RESUMEN
BACKGROUND: Difference in breed, nutrition status and climate in which animals are managed result in differences in response to reproductive hormones. Fertility rate to artificial insemination is very low in Ethiopian Boran and Boran*Holstein crosses. This partly maybe due to adopting estrus and/or ovulation synchronization developed for temperate taurine cattle. Experimental study was conducted to evaluate ovarian response to combinations of Gonadotrophin-Realizing Hormone agonist (gonadorelin) and ProstaglandinF2α (PGF2α) with or without progesterone (Controlled Internal Drug Release/CIDR), and conception rate to timed AI. Postpartum native Ethiopian Boran (n = 60) and Boran*Holstein cross (n = 66) cows were randomly assigned to four treatment groups as Ovsynch (gonadorelin on day of start, PGF2α seven days later, 2nd gonadorelin at 48 h of PGF2α and insemination at 19 h of the 2nd gonadorelin); CIDR + Ovsynch (same as Ovsynch but CIDR device was inserted into vagina for 7 days); Cosynch (same as Ovsynch but insemination was made at the 2nd gonadorelin) and CIDR + Cosynch (same as Cosynch but CIDR was inserted for 7 days). RESULT: There was no difference (P > 0.05) in ovulation rate to day 9 gonadorelin (88.33% in Boran; 78.79% in Boran*Holstein) and interval from day 9 gonadorelin to ovulation (36.5 ± 1.13 h in Boran and 36.057 ± 1.11 h in Boran*Holstein). Dominant follicle immediate to ovulation (14.95 ± 0.19 mm Vs 19.12 ± 0.49 mm) and corpus luteum size (16.31 ± 0.33 mm Vs 20.28 ± 0.43 mm ) respectively were smaller (P < 0.05) in Boran than Boran*Holstein. Plasma progesterone concentration at PGF2α was higher (P < 0.05) in Boran (11.91 ± 0.74ng/mL) than Boran*Holstein (6.13 ± 0.27ng/mL) but luteolysis rate was lower (P < 0.05) in Boran (87.9%) than Boran-Holstein (96.9%). Cows with CIDR had higher conception rate than cows without CIDR (72.00% Vs 39.02% in Boran*Holstein and 74.07%, Vs 51.52% in Boran respectively). Insemination at 19 h of gonadorelin administration resulted in higher conception rate (78.6% for Boran; 71.43% for Boran*Holstein) than insemination at gonadorelin (69.29% for Boran; 66.67% for Boran*Holstein). CONCLUSION: Boran cows have smaller preovulatory follicles, smaller corpus luteum, large amount of progesterone and lower rate of luteolysis to PGF2α compared to Boran*Holstein. The CL of Boran cattle seems les reactive to PGF2α than Boran*Holstein CL. CIDR significantly improved conception rate in Boran and Boran*Holstein cows.
Asunto(s)
Dinoprost , Progesterona , Femenino , Bovinos , Animales , Dinoprost/farmacología , Sincronización del Estro/métodos , Sincronización del Estro/fisiología , Lactancia/fisiología , Hormona Liberadora de Gonadotropina , Inseminación Artificial/veterinaria , Inseminación Artificial/métodosRESUMEN
Sex steroid concentrations modulate endometrial function and fertility in cattle. Our objective was to compare the post-estrus luminal transcriptome of cows that were exposed to contrasting concentrations of progesterone (P4) before luteolysis that displayed estrus and ovulated spontaneously. Cross-bred beef cows received either (1) a new CIDR and GnRH (day -9; high progesterone treatment; HP4; n = 16) or (2) a previously used CIDR, PGF2α, and GnRH (low progesterone treatment; LP4; n = 24). All cows received PGF2α at CIDR removal (day -2). Ovarian ultrasonography and blood collections were performed on days -9, -2, -0.5, and 0 (day of observed estrus), and days 4, 7, and 14 for measurement of ovarian structures, P4, and estradiol (E2). Luminal epithelial cells were collected using a cytology brush on days 4, 7, and 14 for RNAseq. On day -2, CL area and concentrations of P4 were greater, while on day -0.5, concentrations of E2 were decreased in HP4. Ovarian structures and hormonal concentrations were similar on days 4, 7, or 14 (P > 0.05). There were enriched pathways in HP4 related to activation and signaling of the innate immune system at day 4, downregulation in the network involved in the extracellular matrix remodeling at day 7, and exacerbated inflammatory response as well as differentiation and activation of macrophages at day 14 (Benjamini-Hochberg P-value ≤ 0.05). In conclusion, manipulation of pre-luteolysis sex steroid concentrations altered the post-estrus luminal transcriptome even though all cows showed estrus and ovulated spontaneously.
