Superstimulation of ovarian follicular development in beef cattle with a single intramuscular injection of Folltropin-V

The effect of progesterone concentrations during superovulation of Holstein heifers in a randomized trial

The aim of this study was to evaluate the effect of different progesterone (P4) concentrations during the follicular growth on the intensity of estrous expression, ovarian response to the superovulatory treatment, and embryo production and quality in superovulated heifers. A total of 63 Holstein heifers were randomly assigned into 2 experimental groups: Low P4 (n = 31) and High P4 (n = 32). Animals received a pre-synchronization protocol followed by a protocol of superovulation that included the allocated P4 treatment. Activity was monitored continuously by an automated activity monitor, and estrus characteristics (maximum intensity and duration) were recorded. Embryo collection was performed 7 d post artificial insemination (AI). Embryos were counted and graded from good or excellent (1) to degenerated (4). The outcomes of interest were: number and diameter of follicles at the time of AI, ovulation success (confirmed 7 d post-AI), time to estrus event, maximum intensity and duration of estrus, number and quality of embryos. Data were analyzed according to the type of outcome variable using logistic, linear, or Poisson regression models. A total of 105 embryos (High P4: n = 42; Low P4: n = 63) were graded for quality. Different P4 levels did not affect the maximum intensity (High P4 = 497.8 ± 23.9%; Low P4 = 542.2 ± 23.5%) or the duration (High P4 = 13.5 ± 1.5 h; Low P4 = 14.3 ± 1.4 h) of estrus. Heifers in the High P4 treatment had greater number of follicles at time of AI (High P4 = 16.6 ± 1.6 follicles; Low P4 = 13.9 ± 1.2 follicles), but with smaller diameter (High P4 = 11.3 ± 0.1 mm; Low P4 = 12.0 ± 0.1 mm) compared with Low P4. High P4 heifers tended to have better embryo quality compared with Low P4 heifers (odds ratio = 1.98; 95% CI = 0.90-4.35). High P4 heifers had less embryos than Low P4 heifers, but this was modified by the CIDR (intravaginal implant of P4) removal to estrus interval (interval 0-21 h: mean ratio = 1.15, 95% CI = 0.42-1.87; interval 22-46 h: mean ratio = 0.58, 95% CI = 0.27-0.96). Although estrous expression was not associated with embryo quality, as the duration and the maximum intensity of estrous expression increased, the number of embryos recovered 7 d post-AI increased (duration: mean ratio = 1.04; 95% CI = 1.03-1.05; maximum intensity: mean ratio = 1.50; 95% CI = 1.42-1.58). In conclusion, P4 during the follicular growth, and intensity of estrus, are playing a role in regulating the quality and the number of embryos produced by superovulated heifers. This study was supported by contributions from Resilient Dairy Genome Project and the Natural Sciences and Engineering Research Council.

The oocyte: the key player in the success of assisted reproduction technologies

The ovulation of a mature oocyte at metaphase II of meiosis, with optimal potential to undergo fertilisation by a sperm cell, complete meiosis and sustain the switch to mitotic division, and support early embryo development, involves a protracted and disrupted/delayed series of processes. Many of these are targeted for exploitation in vivo , or recapitulation in vitro , by the livestock industry. Reproductive technologies, including AI, multiple ovulation embryo transfer, ovum pick-up, in vitro embryo production, and oestrus and ovulation synchronisation, offer practitioners and producers the opportunity to produce offspring from genetically valuable dams in much greater numbers than they would normally have in their lifetime, while in vitro oocyte and follicle culture are important platforms for researchers to interrogate the physiological mechanisms driving fertility. The majority of these technologies target the ovarian follicle and the oocyte within; thus, the quality and capability of the recovered oocyte determine the success of the reproductive intervention. Molecular and microscopical technologies have grown exponentially, providing powerful platforms to interrogate the molecular mechanisms which are integral to or affected by ART. The development of the bovine oocyte from its differentiation in the ovary to ovulation is described in the light of its relevance to key aspects of individual interventions, while highlighting the historical timeline.

Factors affecting superovulation induction in goats (Capra hericus): An analysis of various approaches

Goats are generally called a "poor man's cow" because they not only provide meat and milk but also other assistance to their owners, including skins for leather production and their waste, which can be used as compost for fertilizer. Multiple ovulation and embryo transfer (MOET) is an important process in embryo biotechnology, as it increases the contribution of superior female goats to breeding operations. The field of assisted reproductive biotechnologies has seen notable progress. However, unlike in cattle, the standard use of superovulation and other reproductive biotechnologies has not been widely implemented for goats. Multiple intrinsic and extrinsic factors can alter the superovulatory response, significantly restricting the practicability of MOET technology. The use of techniques to induce superovulation is a crucial step in embryo transfer (ET), as it accelerates the propagation of animals with superior genetics for desirable traits. Furthermore, the conventional superovulation techniques based on numerous injections are not appropriate for animals and are labor-intensive as well as expensive. Different approaches and alternatives have been applied to obtain the maximum ovarian response, including immunization against inhibin and the day-0 protocol for the synchronization of the first follicular wave. While there are several studies available in the literature on superovulation in cattle, research on simplified superovulation in goats is limited; only a few studies have been conducted on this topic. This review describes the various treatments with gonadotropin that are used for inducing superovulation in various dairy goat breeds worldwide. The outcomes of these treatments, in terms of ovulation rate and recovery of transferrable embryos, are also discussed. Furthermore, this review also covers the recovery of oocytes through repeated superovulation from the same female goat that is used for somatic cell nuclear transfer (SCNT).

