Plasma Progesterone Concentrations Research Articles

Microwave Dielectric Response of Bovine Milk as Pregnancy Detection Tool in Dairy Cows.

The most reliable methods for pregnancy diagnosis in dairy herds include rectal palpation, ultrasound examination, and evaluation of plasma progesterone concentrations. However, these methods are expensive, labor-intensive, and invasive. Thus, there is a need to develop a practical, non-invasive, cost-effective method that can be implemented on the farm to detect pregnancy. This study suggests employing microwave dielectric spectroscopy (MDS, 0.5-40 GHz) as a method to evaluate reproduction events in dairy cows. The approach involves the integration of MDS data with information on milk solids to detect pregnancy and identify early embryonic loss in dairy cows. To test the ability to predict pregnancy according to these measurements, milk samples were collected from (i) pregnant and non-pregnant randomly selected cows, (ii) weekly from selected cows (n = 12) before insemination until a positive pregnancy test, and (iii) daily from selected cows (n = 10) prior to insemination until a positive pregnancy test. The results indicated that the dielectric strength of Δε and the relaxation time, τ, exhibited reduced variability in the case of a positive pregnancy diagnosis. Using principal component analysis (PCA), a clear distinction between pregnancy and nonpregnancy status was observed, with improved differentiation upon a higher sampling frequency. Additionally, a neural network machine learning technique was employed to develop a prediction algorithm with an accuracy of 73%. These findings demonstrate that MDS can be used to detect changes in milk upon pregnancy. The developed machine learning provides a broad classification that could be further enhanced with additional data.

Analysis of gene and protein expression in the endometrium for validation of an ex vivo model of the equine uterus using PCR, digital and visual histopathology

In the past, most research in equine reproduction has been performed in vivo but the use of in vitro and ex vivo models has recently increased. This study aimed to evaluate the functional stability of an ex vivo hemoperfused model for equine uteri with molecular characterization of marker genes and their proteins. In addition, the study validated the respective protein expression and the aptness of the software QuPath for identifying and scoring immunohistochemically stained equine endometrium. After collection, uteri (n = 12) were flushed with preservation solution, transported to the laboratory on ice, and perfused with autologous blood for 6 h. Cycle stage was determined by examination of the ovaries for presence of Graafian follicles or corpora lutea and analysis of plasma progesterone concentration (estrus: n = 4; diestrus: n = 4; anestrus: n = 4). Samples were obtained directly after slaughter, after transportation, and during perfusion (240, 300, 360 min). mRNA expression levels of progesterone (PGR), estrogen (ESR1) and oxytocin (OXTR) receptor as well as of MKI67 (marker of cell growth) and CASP3 (marker of apoptosis) were analyzed by RT-qPCR, and correlation to protein abundance was validated by immunohistochemical staining. Endometrial samples were analyzed by visual and computer-assisted evaluation of stained antigens via QuPath. For PGR, effects of the perfusion and cycle stage on expression were found (P < 0.05), while ESR1 was affected only by cycle stage (P < 0.05) and OXTR was unaffected by perfusion and cycle stage. MKI67 was lower after 360 min of perfusion as compared to samples collected before perfusion (P < 0.05). For CASP3, differences in gene expression were found after transport and samples taken after 240 min (P < 0.05). Immunohistochemical staining revealed effects of perfusion on stromal and glandular cells for steroid hormone receptors, but not for Ki-67 and active Caspase 3. OXTR was visualized in all layers of the endometrium and was unaffected by perfusion. Comparison of QuPath and visual analysis resulted in similar results. For most cell types and stained antigens, the correlation coefficient was r > 0.5. In conclusion, the isolated hemoperfused model of the equine uterus was successfully validated at the molecular level, demonstrating stability of key marker gene expression. The utility of computer-assisted immunohistochemical analysis of equine endometrial samples was also confirmed.

Assessment of Haematological, Biochemical and Hormonal Changes in Mehsana buffaloes with Postpartum True Anestrus following Herbal Heat Inducer Treatment

The present study was designed to explore the effects of a new Herbal heat inducer in Mehsana buffaloes with postpartum true anestrus and consecutive changes in Blood haematological, Biochemical and Hormonal profile. All the buffaloes were orally supplemented with Herbal heat inducer mixture on (Jantana powder-10gm) 1st, (Metrali powder-20gm) 2nd and (Hitali-powder-500mg) 5th day for augmentation of oestrus. Out of total treated animals 10 animals expressed the signs of estrus within 30 days. Post-treatment analysis of the overall blood packed cell volume percent in conceiving buffaloes had a significant (p≤0.05) elevate. Overall blood plasma total cholesterol concentration (mg/dl) was found to be significantly (p≤0.001) elevated in all treated and both conceiving and non-conceiving buffaloes, respectively. Overall blood plasma progesterone concentration (ng/ml) was found to be significantly (p≤0.0001) and (p≤0.001) elevated in all treated and both conceived and non-conceived buffaloes, which indicate the positive favourable effect of all the drugs on postpartum true anestrus condition. However, Overall blood plasma tri-iodothyronine concentration (ng/ml) was found to be significantly (p≤0.001) and (p≤0.01) elevated in all treated and all conceived buffaloes. Findings of the present study revealed that strategic use of Indigenous herbal heat inducer in feed mixture may resolve the postpartum true anestrus problems in buffaloes.

