Applying variations of the Ovsynch protocol at the middle of the estrus cycle on reproductive performance of lactating dairy cows during summer and winter

Two modifications of the Ovsynch protocol, GnRH + TAI after PGF_2α 48 h (CO-48) or 72 h (CO-72), were compared with the original protocol (OVS: GnRH–7 d–PGF_2α–2 d–GnRH–16 h–TAI) to study their effects on reproductive performance in 785 lactating dairy cows (Holstein Friesian, Bos Taurus). Results showed that more cows (P < 0.001) returned to estrus within a week after TAI with CO-48 treatment compared with that in OVS and CO-72 treatments. Pregnancy rates were greater (P < 0.001) for the CO-72 cows than those for both OVS and CO-48 treatments and for primiparous cows compared with multiparous cows. Moreover, pregnancy rates were lower in summer compared with those in winter. Pregnancy losses for cows in both CO-48 and CO-72 were greater (P < 0.05) than that for cows in OVS treatment. Pregnancy losses were greater in summer (P < 0.001) than in winter and for multiparous cows (P < 0.001) than for primiparous cows. In conclusion, primiparous and winter-bred cows had greater pregnancy rates and fewer pregnancy losses than those of multiparous cows and summer-bred cows, respectively. Because of the presence of significant treatment, parity, and season interactions, TAI with ovulation synchronization protocols should be tailored according to the season and parity. CO-72 is recommended for primiparous cows but not for multiparous cows, and CO-48 is not recommended for synchronization. Furthermore, cows that exhibited estrus at any time were inseminated to improve pregnancy rates in ovulation synchronization protocols.     

Effect of PGF2α and GnRH on the reproductive performance of postpartum dairy cows subjected to synchronization of ovulation and timed artificial insemination during the warm or cold periods of the year

This study was designed to evaluate the reproductive performance of lactating dairy cows (Holstein Friesian) after the injection of PGF_2α analogue on Day 15 postpartum, and GnRH analogue on Day 23 after artificial insemination (AI) with Presynch (two injections of PGF_2α, administered 14 days apart starting at 30–35 days postpartum) + Ovsynch-based (GnRH–7 days–PGF_2α–2 days–GnRH–16–20 hours–timed artificial insemination) treatments, during the warm and cold periods of the year. All the cows (n = 313) were assigned to one of the four groups including: M₁ (n = 72) in which the cows were treated with PGF_2α on Day 15 postpartum + Presynch-Ovsynch + GnRH on Day 23 post-AI; M₂ (n = 41) in which the cows received PGF_2α on Day 15 postpartum + Presynch-Ovsynch; M₃ (n = 100) including the cows that got Presynch-Ovsynch; and control group (n = 100) including the cows that were not treated and were inseminated at natural estrus. Pregnancy diagnosis was performed 28 to 35 days post-insemination by means of ultrasound. The results showed that treatment with PGF_2α on Day 15 postpartum significantly decreased the days to conception and the number of services per conception (P < 0.01) and it also improved the first service conception rate (P < 0.1) only in cows that were treated with M₂ protocol. Whereas, the days to first service was not influenced by the treatment of PGF_2α on Day 15 postpartum (P > 0.05). In contrast, administration of GnRH on Day 23 post-AI increased the days to conception and the number of service per conception (P < 0.01) and tended to decrease the first service conception rate (P < 0.1) in cows that were treated with M₁ compared with M₂ protocol. Therefore, it was concluded that Presynch-Ovsynch protocol could be more reproductive and beneficial when a single treatment with PGF_2α was administered at 15 days postpartum (15 days after the PGF_2α, Presynch-Ovsynch protocol was initiated). Interestingly, the administration of a GnRH agonist on Day 23 post-AI not only did not improve the reproductive performance of the cows receiving first postpartum timed artificial insemination after Presynch-Ovsynch protocol but also reduced that.     

Associations between intrauterine bacterial infection,reproductive tract inflammation,and reproductive performance in pasture-based dairy cows

