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Zoo Biology Jul 2021Tigers (Panthera tigris spp.) are endangered in the wild; ensuring sustainable insurance populations requires careful planning within zoological collections. In captive...
Tigers (Panthera tigris spp.) are endangered in the wild; ensuring sustainable insurance populations requires careful planning within zoological collections. In captive situations, contraceptives are often used to control breeding and ensure genetically viable populations that contain manageable numbers of animals; reversible contraceptives are ideal because they offer flexibility for breeding management. Historically, synthetic progestins, such as melengestrol acetate implants, were used in female tigers, but these are associated with an increased risk of reproductive pathology and subsequent infertility. Recent management advice to ex-situ collections has been to transition to the use of gonadotropin-releasing hormone agonists, such as deslorelin acetate implants, which do not appear to have a similar risk of reproductive pathology but are associated with highly variable reversal times in exotic felids. Using data from 917 contraceptive records in female tigers captured by the Association of Zoos and Aquariums Reproductive Management Center and the European Association of Zoos and Aquaria Reproductive Management Group's joint Contraception Database and from supplementary surveys, this study reviews the changing use of contraceptives in captive female tigers. The aim was to describe the historical and current use of contraceptives and provide a comprehensive assessment on the use of deslorelin implants, including data on product protocols, efficacy, pathology, and reversibility. This study determined that current dose, frequency, reversibility, and anatomical placement sites of deslorelin implants are highly variable, indicating that specific, readily available, unified, evidence-based recommendations on the use of deslorelin would be useful for future contraceptive use in managed tiger populations.
Topics: Animals; Animals, Zoo; Contraceptive Agents, Female; Female; Retrospective Studies; Tigers; Triptorelin Pamoate
PubMed: 33724521
DOI: 10.1002/zoo.21601 -
Journal of Chromatography. A Jul 2021A robust and confirmative method was established for the determination of six acetylgestagen residues, namely, flurogestone acetate (FGA), megestrol (MA), melengestrol...
Determination of acetylgestagens in animal-derived matrix samples using enhanced matrix removal lipid clean-up in combination with ultra performance liquid chromatography-tandem mass spectrometry.
A robust and confirmative method was established for the determination of six acetylgestagen residues, namely, flurogestone acetate (FGA), megestrol (MA), melengestrol acetate (MGA), chlormadinone acetate (CMA), medroxyprogesterone (MPA), and hydroxyprogesterone acetate (HPA) in animal-derived matrix samples by utilizing enhanced matrix removal lipid (EMR-lipid) clean-up in combination with ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The analytes were extracted with acetonitrile, purified with a EMR-lipid cartridge, and separated with a reversed-phase C18 column. The limit of quantification (S/N ≥ 10) for CMA, FGA, HPA, MA, and MGA in all matrices was 0.5 ng/g, and for MPA, it was 1.0 ng/g; the limit of detection (S/N ≥ 3) for CMA, FGA, HPA, MA, and MGA in all matrices was 0.1 ng/g, and for MPA, it was 0.2 ng/g. The recoveries were between 61.0% and 114.8%, and the relative standard deviations (RSDs) were below 12%. The method was calibrated in a matrix-assisted standard solution in various linear ranges for the analytes and matrices, and the correlation coefficients (R) exceeded 0.99 for all the matrices.
Topics: Animals; Calibration; Chromatography, High Pressure Liquid; Chromatography, Liquid; Drug Residues; Lipids; Progestins; Tandem Mass Spectrometry
PubMed: 34038780
DOI: 10.1016/j.chroma.2021.462227 -
Archives of Environmental Contamination... May 2021Gestagens are active ingredients in human and veterinary drugs with progestogenic activity. Two gestagens-progesterone (P4), and the synthetic P4 analogue, melengestrol...
Gestagens are active ingredients in human and veterinary drugs with progestogenic activity. Two gestagens-progesterone (P4), and the synthetic P4 analogue, melengestrol acetate (MGA)-are approved for use in beef cattle agriculture in North America. Both P4 and MGA have been measured in surface water receiving runoff from animal agricultural operations. This project aimed to assess the morphometric and molecular consequences of chronic exposures to P4, MGA, and their mixture during Western clawed frog metamorphosis. Chronic exposure (from embryo to metamorphosis) to MGA (1.7 µg/L) or P4 + MGA (0.22 µg/L P4 + 1.5 µg/L MGA) caused a considerable dysregulation of metamorphic timing, as evidenced by an inhibition of growth, narrower head, and lack of forelimb emergence in all animals. Molecular analysis revealed that chronic exposure to the mixture induced an additive upregulation of neurosteroid-related (GABA receptor subunit α6 (gabra6) and steroid 5-alpha reductase 1 (srd5α1) gene expression in brain tissue. Chronic P4 exposure (0.26 µg/L P4) induced a significant upregulation of the expression hypothalamic-pituitary-gonadal (HPG)-related genes (ipgr, erα) in the gonadal mesonephros complex (GMC). Our data suggest that exposure to P4, MGA, and their mixture induces multiple endocrine responses and adverse effects in larval Western clawed frogs. This study helps to better our understanding of the consequences of chronic gestagen exposure and suggests that the implications and risk of high gestagen use in beef cattle feeding operations may extend to the aquatic environment.