18 Progesterone and insulin concentrations during pregnancy in slick and wild type-haired Holstein cows

Abstract In cattle, the presence of the SLICK gene has been associated with shorter calving intervals when exposed to tropical climates. However, the effects this genotype may have in terms of circulating hormones during pregnancy have not been reported. Therefore, the current study aimed to determine if reproductive hormones concentrations differ during the gestation between slick (SH) and wild type-haired (WT) cattle. Holstein heifers were estrus synchronized and inseminated during Winter (December) and Summer (June). A total of 13 SH and 8 WT Holstein heifers became pregnant and are included in the current study. Beginning on the day of insemination (d 0), blood samples were collected every 28 d. Commercially available ELISA kits were used to determine the plasma concentrations of bovine progesterone and insulin. The effects of hair coat genotype, season, day of pregnancy, and the respective interactions were tested by PROC Mixed in SAS. Day of pregnancy was utilized as a repeated measure for each animal. A significant season x day of pregnancy interaction (P &amp;lt; 0.001) was observed for the plasma concentrations of progesterone. On gestational d 0, 28 and 56, progesterone concentrations were greater for heifers inseminated during the Winter (7.11 ± 0.50, 5.31 ± 0.51, 5.39 ± 0.49 ng/mL, for d 0, 28 and 56 of pregnancy, respectively) when compared with those inseminated during the Summer (3.04 ± 0.45, 3.17 ± 0.45, 3.21 ± 0.45 ng/mL, for d 0, 28 and 56 of pregnancy, respectively). For insulin, also a significant interaction of season x day of pregnancy was observed (P = 0.004). On d 112 of pregnancy, the concentrations of insulin were greater for heifers inseminated during Winter (0.337 ± 0.03 ng/mL) when compared with those inseminated during Summer (0.082 ± 0.08 ng/mL). No other significant interactions were observed. Neither differences in progesterone (P = 0.70; 3.7 ± 0.33 and 3.9 ± 0.25 ng/mL, for WT and SH, respectively) nor insulin (P = 0.46; 0.20 ± 0.02 and 0.18 ± 0.01 ng/mL, for WT and SH, respectively) were observed between genotypes. Further research comparing other hormones during pregnancy may provide useful information between genotypes that may help to explain the better reproductive performance of SH dairy cows.

130 Effect of an appeasing substance application on growth, stress, handling quality and reproduction of Bos indicus beef heifers synchronized to fixed-time AI

Abstract This experiment evaluated the effects of an analogue of bovine appeasing substance (BAS) on growth, stress, handling quality, and reproduction of Nellore heifers. Twenty-nine heifers [body condition score (BCS) = 4.84 ± 0.13; body weight (BW) = 371 ± 0.77 kg; 23 ± 2 months of age)] were assigned to 1 of 2 treatments: 1) Saline solution (0.9 NaCl; n = 14) or BAS (Secure Cattle, IRSEA Group, Quartier Salignan, France; n = 15). Both solutions were applied topically in the nuchal skin area (5 mL/heifers) at the beginning (d -9) of the fixed-time artificial insemination protocol (FTAI). Heifers were allocated in two different pastures according to the treatment (one pasture per treatment) for 15 d (time of action of BAS) and then combined in a single group (both treatments in the same pasture). Heifers were inseminated on d 0, and BW and BCS were collected on d -9 and 40. The temperament in the squeeze chute (entry and exit scores; scale 1 – 3; chute score; scale 1 – 5; greater values mean more reactive heifers) and blood samples were collected on d -9, 0, 7, 14 and 30. The percentual of aggression, accident, and dirtiness in the perineal region were evaluated on d 0 along with time to inseminate, estrus expression scores (scale 1 – 3; 1 = no expression, 2 = low expression, 3 = greater expression), and dominant follicle size. The corpus luteum size was measured on d 7 and 14, and the pregnancy and embryo size on d 40. The BAS vs. Saline-treated heifers tended to have greater BW change (23.6 vs. 20.8 ± 1.03 kg; P = 0.09) and had greater BCS change (0.05 vs. -0.21 ± 0.05; P &amp;lt; 0.01). The BAS vs. Saline-treated heifers tended to have lesser entry scores (1.42 vs. 1.67 ± 0.09; P = 0.09) and percentual of dirtiness in the perineal region (48.3 vs. 71.1 ± 8.67 %; P = 0.06), and no effects of treatment were detected (P ≥ 0.39) for chute score, exit score, aggression, accident and time to inseminate. The BAS vs. Saline-treated heifers had greater estrus scores (2.00 vs. 1.27 ± 0.21; P = 0.03), and no effects were detected (P ≥ 0.11) for ovarian variables, pregnancy rate, and conceptus size. Furthermore, no treatment effects were detected (P ≥ 0.25) for serum concentration of cortisol and plasma concentration of haptoglobin, ceruloplasmin, and progesterone. Therefore, BAS application at the beginning of the FTAI protocol could decrease the temperament and dirtiness in the perineal region and increase the growth and estrus expression of beef heifers.

