Processing stored stallion semen doses by Single Layer Centrifugation

The purpose of this study was to determine if the quality of stored stallion semen doses could be enhanced by the scaled-up version of Single Layer Centrifugation using Androcoll-E-Large. Three semen doses from each of fifteen stallions were transported overnight to the Swedish University of Agricultural Sciences (SLU) for processing 24 h after semen collection. Sperm quality in the resulting SLC-selected samples was significantly improved compared to the uncentrifuged samples: mean progressive motility was increased by 8% on the day of processing (P < 0.001) and by 13% after 24 h cold storage (P < 0.001), normal morphology was increased by 4% (P < 0.01), whereas mean %DFI was decreased by 2% (P < 0.001). When these SLC-selected samples were compared retrospectively to fresh samples processed by SLC with Androcoll-E Small, sperm quality was found to be similar, although it was not maintained for as long in the sperm samples stored before SLC. These results suggest an additional option for improving sperm quality in stallion semen doses for artificial insemination.     

Naturally and stimulated levels of reactive oxygen species in cooled stallion semen destined for artificial insemination

The decrease in foaling rates after artificial insemination with cooled semen warrants the search for new predictors of fertility. The objectives were to investigate levels of naturally occurring reactive oxygen species (ROS) in cooled, stored stallion semen doses for artificial insemination (AI), and their relationship with parameters of semen quality and with pregnancy rate. Semen was collected from warmblood stallions (n=15) and used to prepare commercial semen doses for AI. Sperm quality was evaluated after cooled transport to the laboratory overnight. The results were correlated with observed foaling and pregnancy rates. Hydroethidine and dichlorodihydrofluorescein diacetate were used as indicators for the ROS superoxide and hydrogen peroxide, respectively. Sperm morphology, motility, plasma membrane integrity and chromatin integrity were also evaluated. These variables were correlated with each other and with pregnancy rates. We found a high inter-individual variation in the ROS levels between stallions. The proportion of live, hydrogen peroxide-negative spermatozoa was correlated with progressive motility, whereas live hydrogen peroxide-negative spermatozoa and chromatin damage were negatively correlated, indicating that low levels of hydrogen peroxide were correlated with good chromatin integrity. The percentage of dead hydrogen peroxide-positive sperm was negatively related to the foaling rate. The negative relationships were stronger when combining results from both assays for ROS. These results for stored semen samples indicate that high individual variation exists for superoxide and hydrogen peroxide measurements, and that ROS status can influence sperm quality. Thus, ROS may be some of the factors influencing fertility. Moreover, combinations of ROS variables improved the correlation with fertility, indicating the usefulness of including these variables in a future model for prediction of the fertility of a semen sample.     

Pregnancy rates after fixed-time artificial insemination of Brahman heifers treated to synchronize ovulation with low-dose intravaginal progesterone releasing devices, with or without eCG

The objective was to determine whether eCG in an ovulation synchronization protocol with an intravaginal progesterone (P₄)-releasing device (IPRD) containing a low dose of P₄ improves pregnancy rate (PR) to fixed-time AI (FTAI) in Bos indicus heifers. Day 0, 2 y old Brahman heifers were allocated to either eCG+ (n = 159) or eCG- (n = 157) treatment groups. All heifers were weighed, body condition scored (BCS), and ultrasonographically examined to measure uterine horn diameter and presence of a CL. On Day 0, all heifers received a low-dose IPRD (0.78 g P₄) and 1 mg of estradiol benzoate (EB) im. On Day 8, the IPRD was removed, all heifers received 500 μg cloprostenol im, and those in the eCG+ treatment group received 300 IU of eCG im. On Day 9, all heifers received 1 mg EB im. All heifers were FTAI 52 to 56 h after IPRD removal. Ten days after FTAI, heifers were exposed to bulls. Heifers were diagnosed as pregnant to FTAI, natural mating, or not detectably pregnant (NDP) 65 d after FTAI. Treatment with eCG+ as compared to eCG- did not affect PR to FTAI (28.9 vs 30.6%; P = 0.590), natural mating (51.3 vs 47.7%; P = 0.595), or overall (65.4 vs 63.7%; P = 0.872). Mean live weight gain from Days 0 to 65 d post-FTAI was higher in heifers pregnant to FTAI (72.29 ± 4.26 kg; P = 0.033) and overall (66.83 ± 3.65 kg; P = 0.021), compared to heifers that were NDP (60.03 ± 3.16 kg). Uterine diameter group, 9–11, 12–13, and 14–20 mm (26.2, 31.3, and 33.3%; P = 0.256), presence and absence of CL (29.8 vs 29.4%; P = 0.975), AI technicians 1, 2, and 3 (32.6, 28.8, and 22.4%; P = 0.293) and sires A, B, and C (23.9, 36.0 and 27.0%; P = 0.122) had no effect on PR to FTAI, natural mating, or overall. In conclusion, treatment of primarily cycling Brahman heifers with 300 IU eCG in conjunction with a low P₄-dose (0.78 g) IPRD and EB to synchronize ovulation, did not improve PR after FTAI, natural mating, or overall.     

