PGF2 Research Articles

The Effect of Prostaglandin F2 Analog Treatment on the Immunoexpression of Fibrosis-Associated Factors in Patients with Glaucoma Undergoing Deep Sclerotomy

Long-term use of topical prostaglandins might initiate chronic conjunctival inflammation, leading to poor outcomes of glaucoma surgery. The aim of this study was to evaluate the immunoexpression pattern of HSP70, CTGF, SNAIL, aSMA, cMYB, and HIFa in the conjunctiva, episclera, and deep sclera in patients with glaucoma undergoing deep sclerectomy in order to establish an association between staining intensities and prostaglandin F2 (PGF2) treatment. Double immunofluorescence (HSP70, CTGF, SNAIL, aSMA, cMYB, and HIFa) was performed on conjunctiva, episclera, and deep sclera samples, which were obtained from 23 patients treated with PGF2 and 8 patients without PGF2 treatment. When comparing the ocular tissues of patients regarding treatment with PGF2 analogs, we found a significant increase in the immunoexpression of HSP70 in the conjunctival epithelium of patients treated with PGF2 analogs compared to those without PGF2 treatment. These patients also had an increase in SNAIL immunoexpression and a decrease in aSMA immunoexpression in the deep sclera. There were no significant differences in HIFa, CTGF, or cMYB immunoexpression levels between the two groups. Further research into the regulation of these factors in ocular tissues could lead to the development of potential novel therapeutic approaches in glaucoma management.

Prostaglandin F2A Disturbs Oogenesis by Causing Meiotic Spindle Damage

Abstract According to recent data, prostaglandin F2 alpha can have a negative influence on meiosis during oogenesis. Previously, we have found that this prostaglandin may accelerate in a dosage-dependent way the postovulatory aging in ovulated mature oocytes, compromising the integrity of their meiotic spindles. Aim. The study aimed to investigate the effects of prostaglandin F2α on the course and outcome of oocyte meiosis in a mouse model. Materials and Methods. Mouse oocytes were matured in vitro in the presence of prostaglandin F2α in a concentration of 100 ng/ml. Their meiotic stage, spindle morphology and chromosome arrangement were assessed by immunofluorescent labeling of tubulin and fluorescent staining of DNA. Results. We obtained a higher percentage of immature oocytes in metaphase I after the treatment than in untreated control oocytes. In addition, there were specific morphological changes in the meiotic spindles of oocytes exposed to prostaglandin F2α associated with a reduced number of fibers. Conclusion. It is probable that prostaglandin F2α has an impact on the microtubule dynamics of the meiotic spindle that can prevent the transition of maturing oocytes to the second meiotic division, most likely by triggering the spindle assembly checkpoint.

Reproductive efficiency in Bos indicus and Bos indicus crossed: impact of timed artificial insemination (TAI) using a progesterone and estradiol benzoate-based protocol

ABSTRACT Data from 15,342 bovine females subjected to timed artificial insemination (TAI) were analysed with the objective of assessing the pregnancy rate (PR) and its association with breed, number of uses of intravaginal implant, body condition score (BCS), animal categories, number of AI, and estrus expression before TAI. The protocol involved administering intravaginal progesterone + estradiol benzoate (day zero), progesterone removal + prostaglandin F2α+estradiol cypionate + equine chorionic gonadotropin (day 8) and TAI + gonadotropin-releasing hormone (day 10) in animals without estrus. Crossbred cows demonstrated higher PR. Non-suckling cows, those with 1st – and 2nd-use implants, and a single-dose implant demonstrated higher PR between categories; the BCS (>2.75–3.5) resulted in better overall PR. There were no differences in the general PR between number of AI. 2nd-use implants resulted in a better overall PR. Primiparous cows resulted better PR with 3rd-use implants. Animals in estrus before TAI demonstrated a higher PR. In conclusion, this study observed no significant differences in general PR among number of AI. Second-use implants were effective. Crossed and non-suckling cows, and 1st – and 2nd-use and single-dose implants exhibited higher fertility. Estrus before TAI favoured PR.

Metabolic processes of prostaglandin metabolism in women at 28–30 weeks of gestation with COVID-19