Asunto(s)
Luteólisis , Progesterona , Femenino , Bovinos , Animales , Progesterona/farmacología , Dinoprost/farmacología , Folículo Ovárico/fisiología , Transcriptoma , Sincronización del Estro/fisiología , Inseminación Artificial/veterinaria , Hormona Liberadora de Gonadotropina , Lactancia/fisiologíaRESUMEN
The objectives of this retrospective observational study were to determine the associations of anogenital distance (AGD) with (a) postpartum estrous activity, (b) diameter of the preovulatory follicle, (c) intensity of estrous expression, (d) postestrus ovulation, (e) corpus luteum (CL) size, and (f) concentrations of progesterone at estrus and on d 7 after estrus. Lactating Holstein cows (n = 178; 55 primiparous, 123 multiparous) were enrolled into the study during the first postpartum week. All cows were continuously monitored by a pedometer-based automated activity monitoring (AAM) system for estrus. Postpartum estrous activity was assessed using the AAM estrus alerts, in which cows with at least one true estrus alert (i.e., a relative increase in steps from each cow's baseline detected by the AAM and the presence of at least one follicle >15 mm, a CL <20 mm, or no CL detected by ultrasound) by the first 50 d in milk (DIM) were considered to have commenced estrous activity. At the estrus alert >60 DIM, ovulation was determined by ultrasound at 24 h, 48 h, and 7 d after estrus, and blood samples were collected at estrus alert and on d 7 after estrus for progesterone analysis. The AGD was measured from the center of the anus to the base of the clitoris and classified as either short- or long-AGD using 2 cut-points of 148 mm (predictive of the probability of pregnancy to first insemination; short-AGD, n = 115; long-AGD, n = 63) and 142 mm (the median AGD; short-AGD, n = 90; long-AGD, n = 88). Regardless of the cut-point used, early postpartum estrous activity by 50 DIM (67 vs. 54%), duration of estrus (11.6 vs. 9.7 h), and preovulatory follicle diameter (20 vs. 19 mm) were greater in short-AGD than in long-AGD cows. Increased peak of activity at estrus in short-AGD cows (354 vs. 258% mean relative increase) was affected by an interaction between AGD and parity in which multiparous long-AGD cows had lesser relative increase in activity than primiparous cows (217 vs. 386%, respectively). Mean progesterone concentration at estrus was lesser in short-AGD (0.47 vs. 0.61 ng/mL) than in long-AGD cows. The ovulatory response at 24 h did not differ, but at 48 h (91 vs. 78%) and on d 7 after estrus (97 vs. 84%) it was greater in short-AGD cows. Although CL diameter on d 7 after estrus did not differ, short-AGD cows had greater progesterone concentration 7 d after estrus than long-AGD cows (4.1 vs. 3.2 ng/mL, respectively). In conclusion, greater proportions of short-AGD cows commenced estrous activity by 50 DIM, had larger preovulatory follicles, exhibited greater duration of estrus, had reduced progesterone concentration at estrus, had greater ovulation rates and progesterone concentration 7 d after estrus compared with long-AGD cows, with no difference in CL size between AGD groups. Because all the differences in physiological characteristics of short-AGD cows reported herein favor improved reproductive outcomes, we infer that these are factors contributing to improved fertility reported in short-AGD cows compared with long-AGD cows.