Pregnancy rates to timed artificial insemination in dairy cows treated with gonadotropin-releasing hormone or porcine luteinizing hormone

We compared the effects of porcine luteinizing hormone (pLH) versus gonadotropin-releasing hormone (GnRH) on ovulatory response and pregnancy rate after timed artificial insemination (TAI) in 605 lactating dairy cows. Cows (mean ± SEM: 2.4 ± 0.08 lactations, 109.0 ± 2.5 d in milk, and 2.8 ± 0.02 body condition score) at three locations were assigned to receive, in a 2 × 2 factorial design, either 100 μg GnRH or 25 mg pLH im on Day 0, 500 μg cloprostenol (PGF) on Day 7, and GnRH or pLH on Day 9, with TAI 14 to 18 h later. Ultrasonographic examinations were performed in a subset of cows on Days 0, 7, 10, and 11 to determine ovulations, presence of corpus luteum, and follicle diameter and in all cows 32 d after TAI for pregnancy determination. In 35 cows, plasma progesterone concentrations were determined 0, 3, 4, 5, 6, 7, and 12 d after ovulation. The proportion of noncyclic cows and cows with ovarian cysts on Day 0 were 12% and 6%, respectively. Ovulatory response to first treatment was 62% versus 44% for pLH and GnRH and 78% versus 50% for noncyclic and cyclic cows (P < 0.01). Location, ovulatory response to first pLH or GnRH, cyclic status, presence of an ovarian cyst, and preovulatory follicle size did not affect pregnancy rate. Plasma progesterone concentrations after TAI did not differ among treatments. Pregnancy rate to TAI was greater (P < 0.01) in the GnRH/PGF/pLH group (42%) than in the other three groups (28%, 30%, and 26% for GnRH/PGF/GnRH, pLH/PGF/GnRH, and pLH/PGF/pLH, respectively). Although only 3% of cows given pLH in lieu of GnRH on Day 9 lost their embryo versus 7% in those subjected to a conventional TAI using two GnRH treatments, the difference was not statistically significant. In summary, pLH treatment on Day 0 increased ovulatory response but not pregnancy rate. Cows treated with GnRH/PGF/pLH had the highest pregnancy rate to TAI, but progesterone concentrations after TAI were not increased. In addition, preovulatory follicle diameter did not affect pregnancy rate.     

Pregnancy in the domestic cat after artificial insemination with previously frozen spermatozoa

Methods for collection, freeze preservation and artificial insemination of domestic cat semen were developed. Total sperm count and pre-freeze and post-thaw percent motility were significantly greater (P is less than 0.05) for samples collected by an artificial vagina method than for those collected by electroejaculation. Although conception rate was low (10.6%), 6 pregnancies were achieved, 2 after hormonal induction of oestrus.     