Background. COVID-19 negatively impacts pregnancy progression and outcomes. However, data regarding pregnancy complications related to prostaglandin activity during COVID-19 remain insufficient.The aim. To assess markers of metabolic processes related to prostaglandin metabolism in the blood of pregnant women depending on the severity of COVID-19 and to explore associations with the development of pregnancy complications.Methods. The study included 109 pregnant women in their third trimester (28–30 weeks), 36 of whom had mild COVID-19, 38 had moderate COVID-19, and 35 were not infected with SARS-CoV-2. The concentration of prostaglandins E2 and F2α, phospholipase A2 (PLA2), cyclooxygenase 2 (COX2), and arachidonic acid (AA) were measured in the blood using enzyme-linked immunosorbent assays and gasliquid chromatography for AA.Results. Comparative analysis showed that pregnant women with moderate COVID-19 had significantly higher levels of AA, COX2, PLA2, prostaglandins E2 and F2α (p < 0.0001) compared to those with mild disease. These women also experienced more frequent complications, such as chronic placental insufficiency, preterm labor, and premature rupture of membranes. Regression analysis revealed associations between chronic placental insufficiency and prostaglandin E2 levels (p < 0.0001), preterm labor, AA (p = 0.001) and COX2 (p = 0.001); premature rupture of membranes and PLA2 (p = 0.025), COX2 (p < 0.001), AA (p < 0.001).Conclusion. Moderate COVID-19 during the third trimester of pregnancy is associated with increased levels of AA, COX2, PLA2, and prostaglandins E2 and F2α in the blood. The most significant factors increasing the risk of pregnancy complications in women with moderate COVID-19 were elevated levels of AA, COX2, and prostaglandin E2 in the blood.

Impact of Human Chorionic Gonadotropin and Prostaglandin F2α Treatment on Progesterone Concentration, Oestrus and Pregnancy Rate in Friesian Cows

Impact of Human Chorionic Gonadotropin and Prostaglandin F2α Treatment on Progesterone Concentration, Oestrus and Pregnancy Rate in Friesian Cows

Czy lek na jaskrę zrewolucjonizuje leczenie łysienia androgenowego? O repozycjonowaniu leku, którego efekt uboczny stał się pożądanym skutkiem terapii.

Prostaglandins are hormones found in almost all mammalian tissues. As signaling molecules, they play a key role in the regulation of many physiological processes, including hair growth cycle. The article describes the history of the discovery of prostaglandins, including the work of Professor Ryszard Gryglewski - the discoverer of prostacyclin. Particular attention was paid to the synthetic analogue of prostaglandin F2α - latanoprost. Indicated for the treatment of glaucoma, the drug is known for inducing eyelash growth as a side effect. A prodrug, latanoprost is converted to its active metabolite, latanoprost acid. Recent research demonstrated that latanoprost acid has a chance to become an effective alternative to minoxidil and finasteride - the only drugs currently registered for the treatment of androgenetic alopecia. The development of anti-alopecia drugs containing prostaglandin derivatives, including latanoprost acid, will be a much faster process compared to the traditional path of product development based on a new chemical compound.

IMMU-10. IDENTIFICATION OF A NEW THERAPEUTIC ANTIGEN FOR GLIOBLASTOMA USING A MONOCLONAL ANTIBODY LIBRARY FROM PATIENT-DERIVED TUMOR SPHERES

Abstract Glioblastoma (GBM) has a poor prognosis despite intensive treatment by surgery, radiation, and chemotherapy, thus new treatment strategies are urgently needed. Various innovative cancer therapies targeting cancer-specific cell surface antigens, such as chimeric antigen receptor T cell therapy, are developed and more cell surface antigens that is highly specific for GBM cells are needed. Although extensive transcriptome analyses or proteomic analysis of GBM cells were performed, few transcripts specific for GBM cells have been identified. However, GBM cell-specific antigen epitopes formed by post-translational modifications of proteins may have been missed by transcriptome or proteomic analysis, and could still be discovered by thoroughly searching for cancer-specific monoclonal antibodies. In this study, we aimed to identify GBM-specific antigens using a monoclonal antibody library from patient-derived tumor spheres, create CAR-T cells against the antigen, and check antitumor efficiency of the CAR-T cells. Approximately 25,000 monoclonal antibody-producing hybridomas were establishment using BALB/c mice and patient derived tumor spheres. Among them, a antibodies that bind to plural glioblastomas and not to plural normal brain cells were selected and we identified the antigen as Prostaglandin F2 receptor negative regulator (PTGFRN) by the expression cloning method. PTGFRN witch is expressed in several cancers regulate migration, angiogenesis, and cell polarity and decreases the radiosensitivity of GBM cells. We created CAR-T cells against the antigen and co-cultured it with GBM cells, which significantly increased the production of IL-2 and INF-γ. Furthermore, the CAR-T cells injected intracranial in an orthotopic xenograft model with patient-derived GBM cells, significantly reduced tumor growth. PTGFRN CAR-T-cell therapy may be a potential novel therapeutic target for GBM.

