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Journal of Dairy Science Jul 2023This study aimed to determine the effect of 2 simple breeding strategies combining artificial insemination (AI) after detection of estrus (AIED) and timed AI (TAI) on...
Presynchronization with prostaglandin F and gonadotropin-releasing hormone simultaneously improved first-service pregnancy per artificial insemination in lactating Holstein cows compared with Presynch-14 when combined with detection of estrus.
This study aimed to determine the effect of 2 simple breeding strategies combining artificial insemination (AI) after detection of estrus (AIED) and timed AI (TAI) on first-service fertility in lactating Holstein cows. Weekly, lactating Holstein cows (n = l,049) between 40 and 46 d in milk (DIM) were randomly assigned to initiate 1 of 2 breeding strategies for first service: Presynch-14 and PG+G. Presynch-14 is a presynchronization strategy with 2 PGF treatments 14 d apart with the last PGF 14 d before the initiation of the Ovsynch protocol. Cows treated with PG+G receive a simpler presynchronization program that uses PGF and GnRH simultaneously 7 d before Ovsynch. In both treatments, cows detected in standing estrus by tail chalk at any time ≥55 DIM were inseminated, and treatment was discontinued (n = 525). Cows completing treatment received TAI from 78 to 84 DIM (n = 526). In a subgroup of cows that received TAI, blood was collected (n = 163) to assess circulating concentrations of progesterone, and ultrasonographic evaluations of ovaries were performed on the day of first GnRH of Ovsynch (n = 162) and PGF of Ovsynch (n = 122). The proportion of cows that received TAI was greater for PG+G compared with Presynch-14 (63.5 vs. 31.9%), which increased DIM at first service for cows treated with PG+G compared with Presynch-14 (75.5 ± 0.4 vs. 68.7 ± 0.4). For cows receiving TAI, the ovulatory response to first GnRH of Ovsynch (73.8 vs. 48.8%) and the proportion of cows with functional corpora lutea (92.6 vs. 73.1%) were greater for PG+G than Presynch-14. Cows treated with PG+G had greater overall pregnancy per AI (P/AI) 42 ± 7 d after AI (40.2 vs. 33.6%) and calving per AI (32.1 vs. 25.2%) than Presynch-14. For cows receiving AIED, treatment did not affect P/AI 42 ± 7 d after AI. However, for cows receiving TAI, PG+G increased P/AI compared with Presynch-14 (44.6 vs. 35.2%). Overall, cows receiving TAI had greater P/AI 42 ± 7 d after AI (42.5 vs. 31.5%) and calving per AI (34.1 vs. 23.7%) and decreased pregnancy loss (16.8 vs. 25.2%) than cows receiving AIED. In summary, PG+G increased the proportion of cows receiving TAI and the DIM at first service, P/AI, and calving per AI compared with Presynch-14 when both TAI programs were combined with AIED.
Topics: Pregnancy; Female; Cattle; Animals; Gonadotropin-Releasing Hormone; Lactation; Estrus Synchronization; Dinoprost; Estrus; Progesterone; Insemination, Artificial
PubMed: 37164866
DOI: 10.3168/jds.2022-22651 -
Journal of Dairy Science Jun 2023The objective of this observational study was to evaluate the association between increased physical activity at first artificial insemination (AI) and subsequent...