Optimization of gonadotropin stimulation protocols for in vitro embryo production in prepubertal Mediterranean water buffalo

Embryos can be produced from prepubertal donor animals using laparoscopic ovum pickup and in vitro embryo production technologies (LOPU-IVEP). Together, these tools can shorten the interval between generations, rapidly accelerating the rate of genetic gain. Here, we assessed the impact of different gonadotropin stimulation protocols in Mediterranean water buffalo heifer calves aged between 2 and 6 months old. Following gonadotropin stimulation, LOPU was performed at two-week intervals, with animals receiving different protocols on subsequent LOPUs. After collection, the cumulus-oocyte complexes (COCs) were matured and fertilized in vitro, and embryos were cultured to the blastocyst stage followed by transfer into synchronized adult recipients. The number and size of follicles aspirated during LOPU, the number and quality of COCs recovered, as well as cleavage, embryo development and pregnancy rates were assessed. First, we evaluated the impact of using FSH with and without eCG (administered 24-h prior to LOPU) and found that a combination of FSH and eCG was able to significantly improve embryo development rates (20.6 ± 2.0% vs. 9.0 ± 3.6%; P < 0.05). Second, we compared this protocol to a slow-release formulation of FSH reconstituted in hyaluronan. In addition to requiring less work to prepare the animals for LOPU, this slow-release formulation yielded numerically higher, but not statistically different, average number of recovered COCs (14.4 ± 2.1 vs. 10.3 ± 2.0; P > 0.05) and embryo development rates (22.9 ± 4.7% vs. 14.1 ± 5.2%; P > 0.05) compared to FSH given every 12 h. Next, we compared the length of gonadotropin treatment over 3-, 4- and 5-days prior to LOPU and found that as the length of gonadotropin treatment increased, although the number of COCs recovered steadily decreased (14.1 ± 2.4 vs. 8.7 ± 1.0 vs. 6.9 ± 0.7; P < 0.05), the embryo development rates steadily increased (14.4 ± 3.9 vs. 27.3 ± 4.4 vs. 35.9 ± 7.0; P < 0.05), presumably due to an increase in the proportion of large follicles at the time of LOPU. Numerically, the 4-day treatment yielded more transferrable embryos per donor per LOPU (2.70 ± 0.5) than 3-day (1.94 ± 0.6) and 5-day (2.25 ± 0.5) treatments. Finally, following embryo transfer, 26 of 90 recipient females became pregnant (28.9%). Pregnancies were established from all treatments, which suggests that post-implantation development was not affected among the gonadotropin treatments assessed.

Towards Improving the Outcomes of Multiple Ovulation and Embryo Transfer in Sheep, with Particular Focus on Donor Superovulation

Considerable improvements in sheep multiple ovulation and embryo transfer (MOET)protocols have been made; however, unlike for cattle, MOET is poorly developed in sheep, and thus has not been broadly applicable as a routine procedure. The tightly folded nature of the ewe cervix, the inconsistent ovarian response to various superovulatory treatments, and the requirement of labor to handle animals, particularly during large-scale production, has limited the implementation of successful MOET in sheep. Moreover, several extrinsic factors (e.g., sources, the purity of gonadotrophins and their administration) and intrinsic factors (e.g., breed, age, nutrition, reproductive status) severely limit the practicability of MOET in sheep and other domestic animals. In this review, we summarize the effects of different superovulatory protocols, and their respective ovarian responses, in terms of ovulation rate, and embryo recovery and transfer. Furthermore, various strategies, such as inhibin immunization, conventional superovulation protocols, and melatonin implants for improving the ovarian response, are discussed in detail. Other reproductive techniques and their relative advantages and disadvantages, such as artificial insemination (AI), and donor embryo recovery and transfer to the recipient through different procedures, which must be taken into consideration for achieving satisfactory results during any MOET program in sheep, are also summarized in this article.

Plasma profile of follicle-stimulating hormone and sex steroid hormones after a single epidural administration of follicle-stimulating hormone via caudal vertebrae in Holstein dry cows

The conventional follicle-stimulating hormone (FSH) treatment for bovine superstimulation involves multiple intramuscular injections, which is stressful for animals and onerous. We herein investigated whether a single epidural injection of porcine FSH (pFSH) can induce superovulation and peripheral concentrations of pFSH and steroid hormones after the treatment in Holstein dry cows. We intramuscularly administered pFSH twice daily to three cows for 3 days (control) or a single epidural pFSH administration (epidural). Numbers of follicles (≥10 mm in diameter) at estrus and corpora lutea at luteal phase were counted by ultrasonography. Blood was sampled from 0 to 104 h after the first pFSH administration and plasma pFSH, progesterone, androstenedione, testosterone, and estradiol-17β concentrations were measured. Numbers of follicles (control: 18.3 ± 7.5, epidural: 15.7 ± 4.0; mean ± SD) and corpora lutea (control: 7.3 ± 4.2, epidural: 8.0 ± 2.6) were similar between both treatments. Plasma pFSH concentrations were higher in epidural than in control (p < 0.01). Although no significant differences were observed in progesterone, androstenedione, or estradiol-17β concentrations between the groups, testosterone concentrations were slightly lower with the epidural treatment than with the control treatment (p = 0.08). In conclusion, superovulation was induced by a single epidural injection of pFSH, which achieved higher pFSH level than the multiple injections in Holstein dry cows.