Reproductive tract bacterial infections, particularly those caused by Escherichia coli and Trueperella pyogenes, can have a negative impact on reproductive performance. It has been hypothesized that the presence of E coli early postpartum may increase the risk of isolation of T pyogenes later postpartum. The objective of the present study was to examine associations between intrauterine bacterial infections with E coli and T pyogenes and any bacterial growth (irrespective of bacterial species), purulent vaginal discharge (PVD), cytologic evidence of endometritis (an increased proportion of polymorphonuclear cells [PMNs]), and reproductive performance. Dairy cows (n = 272) from six herds were examined at Days 0 (median, 2 days in milk), 21 and 42 postpartum. From each cow two intrauterine samples were collected via triple-guarded cytobrush at Days 0 and 21. The first cytobrush was used for bacteriologic culture. Escherichia coli and T pyogenes were isolated by culture, and E coli isolates were assigned to one of four phylogenetic groups using a two-step triplex polymerase chain reaction. In addition, T pyogenes was confirmed by polymerase chain reaction. The second cytobrush was used to prepare a cytology slide. Nucleated cells (n = 200) were categorized as epithelial cells, PMNs, or macrophages. Cows were also assessed for body condition score, PVD score, the presence of a CL, and pregnancy. Statistical analysis was performed using multivariable models. There was no association between the presence of E coli at Day 0 and probability of isolation of T pyogenes 3 weeks later; however, E coli positive cows at Day 0 were more likely to be diagnosed with E coli at Day 21 (relative risk [RR] = 2.0, P < 0.01). Escherichia coli at Day 0 or T pyogenes at Day 21 increased the risk of PVD diagnosis 3 weeks later (RR = 1.9; P = 0.04 and RR = 3.0; P = 0.05, respectively). Cows with any bacterial growth at Day 21, irrespective of species, were less likely to conceive within 3 weeks after the start of the seasonal breeding program (RR = 0.8; P = 0.05). Interestingly, cows with 25% PMNs or greater at Day 0 had shorter time to pregnancy (hazard ratio = 1.32; P = 0.05). Intrauterine bacterial infection may impair reproductive performance but the presence of E coli was not associated with isolation of T pyogenes 3 weeks later. Increased endometrial flux of PMNs in cows early postpartum may be a physiological process and improve reproductive performance.     

Risk factors for resumption of postpartum estrous cycles and embryonic survival in lactating dairy cows

The objectives of this study were to evaluate factors associated with resumption of postpartum estrous cycles and embryonic survival in lactating dairy cows. Holstein cows, 6396 from four dairy farms were evaluated to determine the relationships among parity, body condition score (BCS) at calving and at AI, season of year when cows calved, and milk yield on resumption of postpartum estrous cycles by 65 days postpartum, and all the previous variables, estrual or anestrus and AI protocol on conception rates and embryonic survival at the first postpartum insemination. Cows had their estrous cycle pre-synchronized with two PGF_2α injections given 14 days apart and were inseminated between 69 and 82 days postpartum following either an estrous or ovulation synchronization protocol initiated 12–14 days after the presynchronization. Blood was sampled and analyzed for progesterone twice, 12–14 days apart, to determine whether cows had initiated onset of estrous cycles after calving. Cows were scored for body condition in the week after calving, and again at AI, between 69 and 82 days postpartum. Pregnancy was diagnosed at 30 ± 3 and 58 ± 3 days after AI. Farm influenced all reproductive outcomes evaluated. More (P < 0.0001) multiparous than primiparous cows had initiated estrous cycles. Onset of estrous cycles was also influenced (P < 0.01) by BCS at calving and at AI, BCS change, season, and milk yield. More (P < 0.001) cows that had initiated estrous cycles than anestrous cows were pregnant at 30 and 58 days after AI, but anestrus did not affect pregnancy loss. Conception rates were also influenced (P < 0.01) by parity, BCS at calving and AI, BCS change, and season; however, milk yield and insemination protocol were not associated with conception rates at 30 and 58 days after AI. Factors that reduced conception rate on day 30 after AI also increased pregnancy loss between 30 and 58 days of gestation. Improving BCS at calving and AI, minimizing losses of BCS after calving, and hastening onset of estrous cycles early postpartum are all expected to increase conception because of enhanced embryonic survival.     

Influence of hormonal and nonhormonal estrus synchronization methods on follicular and oocyte quality in primiparous lactating does at early postpartum period