The objective of this observational study was to evaluate the association between increased physical activity at first artificial insemination (AI) and subsequent pregnancy per AI (P/AI) in lactating Holstein cows following spontaneous estrus or a timed AI (TAI) protocol. We also wanted to identify factors associated with the intensity of activity increase (PA) captured by automated activity monitors (AAM) and fertility. Two experiments were conducted, in which cows either were inseminated based on the alert of the AAM system (AAM cows) or received TAI following a 7-d Ovsynch protocol (TAI cows) if not inseminated within a farm-specific period after calving. Experiment 1 included 2,698 AI services from AAM cows and 1,042 AI services from TAI cows equipped with the Smarttag Neck (Nedap Livestock Management) from a dairy farm in Slovakia (farm 1). In the second experiment, 6,517 AI services from AAM cows and 1,226 AI services from TAI cows fitted with Heatime (Heatime Pro; SCR Engineers Ltd.) from 8 dairy farms in Germany (farms 2-9) were included. Pregnancy diagnosis was performed on a weekly basis by transrectal ultrasound (farms 1, 3, 7, 8) or by transrectal palpation (farms 2, 4-6, 9). Estrous intensity was represented by the peak value of the change in activity. In experiment 1, PA was categorized into low (x-factor 0-20) and high (x-factor 21-100) PA, and in experiment 2 into low (activity change = 35-89) and high (activity change = 90-100) PA. In TAI cows from both experiments, PA was additionally categorized into cows with no AAM alert. Data were analyzed separately for AAM and TAI cows using multinomial logistic regression models for PA in TAI cows and logistic regression models for PA in AAM cows and P/AI in both groups. In experiment 1, P/AI of AAM cows was greater for AI services performed with conventional frozen semen (57.6%) compared with sexed semen (47.2%), whereas type of semen only tended to be associated with P/AI in TAI cows (54.4% conventional frozen semen vs. 48.9% sexed semen). In experiment 2, P/AI was greater for fresh semen (AAM cows: 44.4% vs. TAI cows: 44.2%) compared with conventional frozen semen (AAM cows: 37.6% vs. TAI cows: 34.6%). In both experiments, pregnancy outcomes were associated with PA. In experiment 1, AAM cows with high PA (55.1%) had greater P/AI than cows with low PA (49.8%). Within TAI cows, cows with no alert (38.8%) had reduced P/AI compared with cows with low (54.2%) or high PA (61.8%). In experiment 2, AAM cows with high PA (45.8%) had greater P/AI compared with cows with low PA (36.4%). Timed AI cows with no alert (27.4%) had decreased P/AI compared with cows with low (41.1%) or high (50.8%) PA. The greatest risk factors for high PA were parity (experiment 1) and season of AI (except for TAI cows from experiment 1). We conclude that high PA at the time of AI is associated with greater odds of pregnancy for both AAM and TAI cows. In both experiments, about 2 thirds of AAM cows (experiment 1: 69.9% and experiment 2: 70.7%) reached high PA, whereas only approximately one-third or less of TAI cows (experiment 1: 37.3% and experiment 2: 23.6%) showed high PA. Although we observed similar results using 2 different AAM systems for the most part, risk factors for high PA might differ between farms and insemination type (i.e., AAM vs. TAI).
Topics: Animals; Cattle; Female; Pregnancy; Dinoprost; Estrus; Estrus Synchronization; Fertility; Gonadotropin-Releasing Hormone; Insemination, Artificial; Lactation; Progesterone
PubMed: 37164863
DOI: 10.3168/jds.2022-22057 -
Journal of Dairy Science Jul 2023Our objectives were to evaluate the effects of complete replacement of inorganic salts of trace minerals (STM) with organic trace minerals (OTM) in both pre- and...