Excessive follicle-stimulating hormone during ovarian stimulation of cattle may induce premature luteinization of most ovulatory-size follicles†

High follicle-stimulating hormone (FSH) doses during ovarian stimulation are detrimental to ovulatory follicle function and decrease live birth rate in cattle and women. However, the mechanism whereby excessive FSH causes ovarian dysfunction is unknown. This study tested the hypothesis that excessive FSH during ovarian stimulation induces premature luteinization of ovulatory-size follicles. Small ovarian reserve heifers were injected twice daily for 4 days with 70 IU (N = 7 heifers) or 210 IU (N = 6 heifers) Folltropin-V [commercial FSH-enriched preparation of porcine pituitary glands with minor (<1%) luteinizing hormone (LH) contamination, cpFSH]. Ovulatory-size (≥10 mm) follicles were excised from ovaries after the last cpFSH injection and hormone concentrations in follicular fluid (FF) were determined using ELISA. Luteinization was monitored by assessing cumulus cell-oocyte complex (COC) morphology and measuring concentrations of estradiol (E), progesterone (P), and oxytocin (O) in FF. COCs were classified as having compact (cCOC) or expanded (eCOC) cumulus cell layers, and as estrogen-active (E:P in FF ≥1), estrogen-inactive (EI, E:P in FF ≤1 > 0.1), or extreme-estrogen-inactive (EEI, E:P in FF ≤0.1). A high proportion (72%) of ovulatory-size follicles in 210 IU, but not 70 IU, dose heifers displayed eCOCs. The high doses also produced higher proportions of EI or EEI follicles which had lower E:P ratio and/or E but higher P and/or O concentrations compared with the 70 IU dose heifers. In conclusion, excessive cpFSH doses during ovarian stimulation may induce premature luteinization of most ovulatory-size follicles in heifers with small ovarian reserves.

A novel route of follicle-stimulating hormone administration with a split-single ischiorectal fossa in Thai-Holstein crossbred superovulation programs under heat stress conditions

The objectives of this study were to compare the efficiency of a split single injection of follicle-stimulating hormone (FSH) given by either intramuscular (split-single IM) or ischiorectal fossa (split-single IRF) injection to the traditional treatment and to determine the concentrations of FSH. The temperature and humidity index (THI) values were interpreted together with the ovarian responses and embryo characteristics. The ovarian responses in the split-single IRF group were similar to those of the control group (p > .05) but higher compared with the split-single IM group (p < .05). Higher peak levels of plasma FSH in the split-single IRF group did not differ compared with the control group (p > .05) but were lower in split-single IM administration (p < .05). The results showed a significant decrease in the numbers of large follicles and corpora lutea (CLs) in the moderate THI compared with low and high THI (p < .05). The high THI affected ovulation rate as well as the numbers of transferable embryos and degenerated embryos (p < .05). In conclusion, the split-single IRF administration had a comparable superovulatory response to the traditional twice-daily protocol. Moreover, the ovulation rate, ovarian follicle responses, and embryo quality were affected by heat stress.

Negative impact of high doses of follicle-stimulating hormone during superovulation on the ovulatory follicle function in small ovarian reserve dairy heifers†

When women with small ovarian reserves are subjected to assisted reproductive technologies, high doses of gonadotropins are linked to high oocyte and embryo wastage and low live birth rates. We hypothesized that excessive follicle-stimulating hormone (FSH) doses during superovulation are detrimental to ovulatory follicle function in individuals with a small ovarian reserve. To test this hypothesis, heifers with small ovarian reserves were injected twice daily for 4 days, beginning on Day 1 of the estrous cycle with 35, 70, 140, or 210 IU doses of Folltropin-V (FSH). Each heifer (n = 8) was superovulated using a Williams Latin Square Design. During each superovulation regimen, three prostaglandin F2α injections were given at 12-h interval, starting at the seventh FSH injection to regress the newly formed corpus luteum (CL). Human chorionic gonadotropin was injected 12 h after the last (8th) FSH injection to induce ovulation. Daily ultrasonography and blood sampling were used to determine the number and size of follicles and corpora lutea, uterine thickness, and circulating concentrations of estradiol, progesterone, and anti-Müllerian hormone (AMH). The highest doses of FSH did not increase AMH, progesterone, number of ovulatory-size follicles, uterine thickness, or number of CL. However, estradiol production and ovulation rate were lower for heifers given high FSH doses compared to lower doses, indicating detrimental effects on ovulatory follicle function.