Lipid Imbalance and Inflammatory Oxylipin Cascade at the Maternal-Fetal Interface in Recurrent Spontaneous Abortion

BackgroundRecurrent spontaneous abortion (RSA) is intricately linked to metabolic dysregulation at the maternal-fetal interface during early gestation. Abnormal levels of essential fatty acids and downstream oxylipins in decidua and chorionic villi have been identified as potential risk factors for RSA. Oxylipins have been linked to excessive inflammation, which might disrupt maternal-fetal immune tolerance, potentially contributing to RSA. Nonetheless, the exact fatty acid-oxylipin metabolic pathway at the matrernal-fetal interface in RSA occurrence remains unknown. Therefore, this research aimed to explore the effect of essential fatty acids, their transport, and downstream oxylipins at the maternal-fetal interface on RSA pathogenesis. MethodsPlasma, chorionic villus, and decidual tissue samples from the first trimester were collected from healthy pregnant women undergoing elective pregnancy terminations, as well as from patients experiencing spontaneous abortion. The concentrations of essential fatty acids and their downstream oxylipins in the villi and decidua were quantified using gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-tandem mass spectrometry (LC-MS). The expression of enzymes related to metabolic pathways was investigated by q-PCR. The ratios of M1/M2 macrophages were assessed by flow cytometry (FCM). ResultsThis study found elevated concentrations of omega-6 fatty acids, encompassing arachidonic acid (AA), linoleic acid (LA), and dihomo-gamma-linolenic acid (DGLA) in maternal plasma and chorionic villi, whereas lower concentrations were observed in the decidua, than in samples from normal pregnancies. Further analysis revealed that the transport of these fatty acids was dysregulated at the maternal-fetal interface in RSA women, possibly due to the aberrant expression of the fatty acid translocase (FAT/CD36). In addition, this study revealed that RSA patients displayed higher levels of downstream oxylipins, such as prostaglandin F2a (PGF2a), prostaglandin E2 (PGE2), and leukotriene B4 (LTB4) in chorionic villi and decidua. These compounds may contribute to M1 inflammatory macrophage polarization in RSA, thereby forming a highly inflammatory environment and influencing immunomodulation at the maternal-fetal interface. ConclusionThe study revealed alterations in omega-6 fatty acids, CD36 transport, and AA downstream oxylipins in RSA, which in turn promote M1 macrophage polarization. Thus, this research has established a foundation for identifying potential biomarkers for, and providing novel insights into, the diagnosis and pathophysiology of RSA.

Engineered extracellular vesicles as nanosponges for lysosomal degradation of PCSK9

Proprotein convertase subtilisin/kexin type 9 (PCSK9) plays a crucial role in degradation of low-density lipoprotein receptor (LDLR) and PCSK9 inhibition emerges as an attractive strategy for atherosclerosis management. In this study, extracellular vesicles (EVs) were engineered to nanosponges, which could efficiently adsorb and deliver PCSK9 into lysosomes for degradation. Briefly, nanosponges were engineered by modifying EVs with EGF-A/PTGFRN fusion protein (PCSK9 binding domain EGF-A from the mutant LDLR with higher affinity was fused to the C-terminus of Prostaglandin F2 Receptor Negative Regulator). The modification endowed the EVs with hundreds of EGF-A displayed on the surface and thus the capacity to adsorb PCSK9 efficiently. The adsorbed PCSK9 would thus be delivered into lysosomes for degradation when the nanosponges were endocytosed by liver cell, thus releasing endogenous LDLR from degradation. In ApoE-/- mouse model, tail vein injected nanosponges were able to degrade PCSK9, increase LDLR expression, lower LDL-C level, and thus alleviate atherosclerosis. In summary, we here not only develop a novel strategy for PCSK9 inhibition, but also propose a universal method for adsorption and degradation of circulating proteins for disease management.

Effect of Gonadotropin-Releasing Hormone Treatment on Superovulation Response and Embryo Recovery in Holstein Heifers: A Field Trial at Zagros Milk and Meat Company, Iran

Background: Superovulation is a crucial component of assisted reproductive technology. Inducing superovulation with Gonadotropin-releasing hormone (GnRH) can lead to ovarian hyperstimulation, potentially affecting reproductive outcomes. Objectives: This study aimed to examine the effects of GnRH treatment on superovulation response and embryo recovery in Holstein heifers. Methods: Twenty-one Holstein heifers (age: 135.15 months; weight: 361.05 kg) were selected based on their general health status and ovarian function. All heifers received two consecutive doses of prostaglandin F2α and underwent superovulation. The heifers were inseminated twice: Once at the onset of standing estrus and again 12 hours later. In the treatment group (13 heifers), a single dose of GnRH was administered simultaneously with the second insemination. The superovulation response was evaluated based on the number of corpus luteum (CL), unovulated follicles (UoF), total recovered embryos/ova, and the number of transferable embryos, using logistic regression with the GENMOD procedure in SAS. Results: The mean number of CL was not significantly greater in the control group (13.6) compared to the GnRH group (11.4). The average number of UoF was similar between the two groups (P = 0.1853). However, the control group had a significantly higher average total number of recovered embryos/ova (7.7) compared to the GnRH group (2.1). Additionally, the control group progesterone more transferable embryos, with an average of 2.5, while the GnRH group averaged 0.7 (P < 0.0062). Conclusions: Gonadotropin-releasing hormone likely deactivated the oviduct by disrupting the balance of estradiol and estrogen, leading to a reduction in both the total number of embryos and the number of transferable embryos in heifers.

