Insemination Attempts Research Articles

Effects of extending dairy cow longevity by adjusted reproduction management decisions on partial net return and greenhouse gas emissions: A dynamic stochastic herd simulation study

Prolonging dairy cattle longevity is regarded as one of the options to contribute to more sustainable milk production. Because failure to conceive is one of the main reasons for culling, this study investigates how adjustments in reproduction management affect partial net return at herd level and greenhouse gas emissions per unit of milk, using a dynamic stochastic simulation model. The effects of reproduction decisions that extend cattle longevity on milk yield, calving interval and pregnancy rate were derived from actual performance of Dutch commercial dairy cows over multiple lactations. The model simulated lactations, calving, and health status events of individual cows for herds of 100 cows. Scenarios evaluated differed in the maximum number of consecutive AI attempts (4, 5, or 6 services), or the production threshold (20, 15, or 10 kg of milk/d) at which cows that failed to conceive are culled (reproductive culling). Annual partial net return was computed from revenues of sold milk, calves, and slaughtered cows, and the costs from feed consumption, rearing replacement heifers, AI services, and treatment for clinical mastitis and lameness. Greenhouse gas emissions were computed for feed production, enteric fermentation, and manure management, and were expressed as total CO2 equivalents (CO2-eq). Average age at culling increased with an increased maximum number of AI services. This increase was larger when going from a maximum of 4 to 5 AI attempts (108 d) than from a maximum of 5 to 6 attempts (47 d). Similarly, the average age at culling increased from 1,968 to 2,040 and 2,132 d when the threshold for reproductive culling decreased from 20, to 15 and 10 kg of milk/d, respectively. Average annual partial net return increased by 1.1% from €165,850 per 100 cows at a maximum of 4 AI to €167,670 per 100 cows at a maximum of 6 AI, and increased by 4.3% from €161,210 per 100 cows at a reproductive culling threshold of 10 kg/d to €168,190 per 100 cows at a threshold of 20 kg/d. Greenhouse gas emissions decreased by 1.2% from 0.926 to 0.915 kg CO2-eq per kg of fat- and protein-corrected milk (FPCM) with an increase in a maximum number of AI from 4 to 6 AI. Conversely, greenhouse gas emissions increased by 0.2% from 0.926 kg at a threshold of reproductive culling of 20 kg/d to 0.928 kg CO2-eq/kg FPCM at a threshold of 10 kg/d. Although lowering the threshold for reproductive culling has the potential to extend cattle longevity more than increasing the maximum number of AI services, only the increase in AI services benefits a farm's partial net return, while reducing greenhouse gas emissions.

Case Report: Breaking barriers - Pregnancy achieved by intracytoplasmic sperm injection of a zona-free oocyte

The zona pellucida is a protective layer surrounding the oocytes and early-stage embryos. It is said to be essential for the process of fertilisation and protecting the pre-implantation embryo. Absence of zona pellucida can pose great problems during in vitro fertilisation (IVF), like impaired fertilisation, polyspermy and hindered embryo development, thus leading to a low implantation rate and unsuccessful pregnancy outcome. This case report demonstrates the successful treatment of primary infertility in a 35-year-old female with significantly low anti-Mullerian hormone (AMH) levels and limited ovarian reserve. Her husband (41 years) had oligoasthenozoospermia. The couple had been trying to conceive for two years before seeking medical assistance. Following an unsuccessful intrauterine insemination (IUI) attempt, the decision was made to pursue IVF with ovarian stimulation. Two oocytes were retrieved after ovum pickup, one of which was at the germinal vesicle (GV) stage and later degenerated, while the other was without the zona pellucida. In this case, the intracytoplasmic sperm injection (ICSI) of zona-free oocyte was chosen to prevent polyspermy, resulting in successful fertilization. The embryo progressed to the eight-cell stage and was transferred on day three. A positive beta-human chorionic gonadotropin (β-hCG) test confirmed pregnancy fourteen days later. In assisted reproductive techniques (ART), zona-free oocytes are a common occurrence, but fertilizing those oocytes is not common; they are usually considered to be of no use and rejected. In the present case, we realized that zona-free gametes are not only capable of getting fertilized and developing into good-quality embryos, but also give successful pregnancy outcomes.