Our objectives were to evaluate the effects of complete replacement of inorganic salts of trace minerals (STM) with organic trace minerals (OTM) in both pre- and postpartum diets on ovarian dynamics, estrous behavior measured by sensors, preimplantation conceptus development, and reproductive performance in dairy cows. Pregnant cows and heifers (n = 273) were blocked by parity and body condition score and randomly assigned to either STM or OTM diets at 45 ± 3 d before their expected calving. Pre- and postpartum diets were formulated to meet 100% of recommended levels of each trace mineral in both treatments, taking into consideration both basal and supplemental levels. The final target concentrations of Co, Cu, Mn, Se, and Zn were, respectively, 0.25, 13.7, 40.0, 0.3, and 40.0 mg/kg in the prepartum diet, and 0.25, 15.7, 40.0, 0.3, and 63.0 mg/kg in the postpartum diet. The STM group was supplemented with Co, Cu, Mn, and Zn sulfates and sodium selenite, while the OTM group was supplemented with Co, Cu, Mn, and Zn proteinates and selenized yeast. Treatments continued until 156 d in milk (DIM) and were assigned to individual cows using automatic feeding gates. Starting at 21 DIM, ultrasonography examinations of the ovaries were performed weekly to determine the presence of a corpus luteum and postpartum resumption of ovarian cyclicity. Cows were presynchronized with 2 injections of PGF at 42 and 56 DIM. Estrous behavior was monitored using electronic activity tags that indirectly measured walking activity. Cows detected in estrus after the second PGF were inseminated, and those not detected in estrus by 67 DIM were enrolled in a synchronization program. Cows that returned to estrus after artificial insemination (AI) were reinseminated. Pregnancy diagnosis was performed 33 d after AI, and nonpregnant cows were resynchronized. Transcript expression of interferon-stimulated genes in peripheral blood leukocytes was performed in a subgroup of cows (STM, n = 67; OTM, n = 73) on d 19 after AI. A different subgroup of cows (28 STM, 29 OTM) received uterine flushing 15 d after AI for recovery of conceptuses and uterine fluid for analyses of transcriptomics and metabolomics, respectively. In addition, dominant follicle diameter, luteal size and blood flow, and concentration of progesterone in plasma were measured on d 0, 7, and 15 relative to AI. After flushing, PGF was given and the dominant follicle was aspirated 2 d later to measure the concentration of trace minerals by mass spectrometry. Estrous behavior, size of the dominant follicle and corpus luteum, concentration of progesterone, time to pregnancy, and proportion of cows pregnant by 100 d of the breeding period did not differ between treatments. A greater proportion of cows supplemented with OTM had a corpus luteum detected before presynchronization (64.3 vs. 75.2%), and primiparous cows supplemented with OTM tended to resume cyclicity earlier than their STM counterparts. Cows supplemented with OTM had a greater concentration of Cu in follicular fluid than cows supplemented with STM (0.89 vs. 0.77 µg/mL, respectively). In pregnant multiparous cows, expression of receptor transporter protein 4 in peripheral blood leukocytes was 42% greater in the OTM group. Conceptuses of the 2 treatments had 589 differentially expressed transcripts, with many indicating advanced conceptus elongation and greater transcript expression of selenoproteins in the OTM group. In pregnant cows, 24 metabolites were more abundant in the uterine fluid of OTM, including spermidine, sucrose, and cholesterol. In conclusion, replacing STM with OTM caused modest improvements to resumption of ovarian cyclicity and important changes in preimplantation conceptus development, but it did not alter conception risk and pregnancy rate.
Topics: Pregnancy; Cattle; Animals; Female; Trace Elements; Progesterone; Lactation; Estrus Synchronization; Plant Breeding; Postpartum Period; Diet; Insemination, Artificial; Biology; Dinoprost; Gonadotropin-Releasing Hormone
PubMed: 37164845
DOI: 10.3168/jds.2022-22784 -
Journal of Animal Science Jan 2023This review discusses endocrine and functional changes during the transition from late gestation to lactation that are related to the production of colostrum in... (Review)
Review
This review discusses endocrine and functional changes during the transition from late gestation to lactation that are related to the production of colostrum in different mammalian species. Species covered in this article include ungulate species (cattle, sheep, goats, pigs, horses), rodents (rat, mouse), rabbits, and carnivores (cats, dogs), as well as humans. An immediate availability of high quality colostrum for the newborn after birth is crucial in species where a transfer of immunoglobulins (Ig) does not or only partially occur via the placenta during pregnancy. Declining activity of gestagens, in most species progesterone (P4), is crucial at the end of pregnancy to allow for the characteristic endocrine changes to initiate parturition and lactation, but the endocrine regulation of colostrogenesis is negligible. Both, the functional pathways and the timing of gestagen withdrawal differ considerably among mammalian species. In species with a sustaining corpus luteum throughout the entire pregnancy (cattle, goat, pig, cat, dog, rabbit, mouse, and rat), a prostaglandin F2α (PGF2α)-induced luteolysis shortly before parturition is assumed to be the key event to initiate parturition as well as lactogenesis. In species where the gestagen production is taken over by the placenta during the course of gestation (e.g., sheep, horse, and human), the reduction of gestagen activity is more complex, as PGF2α does not affect placental gestagen production. In sheep the steroid hormone synthesis is directed away from P4 towards estradiol-17β (E2) to achieve a low gestagen activity at high E2 concentrations. In humans the uterus becomes insensitive to P4, as parturition occurs despite still high P4 concentrations. However, lactogenesis is not completed as long as P4 concentration is high. Early colostrum and thus Ig intake for immune protection is not needed for the human newborn which allows a delayed onset of copious milk secretion for days until the placenta expulsion causes the P4 drop. Like humans, horses do not need low gestagen concentrations for successful parturition. However, newborn foals need immediate immune protection through Ig intake with colostrum. This requires the start of lactogenesis before parturition which is not fully clarified. The knowledge of the endocrine changes and related pathways to control the key events integrating the processes of colostrogenesis, parturition, and start of lactation are incomplete in many species.