Effects of repeated embryo flushing without PGF2α administration on luteal function, percentage of unwanted pregnancy and subsequent fertility in mares.

PGF2α is commonly given at the end of embryo flushing (EF) to shorten the interval to the next oestrus and ovulation. To determine the effect of repeated EF on plasma progesterone concentration, percentage of mares with endometritis, unwanted pregnancy and subsequent fertility in mares flushed without the use of PGF2α . Controlled experiments. Nine mares were inseminated in seven consecutive cycles (n = 63), to either perform an EF (n = 54) 7-9 days after ovulation or left pregnant (n = 9). PGF2α was not used to induce oestrus. Ultrasound examination and blood sampling were performed just before the EF and 72 h later to determine changes in progesterone concentration and signs of endometritis. The overall percentage of positive EF/pregnancy was 55.5% (30/54) and 66.7% (6/9), respectively. The likelihood of pregnancy/positive EF in the first three cycles was 55.5% (15/29). This was not different (p > 0.1) from the fertility of the last four cycles (69.4%, 25/36). In five EF cycles (9.3%), mares had signs of endometritis and early luteolysis (progesterone <2 ng/mL) 72 h after EF. The reduction in progesterone concentration by 72 h after EF was greater (p < 0.05) for Day 9 (-2.3 ± 0.7 ng/mL) than Day 7 (-1.0 ± 0.8 ng/mL) or Day 8 (-1.3 ± 1.1 ng/mL) cycles. The progesterone concentration in non-flushed mares did not vary significantly during the sampled period (Day 7-12). There were 5 cycles in which the donor mare remained pregnant after the EF, although four were from a single mare. The mare population was limited to barren and maiden mares. The cycle order and operator allocation to each EF were not randomised. EF induces a subtle, but significant reduction in progesterone concentrations compared with non-EF cycles. However, the percentage of mares with EF-induced full luteolysis is low (9.3%). The fertility of mares after repeated EF without administration of PGF2α was unaffected; however, there is a considerable risk of unwanted pregnancy (5/27 = 18.5%) in donors from which an embryo was not recovered.

Sex-steroid hormones and risk of postmenopausal estrogen receptor-positive breast cancer: a case-cohort analysis.

Sex-steroid hormones are associated with postmenopausal breast cancer but potential confounding from other biological pathways is rarely considered. We estimated risk ratios for sex-steroid hormone biomarkers in relation to postmenopausal estrogen receptor (ER)-positive breast cancer, while accounting for biomarkers from insulin/insulin-like growth factor-signaling and inflammatory pathways. This analysis included 1208 women from a case-cohort study of postmenopausal breast cancer within the Melbourne Collaborative Cohort Study. Weighted Poisson regression with a robust variance estimator was used to estimate risk ratios (RRs) and 95% confidence intervals (CIs) of postmenopausal ER-positive breast cancer, per doubling plasma concentration of progesterone, estrogens, androgens, and sex-hormone binding globulin (SHBG). Analyses included sociodemographic and lifestyle confounders, and other biomarkers identified as potential confounders. Increased risks of postmenopausal ER-positive breast cancer were observed per doubling plasma concentration of progesterone (RR: 1.22, 95% CI 1.03 to 1.44), androstenedione (RR 1.20, 95% CI 0.99 to 1.45), dehydroepiandrosterone (RR: 1.15, 95% CI 1.00 to 1.34), total testosterone (RR: 1.11, 95% CI 0.96 to 1.29), free testosterone (RR: 1.12, 95% CI 0.98 to 1.28), estrone (RR 1.21, 95% CI 0.99 to 1.48), total estradiol (RR 1.19, 95% CI 1.02 to 1.39) and free estradiol (RR 1.22, 95% CI 1.05 to 1.41). A possible decreased risk was observed for SHBG (RR 0.83, 95% CI 0.66 to 1.05). Progesterone, estrogens and androgens likely increase postmenopausal ER-positive breast cancer risk, whereas SHBG may decrease risk. These findings strengthen the causal evidence surrounding the sex-hormone-driven nature of postmenopausal breast cancer.