Efficacy validation of a low-cost handmade simulator (SIMCA-COW) in palpation, ultrasonography evaluation, and artificial insemination in cows.

Using simulators in high education enables practical training by repetition in circumstances close to reality reducing the stress of both animal and operator. The limited resources of veterinary schools, the increase in the number of students in lecture halls, and the low availability of animals for teaching due to welfare regulations, reduce teaching opportunities with live animals being simulator as the better alternative. This study aimed to assess the efficacy of a low-cost handmade simulator (SIMCA-COW) in eight veterinary students inexperienced in palpation, ultrasonography evaluation, and artificial insemination in cows. Two sets of exercises were carried out: structure localization by rectal palpation and ultrasonography were evaluated by the inexpert veterinary students in the SIMCA-COW simulator. Also, evaluated the length of time to insert the insemination catheter through the cervix in the inert simulator during four sessions. All the students were able to palpate both structures and to locate the body and both uterine horns by ultrasonography. Cervix and follicles were located by 5/8 (62.5%) students and 3/8 (37.5%) students found the corpus luteum by ultrasonography. A reduction in time span between the first and fourth intrauterine insemination attempts was observed (8.26 ± 2.7 vs. 3.69 ± 1.7; mean ± standard error; p < 0.05). The simulator validated in this study (SIMCA-COW) allows training and learning by repetition, saving the limitations found in live animal practice.

Are superficial neuromasts proprioceptors underlying fast copulatory behavior?

In male Poeciliid fishes, the modified anal fin (i.e., gonopodium) and its axial and appendicular support are repositioned within the axial skeleton, creating a novel sexually dimorphic ano-urogenital region. During copulation, the relative location of the gonopodium is crucial for successful insemination. Therefore, the repositioning of these structures and organ relied on the reorganization of the efferent circuitry that controls spinal motor neurons innervating appendicular muscles critical for the movement of the gonopodium, including the fast and synchronous torque-trust motion during insemination attempts. Copulation occurs when a male positions himself largely outside a female’s field of view, circumducts his gonopodium, and performs a rapid, complex maneuver to properly contact the female urogenital sinus with the distal tip of the gonopodium and transfers sperm. Although understanding of the efferent circuitry has significantly increased in the last 24 years, nothing is known about the cutaneous receptors involved in gonopodium movement, or how the afferent signals are processed to determine the location of this organ during copulation. Using Western mosquitofish, Gambusia affinis, as our model, we attempt to fill this gap in knowledge. Preliminary data showed cutaneous nerves and sensory neurons innervating superficial neuromasts surrounding the base of adult male gonopodium; those cutaneous nerves projected ventrally from the spinal cord through the 14th dorsal root ganglion and its corresponding ventral root towards the base and fin rays of the gonopodium. We asked what role the cutaneous superficial neuromasts play in controlling the positioning and timing of the gonopodium’s fast and synchronous movements for effective sperm transfer. First, we found a greater number of superficial neuromasts surrounding the base of the male’s gonopodium compared to the base of the female’s anal fin. Second, we systemically removed superficial neuromasts surrounding the gonopodium base and observed significant impairment of the positioning and timing of gonopodial movements. Our findings provide a first step to supporting the following hypothesis: during radical reorganization of the Poeciliid body plan, superficial neuromasts have been partially co-opted as proprioceptors that allow the gonopodium to control precise positioning and timing during copulatory attempts.

An Assessment of Secondary Clinical Disease, Milk Production and Quality, and the Impact on Reproduction in Holstein Heifers and Cows from a Single Large Commercial Herd Persistently Infected with Bovine Viral Diarrhea Virus Type 2.