High-yield lactating does need effective estrus synchronization methods to improve their reproductive outcome by enhancing ovarian function. The aim of the current work was to analyze ovarian follicular and oocyte characteristics of hormonal and nonhormonal estrus synchronization regimes in primiparous lactating rabbit does (Oryctolagus cuniculus) in the early postpartum period (Day 11). Females were randomly treated with either (1) a hormonal standard treatment with 25 IU equine chorionic gonadotropin (eCG) 48 h before artificial insemination (eCG group) or (2) an alternative nonhormonal treatment consisting of doe-litter separation 24 h before artificial insemination (Bio group). No significant differences were found in serum estradiol and progesterone concentrations between experimental groups. During the histologic study, the Bio group presented a higher number of primordial (P < 0.05) and primary follicles (P = 0.07) compared with that of the eCG group, whereas secondary and antral follicular populations were similar. Rates of late atretic follicles assessed by the terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling technique were not different between treatments, but the eCG group showed a significantly higher number of mid-atretic follicles compared with that of the Bio group. Nuclear in vitro oocyte maturation (IVM), measured as metaphase II rate, and in vitro steroidogenic response of cumulus-oocyte complexes, measured by ELISA, did not show significant differences between treatments. However, confocal study showed that cytoplasmic maturation of oocytes, in terms of cortical granule migration rate, was significantly higher in the Bio group compared with that after the eCG treatment. In conclusion, transient doe-litter separation seems to improve ovarian response in terms of follicular health and oocyte competence compared with that after the eCG treatment. Therefore, a 24-h-long transient weaning could be an alternative nonhormonal method for synchronizing estrus in primiparous lactating rabbit does inseminated in the early postpartum period.     

Effects of dietary supplementation of pioglitazone on metabolism,milk yield,and reproductive performance in transition dairy cows

The objective of this study was to investigate the effect of dietary supplementation of pioglitazone (PGT), a specific ligand for PPARγ, on metabolic dynamics, milk production, and reproductive performance of transition dairy cows. Eighty multiparous Holstein cows in their second or more lactations were blocked by the calving date and parity and assigned randomly to four dietary groups (n = 20 cow/treatment) including control (no PGT−/−), supplemented with PGT (6-mg PGT/kg body weight) from Day −14 to +21 relative to parturition (PGT+/+) or only during prepartum (PGT+/−) or postpartum periods (PGT−/+). Postpartum body condition score and body weight loss decreased (P < 0.05) in all PGT-supplemented groups. Milk yield was not affected by PGT supplementation (P > 0.05). Percentage of milk fat decreased (P < 0.05) in all PGT-treated groups; however, milk fat yield was lower (P < 0.05) in PGT (+/+) and PGT (+/−) groups compared with PGT (−/−). Peripartum (Day −7 to +7) concentrations of plasma nonesterified fatty acids and β-Hydroxybutyrate decreased in PGT (+/+) but not in the PGT (−/−) group (P < 0.05). During the postpartum period, PGT reduced (P > 0.05) plasma concentrations of nonesterified fatty acids in all PGT-treated groups but did not affect β-Hydroxybutyrate level. Plasma concentrations of triglycerides decreased in all PGT-supplemented groups. Supplementation of PGT increased the peripartum concentrations of plasma glucose in PGT (+/+) and PGT (+/−) groups compared with control. Plasma concentrations of insulin-like growth factor 1 were higher in PGT (+/+) compared with the control group during both the peripartum and postpartum periods. Plasma concentrations of growth hormone and insulin were not affected by PGT treatment (P > 0.05). Mean days to ovulation were lower in PGT (+/+) and PGT (-/+), and the proportion of cows ovulating by Day 14 postpartum was higher in PGT (+/+) compared with control. Days open were shorter in PGT (+/+), PGT (+/−), and PGT (−/+) groups compared with control. However, the proportion of pregnant cows at 120 days in milk were higher in all PGT-supplemented groups. The results showed positive effects of dietary supplementation of PGT, especially supplementation during both the prepartum and postpartum periods, on metabolic dynamics, ovarian function, and reproductive performance in transition dairy cows.     

Postinsemination treatment of primiparous and multiparous cows with cloprostenol failed to affect ovulation and pregnancy rate in dairy cattle

Previous studies have demonstrated the facilitating effect of a single cloprostenol treatment postinsemination on ovulation and pregnancy rate in dairy cattle and Italian buffalos. This study was conducted to test the effects of 500 μg cloprostenol given intramuscularly immediately postinsemination to 55 primiparous and 60 multiparous Holstein cows (Bos taurus; TR) of a typical dairy operation in East Germany and to compare them with 57 primiparous and 48 multiparous saline-treated cows (CON). Animals of the TR and CON groups did not differ or only differed marginally for age at treatment, interval calving–treatment, lactation number, milk production on the day of treatment, body condition score, and their peri- and postparturient case histories. All animals were clinically and reproductively healthy on the day of treatment. They were inseminated once 12 h after the onset of estrus, scanned 24 h after insemination to confirm ovulation, and tested for pregnancy by transrectal palpation between Days 42 and 48 postinsemination. Treatment did not affect the number of cows ovulating. The overall combined pregnancy rate (PR) was 47.3%. Pregnancy rate did not differ statistically between TR and CON (46.1% vs. 48.6%; P > 0.05). In conclusion, this study failed to demonstrate beneficial effects of a postinsemination treatment of primiparous and multiparous cows with cloprostenol on ovulation and PR in a typical dairy cattle operation in East Germany.     