Circulating endogenous sex steroids and risk of differentiated thyroid carcinoma in men and women.

Thyroid cancer (TC) is substantially more common in women than in men, pointing to a possible role of sex steroid hormones. We investigated the association between circulating sex steroid hormones, sex hormone binding globulin (SHBG) and the risk of differentiated TC in men and women within the European Prospective Investigation into Cancer and nutrition (EPIC) cohort. During follow-up, we identified 333 first primary incident cases of differentiated TC (152 in pre/peri-menopausal women, 111 in post-menopausal women, and 70 in men) and 706 cancer-free controls. Women taking exogenous hormones at blood donation were excluded. Plasma concentrations of testosterone, androstenedione, dehydroepiandrosterone, estradiol, estrone and progesterone (in pre-menopausal women only) were performed using liquid chromatography/mass spectrometry method. SHBG concentrations were measured by immunoassay. Odds ratios (ORs) were estimated using conditional logistic regression models adjusted for possible confounders. No significant associations were observed in men and postmenopausal women, while a borderline significant increase in differentiated TC risk was observed with increasing testosterone (adjusted OR T3 vs T1: 1.68, 95% CI: 0.96-2.92, ptrend = .06) and androstenedione concentrations in pre/perimenopausal women (adjusted OR T3 vs T1: 1.78, 95% CI: 0.96-3.30, ptrend = .06, respectively). A borderline decrease in risk was observed for the highest progesterone/estradiol ratio (adjusted OR T3 vs T1: 0.54, 95% CI: 0.28-1.05, ptrend = .07). Overall, our results do not support a major role of circulating sex steroids in the etiology of differentiated TC in post-menopausal women and men but may suggest an involvement of altered sex steroid production in pre-menopausal women.

Lactation body condition loss impaired conceptus development and plasma progesterone concentration at day 8 post-ovulation in primiparous sows

The current study investigated effects of dietary amino acid (AA) availability on lactational body condition loss and metabolic status, in relation to reproductive parameters after weaning up to Day 8 post-ovulation. Primiparous sows (n = 35) were allocated to one of two lactation diets containing either low crude protein (CP, 140 g/kg) with a low percentage (8%) of slow protein in total protein (LL, n = 18) or high CP (180 g/kg) with a high (16%) percentage of slow protein (HH, n = 17). The HH diet was expected to improve AA utilization by supplying more AA, in a more gradual fashion. The diets did not affect sow body condition loss during lactation, while the HH diet tended to increase litter weight gain during the week 3 of lactation (Δ = 1.3 kg, P = 0.09). On Day 14 post-farrowing, HH diet led to higher plasma urea both pre-feeding and post-feeding (Δ = 2.3 mmol/L, P < 0.01, Δ = 2.4 mmol/L, P < 0.01, respectively), whilst plasma creatinine, NEFA and IGF-1 were similar. No dietary effects on reproductive parameters were found, however several relationships were found between body condition and reproductive parameters. Sows with higher body weight on Day 1 or Day 21 post-farrowing had greater follicle size on Day 3 post-weaning (β = 0.03 mm/kg, P < 0.01, β = 0.04 mm/kg, P < 0.01, respectively). At Day 8 post-ovulation, plasma progesterone concentration was negatively related to loin muscle loss (β = −0.67 ng/ml · mm−1, P = 0.02), backfat loss (β = −2.33 ng/ml · mm−1, P = 0.02), and estimated body fat loss (β = −0.67 ng/ml · mm−1, P = 0.02). Both plasma progesterone and the number of corpora lutea were positively related to the energy balance during lactation (β = 0.03 ng/ml · ME MJ−1, P = 0.01, β = 0.01 CL/ME MJ, P = 0.02, respectively). The conceptus size at Day 8 post-ovulation was negatively related to body weight loss (β = −0.01 mm/kg, P = 0.01), estimated body fat loss (β = −0.02 mm/kg, P = 0.03) and estimated body protein loss (β = −0.06 mm/kg, P = 0.04), and was positively related to the energy balance during lactation (β = 5.2*10−4 mm/ME MJ, P = 0.01). In conclusion, body protein and fat losses during lactation reduced subsequent plasma progesterone concentration and conceptus development at Day 8 post-ovulation.

Equine chorionic gonadotropin treatment and timed artificial insemination for dairy cow production under heat stress.