Topics: Animals; Cattle; Gene Expression; Melengestrol Acetate; North America; Progesterone; Progestins
PubMed: 33856560
DOI: 10.1007/s00244-021-00831-5 -
Scientific Reports Oct 2023The present study aimed to test the efficiency of transcervical artificial insemination techniques with cervical immobilization (TCAI-CI) or cervical traction (TCAI-CT),...
The present study aimed to test the efficiency of transcervical artificial insemination techniques with cervical immobilization (TCAI-CI) or cervical traction (TCAI-CT), associated or not with the use of oxytocin (OT) as a protocol for cervical dilation, in the brown brocket deer (Subulo gouazoubira). The study was carried out in a crossover design using four adult females in two replicates with an interval of 60 days. Estrus was synchronized with oral melengestrol acetate (MGA) associated with estradiol benzoate and sodium cloprostenol. TCAI techniques were performed from 18 to 24 h after estrus onset. All females received either an i.v. application of 50 IU of OT (G-OT, n = 4) or 1 mL of saline solution (G-Control, n = 4) 20 min before the TCAI procedure. The TCAIs were performed using frozen-thawed semen motility 40%, vigor 3, acrosome integrity 87%, membrane integrity of 95% and 13% of total post-thaw defects from the same batch. Behavioral estrus was observed in 100% of the females, in both replicates. It was achieved a 50% (4/8) success of cervical transposition with semen deposition in the uterine. Regarding inseminations, most of them (87.5%) were performed using the TCAI-CT technique, and the overall conception rate was 50%. Cervical transposition times (< 1 min) and TCAI procedures (~ 17 min) were considered satisfactory. Thus, the performance of the TCAI-CI and TCAI-CT techniques was successful, regardless of using OT as a cervical dilation protocol. This procedure is proposed as a method of choice for artificial insemination with greater applicability in different conservation centers, compared to more advanced reproductive biotechniques, and with a favorable impact on the conservation of deer species.
Topics: Animals; Female; Male; Cervix Uteri; Deer; Insemination, Artificial; Oxytocin; Semen Preservation; Uterus; Cross-Over Studies
PubMed: 37833322
DOI: 10.1038/s41598-023-43392-4 -
Theriogenology Jul 2019Fixed-time and split-time AI were compared following the melengestrol acetate (MGA) prostaglandin F (Experiment 1) and 7-d CO-Synch + controlled internal drug release...
Fixed-time and split-time AI were compared following the melengestrol acetate (MGA) prostaglandin F (Experiment 1) and 7-d CO-Synch + controlled internal drug release (CIDR) protocols (Experiment 2). Heifers in Experiments 1 (n = 524) and 2 (n = 456) were assigned within pen to balanced treatments based on weight and reproductive tract score (RTS; Scale 1-5). In Experiment 1, MGA (0.5 mg∙animal∙d) was fed for 14 d, and prostaglandin F (PG; 250 μg im cloprostenol sodium) was administered 19 d after MGA withdrawal. In Experiment 2, gonadotropin-releasing hormone (GnRH; 100 μg gonadorelin acetate) was administered coincident with CIDR (1.38 g progesterone [P]) insertion. Inserts were removed after 7 d, and PG (250 μg im cloprostenol sodium) was administered at CIDR removal. In both experiments, estrus detection aids (Estrotect) were applied at the time of PG administration. Estrous status was recorded at FTAI or STAI. Estrus was defined as removal of ≥ 50% of the grey coating from the Estrotect patch. Heifers assigned to FTAI treatments received GnRH and were artificially inseminated at the standard time for FTAI for each protocol: 72 or 54 h after PG administration for the MGA-PG or 7-d CO-Synch + CIDR protocol, respectively. In the STAI treatments, only heifers that expressed estrus prior to the standard time of FTAI were artificially inseminated at that time. For heifers failing to express estrus, AI was postponed 24 h. Only heifers that failed to exhibit estrus by the delayed time received GnRH concurrent with AI. In both experiments, estrous response prior to the standard time of FTAI did not differ between treatments. Total estrous response was increased (P < 0.01) among heifers assigned to STAI in Experiment 1 (88%, STAI; 72%, FTAI) and 2 (74%, STAI; 47%, FTAI). In Experiment 1, pregnancy rates resulting from AI were greater (P < 0.04) for heifers assigned to STAI compared with FTAI (55% vs 46%, respectively). In Experiment 2, pregnancy rates resulting from AI were similar between treatments (48% and 46%, respectively; P = 0.6). In summary, when compared with FTAI, STAI resulted in greater estrous response following both the MGA-PG and 7-d CO-Synch + CIDR protocols. The increased estrous response through use of STAI was associated with a corresponding increase in pregnancy rates to AI following the MGA-PG protocol; however, a similar improvement in pregnancy rates was not observed following the 7-d CO-Synch + CIDR protocol.