Asunto(s)
Sincronización del Estro , Progesterona , Animales , Bovinos , Estro/fisiología , Sincronización del Estro/fisiología , Femenino , Inseminación Artificial/veterinaria , Lactancia/fisiología , Ovulación/fisiología , Periodo Posparto , EmbarazoRESUMEN
The aim of the study was to determine the luteolytic dose of cloprostenol administered directly into the corpus luteum (CL; intra-luteal treatment, ILT) in dairy cattle. Cows of two control groups were treated with 500⯵g of cloprostenol (Estrumate®) intramuscularly (IM-500) or via ILT with 0.2â¯mL of physiological solution (ILT-0). Cows of four experimental groups were treated by ILT with cloprostenol in doses 5, 25, 50 and 100⯵g (ILT-5, -25, -50 and -100 groups). Progesterone concentrations (P4) and size of CL were evaluated to assess luteolysis at 0, 0.5, 1, 2, 4, 8, 24 and 48â¯h or at 0, 24 and 48â¯h after ILT, respectively. Cows in the ILT-0 and -5 groups were unaffected by ILT. The P4 concentrations were less in cows of the IM-500, as well as ILT-25, -50 and -100 groups at 48â¯h subsequent to ILT. The size of the CL was less in cows of IM-500, as well as ILT-25, -50 and -100 groups at 48â¯h after ILT. There were P4 concentrations of about 1â¯ng/mL 48â¯h after ILT in cows of the IM-500, as well as ILT-50 and -100 groups. In conclusion, the cloprostenol dose of 50⯵g administered intra-luteally is a luteolytic dose in cows.
Asunto(s)
Bovinos , Cloprostenol/administración & dosificación , Cuerpo Lúteo/efectos de los fármacos , Luteólisis/efectos de los fármacos , Animales , Cloprostenol/farmacología , Cuerpo Lúteo/citología , Cuerpo Lúteo/diagnóstico por imagen , Industria Lechera , Vías de Administración de Medicamentos , Sincronización del Estro/efectos de los fármacos , Sincronización del Estro/fisiología , Femenino , Lactancia/efectos de los fármacos , Lactancia/fisiología , Fase Luteínica/sangre , Fase Luteínica/efectos de los fármacos , Luteólisis/fisiología , Ovario/diagnóstico por imagen , Ovario/efectos de los fármacos , Progesterona/sangre , Resultado del Tratamiento , Ultrasonografía/métodos , Ultrasonografía/veterinariaRESUMEN
Objectives were to compare pregnancy percentages per embryo transfer (P/ET) in recipient beef cows following twice daily compared with split-time estrous detection and to determine associations of dominant follicle diameter, CL volume and progesterone concentrations. All cows (nâ¯=â¯695) were treated to synchronize time of estrus among cows using a CIDRâ¯+â¯Select-Synch treatment regimen and randomly assigned to twice-daily or split-time estrous detection (CS-DEET or CS-SEET, respectively). Cows in the CS-DEET group were observed twice daily (eight times) for estrus until 96â¯h after the time of PGF2α administration, whereas cows in the CS-SEET group were observed twice (64 and 84â¯h after PGF2α). In 280 recipient cows, blood sampling (for progesterone) and ultrasonographic assessment of dominant follicle diameter were conducted 48â¯h after the time of PGF2α administration. At 7 d after estrus, the CL was imaged and there was transfer of a frozen-thawed embryo into cows with a CLâ¯≥â¯1.5â¯cm. There were positive correlations between follicle diameter and CL volume (rs = 0.827; Pâ¯<â¯0.001) and CL volume and progesterone concentration (rsâ¯=â¯0.680; Pâ¯<â¯0.001). Progesterone and CL volume differed between cows in CS-SEET and CS-DEET groups Pâ¯<â¯0.05), however, percentage P/ET for cows in the CS-SEET and CS-DEET groups did not differ (Pâ¯>â¯0.1). Dominant follicle diameter, CL volume and progesterone concentrations were greater in pregnant compared with nonpregnant cows. In conclusion, percentage P/ET did not differ when there was twice daily and split-time estrous detection highlighting the value of this approach in beef enterprises.