Topics: Pregnancy; Female; Swine; Cattle; Humans; Rats; Horses; Animals; Rabbits; Sheep; Dogs; Mice; Progestins; Dinoprost; Placenta; Parturition; Colostrum; Progesterone; Rodentia
PubMed: 37158662
DOI: 10.1093/jas/skad146 -
International Journal of Molecular... Apr 2023Prostaglandin F2α (PGF2α), the first-line anti-glaucoma medication, can cause the deepening of the upper eyelid sulcus due to orbital lipoatrophy. However, the...
Prostaglandin F2α (PGF2α), the first-line anti-glaucoma medication, can cause the deepening of the upper eyelid sulcus due to orbital lipoatrophy. However, the pathogenesis of Graves' ophthalmopathy (GO) involves the excessive adipogenesis of the orbital tissues. The present study aimed to determine the therapeutic effects and underlying mechanisms of PGF2α on adipocyte differentiation. In this study primary cultures of orbital fibroblasts (OFs) from six patients with GO were established. Immunohistochemistry, immunofluorescence, and Western blotting (WB) were used to evaluated the expression of the F-prostanoid receptor (FPR) in the orbital adipose tissues and the OFs of GO patients. The OFs were induced to differentiate into adipocytes and treated with different incubation times and concentrations of PGF2α. The results of Oil red O staining showed that the number and size of the lipid droplets decreased with increasing concentrations of PGF2α and the reverse transcription-polymerase chain reaction (RT-PCR) and WB of the peroxisome proliferator-activated receptor γ (PPARγ) and fatty-acid-binding protein 4 (FABP4), both adipogenic markers, were significantly downregulated via PGF2α treatment. Additionally, we found the adipogenesis induction of OFs promoted ERK phosphorylation, whereas PGF2α further induced ERK phosphorylation. We used Ebopiprant (FPR antagonist) to interfere with PGF2α binding to the FPR and U0126, an Extracellular Signal-Regulated Kinase (ERK) inhibitor, to inhibit ERK phosphorylation. The results of Oil red O staining and expression of adipogenic markers showed that blocking the receptor binding or decreasing the phosphorylation state of the ERK both alleviate the inhibitory effect of PGF2a on the OFs adipogenesis. Overall, PGF2α mediated the inhibitory effect of the OFs adipogenesis through the hyperactivation of ERK phosphorylation via coupling with the FPR. Our study provides a further theoretical reference for the potential application of PGF2α in patients with GO.
Topics: Humans; Dinoprost; Adipogenesis; Extracellular Signal-Regulated MAP Kinases; Graves Ophthalmopathy; Fibroblasts; Cells, Cultured
PubMed: 37108173
DOI: 10.3390/ijms24087012 -
Journal of Dairy Science May 2023Increasing progesterone (P4) during early conceptus development may be crucial for establishment of pregnancy in dairy cattle. The objective of this study was to...
