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A feasible and non‐invasive luteal function assessment which enables timely intervention to improve progesterone (P4) support at early pregnancy is not well‐established. The aim of this study was to determine the correlation among morphological and functional assessment methods of corpus luteum (CL) on Day 5 (D5) following timed‐artificial insemination effect on luteal blood perfusion (LBP), CL diameter and serum P4 concentration. Beef heifers (n = 89) were synchronized and inseminated (D0). On D5, CL was scanned by colour‐Doppler ultrasonography using an LBP score (0 = absent; 3 = high blood perfusion); CL diameter was obtained and blood was collected. Diameter of CL had a positive linear effect on P4 concentration (p <.001); and larger CL diameter increased the probability to become pregnant (p <.05; odds ratio =1.21). Heifers with a CL larger than 14.95 mm had a higher pregnancy rate than heifers with a 14.95 mm or smaller CL (p <.05). Animals with LBP 2 and 3 had larger CL when compared to scores 0 and 1 (p <.001). Scores 1, 2 and 3 can accurately estimate heifers with higher P4 (accuracy =0.79, 0.72 and 0.61 respectively). In conclusion, LBP on Day 5 post‐TAI allows to estimate heifers with higher P4 and larger CL size, and a larger CL diameter was positively associated with pregnancy rate. [ABSTRACT FROM AUTHOR]

High‐density lipoprotein (HDL) is the main lipoprotein in the follicular fluid, and it has anti‐inflammatory, antioxidant and cryoprotectant properties. The anti‐inflammatory potential and antioxidant potential are derived from its lipid composition, especially the apolipoprotein AI (ApoAI) and paraoxonase 1 (PON1). The aim of this study was to evaluate the effect of HDL during in vitro maturation (IVM) on oocyte maturation and early bovine embryo development. For this, cumulus–oocyte complexes (COCs) were obtained from bovine ovaries collected at a local slaughterhouse. COCs (n = 2,250) were allocated into three groups (n = 50 COCs/group) according to the addition of HDL protein (HDL‐P) during IVM for 22 hr: 0 (control), 50 and 150 mg/dl. After IVM, COCs were inseminated (in vitro fertilization) and cultivated for 7 days. Total cholesterol concentration, total protein, triglycerides and ApoAI concentrations on IVM medium increased proportionally to HDL‐P addition. However, PON1 activity was not detected in any treatment. The addition of HDL‐P did not affect nuclear maturation rate, endogenous reactive oxygen species and glutathione levels in COCs (p > 0.05). The highest HDL‐P concentration (150 mg/dl) decreased cleavage and blastocyst rate (p < 0.05). Moreover, the HDL‐P 150 mg/dl group had lower cellular count/blastocyst than the 50 mg/dl group (p < 0.05). However, the addition of HDL‐P did not affect relative gene expression of evaluated genes. In conclusion, the complex HDL/ApoAI obtained from human plasma, in the absence of PON1 activity during in vitro oocyte maturation, decreased initial embryo development. [ABSTRACT FROM AUTHOR]