Asunto(s)
Bovinos , Transferencia de Embrión , Detección del Estro/métodos , Índice de Embarazo , Preñez , Animales , Ritmo Circadiano , Dinoprost/farmacología , Transferencia de Embrión/métodos , Transferencia de Embrión/estadística & datos numéricos , Transferencia de Embrión/veterinaria , Detección del Estro/estadística & datos numéricos , Sincronización del Estro/métodos , Sincronización del Estro/fisiología , Femenino , Inseminación Artificial/veterinaria , Folículo Ovárico/citología , Folículo Ovárico/diagnóstico por imagen , Folículo Ovárico/efectos de los fármacos , Embarazo , Factores de Tiempo , Ultrasonografía/veterinariaRESUMEN
Dairy cows frequently undergo a state of negative energy balance (NEB) after parturition and some have impaired ovarian functions that result in delayed resumption of estrous cyclicity and development of follicles without ovulation occurring. During the postpartum period, cows undergo body-fat store losses, hormonal changes, fat mobilization and increases in nonesterified fatty acid (NEFAs) concentrations in blood and follicular fluid. The effect of NEFAs on follicular development and function of follicular cells, however, is not fully understood. The aim of this study, therefore, was to study the effect of an intrafollicular injection of a mixture of oleic, stearic and palmitic NEFAs on dominant follicle development and function of granulosa cells in cows that were not in a NEB state. Follicular size was less at 24 and 48â¯h after administration of NEFAs compared to that of control follicles injected with vehicle only. At 24â¯h after intrafollicular injection, the relative mRNA transcript abundance for proteins involved in steroidogenesis (CYP19A1, 3BHSD, STAR, FSHR), metabolism (GLUT1, GLUT3, INSR, IRS1, IRS2, SLC27A1, PPARG), and cell proliferation and apoptosis (CCND2; XIAP) in granulosa cells, as well as estradiol concentrations in follicular fluid were similar in control and NEFA-treated follicles. In conclusion, the results of this study indicate increased intrafollicular concentrations of NEFAs in cows that are not in a NEB state has a detrimental effect on follicle development. We propose intrafollicular injection is a useful approach to further investigate the local effects of NEFAs on the function of follicular cells.
Asunto(s)
Bovinos , Ácidos Grasos no Esterificados/farmacología , Folículo Ovárico/efectos de los fármacos , Ovulación/efectos de los fármacos , Animales , Aromatasa/genética , Aromatasa/metabolismo , Metabolismo Energético/efectos de los fármacos , Metabolismo Energético/fisiología , Sincronización del Estro/efectos de los fármacos , Sincronización del Estro/fisiología , Ácidos Grasos no Esterificados/administración & dosificación , Femenino , Líquido Folicular/efectos de los fármacos , Líquido Folicular/metabolismo , Regulación de la Expresión Génica/efectos de los fármacos , Células de la Granulosa/citología , Células de la Granulosa/efectos de los fármacos , Células de la Granulosa/metabolismo , Inyecciones , Metabolismo de los Lípidos/efectos de los fármacos , Metabolismo de los Lípidos/fisiología , Oogénesis/efectos de los fármacos , Oogénesis/genética , Folículo Ovárico/fisiología , Ovariectomía/veterinaria , Ovulación/genética , Ovulación/metabolismo , ARN Mensajero/metabolismoRESUMEN
Changes in some vaginal mucus parameters were studied in order to generate predictive models capable of enhancing oestrous cycle staging, using equal groups (unsynchronized-USC [no treatment] and synchronized-SC [Synchromate® i/m on d0, d11]) of Bunaji cows (n = 48) aged 3-4 years. Vaginal mucus was collected (starting d11 in SC) daily over 26 days using standard procedures. Physical (viscosity, elasticity, density, resistivity) and biochemical (pH, glucose, cholesterol, total protein, calcium, magnesium, sodium, potassium) parameters were evaluated using standard procedures. Data were analysed using chi-square and multinomial logit regression modelling. Models generated using oestrus as reference categories were ascertained for accuracies. Chi-square values for viscosity, elasticity and density were significant (p < .01) in USC and SC across stages of the cycle. Results for USC showed that pH and cholesterol were predictive (p < .01) for pro-oestrus, metoestrus and dioestrus, while total protein was predictive (p < .01) for dioestrus only. Similarly, magnesium was predictive (p < .05) for pro-oestrus. For SC, pH, magnesium and cholesterol were predictive (p < .01) for pro-oestrus, metoestrus and dioestrus, while total protein was predictive (p < .01) for pro-oestrus and dioestrus. Potassium and total protein were also predictive for metoestrus at 10% and 5% significance levels, respectively. Though findings suggest the usefulness of magnesium in staging the oestrous cycle only in synchronized cows, pH, total protein and cholesterol appeared to be the more important vaginal mucus parameters in Bunaji cows, regardless synchronization. Furthermore, the models developed showed high accuracy levels for staging the oestrous cycle in USC (100%) and SC (89%).