This study investigated the effects of timed artificial insemination (TAI) and equine chorionic gonadotropin (eCG) administration on lactating dairy cows under heat-stress conditions (average temperature-humidity index: 80). Timed artificial insemination was performed on the cows with (n = 57) or without (control, n = 41) supplementation with 500 IU of eCG at the day of PGF2α treatment using the CIDR-Ovsynch protocol. GnRH was administered, and a progesterone device (CIDR) was inserted on Day -10 of the treatment protocol. The CIDR was removed on Day -3, and the cows were treated with PGF2α. Two days later, a 2nd GnRH injection was administered. Subsequently, AI was performed on Day 0 (16-20 h after the 2nd GnRH injection), and pregnancy was diagnosed on Days 32 and 60. Plasma progesterone (P4) concentrations were measured after AI. Results showed that the eCG group had a higher pregnancy per AI (P/AI) than the control group (43.9 vs. 12.2%, P = 0.002), which was also accompanied by elevated P4 levels. Four cows in the eCG group had multiple calves, representing 7.0 and 16.0% of the group and pregnant cows, respectively. In conclusion, 500 IU of eCG combined with CIDR-Ovsynch in lactating dairy cows under severe heat stress conditions successfully improved fertility. However, the protocol may have a slight risk of multiple births.

Effect of Self Made Intravaginal Progesterone Sponge on Fertility in Goat

Comparative studies of intravaginal sponges containing three different doses of progesterone on estrous synchronization; fertility, fecundity and prolificacy of synchronized does by natural mating were conducted during the breeding season at Central Sheep Breeding Farm, Hisar. A total of 60 Beetal does selected randomly and divided into group I, II and III with 20 does in each, and subsequently intravaginal sponges containing 50, 100 and 150 mg P4 were inserted respectively for 14 days and an i/m injection of PMSG (@200IU/doe) was injected just after sponge removal in each doe. Effective number of animals remained 55 as 5 does dropped their sponges. Forty eight to sixty hrs after sponge removal, 14, 16 and 15 does from group I, group II and group III respectively were synchronized to estrus and subsequently hand mated individually with bucks of proven fertility. The fertility, fecundity and prolificacy per cent after synchronization of oestrus in group I, group II and group III was 78.57, 87.50 and 86.66; 128.57, 156.25 and 166.66; 163.63, 178.57 and 192.30 respectively. Eighteen animals (6 does from each group) selected randomly out of 60 animals for progesterone estimation. Blood samples were collected immediately before insertion of intravaginal sponges (day 0) and then subsequently on day 7, 14 after sponge insertion and 48 and 72 hrs after sponge removal. Progesterone concentration was above basal level in most of animals on day 0 in all the groups. Increase in plasma progesterone concentration (with in group) was recorded on day 7 and decreased on day 14 &amp; 48 hrs after sponge removal. These changes were significant in group II &amp; III while non-significant in group I. Progesterone concentration decreased non-significantly 72 hours after sponge removal in all the three groups. Significant difference in plasma P4 concentration was reported in between group I and group II &amp; III on day 7 &amp; 14.

EFFECT OF GONADOTROPHIN RELEASING HORMONE ON FOLLICULAR DYNAMICS, LUTEINISING HORMONE, AND PROGESTERONE LEVELS IN BUNAJI COWS

This study evaluated the ovarian and hormonal responses of Bunaji cows to ovsynch protocol initiated at random oestrus cycle stages. Fifteen animals were arranged into three groups and treated as follows: control (n=5), 2mL normal saline; group A (n=5), 50mg Gonadotrophin releasing hormone (GnRH) on day 0 and day 9 followed by 500mg of Prostaglandin F2 alpha (PGF2a) on day 7; and group B (n=5) 100mg of GnRH on day 0 and day 9 followed by 500mg PGF2a on day 7. Ultrasound examination of the ovaries was carried out daily from d 1 to d 9 and, thereafter every 12h until ovulation was detected. Blood sampling was carried out at 30 min intervals for 6 h following the GnRH administration for determination of serum luteinizing hormone (LH) and once daily for 12 days after the injection of the first GnRH to determine plasma progesterone concentration. The ovarian response of the treated groups showed no significant difference between the two dosages of ovsynch protocol but differed significantly between the treated and the control groups. Peak values of serum LH obtained on day 0 and day 9 of GnRH administration differed significantly (P&lt;0.05). Plasma progesterone increased among treated groups following injection of GnRH reaching a peak on day 7 compared to control, but did not differ among treated groups. In conclusion, GnRH at 50 mg and 100 mg was able to elicit adequate LH and progesterone responses that caused the disappearance of dominant follicles and, subsequent ovulation thereby increasing the reproductive efficiency of Bunaji cows.

