF and largest subordinate follicle (SF) are 23 mm and 20 mm, respectively. The deviation process begins the day before diameter deviation as indicated in the future DF but not in the future SF by (1) increase in prominence of an anechoic layer and vascular perfusion of the wall and (2) increase in follicular-fluid concentrations of IGF1, vascular endothelial growth factor, estradiol, and inhibin-A. A systemic component of the deviation process is represented by suppression of circulating FSH from secretion of inhibin and estradiol from the developing DF. Production of inhibin is stimulated by IGF1 and LH, and estradiol is stimulated by LH and not by IGF1 in mares. A local intrafollicular component involves the production of IGF1, which apparently increases the responsiveness of the future DF to FSH. The roles of the IGF system have been well studied in mares, but the effect of IGF1 on increasing the sensitivity of the follicle cells to FSH is based primarily on studies in other species. The greater response of the future DF than the SF to the low concentrations of FSH is the essence of selection. During the common growth phase that precedes deviation, diameter of the 2 largest follicles increases in parallel on average when normalized to emergence or retrospectively to deviation. Study of individual waves indicates that (1) the 2 follicles change ranks (relative diameters) during the common growth phase in about 30% of primary waves and (2) after ablation of 1, 2, or 3 of the largest follicles at the expected beginning of deviation, the next largest retained follicle becomes the DF indicating that several follicles have the capacity for dominance; therefore, it is proposed that the deviation process represents the entire mechanism of follicle selection in mares.

Transuterine embryo migration, distribution of sexes within uterine horns, and fetometry in Nellore (Bos indicus) cattle

There is no consensus about the occurrence of transuterine embryo migration under natural breeding circumstances, neither data related to this phenomenon for zebu cattle. In this study, 5431 reproductive tracts of Nellore cows and heifers were evaluated in an abattoir in the state of Mato Grosso do Sul. A total of 1030 animals (19.0%) were pregnant at the time of slaughter (including 2 twin pregnancies). Regarding singleton pregnancies (n = 1028), 39.5% of them, the fetus was located in the left uterine horn and the remaining 60.5% in the right. These frequencies differed statistically from parity. In all 1028 (100.0%) cases, the presence of a single CL was perceived in the ovary ipsilateral (whether right or left) to the pregnant uterine horn, indicating the absence of transuterine embryo migration of the conceptus. The overall sex ratio found was 51.5%, considering only pregnancies with sex identified, not differing significantly between the number of males and the number of females. The sex frequencies obtained from the total number of singleton pregnancies were 46.5% males, 43.9% females, and the remaining 9.6% corresponding to unknown sex fetuses. The supposed sex predilection for uterine horns was not observed because the difference between the numbers of males and females for the same uterine horn was not statistically significant. The crown-rump (CR) and crown-nose (CN) measures, for the conceptus with CR length 2.00 cm to 15.00 cm, showed a high linear correlation coefficient (r = 0.990865), being CN = (0.3027 × CR) + 0.4491, r² = 0.9818, the equation that describes the behavior between the variables for this length interval. In conclusion, in Nellore cattle, the transuterine migration of conceptus may not exist, or consists of a rare event. In addition, the sex ratio and predilection are not distinguished from the symmetrical distribution, and regarding fetometry, an equation that involves CR and CN, could be useful for the veterinary field routine, especially in reproductive evaluation.

A weekly postpartum PGF2α protocol enhances uterine health in dairy cows

Postpartum uterine health in dairy cows is crucial for the maintenance of good reproductive performance. In order to improve uterine health and reduce puerperal intrauterine infection, 608 Holstein cows received a weekly PGF_2α protocol (3 i.m. injections of PGF_2α at 7, 14 and 21 d postpartum). For comparison, 593 cows in the control group received injections of sterile saline at the same time. Uterine score at 14 d postpartum, the prevalence of endometritis at 21-27 d postpartum, and subsequent reproduction performance was evaluated. Cows in the treated group exhibited higher tonicity (P<0.05) of the uterus, with less prevalence of endometritis (10.4%, 63/608 vs. 34.6%, 205/593; P<0.001), and required shorter time to the first AI postpartum (67.5±3.4 d vs. 84.4±3.7 d, P<0.05) and to pregnancy (114.5±5.4 d vs. 131.4±5.8 d, P<0.05). In conclusion, the present study demonstrated that uterine health in Holstein cows can be promoted while puerperal infection can be suppressed by this weekly postpartum PGF_2α protocol.