Asunto(s)
Bovinos/fisiología , Ciclo Estral/fisiología , Moco/química , Vagina/química , Animales , Colesterol/análisis , Elasticidad , Sincronización del Estro/fisiología , Femenino , Concentración de Iones de Hidrógeno , Magnesio/análisis , Proteínas/análisis , ViscosidadRESUMEN
The Tibet minipig is a rare highland pig breed worldwide and has many applications in biomedical and agricultural research. However, Tibet minipigs are not like domesticated pigs in that their ovulation number is low, which is unfavourable for the collection of zygotes. Partly for this reason, few studies have reported the successful generation of genetically modified Tibet minipigs by zygote injection. To address this issue, we described an efficient way to generate gene-edited Tibet minipigs, the major elements of which include the utilization of synchronized oestrus instead of superovulation to obtain zygotes, optimization of the preparation strategy, and co-injection of clustered regularly interspaced short palindromic repeat sequences associated protein 9 (Cas9) mRNA and single-guide RNAs (sgRNAs) into the cytoplasm of zygotes. We successfully obtained allelic TYR gene knockout (TYR-/-) Tibet minipigs with a typical albino phenotype (i.e., red-coloured eyes with light pink-tinted irises and no pigmentation in the skin and hair) as well as TYR-/-IL2RG-/- and TYR-/-RAG1-/- Tibet minipigs with typical phenotypes of albinism and immunodeficiency, which was characterized by thymic atrophy and abnormal immunocyte proportions. The overall gene editing efficiency was 75% for the TYR single gene knockout, while for TYR-IL2RG and TYR-RAG1 dual gene editing, the values were 25% and 75%, respectively. No detectable off-target mutations were observed. By intercrossing F0 generation minipigs, targeted genetic mutations can also be transmitted to gene-edited minipigs' offspring through germ line transmission. This study is a valuable exploration for the efficient generation of gene-edited Tibet minipigs with medical research value in the future.
Asunto(s)
Sincronización del Estro/fisiología , Edición Génica/métodos , Porcinos Enanos/genética , Animales , Sistemas CRISPR-Cas/genética , Citoplasma , Femenino , Masculino , Microinyecciones , Mutación , Superovulación , PorcinosRESUMEN
In recent years, the number of equine invitro-produced embryos (IVP) has increased markedly; as yet, there are few reports on what constitutes an 'ideal' recipient for an IVP embryo. This study retrospectively investigated the effects of recipient mare oestrous cycle characteristics on the likelihood of pregnancy after transfer of IVP (n=264) and invivo-derived embryos (n=262). IVP embryos tolerated only a narrow window of recipient mare 'synchrony', with transfer on Day 4 after ovulation resulting in a higher likelihood of ongoing pregnancy (69%) than transfer on Days 3, 5 or 6 (53.2%, 41.3% and 23.1% respectively; P=0.02). In contrast, Day 8 invivo-derived embryos tolerated a wide range of uterine (a)synchrony, with no difference in pregnancy or pregnancy loss for recipients that ovulated between Day 4 and Day 9 before transfer. However, transferring invivo-derived embryos to recipients that had a longer oestrus preceding transfer resulted in higher Day 12 and ongoing pregnancy rate (P<0.01). This effect was not significant in IVP embryos. In conclusion, Day 6-8 IVP blastocysts survive best after transfer to Day 4 recipient mares; Day 8 invivo-derived embryos survive equally well in Day 4-9 recipients, but do better in mares that have a long preceding oestrus.