The aim of this study was to evaluate secondary clinical disease, milk production efficiency and reproductive performance of heifers and cows persistently infected (PI) with bovine viral diarrhea virus type 2 (BVDV type 2). PI animals (n = 25) were identified using an antigen capture ELISA of ear notch samples. They were distributed into three age groups: ≤ 12 (n = 8), 13 to 24 (n = 6) and 25 to 34 (n = 11) months old. A control group of BVDV antigen ELISA negative female cattle that were age matched to the PI animals was utilized from the same herd. The PI group had a 1.29 higher odds ratio for diarrhea than controls (p = 0.001, IC95% = 1.032–1.623) and 1.615 greater chance of developing bovine respiratory disease (BRD) (p = 0.012, IC95% = 1.155–2.259). The age at first insemination (p = 0.012) and number of insemination attempts required to establish the first pregnancy (p = 0.016) were both higher for PI than controls. Milk production was higher for control cows than PI cows during most of the sampling periods. Somatic cell counts (SCC) were higher in PI cows than the controls at all sampling points across lactation (p ≤ 0.042). PI cattle had a higher incidence of disease, produced less milk, a higher SCC, and poorer reproductive performance than control cattle in this study.

Pregnancies following long luteal phases in southern white rhinoceros (Ceratotherium simum simum).

All extant species in the Rhinocerotidae family are experiencing escalating threats in the wild, making self‐sustaining captive populations essential genetic reservoirs for species survival. Assisted reproductive technologies (ARTs) will become increasingly important for achieving and maintaining ex situ population sustainability and genetic diversity. Previous reports have shown that a large proportion of captive southern white rhinoceros (SWR) females are irregularly cyclic or acyclic, and that cycling females display two different estrous cycle lengths of approximately 30 or 70 days. It has been suggested that the longer estrous cycle length is infertile or subfertile, as no term pregnancies have been observed following long cycles. Here we report the achievement of two pregnancies following long luteal phases, using ovulation induction and artificial insemination with either fresh or frozen‐thawed semen. One female SWR conceived on the first insemination attempt and gave birth to a live offspring. A second female conceived twice in consecutive long cycles although the first embryo was resorbed by 33 days post‐insemination. A pregnancy from this female's second insemination is ongoing with expected parturition in November 2019. Whether prolonged estrous cycles in SWR are subfertile or infertile in natural breeding situations remains unclear. However, our findings demonstrate that the application of ARTs following prolonged cycles can result the successful establishment of pregnancies in SWR. Therefore, with ARTs, female SWR otherwise considered nonreproductive due to long estrous cycles may still have the potential for representation and contribution to the ex situ population.

Strong cryptic prezygotic isolation despite lack of behavioral isolation between sympatric host races of the leaf beetle Lochmaea capreae.

One of the major goals in speciation research is to understand which isolation mechanisms form the first barriers to gene flow. This requires examining lineages that are still in the process of divergence or incipient species. Here, we investigate the presence of behavioral and several cryptic barriers between the sympatric willow and birch host races of Lochmaea capreae. Behavioral isolation did not have any profound effect on preventing gene flow. Yet despite pairs mating indiscriminately, no offspring were produced from the heterospecific matings between birch females and willow males due to the inability of males to transfer sperm to females. We found evidence for differences in genital morphology that may contribute to failed insemination attempts during copulation. The heterospecific matings between willow females and birch males resulted in viable offspring. Yet fecundity and hatchability was remarkably reduced, which is likely the result of lower efficiency in sperm transportation and storage and lower survival of sperm in the foreign reproductive tract. Our results provide evidence for the contribution of several postmating-prezygotic barriers that predate behavioral isolation and act as primary inhibitors of gene flow in this system. This is a surprising, yet perhaps often overlooked feature of barriers acting early in sympatric speciation process.

The role of aedeagus size and shape in failed mating interactions among recently diverged taxa in the Drosophila mojavensis species cluster.