Effects of thiacloprid, a neonicotinoid pesticide, on rat reproductive system: Pregnancy hormone disruption and abortion trends

Thiacloprid (TCL), commonly known as Biscaya, is among the most widely used pesticides in agriculture, designed to eliminate insects by targeting their nicotinic receptors. This study explores the effects of orally administering TCL (at a dose of 50 mg/kg) on the hormone secretion crucial for pregnancy and the factors influencing abortion throughout the early, middle, and late stages of pregnancy in female rats.Following TCL exposure, there were significant increases in levels of 17β-Estradiol, prostaglandins F2α and E2, and serum oxytocin hormone in different stages of pregnancy. In contrast, progesterone and endothelin-1 serum levels notably decreased during the initial and final stages of pregnancy. Additionally, TCL led to a substantial rise in lipid peroxidation levels and a decrease in total thiol molecules and total antioxidant capacity, especially in uterine tissue. Although TCL did not significantly affect the morphological characteristics of the delivered fetuses, it notably increased the number of abortions, especially during the second and third stages of pregnancy.In summary, our findings suggest that TCL elevates the risk of abortion in pregnant rats by disrupting the secretion of hormones crucial for fertility (such as 17β-Estradiol/progesterone) and by increasing the secretion of abortion-inducing hormones like prostaglandins and oxytocin. Furthermore, these effects may be associated with disruptions in the oxidant/antioxidant balance within the ovaries and uterus.

The Mechanism Involved in the Inhibition of Resveratrol and Genistein on the Contractility of Isolated Rat Uterus Smooth Muscle

Purpose: This study aimed to compare the effects of the phytoestrogens resveratrol (RES) and genistein (GEN) on the contractility of isolated uterine smooth muscle from rats, focusing on both spontaneous and stimulated contractions, and to investigate the underlying mechanisms. Methods: Uterine strips were suspended vertically in perfusion chambers containing Kreb’s solution, various concentrations of RES and GEN were added to the ex vivo uterine strips, and contractions were measured before and after incubation with RES or GEN. Results: (1) Both RES and GEN inhibited K+-induced contractions in a dose-dependent manner; the β/β2-adrenoceptor antagonist propranolol (PRO), ICI118551, the ATP-dependent K+ channel blocker glibenclamide (HB-419) and the NO synthase inhibitor N-nitro-L-arginine (L-NNA) diminished the inhibitory effects of RES and GEN on K+-induced contractions. (2) RES and GEN also dose-dependently inhibited PGF2α-induced uterine contractions. (3) The inhibitory effects of RES and GEN were observed in spontaneous contractile activities as well; PRO, ICI118551, HB-419 and L-NNA attenuated the inhibitory effects of RES and GEN on the spontaneous contractions of isolated uterine muscle strips. (4) RES and GEN significantly decreased the cumulative concentration response of Ca2+ and shifted the Ca2+ cumulative concentration–response curves to the right in high-K+ Ca2+-free Kreb’s solution. (5) RES and GEN markedly reduced the first phasic contraction induced by oxytocin, acetylcholine, and prostaglandin F2α but did not alter the second phasic contraction caused by CaCl2 in Ca2+-free Kreb’s solution. Conclusions: RES and GEN can directly inhibit both spontaneous and activated contractions of isolated uterine smooth muscle. The mechanisms underlying the inhibitory effects of RES and GEN likely involve β adrenergic receptor activation, reduced Ca2+ influx and release, the activation of ATP-dependent K+ channels and increased NO production.

7624 m6A mRNA Methylation in Brown Adipose Tissue Regulates Systemic Insulin Sensitivity via an Inter-Organ Prostaglandin Signaling Axis