Controlled delivery of follicle-stimulating hormone in cattle

Embryo transfer in cattle is a key issue requiring in vivo production of several mature follicles as opposed to the normal production of only one. In vivo produced embryos can then be transferred to recipient cows for gestation to occur. To obtain a large number of transferable embryos, the superovulation step is crucial. To allow the growth of ovarian follicles, the most commonly used protocol consists of 2 intramuscular injections per day over 4 days of a saline solution of the follicle-stimulating hormone. To reduce workload, technical errors in the injected dose and animal stress, different strategies have been investigated to sustain the release of this hormone over 4 days in 1 or 2 injections. This review introduces the physicochemical properties of the follicle-stimulating hormone and discusses the limitations of marketed products and all the research that has been conducted to overcome these limitations. In particular, the field of subcutaneous administrations, the development of new formulations such as viscous solutions, implants and microspheres and the modification of the structure of the follicle-stimulating hormone are overviewed and discussed.

Factors affecting embryo production in superovulated Bos taurus cattle

Despite a long history of bovine superovulation research, significant commercial applications did not start until the early 1970s. For some 20 years thereafter, superovulation represented the primary tool for the production of cattle embryos. In the early 1990s, commercial invitro production (IVP) was initiated in cattle. Although ovum pick-up and IVP are now commercially practiced on a wide scale, superovulation and embryo recovery by flushing remain a widespread and very effective approach to the production of cattle embryos. This review covers both the history and the effects of multiple factors on superovulation in Bos taurus cattle. There are three general protocols for suitable pre-FSH programming of donors so that gonadotrophin-responsive follicles are available. Superovulation protocols vary widely based on the FSH source, the diluent used, the number and timing of FSH injections and the timing and utilisation of various prostaglandins, controlled internal progesterone releasing devices, gonadotrophin-releasing hormone, and other means of controlling follicular development and ovulation. The number of oocytes that can be stimulated to grow and ovulate within any given donor can be estimated by either ultrasound-guided sonography or by measuring concentrations of anti-Müllerian hormone in the blood. Animal-related factors that can influence the efficacy of superovulation include cattle breed, age, parity, genetics, lactational status and reproductive history. In addition, nutrition, stress, season, climate, weather and several semen factors are discussed.

An attempt to potentiate the ovarian superstimulatory response in cattle by co-treatment with an aromatase inhibitor

Letrozole is used for the treatment of subfertility in women undergoing ovarian superstimulation, but the mechanism of action has not been investigated critically. The objective was to test the hypothesis that treatment with letrozole will potentiate the superstimulatory response following gonadotropin treatment by increasing the number of follicles present at ovarian follicular wave emergence in cattle. In Experiment 1, ovarian follicular wave emergence was synchronized among beef heifers (n = 8) by transvaginal ultrasound-guided follicle ablation. On Day 0 (wave emergence), a letrozole-releasing device (LRD) was placed intravaginally for 5 days, followed again by transvaginal follicle ablation on Day 5. The number of follicles ≥3 mm was recorded by transrectal ultrasonography on Days 0 and 6.5 (i.e., pre- vs. post-LRD treatment). In Experiment 2, non-lactating dairy cows were assigned randomly to one of two groups (n = 15/gp) after follicle ablation-induced synchronization of wave emergence (Day 0), and given either an LRD or sham device for 5 days. Superstimulatory treatment was initiated on Day 0, consisting of 8 doses of 50 mg of porcine FSH im at 12 h intervals, and luteolytic doses of prostaglandin on Days 3 and 3.5. The LRD/sham devices were removed on Day 3.5, GnRH was given im on Day 5, estrus response was determined on Days 5 and 6, and the ovarian response was recorded by ultrasonography on Days 0, 3.5, 5, 6.5, and 12. In Experiment 1, no difference was detected in the number of antral follicles at wave emergence pre- vs. post-LRD treatment (23.2 ± 3.2 vs. 23.5 ± 3.8 follicles; P = 0.67; mean ± SEM). In Experiment 2, the interval from prostaglandin treatment to estrus was longer (50.3 ± 1.1 vs. 40.7 ± 2.0 h; P < 0.001) and less variable (residuals: 3.1 ± 0.5 vs. 6.7 ± 0.9 h; P < 0.01) in the LRD vs. sham group. The proportion of ovulations (number of CL on Day 12 over the number of follicles ≥3 mm on Day 0) did not differ (0.65 ± 0.02 vs. 0.70 ± 0.02; P = 0.15) nor did the number of CL on Day 12 (15.9 ± 2.5 vs. 19.0 ± 2.0; P = 0.32) between the LRD and sham groups. In summary, treatment with letrozole did not increase the number of antral follicles at wave emergence or the superstimulatory response, but increased precision in the interval to estrus and may be useful for artificial insemination at a fixed time in superstimulatory protocols.

Pursuit of a means of manipulating ovarian function in the cow: An adventure of serendipity, collaboration and friendship

A research career is not only built on ideas and publishable results; it is more often the product of determination, hard work, collegiality and collaboration. It is through our collaborators, family and friends that we really become better persons, and scientists. It is also a matter of being at the right place at the right time. My work in bovine reproduction has progressed from an interest in superovulation and embryo transfer before I became a veterinarian, to the development and application of this technology and fixed-time artificial insemination in beef and dairy herds. Everything that I have done has been possible because of the people that I have worked with over the years. This manuscript combines some of the very exciting things that I have learned about bovine reproduction over the last 30 years and personal stories behind the projects and ideas that we have pursued during that time.