BackgroundInvestigating the evolution of species-specific insect genitalia is central to understanding how morphological diversification contributes to reproductive isolation and lineage divergence. While many studies evoke some form of sexual selection to explain genitalia diversity, the basis of selection and the mechanism of heterospecific mate exclusion remains vague. I conducted reciprocal mate pair trials in the Drosophila mojavensis species cluster to quantify the frequency of failed insemination attempts, historically referred to as pseudocopulation, between lineages with discrete size and shape differences of the male aedeagus.ResultsIn cross-taxon matings aedeagus size had a significant effect on pseudocopulation frequencies, while aedeagus shape and genetic distance did not. The direction of the size difference was an important factor for successful mating. When females were mated to a cross-taxon male with a larger aedeagus than males from her own species, the pair could not establish a successful mating interaction. Females mated to cross-taxon males with a smaller aedeagus than conspecific males were able to establish the mating interaction but had issues disengaging at the end of the interaction.ConclusionsThe results of this study support a role for aedeagus size in the male-female mating interaction, with a secondary role for aedeagus shape. In natural populations, mating failure based on aedeagus size could serve as an important reproductive isolating mechanism resulting in failed insemination attempts after both the male and female show a willingness to mate.Electronic supplementary materialThe online version of this article (doi:10.1186/s12862-014-0255-3) contains supplementary material, which is available to authorized users.

Effect of a GnRH analogue (Maprelin) on the reproductive performance of gilts and sows

The ability of peforelin (l-GnRH-III) to stimulate follicular growth, FSH release, and estrus in gilts after altrenogest treatment and in sows after weaning was investigated. In three farrow-to-wean herds, with at least 600 sows and average production performance, 216 gilts, 335 primiparous, and 1299 pluriparous sows were randomly allocated to three treatments: peforelin (M group: Maprelin), eCG (F group: Folligon), and physiological saline solution (C group). Animals were treated 48 hours after their last altrenogest treatment (gilts) or 24 hours after weaning (sows). The weaning-to-estrus interval, estrus duration, estrus rate (ER), pregnancy rate, and total born (TB), live born, and stillborn (SB) numbers were recorded and compared between treatments for the different parity groups (gilts and primiparous and pluriparous sows). Follicle sizes were measured in representative animals from each group on the occasion of their last altrenogest treatment or at weaning, and also on the occasions of their first (FS1) and second (FS2) attempted inseminations. Blood samples were taken to determine FSH concentrations at weaning and 2 hours after injection, and progesterone concentrations 10 days after the first insemination attempt. The relative change in FSH concentrations was calculated. Significant differences were found for ER within 7 days of weaning in pluriparous sows (95%, 91%, and 90% for the M, F, and C groups, respectively, P = 0.005). Gilts in the F-group had high TB numbers, and pluriparous sows in the M group had high SB numbers (TB gilts = 13.6, 15.4, and 14.9 [P = 0.02] and SB pluriparous sows = 1.8, 1.4, and 1.7 [P = 0.05] for the M, F, and C groups, respectively). The M group had the highest FS1 (for gilts) and FS2 (for pluriparous sows) values: FS1 = 5.4, 4.9, and 4.9 mm [P = 0.02] and FS2 = 6.8, 5.3, and 6.3 mm [P = 0.03] for the M, F, and C groups, respectively. There were no significant differences between the different treatments within each parity group with respect to any of the other variables. Overall, peforelin treatment had small but positive effects on the ER and follicle growth in certain parity groups but did not seem to affect litter sizes or FSH and progesterone levels in sows on the occasions of the corresponding examinations.