Abstract Disclosure: L. Xiao: None. D. F De Jesus: None. C. Ju: None. J. Wei: None. J. Hu: None. A. DiStefano-Forti: None. T. Tsuji: None. C. Cero: None. V. Männistö: None. S.M. Manninen: None. S. Wei: None. O. Ijaduola: None. M. Blüher: Consulting Fee; Self; Amgen Inc, AstraZeneca, Bayer, Inc., Boehringer Ingelheim, Lilly USA, LLC, Novo Nordisk, Pfizer, Inc., Sanofi. A.M. Cypess: None. J. Pihlajamäki: None. Y. Tseng: None. C. He: Advisory Board Member; Self; Accent Therapeutics. R.N. Kulkarni: Advisory Board Member; Self; Novo Nordisk, Biomea, Inversago, REDD. Brown adipose tissue (BAT) has the capacity to regulate systemic metabolism through the secretion of “Batokines” including signaling lipids. N6-methyladenosine (m6A) is the most prevalent and abundant post-transcriptional mRNA modification and has been reported to regulate BAT adipogenesis and energy expenditure. Here, we demonstrate that the absence of the m6A writer, methyltransferase-like 14 (METTL14), modifies the BAT secretome to initiate inter-organ communication to improve systemic insulin sensitivity. Importantly, these phenotypes are independent of UCP1-mediated energy expenditure and thermogenesis. Using lipidomics, we identified prostaglandin E2 (PGE2) and prostaglandin F2a (PGF2a) as M14KO-BAT-secreted insulin sensitizers. Notably, circulatory PGE2 and PGF2a levels are inversely correlated with insulin sensitivity in humans. Furthermore, in vivo administration of PGE2 and PGF2a in high-fat diet-induced insulin-resistant obese mice recapitulates the phenotypes of Mettl14-deficient animals. PGE2 or PGF2a improves insulin signaling by suppressing the expression of specific AKT phosphatases. Mechanistically, METTL14-mediated m6A installation promotes decay of transcripts encoding prostaglandin synthases and their regulators in human and mouse brown adipocytes in a YTHDF2/3-dependent manner. Collectively, these findings reveal a novel biological mechanism in the m6A-dependent regulation of the BAT secretome in modulating systemic insulin sensitivity in both mice and humans. Presentation: 6/1/2024

6828 Exploring Metabolomic Clues in Diabetic Retinopathy

Abstract Disclosure: M.W. Simonson: None. Y. Li: None. J.J. McAnany: None. B. Prasad: None. E.C. Hanlon: None. S. Pannain: None. B.T. Layden: None. E. Van Cauter: None. J.C. Park: None. S.J. Crowley: None. F.Y. Chau: None. K.K. Danielson: None. H. Chen: None. G.E. Chlipala: None. C. Martinez: None. S. Reutrakul: Speaker; Self; Eli Lilly & Company. Background: Diabetic retinopathy (DR) is a common microvascular complication of diabetes. Metabolomics offers the possibility for novel biomarker discovery. The purpose of this study was to determine metabolomic differences that characterized patients with versus without DR. Methods: A total of 62 serum samples were collected from 36 type 2 diabetes (T2D) patients with DR and 26 T2D patients without DR, and analyzed via UPLC-MS. The metabolite data were normalized using median normalization. The differential expression of metabolites was compared among the groups using the limma package in R. The covariates (age, sex, BMI and sleep apnea severity) were accounted for by using a generalized linear model fitted to the data. Significantly different metabolites were filtered by an absolute log2 Fold Change (FC) of 1.5 or greater and Q values < 0.05. Results: Mean (SD) age for DR and no-DR group was 55 (±5.9) versus 54 (±6.7) years, while BMI was 33 (±5.8) versus 33 (±6.3) kg/m2 respectively. Both DR and no-DR groups were 58% female. A1C levels in DR group was marginally higher than in no-DR group (p=0.09). There were significant differences in metabolomic changes between DR versus no-DR, with 166 total differential metabolites after adjusting for covariates and filtering by FC. Notable metabolites included those involved in fatty acid metabolism, acyl carnitines, prostaglandins, and phospholipids. There was an overall upregulation of serum acyl carnitines in DR as compared to no-DR, including 2,6 dimethylheptanoyl carnitine (FC = 3.0) and cis-5-Tetradecenoylcarnitine (FC = 2.0). Additionally, there was a decrease in long chain fatty acids in DR as compared to no-DR, which included 6-hydroxypentadecanedioic acid (FC = -6.6), 10,16-dihydroxy-palmitic acid (FC = -6.0), and tetracosatetraenoyl CoA (FC = -6.1). The 11-beta prostaglandin F2 (11-PGF2) was increased in DR (FC = 1.9). Circulating phospholipids including lysophosphatidylcholine (22:2) (lysoPC) (FC = 1.8) and phosphatidylcholine (24:1/24:1) (PC) (FC = 5.9) were also significantly dysregulated. Conclusions: We identified a subset of metabolites that discriminate T2D patients with or without DR. The changes in acyl carnitines and long chain fatty acids may reflect mitochondrial dysfunction in DR. The presence of certain prostaglandins highlights the inflammatory environment which may facilitate DR progression. Increases in phospholipids such as lysoPC suggest an atherogenic state and higher LDL oxidation, while increases in PC may indicate altered lipogenesis in DR. These findings may serve as new potential serum biomarkers to promote efficient preventive care and provide mechanistic insight into understanding DR pathophysiology. Presentation: 6/2/2024

Effect of the Application of PGF2α Associated With Ovulation Induction in a Fixed-Time Superovulation Programme for Precocious Nellore Heifers.