Asunto(s)
Implantación del Embrión/fisiología , Transferencia de Embrión , Sincronización del Estro/fisiología , Fertilización In Vitro , Caballos , Animales , Transferencia de Embrión/métodos , Transferencia de Embrión/veterinaria , Embrión de Mamíferos , Femenino , Fertilización In Vitro/métodos , Fertilización In Vitro/veterinaria , Caballos/embriología , Caballos/fisiología , Masculino , Ovulación/fisiología , Embarazo , Índice de Embarazo , Estudios Retrospectivos , Factores de Tiempo , Resultado del Tratamiento , Útero/fisiologíaRESUMEN
In this single herd observational study, there is investigation of the effects of 81 sires (with 11,424 artificial inseminations) on conception rates in 1790 Holstein cows for 5 years. Sires were catagorized based on the published sire conception rate (SCR) into different sire fertility groups (low, average and high fertility sires). The performance of different-sire fertility groups was assessed in timed artificial insemination (TAI) and repeat-breeder (RB) cows. With this aim, two logistic regression models with sire, inseminator, cow, and lactation random effects were applied to data on pregnancies assessed at days 30 and 70 post-insemination. Fixed effects of sire fertility group, sire breed, cow-fertility status, insemination type, postpartum problems, milk yield, temperature humidity index, and year were evaluated. Results from the analysis indicated there was a significant individual sire effect on conception rates, and large heterogeneity in values for this variable among sires. Results indicate that SCR could be assessed to predict low fertility sires reasonably well, and the predicted probabilities for pregnancy per AI (P/AI) at 30 and 70 days post-insemination for high fertility sires were consistent for the most part with values for the SCR. The sire breed did not affect conception rates at days 30 and 70 post-insemination nor its interactions with insemination type (estrous detection AI (EDAI) compared with TAI) and cow-fertility status (RB compared with non-RB). Predicting response probabilities for sires with at least 100 inseminations in each insemination group resulted in greater conception probabilities in cows in which there was EDAI than those in the TAI group.
Asunto(s)
Cruzamiento , Bovinos , Padre , Fertilidad/fisiología , Inseminación Artificial , Índice de Embarazo , Animales , Cruzamiento/métodos , Cruzamiento/estadística & datos numéricos , Industria Lechera/métodos , Sincronización del Estro/fisiología , Femenino , Fertilización/fisiología , Inseminación Artificial/métodos , Inseminación Artificial/estadística & datos numéricos , Inseminación Artificial/veterinaria , Masculino , EmbarazoRESUMEN
A reciprocal crossbred embryo production approach was used to assess effects of maternal breed on embryo development in tropical conditions (average temperature 22.0⯰C and 77.9% relative humidity). Oocytes were recovered by ovum pick-up (OPU) from Gyr and Holstein donors (n = 90 Holstein and 83 Gyr OPUs). Female F1 embryos were produced by fertilization with sperm bearing X-chromosomes from Holstein semen (n = 615 Gyr oocytes) or Gyr semen (n = 255 Holstein oocytes). Blastocysts were transferred to recipients 168â¯h post-insemination (h.p.i.) (n = 70-144) and there were assessments of pregnancies until birth. Oocyte number per OPU (Gyr 10.0⯱â¯0.7 compared with Holstein 6.3⯱â¯0.4) and percentage viable oocytes (Gyr 78.8⯱â¯1.9% compared with Holstein 71.2⯱â¯2.2%) were less for Holstein donor animals. There was a 2.8 fold fewer total number of F1 blastocysts when Holstein donors were used (Gyr: 260, Holstein: 91). Pregnancy assessment during the different stages of gestation indicated the percentage pregnancy was less when embryos were produced from Holstein oocytes (Gyr and Holstein respectively: early pregnancy, 47.9% compared with 38.6%; mid-pregnancy, 44.4% compared with 31.4%; late pregnancy, 41.0% compared with 22.9%). Pregnancy length was also affected by maternal breed (Gyr: 280.8⯱â¯0.6, Holstein: 286.3⯱â¯0.7). It is concluded that in a tropical environment the maternal breed affects crossbred embryo development with pregnancy rates during the latter stages of gestation being greater when Gyr oocytes are used for production of embryos.