Transabdominal ultrasound for detection of pregnancy, fetal and placental landmarks, and fetal age before Day 45 of gestation in the sheep

Detection of pregnancy during early gestation is advantageous for flock breeding management. Transabdominal ultrasound is a practical and efficient approach for monitoring pregnancy and fetal growth in small ruminants. However, there is limited information using the transabdominal technique before Day 45 of gestation in sheep. Therefore, our objective was to determine how accurately transabdominal ultrasound could be used to detect pregnancy, to identify pregnancy landmarks, and to quantify fetal length before Day 45 in ewes. Multiparous Western White-faced ewes (n = 99) were estrus synchronized and exposed to one of four Dorset rams. The day a ewe was marked by a ram was considered Day 0 of gestation. Ewes not remarked by Day 20 were separated for ultrasonography. To detect pregnancy and landmarks, ewes were scanned three times per week between Day 26.0 ± 0.3 (mean ± standard error) and Day 40.0 ± 0.2. A single technician performed all scans in the right nonhaired abdominal pit using a real-time portable Eazi-Scan machine and a 5-MHz linear rectal transducer. All data were analyzed using the MIXED procedure in SAS (with repeated measures where appropriate). Because of rebreeding activity, 113 ultrasound periods were initiated. The specificity and positive predictive value were 100% during the entire study. The accuracy, sensitivity, and negative predictive value of ultrasound scanning were greater than 90% beginning at Day 33 ± 1. On average, pregnancy (n = 85) was detected at Day 28.7 ± 0.4 and nonpregnancy (n = 28) at Day 25.5 ± 0.6. Three early fetal losses were identified at Day 39.7 ± 0.7. In pregnant ewes (n = 82), the overall accuracy of fetal counting was 78%. The first observance of an enlarged uterus (P = 0.05) and pregnancy (P = 0.03) was detected earlier when multiple fetuses were developing compared with singletons. Placentome evagination was first observed earlier in triplets compared with twins and singletons (P = 0.02). Fetal length increased with day of gestation (P < 0.0001) but not fetal number (P = 0.72). A fetal number by day of gestation interaction (P = 0.01) indicated differences in fetal length at Day 29 ± 1 and Day 32 ± 1. These data demonstrate that a portable ultrasound using the transabdominal technique can be used to accurately determine pregnancy, identify landmarks indicative of gestation, and estimate fetal age, before Day 45 of gestation in sheep.

Reproductive Disorders in Horses

Reproductive disease is relatively common in the horse, resulting in a variable, yet significant, economic impact on individual horsemen as well as the entire industry. Diverse expertise from the veterinary community ensures and improves individual and population health of the horse. From a pathology and diagnostics perspective, this review provides a comprehensive overview of pathology of the male and female equine reproductive tract. Recognition by clinical and gross features is emphasized, although some essential histologic parameters are included, as appropriate. Where relevant, discussion of ancillary diagnostic tests and approaches are included for some diseases and lesions.

Transabdominal ultrasonography for pregnancy diagnosis and estimation of gestational age in dromedary camels

The objective of this study was to evaluate the use of transabdominal ultrasonography as a method for pregnancy diagnosis and establish some foetal biometrics guidelines of pregnancy staging. Transabdominal ultrasonography was performed weekly on six pregnant camels from the 4th to the 19th week and at 2-week intervals from the 20th to the 52nd week of gestation. Six areas were selected for examination: caudal abdominal (CAA), inside the thigh, above the base of the udder; middle abdominal (MIA), from the base of the udder to the umbilicus; and cranial abdominal (CRA), from the umbilicus to the xiphoid cartilage. Several foetal parameters including orbital diameter (ORD), biparietal diameter (BPD), abdominal diameter (ABD), chest depth (CHD) and ruminal diameter (RUD) were measured using standardized scan plans. The relationships between the gestational age and the foetal parameters were evaluated. From the 6th to the 12th week, the conceptus was always observed through the left CAA approach. Between the 13th and 27th week, the foetus was entirely visualized by the MIA examination. From the 28th to the 52nd week, the conceptus was mainly detected through the left CRA approach. The foetal parameters were measured frequently during mid- and late gestation. All regression and correlation coefficients were highly significant (p < 0.0001). In conclusion, transabdominal ultrasonography was shown to be a reliable technique for pregnancy diagnosis and estimation of gestational age in dromedary camels.

Endometrial echotexture variables in postpartum cows with subclinical endometritis

The aim of this study was to evaluate endometrial echotexture changes on ultrasonographic digital images during subclinical endometritis using a computer-assisted image analysis program. Endometrial samples were collected from 140 Brown Swiss cows (days in milk = 35 ± 3) using a cytobrush method and classified as having a non-inflamed uterus (n = 66) and uterus with acute (n = 42), subacute (n = 21), and chronic (n = 11) inflammations. The mean cellular infiltration density was 0%, 31 ± 5%, 37 ± 6%, and 16 ± 8% for cows with non-inflamed uterus and cows with acute, subacute, and chronic uterine inflammations (P < 0.0001). As the cell infiltration density increased, both cervical diameter and mean gray level did not change. There were a liner decrease in homogeneity and a linear increase in contrast in response to increased cellular infiltration density. The sensitivity and specificity were 79.73% and 46.97% for the homogeneity value and 59.46% and 69.70% for the contrast value, respectively. In conclusion, monitoring endometrial echotexture alterations, especially homogeneity and contrast, changed depending on the cellular density and inflammation status and may be potential diagnostic markers for subclinical endometritis in cows.