Increasing progesterone (P4) during early conceptus development may be crucial for establishment of pregnancy in dairy cattle. The objective of this study was to determine if human chorionic gonadotropin (hCG) at various times after ovulation will increase serum P4 during elongation and increase the chances for, and reduce variability to, initial increase in pregnancy-specific protein B (PSPB) following artificial insemination (AI). Time to PSPB increase was defined as the first day of increase in concentrations of PSPB between d 18 and 28 after ovulation in cows with ≥12.5% increases for 3 consecutive days compared with baseline. Lactating cows (n = 368) synchronized to Double-Ovsynch (first service) or Ovsynch (second or greater service) received one of 4 treatments: no hCG (control), or 3,000 IU of hCG on d 2 (D2), 2 and 5 (D2+5), or 5 (D5) after ovulation. All cows were examined via ultrasound on d 5 and 10 postovulation to determine percentage of cows with hCG-induced accessory CL (aCL) and to quantify and measure all luteal structures. Samples for serum P4 were collected on d 0, 5, 19, and 20 postovulation. The P4 was increased in D2, D2+5, and D5 groups compared with control. The D2+5 and D5 treatments increased aCL and P4 compared with D2 and control. The D2 treatment increased P4 on d 5 after ovulation compared with control. Serum PSPB samples were collected daily from all cows on d 18 through 28 after ovulation for determination of d of PSPB increase. Pregnancy diagnoses were performed via ultrasound examination on d 35, 63, and 100 after ovulation and AI. The D5 treatment reduced percentage of cows with, and increased the time to, PSPB increase. Primiparous cows with ipsilateral aCL had reduced pregnancy loss before d 100 postovulation compared with cows with contralateral aCL. Cows that had PSPB increase >21 d postovulation had 4× greater chances of pregnancy loss compared with cows that had PSPB increase on d 20 or 21. The highest quartile of P4 on d 5, but not on d 19 and 20, was associated with reduced time to PSPB increase. Time to PSPB increase appears to be an important measurement to understand reasons for pregnancy loss in lactating dairy cows. Increasing P4 utilizing hCG after ovulation did not enhance early pregnancy or reduce pregnancy losses in lactating dairy cows.
Topics: Pregnancy; Female; Humans; Cattle; Animals; Progesterone; Lactation; Estrus Synchronization; Chorionic Gonadotropin; Insemination, Artificial; Gonadotropin-Releasing Hormone; Dinoprost
PubMed: 37028965
DOI: 10.3168/jds.2022-22553 -
Journal of Biosciences 2022Iron overload can induce oxidative stress, thereby inducing cell peroxidation. Arachidonic acid (ARA) is widely expressed in mammalian cells and esterified to membrane...
Iron overload can induce oxidative stress, thereby inducing cell peroxidation. Arachidonic acid (ARA) is widely expressed in mammalian cells and esterified to membrane phospholipids. To explore the effect of iron overload on the metabolism of membrane phospholipids MES23.5 cells were treated with various concentrations of ferric ammonium citrate (FAC) to induce oxidative stress. Using UHPLC (I-Class LC, Waters) coupled to a QTRAP (AB Sciex 5500) technology, the contents of 13 substances of ARA and its metabolites were detected. When the cells were given two different concentrations of FAC, we found that both high and low concentrations decrease the expression of ARA (p=0.002, p=0.02) compared with the control group. ARA has three metabolic pathways: the COX pathway, LOX pathway and CYP450 pathway. Compared with the control group, the LTB4 content in the LOX pathway was decreased (p=0.10) after treatment with lowconcentration FAC, while the LTB4 content was increased in the high-concentration treatment group (p=0.06). However, the content of 12S-HETE (p=0.23, p=0.05) in the LOX metabolic pathway decreased with increase of FAC concentration. Similarly, the content of 15S-HETE also decreased with increase of FAC concentration (p=0.17, p=0.02). The other downstream metabolites of ARA, 9S-HODE (p=0.54, p=0.18) and 13S-HODE (p=0.81, p=0.13) were not significantly changed. The contents of thromboxane B2 (TXB2), leukotriene D4 (LTD4), prostaglandin E2 (PGE2), 8-iso-prostaglandin F2α (8-iso-PGF2α), prostaglandin F2α (PGF2α), 6-keto-PGF1α, and prostaglandin D2 (PGD2) were too low to be detected in MES23.5 cells. The above results indicate that oxidative stress caused by iron overload reduces the LOX metabolic pathway of ARA.