Asunto(s)
Blastocisto/citología , Bovinos , Desarrollo Embrionario/fisiología , Hibridación Genética/fisiología , Madres , Oocitos/citología , Animales , Blastocisto/fisiología , Bovinos/embriología , Células Cultivadas , Técnicas de Cultivo de Embriones/veterinaria , Embrión de Mamíferos , Sincronización del Estro/métodos , Sincronización del Estro/fisiología , Femenino , Fertilización In Vitro/métodos , Fertilización In Vitro/veterinaria , Masculino , Madres/clasificación , Recuperación del Oocito/métodos , Recuperación del Oocito/veterinaria , Oocitos/fisiología , Embarazo , Resultado del TratamientoRESUMEN
Two experiments were conducted to investigate the role of relatively lesser and greater progesterone (P4) concentrations during early follicular development on ovulatory follicle growth and pregnancy rate in beef cattle. In Experiment 1, time of ovulation was synchronized with the 5 d CO-Synchâ¯+â¯CIDR (Controlled Internal Drug Release) program in multiparous cows (nâ¯=â¯241). Six days after the 2nd GnRH injection of the pre-synchronization program (d 0), ablation of follicles ≥ 5â¯mm in the ovaries was performed and cows were assigned to receive either a previously used CIDR and 2x-25â¯mg PGF2α doses 8â¯h apart (LoP4), or a new CIDR (HiP4). On d 5, CIDR were removed from all cows, 2x-25â¯mg PGF2α were administered, and estrous detection tail paint was applied. Timed artificial insemination (TAI) was performed on d 8. On d 5, P4 concentrations were greater (Pâ¯<⯠0.01) in the HiP4 (4.9 ± 0.13 ng/mL) than LoP4 (1.0 ± 0.06 ng/mL) treatment group. Conversely, d 5 estradiol (E2) concentrations and follicular diameter were greater (Pâ¯<⯠0.01) in the LoP4 (5.0 ± 0.23 pg/mL and 8.9 ± 0.20 mm) than HiP4 (1.5 ± 0.12 pg/mL and 7.4 ± 0.15 mm) treatment group. Follicular diameter at TAI (12.0 ± 0.12 mm, Table 1) and TAI pregnancy rate did not differ (Pâ¯>⯠0.10) between treatment groups. In Experiment 2, a new follicular wave was induced with estradiol benzoate on d -7, and cows (nâ¯=â¯275) were assigned on d 0 to receive 25â¯mg PGF2α and either have the CIDR replaced with a new CIDR (HiP4) or the used CIDR was left in place (LoP4).Furthermore, all cows received GnRH on d 0. The CIDRs were removed from all cows on d 5 and two doses of -25â¯mg PGF2α were administered. Estrous detection combined with AI 12â¯h later (Estrus-AI) was performed for 60â¯h after CIDR removal with TAI coupled with GnRH administration at 72â¯h if estrus was not detected. The concentrations of P4 on d 5 were greater (Pâ¯<⯠0.01) in the HiP4 (2.8 ± 0.10 ng/ml) than LoP4 (1.7 ± 0.05 ng/mL) treatment group. For cows that were detected in estrus after PGF2α administration, estrous response (83.5%) and interval to estrus (55.0 ± 0.5 h) did not differ between treatment groups. Pregnancy rate (combined Estrus-AI and TAI) that resulted from breeding at the time of the synchronized time of estrus was similar between treatment groups (HiP4: 77.1%; LoP4: 82.3%). In conclusion, differences in P4 concentrations during early follicular development do not effect pregnancy rate in beef cows when the cows are inseminated at the time of a synchronized estrus if the cows have similar intervals of proestrus.