Effects of an energy-dense diet and nicotinic acid supplementation on production and metabolic variables of primiparous or multiparous cows in periparturient period

It is well observed that feeding energy-dense diets in dairy cows during the dry period can cause metabolic imbalances after parturition. Especially dairy cows with high body condition score (BCS) and fed an energy-dense diet were prone to develop production diseases due to metabolic disturbances postpartum. An experiment was conducted to determine the effects of an energy-dense diet and nicotinic acid (NA) on production and metabolic variables of primiparous and multiparous cows in late pregnancy and early lactation which were not pre-selected for high BCS. Thirty-six multiparous and 20 primiparous German Holstein cows with equal body conditions were fed with energy-dense (60% concentrate/40% roughage mixture; HC group) or adequate (30% concentrate/70% roughage mixture; LC group) diets prepartum. After parturition, concentrate proportion was dropped to 30% for all HC and LC groups and was increased to 50% within 16 days for LC and within 24 days for HC cows. In addition, half of the cows per group received 24 g NA supplement per day and cow aimed to attenuate the lipid mobilisation postpartum. Feeding energy-dense diets to late-pregnant dairy cows elevated the dry matter (p < 0.001) and energy intake (p < 0.001) as well as the energy balance (p < 0.001) without affecting the BCS (p = 0.265) during this period. However, this did not result in any metabolic deviation postpartum as the effects of prepartum concentrate feeding were not carried over into postpartum period. Multiparous cows responded more profoundly to energy-dense feeding prepartum compared with primiparous cows, and parity-related differences in the transition from late pregnancy to lactation were obvious pre- and postpartum. The supplementation with 24 g NA did not reveal any effect on energy metabolism. This study clearly showed that energy-dense feeding prepartum did not result in metabolic imbalances postpartum in multiparous and primiparous cows not selected for high BCS. A genetic predisposition for an anabolic metabolic status as indicated by high BCS may be crucial for developing production diseases at the onset of lactation.     

Reproductive performance of lactating dairy cows treated with gonadotrophin-releasing hormone (GnRH) and/or prostaglandin F2a (PGF2a) for synchronization of estrus and ovulation

The objective of this study was to determine the reproductive performance of lactating dairy cows treated with GnRH and/or PGF2a for synchronization of estrus and ovulation. Between Days 43 and 57 post partum, a total of 374 dairy cows was divided into 4 groups. Cows in Group 1 (n = 62) were treated with 25 mg, i.m. PGF2a on Days 43 and 57; cows in Group 2 (n = 65) were not treated at this time; cows in Group 3 (n = 118) were treated with 100 ug, i.m. GnRH on Day 50, 25 mg, i.m. PGF2a on Day 57, 100 ug, i.m. GnRH on Day 59, and time-inseminated 16 h later; cows in Group 4 (n = 129) were treated with 25 mg, i.m. PGF2a once on Day 57. Cows in Groups 1 and 4 were inseminated at an induced estrus within 7 d after the last PGF2a treatment, and cows in Group 2 were inseminated at a noninduced estrus within a corresponding period of time. Conception rate, estrus detection rate and pregnancy rate were analyzed using logistic regression, and controlled for lactation number, body condition score and time of year. Days from calving to conception were analyzed using the GLM procedures of SAS, and the model included group, body condition score, lactation number, time of year, and their interactions. Cows in Group 3 had a significantly higher pregnancy rate than cows in Groups 1, 2 and 4. Orthogonal contrasts of mean days from calving to conception showed that cows in Group 3 had significantly (P < 0.01) less days from calving to conception than cows in Group 1 and Group 4. There was a significant effect of time of year on pregnancy rate and days from calving to conception, but there was no interaction between time of year and these reproductive characteristics. There was no effect of body condition score and lactation number on the reproductive characteristics evaluated. From the results of this study, it was concluded that better reproductive performance was observed in cows inseminated at a synchronized ovulation than in those inseminated at a synchronized estrous period.     