Background Estradiol (E2) receptors mediate E2 effects on cell proliferation and apoptosis under normal and pathological conditions. However, the mechanisms involved in E2 signaling are not, completely understood. The objectives in this study were to evaluate the expression of estrogen receptors (ESRs) during follicular selection in cattle, and the effect of intrafollicular injection of fulvestrant (an antagonist of ESRs) on follicular development and transcript abundance in granulosa cells. Methods Granulosa cells were obtained from the two largest follicles around follicular deviation, after FSH treatment and after intrafollicular injection of fulvestrant. Ovarian follicular dynamics monitored by ultrasonography and quantitative real time PCR were used to validate the in vivo model and investigate the effects of FSH supplementation or ESR blockade on mRNA expression of estradiol-related genes. Results ESR1 and ESR2 were expressed in granulosa cells of both dominant (F1) and subordinate (F2) follicles, but their transcripts levels were higher in F1 than F2 after follicular deviation. FSH treatment maintained mRNA levels of both ESR1 and ESR2 in F2 follicles at similar levels observed in F1 follicles. Intrafollicular injection of 100 μM fulvestrant inhibited follicular growth and decreased CYP19A1 mRNA levels. Transcript levels for both ESR1 and ESR2 were not affected by fulvestrant injection. Analyses of FSH-regulated genes revealed that ESRs inhibition in the dominant follicle decreased the transcript levels of the GJA1 but not those of PRKAR2B, MRO or LRP11 genes. Conclusions Our findings indicate that: both ESR1 and ESR2 are regulated during follicular deviation and dominance in cattle and in response to FSH treatment, and ESRs are required for normal gene expression and development of the dominant follicle. Furthermore, we have validated an in vivo model to study estrogen signaling during follicular development that allows paracrine signaling between different follicular cells in a physiological endocrine environment. [ABSTRACT FROM AUTHOR]

The objective of this study was to characterize the profiles of Ang-(1-7), MAS receptor, ACE2, NEP and PEP during the ovulatory process in cattle. For this study, 40 synchronized cows with follicular diameter ≥ 12 mm were ovariectomized at different time-points (0, 3, 6, 12 and 24 h) after i.m. application of gonadotropin-releasing hormone (GnRH) to induce a luteinizing hormone surge. Follicular fluid was collected for measuring Ang-(1-7) by radioimmunoassay. Theca and granulosa cells were isolated from the preovulatory follicles to evaluate the gene expression of MAS receptor, ACE2, NEP and PEP by qRT-PCR assay. Cross-contamination between theca and granulosa cells was tested by RT-PCR to detect cytochrome P450 aromatase (CYP19A1) and 17α-hydroxylase (CYP17A1) mRNA. Ang-(1-7) levels were constant until 12 h and then increased (p < 0.05) at 24 h after GnRH. Messenger RNA expression of MAS, ACE2, NEP and PEP was detected in theca and granulosa cells at all time-points after GnRH. In granulosa cells, ACE2, NEP and PEP were differentially expressed after GnRH treatment (p < 0.05). In conclusion, the Ang-(1-7), MAS receptor, ACE2, NEP and PEP profiles in preovulatory follicles indicate that Ang-(1-7) plays a role in the regulation of the ovulatory process in cattle. [ABSTRACT FROM PUBLISHER]

The aim of this study was to evaluate the economic viability of the use of a lactation induction protocol in Holstein heifers. Were collected data of nutritional, reproductive and sanitary management pre and post-lactation period from 30 induction heifers (IG) and 30 pregnant heifers (CG). All animals were inseminated around 14 months of age and started lactation at 23±4 months. The animals of IG were heifers do not pregnant after two inseminations and natural service e were induced to lactation according to protocol: from the 1st to the 8th day, 30 mg of estradiol benzoate were administered daily, together with 300 mg of progesterone. From the 9th until the 14th, animals only received daily doses of 20 mg estradiol benzoate. On 16th day, 0.56 mg of sodium cloprostenol was administered and injections of 40 mg of dexamethasone sodium phosphate were administered daily from the 19th to the 21st day. On the 1st, 8th, 15th and 22nd day, the animals received a dose of sometribove zinc. The animals of CG were managed according to the farm routine. The costs of the CG during pre and post lactation (nutrition, sanitary, reproduction management) e were higher than the IG, however, when evaluating the economic viability due to lower milk production, the induced group did not leave profit in the first year of use. When comparing the lactation induction with the sale of animals that did not conceive and purchase of animals for replacement, this last scenario showed itself as a better alternative. [ABSTRACT FROM AUTHOR]