34-Year-Old Woman With Abdominal Pain and Blood-Streaked Diarrhea

R c a C ( M C ( d m Mayo Clinic, Rochester, MN (A.B.). A 34-year-old woman presented to the emergency department for evaluation of a 12-hour history of sudden severe epigastric pain and bilateral leg weakness during exercise associated with nausea and vomiting. She experienced 2 episodes of diarrhea; 1 of which was blood streaked. The patient reported not eating or drinking much that day. She described a few previous less severe episodes of abdominal pain and diarrhea since childhood associated with certain foods. She denied fever or chills but reported a 5-lb intentional weight loss during the past month. She denied changes in her appetite, myalgia, arthralgia, or vision changes. She had no recent travel, sick contacts, or antibiotic drug use. She denied current pregnancy. The patient was previously healthy; her medical history included recurrent urinary tract infections and infertility, with a previous artificial insemination attempt resulting in a missed abortion. Current medication use includes clomiphene and progesterone vaginal suppository. At presentation, her vital signs were as follows: temperature, 36.9°C; heart rate, 69 beats/min; respiratory rate, 16 breaths/min; and blood pressure, 98/60 mm Hg. On examination, the patient appeared uncomfortable but was in no acute distress. Her abdomen was soft and nondistended, with positive bowel sounds. She had generalized tenderness in all 4 quadrants, with absence of guarding and rebound tenderness. Her mucous membranes appeared dry. Lower extremity strength was normal. Results of a urine pregnancy test obtained on arrival to the emergency department were negative.

Deep intra-uterine artificial inseminations using cryopreserved spermatozoa in beluga ( Delphinapterus leucas)

Artificial insemination (AI) with liquid-stored spermatozoa and sperm cryopreservation using directional freezing (DF) have been successful in the beluga. This study built on this foundation to develop a deep intra-uterine AI technique with frozen-thawed semen in beluga. Forty-two ejaculates from one male were cryopreserved using DF technology and subsequently used for 10 insemination attempts with seven females. Percentage pre- and post-thaw progressive motility and viability were (mean ± SD) 73.0 ± 12.2, 38.4 ± 8.8, 88.0 ± 0.1, and 59.3 ± 15.7%, respectively. A series of GnRH injections (3 x 250 μg, IV, 1.5 to 2 h apart) were used to induce ovulation, once a growing follicle >2.5 cm in diameter was visualized via trans-abdominal ultrasonography. Artificial insemination was performed at 30.1 ± 3.8 h post-initial GnRH injection with semen deposited in the uterine horn, 92.6 ± 16.2 cm beyond the genital opening using a flexible endoscope. The external cervical os (cEOS) was located beyond a series of 5 to 10 vaginal rings, 44.8 ± 9.3 cm from the external genital opening. The internal bifurcation of the uterus was 27 ± 6.8 cm beyond the cEOS. Ovulation occurred at 8.5 ± 7.6 h post-AI. Two of 10 inseminations (20%) resulted in pregnancy. The first pregnancy resulted in twins; both calves were born 442 d after AI, with one surviving. The second pregnancy is ongoing. These findings represent the first successful application of AI using frozen-thawed semen in beluga, and are important examples of how assisted reproductive technologies can provide tools for the global management of threatened species.

Early postabortion recovery of Neospora-infected lactating dairy cows

This study was designed to assess the reproductive performance of Neospora caninum–infected dairy cows (Bos taurus) after abortion. The population examined was composed of 92 aborting cows subsequently subjected to at least one artificial insemination (AI) attempt. Of these animals, 68 were N. caninum seropositive and 24 were seronegative. Only animals producing at least 25 kg milk at the estrus after abortion were inseminated. Normal uterine involution was verified at first AI after abortion in cows showing estrous signs within 30 d of abortion. Of the 92 aborting cows, 73 (79.3%) became pregnant after abortion: 57 (83.8%) and 16 (66.7%) of the N. caninum seropositive and seronegative cows, respectively. The factors days of gestation and lactation number at abortion failed to differ between the two Neospora serostatus groups, based on Student's t-test or Kruskal-Wallis tests, respectively. The interval from abortion to first AI, the number of AIs necessary for an animal to become pregnant, and the interval from abortion to next pregnancy in cows becoming pregnant were lower for the N. caninum–seropositive than for the N. caninum–seronegative cows (P < 0.0001). Logistic regression analysis indicated no significant effects of herd, lactation number, days of gestation at abortion, and the interval from abortion to AI on the likelihood of pregnancy at first AI after abortion. Based on the odds ratio, Neospora-seropositive cows were 6.22 times more likely to become pregnant at first AI after abortion compared with their seronegative partners. Fifty-three of the Neospora-seropositive cows (78%) were inseminated within 30 d after abortion and 26 (49%) became pregnant, whereas only one seronegative cow (4.2%) was ready for insemination within this 30-d period and remained open after first AI. These results indicate that Neospora-infected cows suffering abortion can be inseminated with a likelihood of high fertility within the first month of abortion. We recommend checking that uterine involution is normal early after abortion in N. caninum–seropositive cows.