Pregnancy loss in heifers after artificial insemination with frozen-thawed,sex-sorted,re-frozen-thawed dairy bull sperm

The use of sex-sorted sperm by the dairy industry is often limited by the geographical distance between potential sires and the sex-sorting facility. One method that may be used to overcome this limitation is sex-sorting sperm that have been previously frozen, or transported to the sorting facility as cooled liquid semen. In this study the in vivo fertility of frozen-thawed, sex-sorted, re-frozen-thawed (FSF) and cooled, sex-sorted, frozen-thawed (CSF) bull sperm was determined after artificial insemination (AI) of Holstein heifers. Semen from two bulls was frozen in straws, or transported to the sorting facility in an egg yolk diluent at 5 °C over 24 h. Thawed or re-warmed semen was processed through a PureSperm^® density gradient, and sperm were sorted for sex and frozen (2 or 4 × 10⁶ sperm/straw). Synchronised heifers (n = 183) were inseminated with either non-sorted control sperm (Control; 20 × 10⁶ dose) or with FSF or CSF ‘X’ sperm (2 or 4 × 10⁶/dose). Pregnancy rates (detected at 7–9 weeks) after AI with control sperm were higher than with FSF or CSF sperm (57.4 vs. 4.1 and 7.3% respectively; p < 0.001). There was a significant difference between bulls (Bull 1: Control 63.0%, FSF 8.6%, CSF 10.0%; Bull 2: Control 45.5%, FSF 0%, CSF 4.8%; p = 0.001). Five out of six (83.3%) pregnancies produced with sexed sperm were lost after pregnancy diagnosis. The exception was one heifer inseminated with CSF sperm (2 million sperm dose), which produced a heifer calf. In the non-sorted control group, three pregnancies were lost (8.3%) and three stillbirths occurred (8.3%). The low fertility and high rate of pregnancy loss in the sexed groups, in addition to environmental influences, may be attributed to impaired sperm function caused by sex-sorting and re-freezing, leading to poor embryo quality or altered gene expression. More precise timing of insemination and higher sperm doses might improve the fertility of FSF sperm. Moreover, the in vitro function of double-frozen sexed compared with non-sorted sperm requires further investigation.     

Impact of supplementation of semen extender with antioxidants on the quality of chilled or cryopreserved Arabian stallion spermatozoa

The aim of the present study was to evaluate the effects of supplementation of semen extender with various non-enzymatic antioxidants on the quality of cooled or cryopreserved Arabian stallion spermatozoa. Semen collected from four pure Arabian stallions was centrifuged at 600g for 15 min. Spermatozoa were then diluted in INRA-82 extender supplemented with bovine serum albumin (BSA; 0, 10, 15 and 20 mg/mL) or trehalose (0, 75, 100 and 150 mM) or zinc sulphate (0, 100, 150 and 200 μM). The diluted semen was then either cooled at 5 °C or cryopreserved in 0.5–ml plastic straws. After cooling or thawing, sperm motility, viability, sperm abnormalities, viability index, and plasma membrane integrity were evaluated. The results showed that supplementation of semen extender with 150 mM trehalose or with 200 μM zinc sulphate significantly (P < 0.05) improved motility, viability, sperm membrane integrity and acrosome status in Arabian stallion spermatozoa after cooling or after freezing and thawing compared with controls (non-supplemented media) or with those supplemented with other concentrations of trehalose or zinc sulphate. Supplementation of semen extender with BSA did not improve sperm motility or cryosurvival of Arabian stallion spermatozoa after cooling or after freezing and thawing. In conclusion, supplementation of semen extender with non-enzymatic antioxidants (trehalose or zinc sulphate) improved the quality of chilled and frozen/thawed Arabian stallion spermatozoa. The most beneficial effects occur when semen diluent was supplemented with 150 mM trehalose or 200 μM zinc sulphate.     