Superstimulation of ovarian follicles in cattle: Gonadotropin treatment protocols and FSH profiles

The objective of ovarian superstimulatory treatments in cattle is to obtain the maximum number of viable embryos by stimulating growth of antral follicles and ovulation of competent oocytes. While factors inherent to the donor animal are critical, an increased knowledge of ovarian physiology, gonadotropin biochemistry and the ability to manipulate ovarian function have provided alternatives for the design of simple and successful protocols for superovulation in cattle. Recent protocols have also been made more user-friendly and allowed for the grouping of donors for successful superovulation. Although the number of reports associating FSH profiles with superovulatory response is limited, studies designed to reduce the number of FSH treatments necessary to induce superstimulation may provide guidance for the development of optimized gonadotropin treatment protocols. Although high peak levels of circulating FSH following a single administration of Folltropin-V have been shown to be associated with a reduced superstimulatory response, the ideal treatment protocol would seem to be to increase circulating FSH levels to values comparable to those required for the induction of follicle wave emergence, and to maintain these levels for at least 72 h (or 36 h for superstimulation prior to ovum pick-up) to allow follicles to reach an ovulatory size and acquire the capacity to ovulate.

Follicle priming by FSH and pre-maturation culture to improve oocyte quality in vivo and in vitro

Nowadays there is strong demand to produce embryos from premium quality cattle, and we can produce embryos using oocytes collected from living premium animals by ovum-pick up (OPU) followed by in vitro fertilization (IVF). However, the developmental competence of IVF oocytes to form blastocysts is variable. The developmental competence of oocytes depends on the size and stages of follicles, and follicle-stimulating hormone priming (FSH-priming) prior to OPU can promote follicular growth and improve the developmental competence of oocytes. Furthermore, following the induction of ovulation using an injection of luteinizing hormone or gonadotropin-releasing hormone after FSH-priming, we can collect in vivo matured oocytes from ovulatory follicles, which show higher developmental competence than oocytes matured in vitro. However, the conventional protocols for FSH-priming consist of multiple FSH injection for 3-4 days, which is stressful for the animal and labor-intensive for the veterinarian. In addition, these techniques cannot be applied to IVF of oocytes collected from bovine ovaries derived from slaughterhouses, which are important sources of oocytes. Here, we review previous research focused on FSH-priming, especially for collecting in vivo matured oocytes and a simplified method for superstimulation using a single injection of FSH. We also introduce the previous achievements using in vitro pre-maturation culture, which can improve the developmental competence of oocytes derived from non-stimulated animals.

Effect of FSH treatment on cumulus oocyte complex recovery by ovum pick up and in vitro embryo production in beef donor cows

This study was conducted to evaluate oocyte recovery and in-vitro blastocyst production of donor cows superstimulated for ovarian follicular development with FSH administered as twice-daily injections in saline or a single injection diluted in 0.5 % hyaluronan before oocyte aspiration. In Experiment 1, cows were treated with 160 mg of Folltropin-Vdiluted in saline, administered in four twice-daily i.m. injections for 2 days (Multiple FSH group); 160 mg of Folltropin-V diluted in hyaluronan and administered in a single i.m. injection (Single FSH group); or no FSH treatment (Control). In Experiment 2, donor cows were treated with either a single FSH i.m. injection or there was no treatment (Control) before ovum pick up (OPU) was performed. In both experiments, COCs collected using OPU were classified, matured, fertilized and cultured at 38.8 °C in a humidified atmosphere for 7 days. In Experiment 1, the number of follicles aspirated and COCs recovered were greater (P < 0.05) in cows treated with multiple and single doses of FSH. Number of blastocysts produced, however, did not differ among groups. In Experiment 2, mean number of follicles aspirated and COCs recovered were also greater (P < 0.05) in FSH-treated cows. Nevertheless, number of blastocysts produced did not differ. In summary, single and multiple FSH administrations induced similar follicular stimulation for OPU. Furthermore, with both FSH treatments there was induction of development of a larger number of follicles to be aspirated and COCs recovered by OPU compared with these values for donor beef cows with no FSH treatment for follicular stimulation.

A 100-Year Review: Reproductive technologies in dairy science

Reproductive technology revolutionized dairy production during the past century. Artificial insemination was first successfully applied to cattle in the early 1900s. The next major developments involved semen extenders, invention of the electroejaculator, progeny testing, addition of antibiotics to semen during the 1930s and 1940s, and the major discovery of sperm cryopreservation with glycerol in 1949. The 1950s and 1960s were particularly productive with the development of protocols for the superovulation of cattle with both pregnant mare serum gonadotrophin/equine chorionic gonadotrophin and FSH, the first successful bovine embryo transfer, the discovery of sperm capacitation, the birth of rabbits after in vitro fertilization, and the development of insulated liquid nitrogen tanks. Improved semen extenders and the replacement of glass ampules with plastic semen straws followed. Some of the most noteworthy developments in the 1970s included the initial successes with in vitro culture of embryos, calves born after chromosomal sexing as embryos, embryo splitting resulting in the birth of twins, and development of computer-assisted semen analysis. The 1980s brought flow cytometric separation of X- and Y-bearing sperm, in vitro fertilization leading to the birth of live calves, clones produced by nuclear transfer from embryonic cells, and ovum pick-up via ultrasound-guided follicular aspiration. The 20th century ended with the birth of calves produced from AI with sexed semen, sheep and cattle clones produced by nuclear transfer from adult somatic cell nuclei, and the birth of transgenic cloned calves. The 21st century has seen the introduction of perhaps the most powerful biotechnology since the development of artificial insemination and cryopreservation. Quick, inexpensive genomic analysis via the use of single nucleotide polymorphism genotyping chips is revolutionizing the cattle breeding industry. Now, with the introduction of genome editing technology, the changes are becoming almost too rapid to fully digest.