This study evaluated the effect of prostaglandin F2α (PGF2α) associated with gonadotropin-releasing hormone (GnRH) for ovulation induction in precocious indicus heifers submitted to a fixed-time superovulation (SOV) programme. Precocious Nellore heifers (n = 35), aged 13 months, were subjected to the SOV protocol. On day 0 (D0), all animals received intravaginal insertion of a progesterone (P4) device along with intramuscular administration of 2 mg of oestradiol benzoate, plus 200 IU of follicle-stimulating hormone in decreasing doses, with 12-h intervals between D4 and D7, in addition to 150 μg of D-cloprostenol on D6 and device removal on D7. On D8, the donors received 10.5 μg of buserelin acetate and the treatment group received 300 μg of D-cloprostenol/PGF2α. Artificial insemination was performed 12 h and 24 h after GnRH administration using frozen semen. On D15 of the protocol (i.e., D7 after insemination), the embryos were collected and evaluated. All animals passed through the control and treatment groups. Results were evaluated by analysis of variance using an adjusted mixed-effects model (p < 0.05). There was no difference in the total number of embryos between the control and treatment groups (10.40 ± 1.52 vs. 9.60 ± 1.36; p = 0.63) or viable embryos (6.30 ± 1.22 vs. 4.30 ± 0.71). For precocious indicus heifers, treatment with PGF2α in association with GnRH did not affect embryo production in the fixed-time SOV protocol.

PSXII-11 Impact of pre-breeding and breeding supplementation in May-born range heifers on growth rates and reproductive performance

Abstract Our objectives were to determine the impact rumen undegradable protein (RUP) supplementation prior to and during the breeding season had on growth rates and reproductive performance in May-born yearling range heifers. This study was conducted over a 3-yr period at the University of Nebraska, Gudmundsen Sandhills Laboratory (GSL) near Whitman, NE and utilized May-born Red Angus x Simmental crossbred heifers [n = 192; weaning body weight (BW) = 200 kg ± 28 kg]. Heifers were randomly assigned by pre-breeding BW to one of two treatments: 1) received 0.908 kg of a dried distillers grain supplement (DDGS; Supp, n = 66) pre-breeding through the breeding season or 2) received no supplement (NoSupp, n = 138). Each year, treatments were initiated in July and ended in August (55 ± 3 d). Using a C-Lock Smart Feeder (Rapid City, SD) heifers had individual access to their allotted DDGS supplementation. On average, NoSupp heifers consumed 0.09 kg/d (yr 1) and 0.02 kg/d (yr 2 and 3); whereas, Supp heifers averaged 0.59, 0.74, and 0.76 kg/d in yr 1, 2, and 3, respectively. Heifer BW was collected pre-trial (May), pre-breeding (July), breeding (August), pregnancy diagnosis (October), and pre-calving (April). Body condition score (BCS) was collected at pregnancy diagnosis (October) and pre-calving (April; Yr 1 and 2). Before each breeding season, two blood samples were collected 10 d apart to determine pubertal status. Heifers were synchronized with a single 5 mL intramuscular injection of prostaglandin F2 alpha (Lutalyse, Zoetis, Parsippany, NJ) 5 d after bull turnout during a 30 d natural service breeding season. Pregnancy diagnosis was determined via rectal ultrasound in October. No differences (P &amp;gt; 0.12) in BW were noted among treatments for all measurement timepoints. Moreover, SUPP heifers had greater (P &amp;lt; 0.02) average daily gain (ADG) from pre- trial to pregnancy diagnosis compared with NoSUPP heifers. However, there was no differences (P = 0.11) in ADG from pregnancy diagnosis to pre- calving. At pregnancy diagnosis (October), a treatment x year interaction (P = 0.02) for BCS was present where Supp heifers had a greater BCS than NoSupp heifers in yr 3. Heifer BCS pre-calving was not affected (P = 0.12) by treatment. There was a greater percentage (P &amp;lt; 0.01) of SUPP heifers cycling compared with NoSUPP heifers. However, there were no differences (P &amp;gt; 0.24) in pregnancy rates, the percentage that calved in the first 21 d, calf birth BW, or subsequent calving date. Ultimately, this study implies that providing a RUP supplement prior to and during the breeding season will increase the percentage of heifers that are cycling before breeding and have a greater ADG through pregnancy diagnosis; however, supplementation will not impact other reproductive parameters or BW gains.