Pregnancy outcome in dairy and beef cattle after artificial insemination and treatment with seminal plasma or transforming growth factor beta-1

Reduced capability of the uterus to support pregnancy in the absence of its interaction with secretions from male accessory glands has been demonstrated in rodents and to some extent in pigs. However, in cattle, the role of postmating inflammatory response on pregnancy success has not been studied. The current study examined the influence of uterine presensitization with seminal antigens at breeding on pregnancy outcome in cows. Lactating beef (n = 1090) and dairy (n = 800) cows received 0.5 mL seminal plasma (SP), 40 ng recombinant human transforming growth factor-β1 (rhTGF-β1), or 0.5 mL bovine serum albumin (BSA), or were left untreated before or at insemination. Semen was deposited into the anterior cervix using a second insemination gun. Pregnancy was diagnosed at 35 to 40 d postinsemination by transrectal ultrasonography or from records of calves born the subsequent calving season. Pregnancy rates in beef cows did not differ among treatments but differed among trials (69.8%, 52.5% vs. 40.3%; P < 0.05). In trials where average pregnancy rates were below 50%, treatments with TGF-β1 but not SP tended (P < 0.07) to increase pregnancy rates in beef cows. In dairy cows, SP and TGF-β1 improved pregnancy outcome by 10 percentage points, but these increments did not achieve statistical significance. In conclusion, this study did not find any conclusive evidence for the effect of TGF-β1 or seminal plasma on pregnancy outcome in lactating dairy or beef cows but realized marginal improvements when pregnancy rates were below 50% (compromised fertility).     

Fixed-time AI pregnancy rate following insemination with frozen-thawed or fresh-extended semen in progesterone supplemented CO-Synch protocol in beef cows

The objective of this study was to compare fixed-time AI pregnancy rate in Angus crossbred beef cows inseminated with frozen-thawed or fresh-extended semen. Two ejaculates from each of two Angus bulls were collected by artificial vagina and pooled for each bull. The pooled semen from each bull was divided into two aliquots; Aliquot 1 was extended using Caprogen^® (LIC, Hamilton, New Zealand) to a concentration of 3 × 10⁶ sperm/straw and Aliquot 2 was extended using egg-yolk-glycerol extender to a concentration of 20 × 10⁶ sperm/straw. Semen extended with Caprogen^® was maintained at ambient temperature and semen extended with egg-yolk-glycerol extender was frozen and maintained at −196 °C until insemination. In each of two breeding seasons (Fall 2007 and Spring 2008), Angus-crossbeef cows (N = 1455) at 12 locations were randomly assigned within location to semen type [Fresh (N = 736) vs. Frozen (N = 719)] and sire [1 (N = 731) vs. 2 (N = 724)]. All cows were synchronized with 100 μg of GnRH im and a progesterone Controlled Internal Drug Release insert (CIDR) on Day 0, and on Day 7, 25 mg of PGF2_α im and CIDR removal. All cows received 100 μg of GnRH im and were inseminated at a fixed-time on Day 10, 66 h after CIDR removal. Timed-AI pregnancy rates were influenced by season (P < 0.05), cows detected in estrus prior to and at AI (P < 0.001), and dam age (P < 0.01). Pregnancy rates were not affected by semen type (Fresh = 51.5% vs. Frozen = 50.4%; P = 0.66) and there were no significant interactions of semen type by estrus expression, semen type by sire, or semen type by season (P > 0.1). In conclusion, commercial beef cows inseminated with fresh-extended semen (3 × 10⁶ sperm/straw) yielded comparable pregnancy rates to conventional frozen-thawed semen in a progesterone supplemented, CO-Synch fixed-time AI synchronization protocol and may provide an alternate to frozen semen for more efficient utilization of superior genetics.     

GnRH treatment at artificial insemination in beef cattle fails to increase plasma progesterone concentrations or pregnancy rates