Experimental Findings with Spermantibodies: Condom Therapy (A Case Report)

A couple with no demonstrable cause for their infertility, except for a pronounced antisperm activity in the blood serum of the female partner, were instructed to use a condom while our laboratory monitored the wifes antibody titer. The antibody activity declined sufficiently and an artificial husband insemination were performed after seven months of therapy. A precise report of the spermantibody activity over an eleven month period are given by the authors.

Within and Between Species Variation in Male Mating Behaviors in the Mexican Sailfin Mollies Poecilia velifera and P. petenensis

AbstractPolymorphism in male morphology is often correlated with the expression of alternate behavioral tactics. This relationship between behavioral and morphological polymorphisms, however, is less well understood. We characterized male mating behaviors and morphological variation within and between Poecilia velifera and P. petenensis to understand mating signal evolution in the sailfin molly lineage. In addition, we examined whether differences between these species in the size range of mature males and the strength of allometry between dorsal fin size and body length could explain the variation observed in their expression of different mating behaviors. We determined each male's mating behavior profile by observing the behavior of a single male in the presence of a receptive female. We found that P. velifera showed evidence of an alternate male mating strategy, with small males generally performing only gonopodial thrusts (forced insemination attempts) towards receptive females, while large males performed courtship displays as well as gonopodial thrusts. Males of P. petenensis performed similar rates of courtship displays and gonopodial thrusts regardless of body length. Little variation existed among populations of P. velifera in mating behaviors, while males from different populations of P. petenensis showed population‐specific average rates of each mating behavior. Population differences in P. petenensis may be driven, in part, by its occurrence in more variable habitats than those occupied by P. velifera. Variation among individuals in the mating repertoire of P. velifera, but not P. petenensis, suggests that the greater range of variation in male size at maturity, as well as considerably stronger allometry between dorsal fin size and body length, may explain why males of P. velifera show the greatest degree of expression of alternate male mating behaviors when compared to other sailfin species. These results also suggest an important role of morphological polymorphisms in predicting the expression of alternate male mating behaviors.

Characterizing the mating behaviours of the Tamesí molly, Poecilia latipunctata, a sailfin with shortfin morphology

The Tamesi molly is an unusual molly species because it has features of both shortfin and sailfin mollies. Morphologically, it is classified as a shortfin species, yet phylogenetic evidence and observations of male courtship behaviour indicate that it should be classified as a sailfin molly. We characterized the mating behavioural profiles of dark and silver male P. latipunctata by varying the competitive environment (presence or absence of male competitors) and the degree of female receptivity (unreceptive versus receptive females), both factors known to increase rates of courtship displays in sailfin species. We measured rates of three mating behaviours: courtship displays, gonoporal nibbles and gonopodial thrusts (forced insemination attempts) under both types of competitive and female receptivity conditions. Rates of courtship displays were strongly influenced by female receptive state; both dark and silver males elevated their rates of courtship displays in the presence of receptive females in either competitive environment. In addition, the influence of competition for mates (presence of a competitor) had a stronger effect on the courtship display rates of dark males, but only in the presence of receptive females; courtship display rates were almost eight times higher for dark males when at least one female in the social group was receptive (≤24 h postpartum). These results suggest that dark males actively compete for receptive females by increasing their reliance on courtship, a behavioural response clearly characteristic of other sailfin molly species.

Adjustment to a dyadic stressor: A longitudinal study of coping and depressive symptoms in infertile couples over an insemination attempt.

Adjustment to a dyadic stressor: A longitudinal study of coping and depressive symptoms in infertile couples over an insemination attempt.

Adjustment to a dyadic stressor: a longitudinal study of coping and depressive symptoms in infertile couples over an insemination attempt.