Genome-wide association study of age at puberty and its (co)variances with fertility and stature in growing and lactating Holstein-Friesian dairy cattle

Reproductive performance is a key determinant of cow longevity in a pasture-based, seasonal dairy system. Unfortunately, direct fertility phenotypes such as inter-calving interval or pregnancy rate tend to have low heritabilities and occur relatively late in an animal's life. In contrast, age at puberty (AGEP) is a moderately heritable, early-in-life trait, that may be estimated using an animal's age at first measured elevation in blood plasma progesterone (AGEP4) concentrations. Understanding the genetic architecture of AGEP4 in addition to genetic relationships between AGEP4 and fertility traits in lactating cows is important, as is its relationship with body size in the growing animal. Thus, the objectives of this research were 3-fold. First, to estimate the genetic and phenotypic (co)variances between AGEP4 and subsequent fertility during first and second lactations. Second, to quantify the associations between AGEP4 and height, length, and body weight (BW) measured when animals were around 11 mo old (SD = 0.5). Third, to identify genomic regions that are likely to be associated with variation in AGEP4. We measured AGEP4, height, length, and BW in around 5,000 Holstein-Friesian or Holstein-Friesian x Jersey crossbred yearling heifers, across 54 pasture-based herds managed in seasonal calving farm systems. We also obtained calving rate (CR42: success or failure to calve within the first 42 d of the seasonal calving period), breeding rate (PB21: success or failure to be presented for breeding within the first 21 d of the seasonal breeding period) and pregnancy rate (PR42: success or failure to become pregnant within the first 42 d of the seasonal breeding period) phenotypes from their first and second lactations. The animals were genotyped using the Weatherby's Versa 50K SNP array (Illumina, USA). The estimated heritabilities of AGEP4, height, length, and BW were 0.34 (0.30, 0.37), 0.28 (0.25, 0.31), 0.21 (0.18, 0.23), and 0.33 (0.30, 0.36), respectively. In contrast, the heritabilities of CR42, PB21 and PR42 were all < 0.05 in both first and second lactations. The genetic correlations between AGEP4 and these fertility traits were generally moderate ranging from 0.11 to 0.60, whereas genetic correlations between AGEP4 and yearling body conformation traits ranged from 0.02 to 0.28. Our genome wide association study (GWAS) highlighted a genomic window on chromosome 5 that was strongly associated with variation in AGEP4. We also identified 4 regions, located on chromosomes 14, 6, 1 and 11 (in order of decreasing importance), that exhibited suggestive associations with AGEP4. Our results show that AGEP4 is a reasonable predictor of estimated breeding values (EBVs) for fertility traits in lactating cows. While the GWAS provided insights into genetic mechanisms underpinning AGEP4, further work is required to test genomic predictions of fertility that use this information.

Oral dydrogesterone versus micronized vaginal progesterone for luteal phase support: a double-blind crossover study investigating pharmacokinetics and impact on the endometrium.

Oral dydrogesterone versus micronized vaginal progesterone for luteal phase support: a double-blind crossover study investigating pharmacokinetics and impact on the endometrium.

Hormone secretion in serum of bactrian camels during breeding and nonbreeding seasons: Insights into reproductive physiology

To enhance Bactrian camel population through reproductive technologies, 12 female camels (FC) aged 8-12 years underwent reproductive experiments involving synchronized estrus, superovulation, and artificial insemination. Using the enzyme-linked immunosorbent assay (ELISA), we examined the secretion patterns of follicle-stimulating hormone (FSH), luteinizing hormone (LH), estrogen (E2), and progesterone (PROG) in reproductive and non-reproductive seasons of FC. Exogenous hormones GnRH+GnRH, GnRH+PGF2α, and PMSG were given to synchronize estrus in FC. Comparing peak times and secretion levels of reproductive hormones determined the optimal protocol for synchronized estrus. The study found a positive correlation between FSH and LH secretion in FC, with LH higher. Female camels exhibited an increase in E2 secretion during the transition from non-reproductive to reproductive seasons. Conversely, the concentration of PROG in plasma was higher during the Non-reproductive season compared to the reproductive season. A positive correlation was observed between E2 and PROG levels in FC during reproductive and non-reproductive seasons. Exogenous hormones induce LH and E2 peaks in 2-4 hours and 2-8 hours, respectively, for synchronized estrus. The GnRH+PGF2α hormone superior for estrus synchronization. Our study reveals distinct hormone secretion patterns in female camels during reproductive and non-reproductive seasons. Our findings have significant implications for novel breeding technologies.