Treatment with GnRH at the onset of standing estrus increased pregnancy percentages and circulating concentrations of progesterone in repeat breeder dairy cows. The objective of this study was to determine the effect of treatment with GnRH at AI on concentrations of progesterone and conception rates in beef cattle that exhibited estrus. Two hundred ninety-three heifers at four locations were synchronized with the Select Synch plus CIDR protocol (given GnRH and a CIDR was placed into the vagina, and 7 d later, given PGF_2α and CIDR removed; n = 253) or the 14-19 melengestrol acetate (MGA) protocol (MGA fed at 0.5 mg/head/d for 14 d, with PGF_2α 19 d after MGA withdrawal n = 40) and AI was done after detection of estrus. At Location 1, blood samples were collected on Day 2, 4, 6, 10, 15, and 18 after AI (Day 0 = AI). Two hundred and fifty postpartum cows at two locations were synchronized with the Select Synch plus CIDR protocol, and AI was performed after detection of estrus. At AI, cattle were alternately assigned to one of two treatments: (1) treatment with GnRH (100 μg) at AI (n = 127 heifers and n = 108 cows); or (2) non-treated control (n = 120 heifers and n = 119 cows). Concentrations of progesterone tended to be greater in control heifers compared to GnRH-treated heifers on Days 6 (P = 0.08), 10 (P = 0.07), and 15 (P = 0.11). Overall conception rates were 68% and 66% for GnRH treated and control, respectively, and were not different between treatments (P = 0.72). In summary, treatment with GnRH at time of AI had no influence on conception rates in cattle that had exhibited estrus.     

Pregnancy and conception rate after two intravaginal inseminations with dog semen frozen either with 5% glycerol or 5% ethylene glycol

The primary goal of this study was to compare the effects of 5% ethylene glycol (EG) and 5% glycerol (G) on fertility of frozen–thawed dog semen following intravaginal insemination. The sperm-rich fraction of the ejaculate of three male dogs was collected, pooled and divided into two aliquots, and then frozen with a Tris–glucose–egg yolk–citric acid extender containing either 5% G or 5% EG. A total of 10 bitches were inseminated twice, five with G-frozen–thawed semen and five with EG-frozen–thawed semen; intravaginal inseminations were performed the 4th and the 5th day after the estimated LH peak; four straws, thawed in a 37 °C water bath for 1 min and diluted in a Tris buffer, were used for insemination (200 × 10⁶ spermatozoa); the insemination dose was introduced in the cranial vagina of the bitch using a sterile plastic catheter. Ovariohysterectomy was performed in all bitches between days 29 and 31 after the calculated LH surge, and pregnancy status, and the number of conceptuses and corpora lutea were recorded. All bitches were pregnant. Neither the number of conceptuses, nor the ratio of conceptuses to corpora lutea (conception rate) was significantly different between groups. In this first screening, with a limited number of bitches, EG-frozen semen did not show a higher fertility than G-frozen semen when used for two intravaginal inseminations. Irrespective of the semen used, conception rate was 0.50.     

Sperm distribution and fertilization after unilateral and bilateral laparoscopic artificial insemination with frozen-thawed goat semen

Generally, laparoscopic artificial insemination (LAI) provides a higher success rate than of cervical insemination in goats. However, the sperm distribution after LAI in goats remains unknown, particularly when frozen-thawed semen is used. This study evaluated the distribution of frozen-thawed goat spermatozoa after LAI and compared the effects of sperm numbers and deposition sites (unilateral and bilateral sites) on pregnancy rate. In experiment 1, the frozen-thawed spermatozoa were stained either with CellTracker Green CMFDA (CT-Green) or CellTracker Red CMPTX (CT-Red), and in vitro evaluations of viability and motility were performed. In experiment 2, the labeled spermatozoa were deposited via LAI into the left (CT-Green) and right (CT-Red) uterine horns (n = 4). After ovariohysterectomy (6 hours after insemination), the distributions of green- and red-colored spermatozoa were assessed via tissue section, flushing, and the oviductal contents were also collected. Experiment 3 was designed to test the pregnancy rates in a group of 120 does after LAI using different numbers of spermatozoa (60 and 120 × 10⁶ sperm per LAI) and different deposition sites. The results demonstrated that the fluorochromes used in this study did not impair sperm motility or viability. Frozen-thawed goat spermatozoa can migrate transuterinally after LAI, as evidenced by the observations of both CT-Green– and CT-Red–labeled spermatozoa in both uterine horns. Lower numbers of spermatozoa (60 × 10⁶) that are inseminated unilaterally (either ipsilateral or contralateral to the site of ovulation) can efficiently be used for LAI in goats (with a 56.67% pregnancy rate).     