This aim of this study was to investigate the effectiveness of intravaginal devices (IVDs), containing medroxyprogesterone acetate (MPA), for controlling the estrous cycle in pubertal gilts. Gilts were assigned to four treatments: Control (no IVD); IVD containing 100 (IVD100), 200 (IVD200) or 400 mg (IVD400) of MPA. The IVDs were inserted on day 12 of the estrous cycle and maintained intra-vaginally for 14 days. The percentage of gilts in estrus, interval between IVD removal and estrous onset, adjusted farrowing rate (AFR), total number of piglets born (TPB), follicle size and serum progesterone (P4) were recorded. None of the gilts expressed estrus during the IVD treatment period. All gilts of the control group expressed estrus (15/15; 100%) which was greater (P = 0.03) than all IVD-treated gilts (33/44; 75%); however, there were no treatment differences (P = 0.09). The interval between IVD removal and estrous onset was shorter for IVD100 (3.8 ± 0.6 d) compared to IVD400 (5.3 ± 0.6 d; P = 0.05). The IVD400-treated gilts had smaller follicles than the IVD100-treated gilts (P = 0.05). The P4 concentrations were similar among treated groups (P = 0.99). The AFR did not differ among treatment groups (P = 0.37); however, the control group had a greater TPB than the other treatment groups (P = 0.04). The gilts treated with IVDs had longer interval to estrous expression. The most effective dosage was 400 mg of MPA, considering both the minimal follicular growth during the IVD treatment period and the lesser numbers of persistent follicles. [ABSTRACT FROM AUTHOR]

Gestation length in swine has a considerable amplitude and both early and delayed parturition are common. This variation increases the occurrence of unassisted farrowing and could lead to a wide-ranging age at weaning for piglets born from one batch. Supervision of sow parturition is crucial to reduce mortality of neonate piglets. To facilitate assistance, induction of farrowing using prostaglandin F2a (PGF) has been widely used in batch farrowing systems, whereby synchronization would concentrate the time of farrowing, allowing for better organization of employees. However, a viable alternative method that can be implemented to manage farrowing is to sustain high progestagen levels in the final days of gestation and, consequently, prevent early parturition. Efficient techniques to delay farrowing such as using oral progestagen supplementation have been previously described, but are only recently being considered for commercial use. The present manuscript reviews publications regarding delaying parturition and discusses the use of intravaginal devices (IVDs) containing progestagen. There is limited data addressing the effect of progestagen treatment during gestation on productive and reproductive performance. Therefore, future studies should focus on improving synchronization protocols following progestagen supplementation and evaluating piglet viability and sow fertility, before widely using progestagen supplementation to manipulate parturition. [ABSTRACT FROM AUTHOR]

Pregnancy diagnosis is an important tool for farm management. Ultrasonography is the main technique used for pregnancy diagnosis in ewes. As an alternative, radioimmunoassay (RIA) allows accurate and early detection of pregnancy-associated glycoproteins (PAGs) in sheep blood. However, radioactive-based techniques, as RIA, have been increasingly inadvisable due to environmental risk. Homology between ovine and bovine PAGs is high, and ELISA kits used for PAGs detection in cattle are safer than RIA. Thus, this study aimed to evaluate the feasibility of PAGs detection for pregnancy diagnosis in sheep serum samples using an ELISA kit produced for cattle. The sensitivity and specificity of the ELISA kit were 93.5% and 98.9%, respectively, whereas positive and negative predictive values were 99.0% and 93.1%, respectively, in comparison to ultrasonography diagnostic (control). PAGs reached consistently detectable concentrations in ovine serum around 33 days after mating. Accuracy of the ELISA test was 96.1% from 33 days of pregnancy until lambing. After parturition, PAGs were still detectable seven days post-lambing. However, from 21 days post-parturition, PAGs from the previous pregnancy were no longer detected in serum samples. In conclusion, the bovine ELISA kit can accurately detect pregnancy in sheep 33 days following mating, while PAGs levels from the previous gestation are no longer detected from 21 days post-partum. The evaluated ELISA test is a reliable tool for pregnancy diagnosis in sheep at random stages and as a complementary exam at early gestation. [ABSTRACT FROM AUTHOR]