Urinary hormone analysis assists reproductive monitoring and sex identification of bell frogs (Litoria raniformis)

With the world currently facing a global amphibian extinction crisis, the development of techniques to help meet the needs of conservation managers and researchers studying the reproductive biology of amphibians is needed. Here, we developed enzyme immunoassays to measure estrone, testosterone, and progesterone hormone metabolites in the urine of Litoria raniformis, the southern bell frog. Concentrations of urinary estrone, testosterone, and progesterone increased during the breeding season for females (P < 0.05). Concentrations of urinary testosterone and progesterone increased for males during the breeding season compared with that for months where no reproductive behaviors were observed (P < 0.05). Furthermore, urinary estrone concentrations proved to be a reliable sexing tool for adult frogs, with no overlap between the sexes in 98% of cases, regardless of season. There was no difference in estrone (P = 0.204) or testosterone (P = 0.485) metabolite concentrations between samples taken immediately upon capture and those taken 12 to 24 h later from the same individual. Progesterone metabolite concentrations were lower on Day 2 than upon collection (P = 0.004). This is the first study to show that urinary hormone analysis can be a useful technique for reproductive monitoring in an amphibian. Additionally, hormone metabolite measures offer promise as sex identification tools for monomorphic species and for those whose secondary sex characteristics are visible only during the breeding season.     

Prostaglandin F2α, oxytocin and progesterone secretion by bovine luteal cells at several stages of luteal development: Effects of oxytocin, luteinizing hormone, prostaglandin F2α and estradiol-17β

Bovine luteal cells from Days 4, 8, 14 and 18 of the estrous cycle were incubated for 2 h (1 × 10⁵ cells/ml) in serum-free media with one or a combination of treatments [control (no hormone), prostaglandin F₂α (PGF), oxytocin (OT), estradiol-17β (E) or luteinizing hormone (LH)]. Luteal cell conditioned media were then assayed by RIA for progesterone (P), PGF, and OT. Basal secretion of PGF on Days 4, 8, 14 and 18 was 173.8 ± 66.2, 111.1 ± 37.8, 57.7 ± 15.4 and 124.3 ± 29.9 pg/ml, respectively. Basal release of OT and P was greater on Day 4 (P<0.01) than on Day 8, 14 and 18 (rmOT: 17.5 ± 2.6 versus 5.6 ± 0.7, 6.0 ± 1.4 and 3.1 ± 0.4 pg/ml; P: 138.9 ± 19.5 versus 23.2 ± 7.5, 35.4 ± 6.5 and 43.6 ± 8.1 ng/ml, respectively). Oxytocin increased (P<0.01) PGF release by luteal cells compared with control cultures irrespective of day of estrous cycle. Estradiol-17β stimulated (P<0.05) PGF secretion on Days 8, 14 and LH increased (P<0.01) PGF production only on Day 14. Prostaglandin F₂α, E and LH had no effect on OT release by luteal cells from any day. Luteinizing hormone alone or in combination with PGF, OT or E increased (P<0.01) P secretion by cells from Days 8, 14 and 18. However on Day 8, a combination of PGF + OT and PGF + E decreased (P<0.05) LH-stimulated P secretion. These data demonstrate that OT stimulates PGF secretion by bovine luteal cells in vitro. In addition, LH and E also stimulate PGF release but effects may vary with stage of estrous cycle.     

Physiological and behavioural responses of cows from two beef breeds submitted to different suckling strategies

This experiment was designed to study the effects of avoiding calf contact and genotype on the metabolic, behavioural and reproductive traits of beef cows during lactation. Fifty-two multiparous cows, 25 Parda de Montaña (PA) and 27 Pirenaica (PI), fed at maintenance were assigned from the day after calving to twice-daily nursing (2× 30-min sessions at 0800 and 1600 h) either with fence contact with their calves (partial contact, PC) or without visual, tactile and olfactory contact (non-contact, NC) between suckling periods. Blood samples were collected to analyse metabolites (triglycerides, cholesterol, non-esterified fatty acids (NEFA), β-hydroxybutyrate and urea) and progesterone at different intervals. Cow–calf behaviour was monitored on weeks 4, 9 and 15 of lactation. Cow activity at oestrus was recorded through collars. Cows from both treatments and breeds showed similar live-weight gains during the first three months post-partum (P > 0.10). Milk yield and calf gains were not affected by treatment (P > 0.10) but they were greater in PA than in PI (P < 0.05). Plasma triglycerides and urea in the cows were not affected either by calf contact, breed or week post-partum (P > 0.10). Plasma cholesterol increased from week 6 post-partum onwards in PA cows (P < 0.05) while this rise was delayed to week 7 of lactation in PI breed (P < 0.05). Plasma NEFA was greater in blood from PC–PA cows than in the rest of groups (P < 0.05), and these metabolites were greater on week 1 and lower on week 11 than in rest of samplings (P < 0.05). Plasma β-hydroxybutyrate was not affected by either calf contact or breed (P > 0.10), but it was greatest on weeks 1–3 than in the rest of lactation (P < 0.05). Cows with PC calves took less time to first contact after they entered the barn than their NC counterparts (P < 0.05). Dams from both contact treatments nursed their offspring and remained in close proximity for similar time within suckling periods (P > 0.10). PA cows devoted more time than PI ones to lick their young (P < 0.001). There were no differences throughout lactation in any of the studied maternal behaviours (P > 0.10). Calf contact and breed did not affect the interval to first post-partum ovulation or oestrus in these cows (P > 0.10). Under twice-daily nursing conditions, the limitation of visual, tactile and olfactory contact with calves did not trigger different maternal or reproductive traits in these breeds but only a slightly higher mobilisation of body fat substrates in Parda de Montaña compared to Pirenaica.     