Pregnancy rates in mares inseminated with 0.5 or 1 million sperm using hysteroscopic or transrectally guided deep-horn insemination techniques

Placement of sperm deep in the equine uterine horn allows fewer sperm to be inseminated while maintaining acceptable fertility, and has been promoted for use in circumstances when fertility would be expected to be low if standard insemination were used (e.g., semen from a subfertile stallion, or frozen-thawed semen). Two main techniques, transrectally guided (TRG) and hysteroscopic (HYS) insemination, have been developed for this purpose; however, there is some controversy regarding their comparative efficacy. This study was conducted to compare pregnancy rates when mares were inseminated by TRG or HYS, using sperm numbers approaching and under the minimum threshold, resulting in reduced fertility. When 1 × 10⁶ sperm were inseminated, pregnancy rates were not different (P > 0.10) between techniques HYS (10/13, 77%) and TRG (11/15, 73%). Similarly, when 0.5 × 10⁶ sperm were inseminated, pregnancy rates were not different (P > 0.10) between techniques HYS (3/15, 20%) and TRG (4/13, 31%). Combined pregnancy rates for the two treatments were 13/28 (46%) for HYS and 15/28 (54%) for TRG (P > 0.10). Pregnancy rates using a subthreshold number of sperm were not significantly affected by a deep-horn insemination technique.     

Birth of a chimpanzee (Pan troglodytes) after artificial insemination with cryopreserved epididymal spermatozoa collected postmortem

A male chimpanzee (Pan troglodytes) suddenly died of acute hemorrhagic enteritis at the age of 18 years. Within 24 hours after its death, a large quantity of spermatozoa of excellent quality was recovered from the distal cauda epididymides and was subsequently cryopreserved. After storage for 67 days, the frozen spermatozoa were thawed and inseminated in an adult, normal cycling, nulliparous female. The optimal day for insemination was estimated by monitoring the swelling of the female’s sex skin and urinary luteinizing hormone concentrations. Pregnancy was confirmed by a urinary chorionic gonadotropin test, and a normal female infant was born after 214 days of gestation. This birth demonstrates that distal cauda epididymal spermatozoa recovered from a dead male can be cryopreserved and successfully inseminated in a female chimpanzee. Zoo Biol 20:135–143, 2001. © 2001 Wiley‐Liss, Inc.     

Embryo production from superovulated Holstein-Friesian dairy heifers and cows after insemination with frozen-thawed sex-sorted X spermatozoa or unsorted semen

The aim of this study was to evaluate embryo production in superovulated Holstein-Friesian dairy heifers and cows inseminated with either X-sorted spermatozoa (2 million/dose) or unsorted semen (15 million/dose). Experiment 1 at the research farm involved eight heifers, six cows and semen of one Holstein bull. All transferable embryos were diagnosed for sex. Experiment 2 included embryo collections on commercial dairy farms: X-sorted spermatozoa from three Holstein bulls were used for 59 collections on 28 farms and unsorted semen from 32 Holstein bulls were used for 179 collections on 79 farms. Superovulations were induced by eight declining doses of FSH (total of 12 ml for heifers and 19 ml for cows) starting on days 8-12 of the estrus cycle. Inseminations began 12h after the onset of estrus and were performed two to four times at 9-15 h intervals. Low-dose X-sorted inseminates were deposited into uterine horns and unsorted semen was placed into the uterine body. In Experiment 1, on average 70.3 and 75.0% of embryos recovered from heifers, and 48.4 and 100% of embryos recovered from cows were of transferable quality in X-sorted and unsorted groups, respectively. The proportion of transferable female embryos produced approximately doubled when insemination was with X-sorted spermatozoa compared to insemination with unsorted semen (heifers 96.4% versus 41.1%; cows 81.1% versus 39.8%). In Experiment 2, estimated 53.9 and 65.5% of embryos recovered from heifers, and 21.1 and 64.5% of embryos recovered from cows were of transferable quality in X-sorted and unsorted groups, respectively. Proportions of unfertilized oocytes were 21.1 and 10.6% for heifers and 56.0 and 14.4% for cows in X-sorted and unsorted groups, respectively. Consequently, cows inseminated with X-sorted spermatozoa produced significantly smaller proportions of transferable embryos (p<0.005) and significantly larger proportions of unfertilized oocytes (p<0.001) than those inseminated with unsorted semen. Proportions of quality 1 or degenerated embryos were similar for the two treatments in both heifers and cows. Within treatments, bulls did not significantly affect the proportions of transferable, unfertilized or degenerated oocytes/embryos. It was concluded that using low-dose X-sorted spermatozoa rather than normal-dose unsorted semen for the insemination of superovulated embryo donors can improve the proportion of transferable female embryos produced but this potential may not be achieved in commercial practice, particularly in cows, because of reduced fertilization rates when using low doses of X-sorted spermatozoa.     