In a study designed to examine how intimate partners' coping processes with regard to infertility predicted depressive symptoms across the course of a treatment cycle, 43 couples completed assessments in the week prior to and the week after receiving a negative pregnancy result from an alternate insemination attempt by the partner. Depressive symptoms in both partners increased significantly after the pregnancy result receipt. As hypothesized, avoidant coping predicted increased distress over time. and approach-oriented coping (e.g., problem-focused coping, emotional processing, and expression) predicted decreased distress. Coping strategies engaged in by both individuals and partners predicted depressive symptoms, and for women, interactions also emerged between their own and their partners' coping.

Conception failure in swine: importance of the sex ratio of a female's birth litter and tests of other factors.

Failure of gilts and sows to conceive when they are mated is a potentially serious economic cost for swine producers. In Exp. 1, we determined that anogenital distance of newborn gilts is related to the proportion of males in the litter (P < .001). Gilts from litters with more males have larger anogenital distances (mean = 8.0 +/- .2 mm); those from litters with low proportions of males have smaller anogenital distances (mean = 5.7 +/- .1 mm). In Exp. 2, we examined the effect of birth litter sex ratio of sows and gilts on reproductive performance using a 13-yr database of breeding and litter data. Gilts that failed to become pregnant on the first breeding attempt came from litters with significantly higher proportions of males than gilts that successfully conceived on the first breeding attempt. Overall, female swine were significantly more likely to exhibit lower rates of successful breeding during their first four breeding attempts if they had been born in a male-biased litter. These results have implications for swine producers deciding which gilts to keep and which to market. Given the higher probability of reproductive problems for gilts from litters of 12 or more pigs with 67% or more males, these females should likely become market hogs. Sow's age, mode of insemination, and the number of insemination attempts at an estrus period, but not season, can affect successful breeding.

Factors influencing the success of transcervical insemination in Merino ewes

The experiments described examined the effects of a number of factors on the level of uterine insemination achieved in Merino ewes by a transcervical insemination technique (Guelph system for transcervical artificial insemination; GST-AI). Cervical penetration rate is an important limitation to the use of such methods in Merinos. Simulated insemination was performed to estimate the proportion of ewes in which a pipette could be passed through the cervix to the uterus. In Experiment 1, cervical penetration rate (n = 14 to 30)was unaffected by an increase in postpartum interval at AI from 12 to 26 wk. The results of cervical penetration for individual ewes were found to be repeatable (P < 0.05). Experiment 2 (197 ewes) revealed a clear effect of ewe parity on penetration rates in hormonally synchronized ewes during the nonbreeding season (P < 0.05). In Experiment 3, estrus synchronization using progestagen (n = 51) or prostaglandin (n = 50) did not affect penetration rate. The penetration rate was slightly higher in the naturally cycling ewes, but the difference was not significant. Comparison of ewes from Experiments 2 and 3 suggests the possibility of a major effect of stage of the breeding season on the penetration rate (P < 0.05). It is concluded that ewe selection and management techniques may be used to increase the proportion of transcervical insemination attempts resulting in uterine insemination. However, fertility testing will be required to determine whether such improvements translate into correspondingly increased pregnancy rates.

Localization of fucosyl glycoconjugates in human oocytes following insemination for in vitro fertilization

Human oocytes that failed to cleave after insemination were examined for the presence of fucosyl glycoconjugates in the perivitelline space by staining with Ulex europeaus lectin conjugated to fluorescein isothiocynate. Oocytes that formed two or three pronuclei following first insemination always exhibited positive lectin staining similar to that observed with in vitro fertilized mouse oocytes. Among those oocytes that failed to form any pronuclei after the first insemination attempt, only 5% contained lectin positive substances in the perivitelline space. Upon reinsemination, a higher percentage of those oocytes produced lectin-positive materials, although pronuclei were still absent. The appearance of fucosyl glycoconjugates in these oocytes might be the result of the release of cortical granules triggered by sperm penetration or, more likely, due to spontaneous granule discharge in senescent oocytes.