Topics: Animals; Arachidonic Acid; Dinoprost; Leukotriene B4; Oxidative Stress; Iron Overload; Phospholipids; Hydroxyeicosatetraenoic Acids; Mammals
PubMed: 36550694
DOI: No ID Found -
Experimental and Molecular Pathology Feb 202317-trifluoromethylphenyl trinor prostaglandin F (17-CFPTPGF) was reported recently to exhibit in vitro and in vivo anticancer activity. Based solely on the results of in...
17-trifluoromethylphenyl trinor prostaglandin F (17-CFPTPGF) was reported recently to exhibit in vitro and in vivo anticancer activity. Based solely on the results of in silico molecular docking, it was claimed that this compound is NK1 receptor (NK1R) antagonist and that its activity is through this receptor. In this contribution we show that 17-CFPTPGF is only a very weak NK1R ligand (IC > 200 μM). In connection with that we discuss the issue of this compound's molecular target. Finally, we briefly narrate on the proper use of molecular docking in biomedical research.
Topics: Dinoprost; Receptors, Neurokinin-1; Ligands; Molecular Docking Simulation
PubMed: 36526011
DOI: 10.1016/j.yexmp.2022.104849 -
Journal of Sports Science & Medicine Dec 2022Dysmenorrhea with high prevalence has been categorized as primary dysmenorrhea (PD) and secondary dysmenorrhea due to differences in pathogenesis. A significant number... (Randomized Controlled Trial)
Randomized Controlled Trial
The Sprint-Interval Exercise Using a Spinning Bike Improves Physical Fitness and Ameliorates Primary Dysmenorrhea Symptoms Through Hormone and Inflammation Modulations: A Randomized Controlled Trial.
Dysmenorrhea with high prevalence has been categorized as primary dysmenorrhea (PD) and secondary dysmenorrhea due to differences in pathogenesis. A significant number of reproductive females suffering from monthly menstruation have to deal with negative impacts on their quality of life, work/study productivity, activities, and social relationships. In addition to medical treatment, exercise has been recognized as a complementary and alternative strategy for disease prevention, alleviation, and rehabilitation. This study aimed to investigate the potential effects of exercise on the severity of primary dysmenorrhea, physiological modulation, and physical fitness. Participants consisted of university students who were enrolled in the study and divided into a non-PD (Control) and a PD group based on recruiting criteria, the latter being randomly assigned to either an untreated dysmenorrhea group or a dysmenorrhea group that underwent 10 weeks of high intensity interval training (HIIT) exercise (Dysmen and DysmenHIIT, respectively). The DysmenHIIT group used spinning bikes and the training intensity was validated by heart rate monitors and BORG rating of perceived exertion. Forms containing participant information (premenstrual symptoms, menstrual distress, and a Short Form McGill Pain Questionnaire) as well as physical fitness, biochemical variables, hormone and prostaglandin (PGE2 and PGF2α) levels were assessed before and after the exercise intervention. After intervention, premenstrual symptoms (anger, anxiety, depression, activity level, fatigue, etc.), menstrual distress symptoms (cramps, aches, swelling, etc.), and pain severity were shown to be significantly mitigated, possibly through hormone (estradiol, prolactin, progesterone, and cortisol) modulation. Furthermore, high-sensitivity C-reactive protein (HsCRP), PGE2 and PGF2α levels were also down-regulated, resulting in the amelioration of uterine contraction and inflammation. Participants' physical fitness, including cardiovascular endurance and explosive force, was significantly improved after HIIT. The 10-week HIIT spinning bike exercise used in this study could be employed as a potential and complementary treatment for PD symptoms alleviation and considered as part of an educational health plan for promoting women's health. However, the effects of HIIT utilizing different exercise methods and accounting for different age populations and secondary PD warrant further investigation.