Effect of the addition of beta-mercaptoethanol to a thawing solution supplemented with caffeine on the function of frozen-thawed boar sperm and on the fertility of sows after artificial insemination

We have reported that artificial insemination (AI) with frozen-thawed boar semen supplemented with caffeine increased the number of uterine sperm by inhibiting the migration of polymorphonuclear leukocytes (PMNs) into the uterine lumen, thereby improving the fertility of gilts and sows. The objective of the present study was to examine the effects of the addition of the antioxidant beta-mercaptoethanol (bME) and caffeine to the thawing solution on the function of frozen-thawed sperm, on the phagocytic activity of PMNs for sperm, and on the fertility of sows after AI. When frozen-thawed sperm were cultured in the presence of 25 or 50 μm bME, sperm capacitation and spontaneous acrosome reactions were inhibited (P < 0.01). There was no effect of bME on phagocytic activity of PMNs for sperm in vitro. When hormonally treated (400 IU of equine chorionic gonadotropin + 200 IU of human chorionic gonadotropin) weaned sows experienced a single intrauterine insemination with frozen-thawed sperm (25 × 10⁸ sperm per 50 ml dose) 40 h after subsequent hCG administration, pregnancy and farrowing rates were unaffected by the addition of 50 μm bME (pregnancy rate, 20 vs 21% in controls; farrowing rate, 20 vs 21%; n = 15 and 14, respectively). However, litter size tended to be higher than in the presence of 50 μm bME compared to its absence (10.0 ± 1.0 vs 5.7 ± 1.5, respectively; P < 0.07). Thus, the addition of bME to the thawing solution containing caffeine could be of benefit for improving the function of frozen-thawed sperm without influencing the phagocytic activity of PMNs for sperm. Although there were no statistically significant effects of bME on pregnancy or farrowing rates, the litter size tended to be higher in the sows subjected to a fixed-time single AI treatment with synchronized ovulation.     

Fertility trial in Zebu cattle after a natural or controlled estrus with prostaglandin F2 Alpha, comparing natural mating with artificial insemination

With the object of comparing reproductive efficiency obtained by natural mating and by artificial insemination (AI), not only following a natural estrus but also after an induced estrus with PGF2Alpha in Zebu cattle in the tropics, 244 adult cows were divided into 4 groups. Group I (N = 69) and Group III (n = 62) were injected with 25 mg of PGF2Alpha when a functional CL was found on rectal examination. Group I was inseminated and group III was served by natural mating, both groups within five days after injection. Groups II (n = 57) and IV (n = 56) were left untreated, group II being AI and group IV ran with a fertile bull for 22 days. Estrus detection was carried out only in the injected groups (I and III) for 15 minutes every three hours between 0600 and 1800. All information was analyzed by linear trigonometric models. The onset of estrus occurred on average 68.7 h after injection in group I and 59.5 h in group III. However only 46.3% and 54.8% of animals were detected in estrus in group I and III respectively, the difference being significant (P < 0.10). Conception rates were 18.6%, 29.8%, 19.3% and 33.9% for groups I, II, III, and IV respectively. A significant difference (P < 0.10) existed between the injected groups and the untreated ones.     