Beta-cypermethrin impairs reproductive function in male mice by inducing oxidative stress

Cypermethrin (CYP), an insecticide, has deleterious effects on male reproductive function. The objective was to identify whether the effects of beta-CYP on male reproductive organs were associated with oxidative stress. Three doses of beta-CYP (1, 10, and 20 mg/kg) were administered to male mice for 35 d, with or without vitamin E (20 mg/kg). The moderate (10 mg/kg) and high (20 mg/kg) doses of beta-CYP not only decreased body weight and the weight of the testes, epididymides, seminal vesicles, and prostate (P < 0.05) but also reduced serum testosterone concentration and the expression of steroidogenic acute regulatory protein (P < 0.05), in addition to damaging the seminiferous tubules and sperm development. Furthermore, moderate and high doses of beta-CYP administration decreased sperm number, sperm motility, and intact acrosome rate (P < 0.05). Based on ultrastructural analyses, high doses of beta-CYP produced swelling and degeneration of mitochondria and the smooth endoplasmic reticulum of Leydig cells and caused the formation of concentric circles. These toxic effects of beta-CYP may be mediated by increasing oxidative stress, as the moderate and high doses of this compound increased malondialdehyde and nitric oxide in testes (P < 0.05); reduced the activity of catalase, glutathione peroxidase (GSH-Px), and superoxide dismutase (P < 0.05); and activated ERK1/2 (P < 0.05). Vitamin E reversed the effects of beta-CYP on testosterone production and testis damage (P < 0.05 vs. the high-dose group). Therefore, we inferred that beta-CYP damaged the structure of testes and decreased sperm output by inducing oxidative stress.     

The Impact of Estradiol and 1,25(OH)2D3 on Metabolic Syndrome in Middle-Aged Taiwanese Males

In addition to adipocytokines, estradiol (E2) and vitamin D have been reported to affect insulin sensitivity, glucose homeostasis and body weight. However, studies about the impact of E2 and vitamin D on metabolic syndrome (MetS) are still limited. The aim of this study is to clarify the roles of circulating E2 and vitamin D on the risk of MetS in middle-aged Taiwanese males. A total of 655 male volunteers, including 243 subjects with MetS (mean age: 56.7±5.8 years) and 412 normal controls (mean age: 55.1±3.6 years), were evaluated. Subjects with MetS had significantly lower circulating E2, 1,25(OH)₂D₃, and adiponectin, and higher leptin than those without MetS (P<0.001 for all comparisons). E2 and 1,25(OH)₂D₃ were significantly associated with 4 individual components of MetS; more than adiponectin and leptin that were only associated with 3 individual components. In multivariate regression analysis, E2 (beta = −0.216, P<0.001) and 1,25(OH)₂D₃ (beta = 0.067, P = 0.045) were still significant predictors of MetS independent of adiponectin and leptin. Further large studies are needed to confirm our preliminary results and elucidate the possible mechanism.     

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.     

Effects of gonadotropin releasing hormone and prostaglandin F(2)alpha on the reproductive performance in postpartum cows