PSIII-6 Multi-sire artificial insemination of beef heifers in the Nebraska Sandhills effect on pregnancy rate compared with single-sire insemination

Abstract The objective of this study was to compare pregnancy outcomes resulting from artificial insemination (AI) with multi-sire semen (MS) compared with single-sire semen (SS) in beef heifers. Another study observed pregnancy and paternity outcomes to sexed MS without a control treatment. In the first study, unrelated ABS Global Angus bulls (n = 3) were selected for AI to 441 (Yr 1) and 391 (Yr 2) Angus crossbred heifers. Heifers were synchronized with the melengestrol acetate – prostaglandin F2α timed-AI protocol. Conventional semen, from each bull, were labeled A, B, or C. Remaining semen was pooled in equal amounts to form conventional MS straws. Heifers were AI using alternating treatment of MS or SS: A, B, or C with one-half of inseminated heifers receiving either MS or SS. The GLIMMIX procedure in SAS 9.4 analyzed responses to treatments using the BIN distribution option and reported as LSMEANS. Contrasts and estimates analyzed responses between treatments. Ultrasound determined SS pregnancy rate averaged 60% (SS-A = 64%, SS-B = 58%, SS-C = 58%) and MS average 62% (P = 0.63). Paternity was determined in 57 MS calves and confirmed in 49 SS calves. In Yr 1, Bull A sired 7%, bull B sired 56%, and bull C sired 37%. Although bull A was much less successful than bull B or C, the values are not significantly different due to the small sample size (P = 0.11 and P = 0.24, respectively). Few conclusions can be made from the ongoing study, but it is hypothesized MS may improve consistency of pregnancy rate by equilibrating semen quality in herds subjected to timed AI. In the observational study, multiple 5-way cross bulls born from the ranch herd were selected for AI of 951 ± 41 heifers for 3 yr. Heifers were synchronized using the previously mentioned protocol with split-time AI. Unequal amounts of semen were collected, pooled, and sexed to favor heifer progeny at an expected ratio of 9:1. Semen from 2 to 4 random bulls were pooled making 3 to 4 MS groups each year. Heifers exhibiting estrus were administered sexed MS, but there was no control treatment. The observed ultrasound determined average pregnancy rate of heifers administered sexed MS was 65% (Yr 1), 75% (Yr 2), and 72% (Yr 3). Previous literature suggests average pregnancy rate to AI with sexed SS is 53%. Paternity testing in Yr 2 found semen contribution mirrored paternity ratios within some groups but the sire group with 2 bulls found one sired 15% and the other sired 85%. This study exemplified a viable method for AI that requires further research. Further research into semen quality of a single sire, and pooled semen could lead to optimization of fertilization among individuals within a herd.

PSLBI-3 The use of meloxicam oral suspension (15 mg/mL) to control post-partum pain and inflammation in dairy cattle following dystocia

Abstract Dystocia is painful, given the increased time, tissue damage, and stress associated with handling and forced extraction. Around parturition, dry matter intake is reduced, and cows experience increased inflammatory mediators. This could lead to subsequent health issues, including an increased risk of metabolic disease, reduced reproductive performance, and decreased milk production. Controlling pain and disease are important for animal welfare so it is critical to alleviate dystocia pain and inflammation. The administration of a non-steroidal anti-inflammatory drug (NSAID) could aid in alleviating the negative sequelae of dystotic parturition. Meloxicam (MOS) is an NSAID with greater oral bioavailability and inhibits cyclooxygenase, the enzyme responsible for converting arachidonic acid to prostaglandin. The reduction in prostaglandin, specifically prostaglandin F2α, resulting from meloxicam administration following a dystotic calving could minimize pain and control systemic inflammation. Objectives were: 1) to demonstrate post-partum administration of MOS in dystotic lactating dairy cows reduces pain (for up to 3 d) as measured by a significant reduction in plasma substance P expression levels (P &amp;lt; 0.05); 2) to demonstrate post-partum administration of MOS in dystotic lactating dairy cattle reduces inflammation (for up to 14 d) as measured by a significant reduction in plasma haptoglobin expression levels (P &amp;lt; 0.05); and 3) to evaluate the safety of administering MOS in post-partum dairy cattle, especially as it pertains to reproductive health. The study included dairy farms in three geographical areas in Canada, with nine farms and 145 cows. Primiparous and multiparous cows identified as having dystotic calvings were enrolled based on observation by the producer or study technician. Cows were randomly assigned to a treatment group of MOS or the placebo within each farm site. Animals received test or control treatment 0 to 12 h post-dystotic calving. The calving and treatment times were recorded. No analgesics was given before calving. Data collected included: 1) pain-related behaviors; 2) physiological markers of pain; 3) physiological markers of inflammation measured as acute phase proteins; 4) vulvovaginal inflammation; 5) physical evaluation including daily observations, body weight, rumination, blood and urinalysis, reproductive evaluation, time to first insemination and daily milk weights. The data are being evaluated and initial results show favorable responses to the treatment.