37 Precision Feeding of Prolific Sheep in Highly Productive Management Systems

Abstract Globally lamb production is constrained by seasonal reproduction and flock productivity. There is potential to reduce both with improved reproductive and nutritional management in systems with a reduced interbirth interval. These accelerated systems can improve productivity &amp;gt;2 times compared with conventional systems. Successful adoption of these systems has been hampered; however, by low and variable reproductive efficiency during the suboptimal breeding period (February to July). We designed a series of studies to address this problem using an 8-month birth interval system with Polled Dorset x Polypay ewes without the use of exogenous hormone or photoperiod therapies. In study 1, we examined prebreeding nutrition combined with the male effect on reproductive outcomes in both long (April/May) and short-day (Dec./Jan.) breeding seasons. Ewes were randomly allocated to one of 3 nutritional treatments after weaning during a 21-day prebreeding period: 50%, 100% or 200% of maintenance energy intake. Ewes were exposed to vasectomized rams the last 14 days of treatment followed immediately with fertile rams for a 34-day breeding period (22 to 27 ewes per vasectomized or fertile ram). Both litter size (1.60 short vs. 1.34 long) and conception (96% short vs. 86% long) were greater in the short season (P &amp;lt; 0.001). Nutrition did not impact conception in either season; however, litter size was increased 15% in long and 25% in short day breeding season in ewes fed 200% compared the other treatments. These results suggest that litter size can be improved in these systems regardless of season by elevating energy intake above current recommendations. In study 2, we examined the impact of energy status during 2 preconception periods: lactation (last 30 days of previous lactation) and flushing (21 days pre-breeding plus 34-day breeding period). During lactation ewes received either 70% (L), 100% (C), and 150% (H) of energy requirements according to litter size. During flushing, ewes received 70%, 100% and 160% of maintenance energy with reproductive management as for study 1. Blood samples collected every 3 to 4 days were analyzed for plasma progesterone concentration via radioimmunoassay. Season had a great impact on return to estrus with 18% of ewes exhibiting luteal phases before teaser ram introduction during long as compared with 99% during short-day season. Nutrition during lactation also impacted return to estrus but only in long days with 40% of ewes on the H diet exhibiting luteal phases compared with 14% on the L diet before teaser ram introduction. Collectively, this indicates that an increased rate on conception is possible without the use of exogenous hormones or photoperiod manipulation in accelerated systems. Furthermore, a high plane of preconception nutrition improves litter size regardless of season and may hasten return to estrus during the suboptimal breeding period.

MX2 gene mRNA expression as potential biomarker for early pregnancy diagnosis in cattle

Early pregnancy diagnosis is vital for economic sustainability of dairy farms and maintaining the reproductive efficiency of the herd. There are many techniques including progesterone assay, pregnancy specific proteins and interferon stimulated genes have been explored for early pregnancy diagnosis but, they are associated with varying level of efficacy. In the present experiment, interferon stimulated gene (Myxovirus resistance gene 2/MX2) expression pattern was used as a potential biomarker for early pregnancy in cattle. The association of MX2 gene expression in relation to progesterone assay was studied to explore its potential use as biomarker of early pregnancy. The plasma progesterone concentration in conceived animals on day 7 (2.26±0.19 ng/ml), 17 (5.42±0.35 ng/ml) and 21(6.38±0.39 ng/ml) was recorded to be significantly higher as compared to respective values in non-conceived animals, i.e. 1.55±0.09 ng/ml, 4.14±0.14 ng/ml and 0.81±0.06 ng/ml. The sudden decrement in plasma progesterone concentration after day 17th discriminates conceived and non-conceived animals. MX2 expression levels were observed to spike in blood due to release of interferon tau (τ) after implantation of embryo. The relative mRNA expression of MX2 gene showed a 9.5 to 28.64-fold higher expression on 17 days post insemination in pregnant animals as compared to non-pregnant animals. Thus, MX2 gene can be used as a reliable biomarker for the early detection of pregnancy.

Effects of 17β-estradiol on the uterine luteolytic cascade in bovine females at the end of diestrus

In cattle, 17β-estradiol (E2) is essential for triggering luteolysis via the synthesis of prostaglandin F2α (PGF2α). We aimed to evaluate the effects of E2-treatment on day 15 of the estrous cycle on the transcript abundance of genes involved in the PGF2α synthetic cascade. Nelore heifers (N = 50) were subjected to a hormonal protocol for the synchronization of ovulation. Between days 14 and 23 after estrus, the area (cm2) and blood perfusion (%) of the corpus luteum (CL) and progesterone (P4) plasma concentrations were evaluated daily. On day 15, the heifers were assigned to the Control (2 mL of pure sesame oil, N = 21) or Estradiol group (1 mg of E2 diluted in 2 mL of sesame oil, N = 23). After the treatments at 0 h, uterine biopsies were collected at times 1.5 h (C1.5h, N = 8 and E1.5h, N = 10) or 3 h (C3h, N = 8 and E3h, N = 11); and blood samples were obtained from 0, 3, 4, 6 and 7 h for the measurement of 13,14-dihydro-15-keto-PGF2α (PGFM) concentrations by ELISA. Transcript abundance was determined by RT-qPCR and protein abundance of ESRβ and OXTR was determined by Western Blotting. The Estradiol group showed greater (P < 0.05) concentrations of PGFM at 6 and 7 h compared to the Control group. A progressive decrease in plasma P4 concentrations characterized a hastened functional luteolysis, followed by structural luteolysis in the Estradiol group (P < 0.05). Among the treatment groups, no significant difference was detected for the abundance of PRKCα, PRKCβ, AKR1B1, PTGS2 and ESRα transcripts (P > 0.05). Estradiol treatment decreased the abundance of PLA2G4A, AKR1C4, and ESRβ both 1.5h and 3h after treatment (P < 0.05). The relative expression of PGR and OXTR was greater in E3h compared to the C3h (P > 0.05). Protein abundance did not differ between treatment groups at either experimental times (P > 0.05). Overall, E2 promoted an increase in PGFM concentrations and the hastening of functional and structural luteolysis in Nelore heifers through the upregulation of PGR and OXTR, demonstrating for the first time that the expression of these receptors within 3 h after E2 stimulus was associated with triggering luteolysis in cattle.