Effect of a single epidural administration of follicle-stimulating hormone via caudal vertebrae on superstimulation for in vivo and in vitro embryo production in Japanese black cows

Here, we describe a simplified procedure for embryo production in the Japanese black cow that uses a single caudal epidural injection of follicle-stimulating hormone (FSH). First, we compared the efficiency of superovulation for in vivo embryo production between conventional multiple FSH treatment (control, n = 10) and single epidural administration (epidural, n = 5). The number of transferable blastocysts was similar between control and epidural groups (4.7 ± 3.5 and 9.0 ± 6.0, respectively). Next, we compared in vitro embryo production by ovum pick-up and in vitro fertilization (OPU-IVF) between control (n = 12) and epidural groups (n = 12). The rate of development to transferable blastocysts was higher in the epidural group than in the control (23.3 vs. 10.5%, P < 0.001). In conclusion, a single epidural administration of FSH can induce follicular development comparable to that of the conventional superovulation protocol and may improve the productivity of OPU-IVF.

Pursuit of a method for single administration of pFSH for superstimulation in cattle: What we have learned

A single dose protocol of FSH for superstimulation in cattle may improve compliance and superovulatory response. A single subcutaneous (sc) administration of pFSH was efficacious, but response depended on body condition and injection site; the adipose tissue pad behind the shoulder was most efficacious. Inconsistent results in Holsteins were partially overcome by sc administration of 75% of the total pFSH dose behind the shoulder on the first day followed by 25% 48 h later. An alternative would be to combine FSH with polymers that cause it to be released slowly over several days. Hyaluronan is found normally in most animal tissues and is nonreactive when administered parentally. A single intramuscular (im) administration of pFSH in a 2.0% hyaluronan induced a superovulatory response that did not differ from twice daily im administration over 4 d. However, 2.0% hyaluronan was viscous and difficult to mix with FSH. Although solutions of 1.0 and 0.5% hyaluronan were less viscous, they lacked efficacy as a single im administration. However, superovulatory response was high when either 1.0 or 0.5% hyaluronan was used in a two-dose im protocol; two-thirds on the first day and one-third 48 h later. A single im administration of FSH in 0.5% hyaluronan effectively induced superstimulation for OPU in cattle. Successful superovulation in the cow was associated with circulating FSH levels that were similar to endogenous FSH levels prior to follicular wave emergence; however, levels must be maintained above baseline for at least 72 h, or 36 h for OPU. Circulating FSH levels following a single sc administration of 400 mg NIH-FSH-P1 behind the shoulder in beef cows increased to 1.0 or 1.2 ng/mL at 12 h and were back near baseline in approximately 60 h, while FSH levels following im administration of 200 mg NIH-FSH-P1 in 0.5% hyaluronan into Holstein donors reached 1.5 ng/mL at 12 h and returned to baseline in approximately 36 h.

Superovulation with a single administration of FSH in aluminum hydroxide gel: a novel superovulation method for cattle

Superovulation (SOV) is a necessary technique to produce large numbers of embryos for embryo transfer. In the conventional methods, follicular stimulating hormone (FSH) is administered to donor cattle twice daily for 3 to 4 days. As this method is labor intensive and stresses cattle, improving this method has been desired. We previously developed a novel and simple SOV method, in which the intramuscular injection of a single dose of FSH in aluminum hydroxide gel (AH-gel) induced the growth of multiple follicles, ovulation and the production of multiple embryos. Here we show that AH-gel can efficiently adsorb FSH and release it effectively in the presence of BSA, a major interstitial protein. When a single intramuscular administration of the FSH and AH-gel mixture was performed to cattle, multiple follicular growth, ovulation and embryo production were induced. However, the treatments caused indurations at the administration sites in the muscle. To reduce the muscle damage, we investigated alternative administration routes and different amounts of aluminum in the gel. By administering the FSH in AH-gel subcutaneously rather than intramuscularly, the amount of aluminum in the gel could be reduced, thus reducing the size of the induration. Moreover, repeated administrations of FSH with AH-gel did not affect the superovulatory response. These results indicate that a single administration of FSH with AH-gel is an effective, novel and practical method for SOV treatment.