420 Automated identification and behavioral estrus detection in freestall-housed dairy cows using computer vision and machine learning: A two-layered algorithm approach

Abstract A critical aspect of dairy management involves maintaining accurate records of individual animals and promptly detecting estrus behavior, which is vital for successful breeding and reproductive outcomes. Recent advancements in precision livestock management, utilizing computer vision and machine learning technologies, have paved the way for automated and precise solutions in these areas. The objective of this study is to investigate the application of computer vision and machine learning for animal identification and behavioral estrus detection in dairy cows housed in freestall settings, employing a two-layered algorithmic approach. The research was conducted at the Joe Bearden Dairy Research Center, where a total of 10 lactating Holstein-Friesian cows were assessed across a 7-d trial period. For synchronization efforts, cows were provided a single injection of Prostaglandin F2α at trial initiation with expected estrus behaviors to be exhibited within the following 56 h. Continuous video was captured in 4k resolution using a five-camera closed caption media recording system strategically placed in the pen corners and over the feed bunk alleyway to capture multiple perspectives. Video data extrapolated into frames and manual annotation was utilized to generate the machine learning algorithm’s training data. Frames were randomly selected from a scattering of 56 h of video across all five camera viewpoints and down sampled to 384 x 640 p for both layers. A two-layer approach was employed utilizing an algorithm for each aspect of the study with the first model detecting the behavior, and the second model using the detected region of interest to identify specific cows. The first layer was trained on 682 frames and validated against 123 manually annotated frames. The second layer was trained on 102 frames and validated against 16 frames manually annotated for individual animals. Results demonstrated that the model used for mounting behavior identification has high precision (0.819) and recall (0.89), achieving a 0.926 mAP at an IoU of 0.5. This model achieved an F1 score of 0.86 at a confidence threshold of 0.268. The results demonstrated that the model used for individual animal identification across different classes achieved high precision (0.861) and recall (0.842), with a mAP of 0.897 at an IoU of 0.5. The F1 score for all classes was 0.89 at a confidence threshold of 0.788. In conclusion, these promising findings underscore the potential of computer vision and machine learning technologies to revolutionize dairy cow management practices. This innovative approach not only has potential to enhance operational efficiency, but also contributes significantly to improved reproductive management, thereby advancing precision and productivity in dairy operations.

182 Converting spring-born heifers into a summer-calving herd increases subsequent cow longevity and productivity

Abstract Developing replacement heifers is one of the most expensive and complex management decisions for a cow-calf producer, which also has long-term implications for profitability. The objective of this study was to determine the impact of converting spring-born heifers into a summer-calving herd on growth, reproductive performance, longevity, and productivity compared with early or late-born May heifers. Over a 3 yr period, Red Angus/Simmental crossbred heifers (n = 273) were utilized to determine the impact of converting March-born heifers (Convert; n = 90) to a May-calving herd compared with May-born heifers on reproductive performance, body weight (BW), and calf performance from a yearling to 5 yr of age. May-born heifers were retrospectively grouped into 2 different groups: heifers born in the first 21 d of calving as a heifer calf (Early; n = 123) or heifers born after the 21 d of calving as a heifer calf (Late; n = 60). Heifers were exposed to bulls for a 45-d breeding season with a bull-to-heifer ratio of 1:20. Heifers were synchronized with a single injection of prostaglandin F2α (5-mL i.m.; Lutalyse, Zoetis, Parsippany, NJ) 5 d after bulls were introduced in the pasture for breeding. Data were analyzed as a randomized design using the MIXED procedure (SAS Inst. Inc., Cary, NC, USA). All binomial data were analyzed using PROC GLIMMIX. Heifer served as the experimental unit with treatment and year developed set as fixed effects. Heifer BW at December, May, July, and pregnancy check (Oct) were greater (P &amp;lt; 0.01) for Convert heifers with no difference between Early and Late born heifers. Heifer BCS at pregnancy check was not different (P = 0.13) among heifer treatment groups. However, pregnancy rate tended (P = 0.08) to increase for Convert heifers with no difference between Early and Late born May heifers. After 5 yr of age, retention rate was increased (P = 0.04) in Convert cows compared with Early and Late May-born cows with no difference (P = 0.84) between the two May-born heifer groups. Total kilograms of calf weaned was greater (P = 0.04) in Convert cows than their counterparts with no differences (P = 0.94) between Early and Late May-born cows. This study implies that selecting replacement heifers from an earlier calving season for replacements in a later calving season increases the longevity and long-term productivity of the cowherd than selecting heifers within the same calving season. This may be even more important in resource-poor breeding environments that create reproductive challenges for heifers and rebreeding young cows.