A study was conducted to determine whether treatment with gonadotropin releasing hormone (GnRH) in combination with prostaglandin F(2)alpha (PGF(2)alpha) could enhance ovarian activity and uterine involution in postpartum dairy cows to reduce the calving interval. Cows were randomly assigned to one of three treatment groups. Cows (n = 8) in Group 1 received 100 mug GnRH intramuscularly (i.m.) twice on Day 20 and Day 35 postpartum, and 25 mg PGF(2)alpha i.m. on Day 47 postpartum. Group 2 (n = 8) received a single i.m. injection of 100 mug GnRH on Day 25 postpartum and 25 mg PGF(2)alpha i.m. on Day 37 postpartum. The Control Group (n = 9) did not receive hormonal treatment. Palpation per rectum of the reproductive organs and serum progesterone (P) determination were performed twice a week to monitor ovarian activity and uterine involution. Postpartum interval to the first ovulation was short in treated groups (Group 1, 21.0 d; Group 2, 26.3 d) compared with Control Group (30.1 d, P < 0.05). Likewise, mean frequency of ovulation was increased in both treated groups compared with the Control Group (P < 0.05). Cows in treated groups required fewer days to complete uterine involution than in the Control Group. The mean interval to the first service, the conception rate at first service and the number of services per conception showed no significant differences among the three groups, but the mean days from calving to conception were shorter for the treated groups (78.7 d in Group 1; 83.3 d in Group 2) than (109.1 d, P < 0.05) for the Control Group. Our results suggest that combined treatment with GnRH and PGF(2)alpha may enhance ovarian activity in the postpartum cow, resulting in improved reproductive performance.     

Effects of feed restriction during pregnancy on maternal reproductive outcome,foetal hepatic IGF gene expression and offspring performance in the rabbit

Primiparous female rabbits have high nutritional requirements and, while it is recommended that they are subjected to an extensive reproductive rhythm, this could lead to overweight, affecting reproductive outcomes. We hypothesised that restricting food intake during the less energetic period of gestation could improve reproductive outcome without impairing offspring viability. This study compares two groups of primiparous rabbit does in an extensive reproductive programme, one in which feed was restricted from Day 0 to Day 21 of gestation (R021), and another in which does were fed ad libitum (control) throughout pregnancy. The mother and offspring variables compared were (1) mother reproductive outcomes at the time points pre-implantation (Day 3 postartificial insemination [AI]), preterm (Day 28 post-AI) and birth; and (2) the prenatal offspring characteristic IGF system gene expression in foetal liver, liver fibrosis and foetus sex ratio, and postnatal factor viability and growth at birth, and survival and growth until weaning. Feed restriction did not affect the conception rate, embryo survival, or the number of morulae and blastocysts recovered at Day 3 post-AI. Preterm placenta size and efficiency were similar in the two groups. However, both implantation rate (P < 0.001) and the number of foetuses (P = 0.05) were higher in the R021 mothers than controls, while there was no difference in foetal viability. Foetal size and weight, the weights of most organs, organ weight/BW ratios and sex ratio were unaffected by feed restriction; these variables were only affected by uterine position (P < 0.05). Conversely, in the R021 does, foetal liver IGBP1 and IGF2 gene expression were dysregulated despite no liver fibrosis and a normal liver structure. No effects of restricted feed intake were produced on maternal fertility, prolificacy, or offspring birth weight, but control females weaned more kits. Litter weight and mortality rate during the lactation period were also unaffected. In conclusion, pre-implantation events and foetal development were unaffected by feed restriction. While some genes of the foetal hepatic IGF system were dysregulated during pregnancy, liver morphology appeared normal, and the growth of foetuses and kits until weaning was unmodified. This strategy of feed restriction in extensive reproductive rhythms seems to have no significant adverse effects on dam reproductive outcome or offspring growth and viability until weaning.     

Ovarian response and embryo production in llamas treated with equine chorionic gonadotropin alone or with a progestin-releasing vaginal sponge at the time of follicular wave emergence

The objective of the study was to compare the ovulatory response and embryo production in llamas (Lama glama) treated with a single dose of equine chorionic gonadotropin (eCG) alone or combined with intravaginal medroxyprogesterone acetate (MPA) at the time of follicular wave emergence. Llamas with a growing follicle ≥7 mm in diameter were assigned to one of the following groups: (1) Control (n = 28): Nonstimulated llamas were mated and embryos were collected 7 d after mating. (2) eCG (n = 32): Llamas were given 5 mg luteinizing hormone (LH) (Day 0) to induce ovulation, 1000 IU eCG on Day 2, a luteolytic dose of prostaglandin F_2α on Day 6, mating on Day 7, and embryo collection on Day 14. (3) eCG+MPA (n = 34): Llamas were treated as those in the eCG group, but a sponge containing 60 mg MPA was placed intravaginally from Days 2 to 6. Llamas that did not respond to synchronization or superstimulation were excluded, leaving data from n = 26, 26, and 27 in the control, eCG, and eCG+MPA groups, respectively, for statistical analysis. The mean (±SD) number of follicles > 7 mm at the time of mating was greatest in the eCG group, intermediate in the eCG+MPA group, and lowest in the control group (16.6 ± 5.3, 12.9 ± 3.7, and 1.0 ± 0.0, respectively, P < 0.001). The number of corpora lutea was similar between eCG and eCG+MPA groups (10.1 ± 2.9 and 8.6 ± 3.7, respectively); both were higher (P < 0.001) than in controls (0.9 ± 0.3). The number of embryos did not differ significantly between the eCG and eCG+MPA groups (4.8 ± 2.8 and 3.5 ± 3.0, respectively), but both were higher (P < 0.001) than in the controls (0.7 ± 0.4). In conclusion, eCG, with or without MPA effectively induced a superovulatory response and multiple embryo production in llamas.     