Comparison of Gonadotropin-Releasing Hormone versus Estrogen-Based Fixed-Time Artificial Insemination Protocols in Grazing Bos taurus Suckled Beef Cows.

Fixed-timed artificial insemination (FTAI) protocols for beef cattle in South America are primarily based on estradiol esters and intravaginal progesterone-releasing devices (IVPD). The objective of this study was to determine the optimal gonadotropin-releasing hormone (GnRH)-based protocol as an alternative to the use of estrogen-based protocols in grazing Bos taurus suckling beef cows. All cows received an IVPD on the day of protocol initiation and prostaglandin F2α (PG) plus equine chorionic gonadotropin (eCG) treatments at the time of IVPD removal. In Experiment 1, cows (n = 235) were randomly assigned to one of four treatments: (i) 7-day estradiol = 2 mg of estradiol benzoate (EB) at IVPD insertion on Day 9 and 1 mg of estradiol cypionate (ECP) at IVPD removal on Day 2; (ii) 7-day GnRH = 10 µg of GnRH at IVPD insertion on Day 10, IVPD removal on Day 3 and GnRH at FTAI; (iii) 7 & 7 estradiol = PG at IVPD insertion on Day 16, EB on Day 9 and ECP at IVPD removal on Day 2; (iv) 7 & 7 GnRH = PG at IVPD insertion on Day 17, GnRH on Day 10, IVPD removal on Day 3 and GnRH at FTAI. In Experiment 2, cows (n = 462) were randomly assigned to one of four treatments: (i) 6-day estradiol = EB at IVPD insertion on Day 9, IVPD removal on Day 3 and GnRH at FTAI; (ii) 7-day estradiol; (iii) 7-day GnRH; (iv) 7 & 7 GnRH. In Experiment 1, plasma progesterone concentrations and percentage of cows with a corpus luteum (CL) at IVPD removal, and pregnancy per AI (P/AI) were greater for cows subjected to GnRH-based protocols compared with cows subjected to estrogen-based protocols (p < 0.01). In Experiment 2, cows subjected to the 7 & 7 GnRH protocol had the greatest P/AI (p < 0.01). In summary, GnRH-based FTAI protocols resulted in similar or greater P/AI compared to estrogen-based FTAI protocols in grazing postpartum Bos taurus suckled beef cows. The greatest P/AI was attained with the 7 & 7 GnRH protocol.

Abundance of Anti-Muellerian hormone in cat ovaries and correlation of its plasma concentration with animal age, weight and stage of the estrous cycle

In female animals of different species, Anti-Müllerian hormone (AMH) is produced by follicular granulosa cells and has been associated with the ovarian follicle pool. Because concentration of AMH in plasma of ovary-intact female cats is apparently more variable than previously assumed, we have analysed AMH concentration in blood of cats (n = 93) presented for routine ovariectomy and assessed ovarian histology and AMH protein expression in the surgically removed ovaries. We hypothesised that AMH is synthesized only in preantral and small antral follicles and that plasma AMH concentration reflects the antral follicle count (AFC). Corpora lutea were detected in 35% of the female cats, whereas plasma progesterone concentration was ≥1 ng/mL in 57% of the cats. Follicular cysts were present in 15 cats (16%). Positive immunostaining for AMH protein was detected in close to all primordial and antral follicles, ovarian cysts, 70% of corpora lutea and 28% of atretic follicles. Concentration of AMH in plasma averaged 6.8 ± 0.5 ng/mL (range 1.3–21.7 ng/mL). The AFC increased with increasing AMH concentration with a moderate positive correlation between AFC and AMH (r = 0.286, p < 0.01). Plasma AMH concentration was not affected by season or cats’ age, weight, stage of the estrous cycle and presence of follicular cysts. In conclusion, AMH protein is expressed in all endocrine structures of the cat ovary. While AMH is a marker for the presence of ovarian tissue, its usefulness to assess ovarian function in individual female cats is of limited value.