Superovulatory response in Japanese Black cows receiving a single subcutaneous porcine follicle-stimulating hormone treatment or six intramuscular treatments over three days

To reduce labor for superovulation treatment by twice-daily intramuscular (im) administration of FSH for more than 3 to 4 days, we investigated the superovulatory responses of Japanese Black cows to porcine FSH (pFSH) used as a single subcutaneous (sc) administration at two different doses in two different volumes of saline. In experiment 1, 20 Armour units (AU) of pFSH dissolved in either 10 mL (treatment A; n = 14) or 50 mL (treatment B; n = 14) of saline was administered subcutaneously in the neck region. In experiment 2, 30 AU of pFSH dissolved in either 10 mL (treatment C; n = 15) or 50 mL (treatment D; n = 15) of saline was administered subcutaneously in the neck region. The control animals in experiment 1 (n = 14) and experiment 2 (n = 15) received 20 AU of pFSH administered intramuscularly twice daily in decreasing doses for more than 3 days. In experiment 1, mean (±SEM) numbers of CL (15.4 ± 2.5, 18.1 ± 3.4, and 17.2 ± 2.6), total number of ova and embryos (12.9 ± 1.4, 15.9 ± 3.5, and 16.2 ± 2.8), and transferable embryos (7.5 ± 2.0, 10.4 ± 2.8, and 8.0 ± 2.1) did not differ among treatments A, B, and control. In experiment 2, mean (±SEM) numbers of CL (20.5 ± 4.3, 20.4 ± 2.7, and 20.1 ± 3.4), total number of ova and embryos (21.7 ± 4.2, 17.3 ± 3.4, and 16.5 ± 3.2), and transferable embryos (8.1 ± 1.6, 9.3 ± 2.2, and 9.5 ± 1.9) did not differ among treatments C, D, and control. Although there were no differences in serum pFSH concentrations among the three treatments at each of the time points in experiment 1, in experiment 2, the serum pFSH concentration at 6 and 8 hours after pFSH administration in treatment C (3.1 ± 0.8, 2.7 ± 0.5 ng/mL, mean ± SEM) was significantly greater (P < 0.05) than in the control (0.7 ± 0.1, 1.1 ± 0.2 ng/mL). At 10 hours after administration, the pFSH concentration had decreased and there were no differences among the three treatments at subsequent time points. These results suggest that increasing the volume of saline or the dose of pFSH does not affect the absorption pattern of pFSH administered as a single sc administration. In conclusions, single sc administration of pFSH at a dose of 20 or 30 AU dissolved in 10 or 50 mL of saline is able to induce a superovulatory response comparable with that obtained by twice-daily im administration in Japanese Black cows.

Use of a single injection of long-acting recombinant bovine FSH to superovulate Holstein heifers: a preliminary study

Our objective was to compare several experimental preparations of a single injection of long-acting recombinant bovine FSH (rbFSH; types A and B) to a porcine pituitary-derived FSH (Folltropin) to superovulate Holstein dairy heifers. Nonlactating, nonpregnant virgin Holstein heifers (n = 56) aged 12 to 15 months were randomly assigned to one of four superstimulatory treatments. Beginning at a random stage of the estrous cycle, all follicles greater than 5 mm were aspirated. Thirty-six hours later, heifers received an intravaginal P4 device and superstimulatory treatments were initiated. Treatments were (1) 300 mg of pituitary-derived FSH (Folltropin) administered in eight decreasing doses over a period of 3.5 days; (2) a single injection of 50 μg of A-rbFSH; (3) a single injection of 100 μg of A-rbFSH; and (4) a single injection of 50 μg of B-rbFSH. All heifers received 25 mg PGF2α at 48 and 72 hours after the insertion of P4 device. At 84 hours after insertion, P4 devices were removed, and ovulation was induced 24 hours later with hCG (2500 IU). Heifers were inseminated at 12 and 24 hours after hCG treatment. The number of ovulatory follicles was greatest for heifers treated with Folltropin and B50-rbFSH, least for heifers treated with A50-rbFSH, and was intermediate for heifers treated with A100-rbFSH (25.7 ± 3.2, 18.9 ± 3.2, 5.9 ± 0.9, and 16.6 ± 3.1, respectively; P < 0.001). The number of corpora lutea was greatest for heifers treated with Folltropin, B50-rbFSH, and A100-rbFSH, and least for heifers treated with A50-rbFSH (19.1 ± 2.4, 16.1 ± 3.0, 15.9 ± 2.9, and 2.6 ± 0.9, respectively; P < 0.001). The number of good-quality embryos differed among treatments and was greatest for heifers treated with B50-rbFSH, Folltropin, and A100-rbFSH and least for heifers treated with A50-rbFSH (7.6 ± 2.4, 6.5 ± 1.7, 4.3 ± 1.5, and 0.8 ± 0.5, respectively; P < 0.001). In conclusion, a single injection of a preparation of long-acting rbFSH (either 100 μg of A-rbFSH or 50 μg of B-rbFSH but not 50 μg of A-rbFSH) produced similar superovulatory responses resulting in the production of good-quality embryos when compared with a pituitary-derived FSH preparation administered twice daily for 4 days. More studies using different types of cattle and different doses of rbFSH are needed to confirm the findings reported in this preliminary study.