Topics: Humans; Female; Dysmenorrhea; Bicycling; Quality of Life; Dinoprost; Dinoprostone; Physical Fitness; Hormones; Inflammation
PubMed: 36523895
DOI: 10.52082/jssm.2022.595 -
Journal of Dairy Science Feb 2023This study was designed to evaluate whether the utilization of a second PGF treatment at the end of an estradiol/progesterone (E2/P4)-based protocol with or without GnRH...
Effects of additional gonadotropin-releasing hormone and prostaglandin F treatment to an estradiol/progesterone-based embryo transfer protocol for recipient lactating dairy cows.
This study was designed to evaluate whether the utilization of a second PGF treatment at the end of an estradiol/progesterone (E2/P4)-based protocol with or without GnRH at the beginning of the protocol would improve pregnancy rates of lactating Holstein cows assigned to timed embryo transfer. A total of 501 lactating Holstein cows in 5 farms were enrolled in the experiment. Within farm, cows were blocked by parity and, within block, were assigned randomly to (1) insertion of an intravaginal P4 device (controlled internal drug-releasing device; CIDR) and estradiol benzoate on d -11, PGF on d -4, CIDR withdrawal and an injection of estradiol cypionate on d -2, and timed embryo transfer on d 7 (1-PGF; n = 164); (2) the same treatments as 1-PGF, but with PGF administered on d -4 and -2 (2-PGF; n = 171); and (3) 2-PGF with the addition of a GnRH treatment on d -11 (GnRH2-PGF; n = 166). Ovaries were scanned by transrectal ultrasonography on d -11, -4, and 7, and blood samples were collected on d -11, -4, 0, and 7 for P4 determination. Treatment comparisons were performed using contrasts. The proportion of cows with a new corpus luteum on d -4 was greater in GnRH2-PGF cows. Cows in 1-PGF had a greater P4 concentration on d 0 but lesser P4 on d 7 compared with cows in the other groups. Cows assigned to receive 2-PGF (2-PGF and GnRH2-PGF) had greater estrus expression, and a greater proportion of cows ovulated to estradiol cypionate. No further contrast effects were observed for follicle diameter, double ovulation rate, pregnancy per embryo transfer (P/ET) on d 32 and 60, or pregnancy loss. As P4 concentration on d -4 increased, P/ET on d 60 tended to increase. Cows with P4 ≥3.66 ng/mL on d -4 had greater P/ET on d 32 and 60 than those with P4 below that threshold. Regardless of treatment, cows with P4 concentration ≥3.66 ng/mL also had a greater pregnancy per synchronized protocol (P/SP) on d 60. Also, a P4 concentration on d -4 (low or high) × follicle diameter (continuous) interaction tendency was observed when evaluating P/ET. Although P/ET did not differ among cows with different follicles sizes with reduced P4 concentration on d -4 (<3.66 ng/mL), it increased in cows with larger follicles exposed to increased P4 concentration (≥3.66 ng/mL). When P4 on d 0 was evaluated, P/ET on d 32 and 60 was greater for cows with low (≤0.09 ng/mL) versus high (>0.21 ng/mL) P4; as P4 concentration on d 0 increased, P/ET linearly decreased. In summary, cows with increased P4 concentrations during growth of the ovulatory follicular wave had improved P/ET. Administering a second PGF dose reduced P4 concentration on d 0 and increased ovulatory response to the protocol, but no benefits were observed on P/ET or P/SP.
Topics: Pregnancy; Female; Cattle; Animals; Gonadotropin-Releasing Hormone; Progesterone; Lactation; Dinoprost; Estrus Synchronization; Estradiol; Ovulation; Embryo Transfer; Insemination, Artificial
PubMed: 36460499
DOI: 10.3168/jds.2022-22134