Topics: Animals; Cattle; Estrus Synchronization; Female; Insemination, Artificial; Pregnancy; Pregnancy Rate; Progestins; Time Factors
PubMed: 31125868
DOI: 10.1016/j.theriogenology.2019.04.011 -
Animal Reproduction Jan 2021Deer are sensitive to stressful stimuli by handling and their reproductive physiology could be altered by these procedures, making it necessary to develop less invasive...
Deer are sensitive to stressful stimuli by handling and their reproductive physiology could be altered by these procedures, making it necessary to develop less invasive protocols for ART. Melengestrol acetate (MGA), a synthetic progestin administered orally, appears as an alternative for estrous synchronization protocols (ESP), such as reported in cattle. Firstly, we compared two MGA doses (0.5 and 1.0 mg/day/animal), which would have suppression effect in estrous behavior (EB). Eight females were randomly and equally distributed in Group 1 (G1) and Group 2 (G2), which received 0.5 and 1.0 mg/day/animal respectively for 15 days (D1 to D15). Two cloprostenol (CP) applications were performed on D0 and D11. Estrus detection (ED) was performed every day. All females from G1 displayed estrus during treatment period, whereas all females from G2 displayed estrus after treatment, suggesting a suppressive effect of 1.0 mg in the EB. Once the suppressive MGA dose (1.0 mg) was defined, we used this dose for assessing ESP. The same eight females received 1.0 mg/animal for eight days (D-8 to D-1), followed by 0.25 mg of estradiol benzoate on D-8 and 265 μg of CP on D0. Feces for fecal progesterone metabolites (FPM) measurement were collected from D0 until seven days after the last day of estrus. Seven females displayed estrus between 12 and 72 h after CP application, which was followed by a significant increase in FPM levels (except female MG6), suggesting the formation of corpus luteum. After ED, females were placed with a fertile male to assess the fertility of the protocol. Pregnancy was confirmed by ultrasound 30 days after mating in 3/6 individuals. Although the low effectiveness of MGA protocol, it should be considered as a promising alternative in deer ESP since this protocol has less stressful effect on the animal during reproductive management when compared to other ESP.
PubMed: 33791030
DOI: 10.1590/1984-3143-AR2020-0526 -
Animal Reproduction Science Jul 2020This experiment was designed to evaluate breeding strategies involving natural service or fixed-time artificial insemination (FTAI) in Bos indicus-influenced beef...
Comparison of long-term progestin-based protocols to synchronize estrus prior to natural service or fixed-time artificial insemination in Bos indicus-influenced beef heifers.
This experiment was designed to evaluate breeding strategies involving natural service or fixed-time artificial insemination (FTAI) in Bos indicus-influenced beef heifers (n = 1456) when there were field-type management conditions. Body weights and reproductive tract scores (RTS; Scale 1-5) were obtained for heifers before assignment to one of five treatments: 1) Non-synchronized control exposed for natural service (NS), n = 299; 2) melengestrol acetate + natural service (MGA + NS; 0.5 mg/heifer/d), n = 295; 3) 14-d controlled internal drug release insert + natural service (CIDR + NS), n = 289; 4) 14-d MGA-prostaglandin F (PG) + FTAI, n = 295; or 5) 14-d CIDR-PG + FTAI, n = 278. Fertile bulls were placed in pastures with heifers of the three NS treatment groups for a 65-day period which began 10 days after progestin treatments (MGA or CIDR) ended. Heifers in FTAI treatment groups were administered PG (25 mg, IM) 16 days after CIDR removal or 19 days following MGA withdrawal, respectively, and FTAI was performed at 66 (CIDR-PG) or 72 h (MGA-PG) after PG. Gonadotropin-releasing hormone (GnRH; 100 μg, i.m.) was administered at FTAI. Pregnancy status was determined at the end of a 65-day breeding period. Pregnancy rates on Days 21 and 65 of the breeding period differed among treatment groups based on pre-treatment pubertal status (P ≤ 0.02) and body weight (P ≤ 0.05) but did not differ by group. These data highlight the need for continued research efforts to improve reproductive management of Bos indicus-influenced females.
Topics: Animals; Cattle; Estrus Synchronization; Female; Insemination, Artificial; Melengestrol Acetate; Ovary; Pregnancy; Pregnancy Rate; Progesterone; Progestins
PubMed: 32507258
DOI: 10.1016/j.anireprosci.2020.106475