Current and future assisted reproductive technologies for mammalian farm animals

Reproduction in domestic animals is under control by man and the technologies developed to facilitate that control have a major impact on the efficiency of food production. Reproduction is an energy-intensive process. In beef cattle, for example, over 50 % of the total feed consumption required to produce a unit of meat protein is consumed by the dam of the meat animal (Anim Prod 27:367-379, 1978). Sows are responsible for about 20 % of the total feed needed to produce animals for slaughter (Adv Pork Prod 19:223-237, 2008). Accordingly, energy input to produce food from animal sources is reduced by increasing number of offspring per unit time a breeding female is in the herd. Using beef cattle as an example again, life-cycle efficiency for production of weaned calves is positively related to early age at puberty and short calving intervals (J Anim Sci 57:852-866, 1983). Reproductive technologies also dictate the strategies that can be used to select animals genetically for traits that improve production. Of critical importance has been artificial insemination (AI) (Anim Reprod Sci 62:143-172, 2000; Stud Hist Philos Biol Biomed Sci 38:411-441, 2007; Reprod Domest Anim 43:379-385, 2008; J Dairy Sci 92:5814-5833, 2009) and, as will be outlined in this chapter, emerging technologies offer additional opportunities for improvements in genetic selection. Given the central role of reproduction as a determinant of production efficiency and in genetic selection, improvements in reproductive technologies will be crucial to meeting the challenges created by the anticipated increases in world population (from seven billion people in 2011 to an anticipated nine billion by 2050; World population prospects: the 2010 revision, highlights and advance tables. Working Paper No. ESA/P/WP.220, New York) and by difficulties in livestock production wrought by climate change (SAT eJournal 4:1-23, 2007).The purpose of this chapter will be to highlight current and emerging reproductive technologies that have the potential to improve efficiency of livestock production. The focus will be on technologies that manipulate male and female gametes as well as the stem cells from which they are derived and the preimplantation embryo. While technology is crucial to other interventions in the reproductive process like control of seasonal breeding, hormonal regulation of ovulation, estrous cyclicity and pregnancy establishment, feeding to optimize reproduction, minimizing environmental stress, and selection of genes controlling reproduction, these will not be considered here. Rather the reader is directed to other chapters in this volume as well as some reviews on other aspects of artificial manipulation of reproduction (Reprod Fertil Dev 24:258-266, 2011; Reprod Domest Anim 43:40-47, 2008; Reprod Domest Anim 43:122-128, 2008; Soc Reprod Fertil Suppl 66:87-102, 2009; Comprehensive biotechnology, Amsterdam, pp 477-485; Dairy production medicine, Chichester, pp 153-163; Theriogenology 76:1619-1631, 2011; Theriogenology 76:1568-1582, 2011; Theriogenology 77:1-11, 2012). Given the large number of mammalian species used for production of products useful for man and the diversity in their biology and management, the review will not be comprehensive but instead will use results from species that are most illustrative of the opportunities generated by assisted reproductive technologies.

A superovulation protocol for the spiny mouse (Acomys cahirinus)

This study aimed to develop a superovulation protocol for the spiny mouse (Acomys cahirinus). The spiny mouse is a desert-adapted rodent species, with a long oestrus cycle (11 days) compared with rat and mouse, and gives birth to few (mean litter size is 3) precocial offspring after a relatively long gestation (39 days). We successfully optimised a superovulation protocol that elicited a 5-fold increase in the normal ovulation rate of this species. To induce superovulation in the spiny mouse 2 injections of equine chorionic gonadotrophin (eCG, 10 IU each), 9h apart, were required, followed by 20 IU of human chorionic gonadotrophin (hCG). This protocol was successful in 100% of females trialed and at 33 h post-hCG an average of 14.7 ± 1.5, 1-2 cell embryos were recovered. Histological analysis of ovaries following superovulation revealed large corpus lutea and post-ovulatory follicles occupying a large part of the ovary. Ovulation commenced 6-12 h after the hCG injection and continued until 24-33 h post-hCG as indicated by both histological analysis of ovaries and the presence of oocytes/embryos in the oviduct. This superovulation protocol will facilitate the development of an in vitro culture system for spiny mouse embryos.

Superstimulation of follicular growth in Thai native heifers by a single administration of follicle stimulating hormone dissolved in polyvinylpyrrolidone

This study was undertaken to determine whether a single i.m. injection of FSH dissolved in 10 ml of 30% (wt/vol) polyvinylpyrrolidone (PVP; MW=40,000) to form FSHp would induce follicular growth in Thai native heifers and to determine its optimal dose. In Group 1, heifers (n=4) were given multiple i.m. injections of FSHp every 12 h for 3 days at decreasing doses, for a total of 100 mg (control). In Groups 2, 3 and 4, heifers (n=4 in each group) were given single i.m. injections of FSHp at 50, 100 and 150 mg. All heifers received a single injection of 750 μg PGF2α 48 h after the initiation of exogenous FSH treatment. Ovaries of treated heifers were examined by transrectal ultrasonography every day until they showed estrus. Group 3 showed significantly higher numbers of ovulation follicles, significantly higher growth rates of follicles per day and significantly larger diameters of follicles and corpora lutea than groups 1 and 2 but not Group 4 (P<0.05). Group 4 showed significantly higher numbers of large follicles (≥5 mm in diameter), unovulated follicles and ovulations, a significantly higher growth rate of follicles per day, and significantly larger diameters of follicles and corpora lutea (P<0.05) than those of the other groups. This indicates a state of overstimulation of ovaries in this group. Besides, the plasma levels of FSH in Group 4 were significantly higher (P<0.05) than in the other group and were maintained in the range of 2.2-0.7 ng/ml over a period of 6 to 66 h after the FSHp injection. Meanwhile, the plasma levels of P4 and E2 did not differ in any of the groups in the period of 0 to 96 h during the superstimulation program. In conclusion, it was demonstrated that a single i.m. injection of 100 mg FSHp was the most effective dose for superstimulation of follicular growth in Thai native heifers under the experimental conditions in this study.