Effect of natural or vaccine-induced porcine circovirus type 2 (PCV2) immunity on fetal infection after artificial insemination with PCV2 spiked semen

The objectives of this study were to determine if vaccination against porcine circovirus type 2 (PCV2) or previous PCV2 infection of the dam are sufficient to prevent fetal infection when dams are artificially inseminated with PCV2-spiked semen. Nine sows (Sus domestica) were allocated into three groups of three dams each: The PCV2 naïve negative control Group 1 was artificially inseminated with extended PCV2 DNA negative semen during estrus, whereas the extended semen used in the vaccinated Group 2 (PCV2 vaccine was given 8 wk before insemination) and PCV2-exposed Group 3 (infected with PCV2 12 wk before insemination) was spiked with 5 mL of PCV2 inoculum with a titer of 10^4.2 tissue culture infectious dose (TCID₅₀) per milliliter at each breeding. The dams in the vaccinated and PCV2-exposed groups were positive for PCV2 antibody but negative for PCV2 DNA in serum at the time of insemination. Three negative control dams, two vaccinated dams, and three dams with previous PCV2 exposure became pregnant and maintained pregnancy to term. After artificial insemination, viremia was detected in one of three vaccinated dams and in two of three dams with previous PCV2 exposure. At farrowing, PCV2 infection was not detected in any piglets or fetuses expelled from the negative control dams or from dams with previous PCV2 exposure. In litters of the vaccinated dams, 15 of 24 live-born piglets were PCV2 viremic at birth, with 6 of 26 fetuses having detectable PCV2 antigen in tissues. In conclusion, vaccine-induced immunity did not prevent fetal infection in this sow model using semen spiked with PCV2.     

The relationship of maternal characteristics and circulating progesterone concentrations with reproductive outcome in the bottlenose dolphin (Tursiops truncatus) after artificial insemination, with and without ovulation induction, and natural breeding

Bottlenose dolphins (Tursiops truncatus) undergoing natural breeding and artificial insemination (AI) were examined to characterize serum progesterone concentrations and determine relationships among age, parity, and reproductive outcome. Progesterone profiles of five cycle types (n = 119 total cycles from 54 animals) were characterized as follows: (i) conception and production of a live term calf (conceptive-term, n = 73); (ii) conception and abortion after Day 60 (conceptive-abortion, n = 12); (iii) unknown conception status with prolonged, elevated progesterone and absence of a fetus (conceptive-unknown, n = 14); (iv) conception failure with normal luteal phase progesterone concentrations (non-conceptive, n = 14, AI cycles only); and (v) conception failure with progesterone insufficiency occuring after spontaneous ovulation or owing to premature ovulation induction using GnRH (non-conceptive-PI, n = 6, AI cycles only). By Day 21 post-insemination (PI), progesterone concentrations were similar (P > 0.05) among conceptive-term, conceptive-abortion and conceptive-unknown, and higher (P < 0.05) for conceptive-term than non-conceptive and non-conceptive-PI cycles. Progesterone concentrations of known conceptive cycles peaked by Week 7 PI (P < 0.05) and remained elevated for the remainder of pregnancy (Weeks 8 up to 54, ≥5 days pre-partum). During midpregnancy (Days 121-240), conceptive-term cycles had higher (P > 0.05) progesterone concentrations than conceptive-abortion and unknown conception status cycles. Parity was not associated with reproductive outcome based on cycle type (P > 0.05). Age of females in conceptive-unknown (26.5 ± 10.1 yrs) and conceptive-abortion (22.1 ± 9.4 yrs) groups was higher (P < 0.05) than in conceptive-term (15.7 ± 7.2 yrs). The conceptive-unknown cycle type possibly represents undetected early embryonic loss occurring before Day 60 PI. Length of gestation using known conception dates was 376.1 ± 11.0 days and the range of this parameter (355-395 days) has implications for peri-parturient management procedures for the species.