[18F]FLT and [18F]FDG PET for Non-invasive Treatment Monitoring of the Nicotinamide Phosphoribosyltransferase Inhibitor APO866 in Human Xenografts

Introduction

APO866 is a new anti-tumor compound inhibiting nicotinamide phosphoribosyltransferase (NAMPT). APO866 has an anti-tumor effect in several pre-clinical tumor models and is currently in several clinical phase II studies. 3′-deoxy-3′-[18F]fluorothymidine ([18F]FLT) is a tracer used to assess cell proliferation in vivo. The aim of this study was non-invasively to study effect of APO866 treatment on [18F]FLT and 2-deoxy-2-[18F]fluoro-D-glucose ([18F]FDG) uptake.

Methods

In vivo uptake of [18F]FLT and [18F]FDG in human ovary cancer xenografts in mice (A2780) was studied at various time points after APO866 treatment. Baseline [18F]FLT or [18F]FDG scans were made before treatment and repeated after 24 hours, 48 hours and 7 days. Tumor volume was followed with computed tomography (CT). Tracer uptake was quantified using small animal PET/CT. One hour after iv injection of tracer, static PET scans were performed. Imaging results were compared with Ki67 immunohistochemistry.

Results

Tumors treated with APO866 had volumes that were 114% (24 h), 128% (48 h) and 130% (Day 7) relative to baseline volumes at Day 0. In the control group tumor volumes were 118% (24 h), 145% (48 h) and 339% (Day 7) relative to baseline volumes Day 0. Tumor volume between the treatment and control group was significantly different at Day 7 (P = 0.001). Compared to baseline, [18F]FLT SUVmax was significantly different at 24 h (P<0.001), 48 h (P<0.001) and Day 7 (P<0.001) in the APO866 group. Compared to baseline, [18F]FDG SUVmax was significantly different at Day 7 (P = 0.005) in the APO866 group.

Conclusions

APO866 treatment caused a significant decrease in [18F]FLT uptake 24 and 48 hours after treatment initiation. The early reductions in tumor cell proliferation preceded decrease in tumor volume. The results show the possibility to use [18F]FLT and [18F]FDG to image treatment effect early following treatment with APO866 in future clinical studies.     

Effects of body condition and leptin on the reproductive performance of Lusitano mares on extensive systems

The aim of this study was to investigate the effects of body condition (BC), BC changes, and plasma leptin concentrations on the reproductive performance of Lusitano broodmares on extensive systems. Data from 119 mares (ranging from 4 to 22 years of age) were collected over a period of four consecutive breeding seasons. Each case was considered as one foaled mare bred in 1 year. Body condition changes at conception (ΔBCScon) showed a strong effect on fertility at the first two postpartum estrous cycles and a significant interaction with body condition score at conception (BCScon) was observed (P < 0.01). The best fertility results were obtained with positive and greater ΔBCScon. The best predictive value of fertility (91%) was achieved when the BCScon was 3.0 and ΔBCScon was 0.375. Global foaling rate for the 4-year period was 74.5%. Mean foaling interval and gestation length were, respectively, 368.0 ± 2.8 and 340.3 ± 1.0 days. Gestation length was influenced by the month of foaling (P < 0.05) and decreased as mares got older (P < 0.01). The number of estimated estrous cycles per live foal was 1.78 ± 0.12, including foal heat ovulation. Leptin was correlated with BCS (0.41; P < 0.001), but in the present study, plasma leptin concentrations on late gestation and early lactation did not influence fertility results. At 90 days of age, lower growth performances were obtained in foals which dams presented negative BCS changes on the first 3 months of lactation (P < 0.05). In conclusion, BC changes at early postpartum period influence the reproductive efficiency of broodmares and the growth of their suckling foals. These findings are important to help breeders on management options concerning feeding strategies in the Lusitano production systems and others under similar conditions.