Asunto(s)
Bovinos/fisiología , Sincronización del Estro/fisiología , Índice de Embarazo , Progesterona/fisiología , Animales , Dinoprost , Femenino , Hormona Liberadora de Gonadotropina , Inseminación Artificial , Embarazo , Progesterona/sangreRESUMEN
The aim of the present study was to investigate the effects of a strategy for extending pro-oestrus (the interval between luteolysis and ovulation) in an oestrus synchronisation protocol (named J-Synch) in beef heifers on follicular growth, sexual steroid concentrations, the oestrogen receptor ERα and progesterone receptors (PR) in the uterus, insulin-like growth factor (IGF) 1 and pregnancy rates. In Experiment 1, heifers treated with the new J-Synch protocol had a longer pro-oestrus period than those treated with the conventional protocol (mean (±s.e.m.) 93.7±12.9 vs 65.0±13.7h respectively; P<0.05). The rate of dominant follicle growth from the time of progesterone device removal to ovulation was greater in heifers in the J-Synch than conventional group (P<0.05). Luteal area and serum progesterone concentrations were greater in the J-Synch Group (P<0.05) for the 12 days after ovulation. Progesterone receptor (PGR) staining on Day 6 after ovulation in the uterine stroma was lower in the J-Synch than conventional group (P<0.05), and the expression of PR gene (PGR) and IGF1 gene tended to be lower in J-Synch-treated heifers (P<0.1). In Experiment 2 (n=2349), the pregnancy rate 30-35 days after fixed-time AI (FTAI) was greater for heifers in the J-Synch than conventional group (56.1% vs 50.7% respectively). In conclusion, our strategy for extending pro-oestrus (i.e. the J-Synch protocol) significantly improves pregnancy establishment in beef heifers. This improvement was related to an increased rate of growth of the dominant ovulatory follicle, greater progesterone concentrations during the ensuing luteal phase and different uterine patterns of PGR and IGF1, which may have favoured embryo development and pregnancy establishment.
Asunto(s)
Estradiol/análogos & derivados , Sincronización del Estro/fisiología , Ovario/fisiología , Proestro/fisiología , Progesterona/administración & dosificación , Útero/fisiología , Animales , Bovinos , Estradiol/administración & dosificación , Estradiol/sangre , Sincronización del Estro/efectos de los fármacos , Femenino , Folículo Ovárico/diagnóstico por imagen , Folículo Ovárico/efectos de los fármacos , Ovario/diagnóstico por imagen , Ovario/efectos de los fármacos , Embarazo , Proestro/efectos de los fármacos , Progesterona/sangre , Receptores de Estrógenos/metabolismo , Receptores de Progesterona/metabolismo , Útero/diagnóstico por imagen , Útero/efectos de los fármacosRESUMEN
The objective of this study was to evaluate the economic performance of dairy cows managed with a voluntary waiting period (VWP) of 60 or 88 d. A secondary objective was estimating variation in cash flow under different input pricing scenarios through stochastic Monte Carlo simulations. Lactating Holstein cows from 3 commercial farms were blocked by parity group and total milk yield in their previous lactation and then randomly assigned to a VWP of 60 (VWP60; n = 1,352) or 88 d (VWP88; n = 1,359). All cows received timed-artificial insemination (TAI) for first service after synchronization of ovulation with the Double-Ovsynch protocol. For second and greater services, cows received artificial insemination (AI) after detection of estrus or the Ovsynch protocol initiated 32 ± 3 d after AI. Two analyses were performed: (1) cash flow per cow for the calving interval of the experimental lactation and (2) cash flow per slot occupied by each cow enrolled in the experiment for an 18-mo period after calving in the experimental lactation. Extending the VWP from 60 to 88 d delayed time to pregnancy during lactation (â¼20 d) and increased the risk of leaving the herd for multiparous cows (hazard ratio = 1.21). As a result, a smaller proportion of multiparous cows calved again and had a subsequent lactation (-6%). The shift in time to pregnancy combined with the herd exit dynamics resulted in longer lactation length for primiparous (22 d) but not multiparous cows. Longer lactations led to greater milk income over feed cost and a tendency for greater cash flow during the experimental lactation for primiparous but not multiparous cows in the VWP88 group. On the other hand, profitability per slot for the 18-mo period was numerically greater ($68 slot/18 mo) for primiparous cows but numerically reduced (-$85 slot/18 mo) for multiparous cows in the VWP88 treatment. For primiparous cows most of the difference in cash flow was explained by replacement cost, whereas for multiparous cows it was mostly explained by differences in replacement cost and income over feed cost. Under variable input pricing conditions generated through stochastic simulations, the longer VWP treatment always increased cash flow per 18 mo for primiparous and reduced cash flow for multiparous cows. In conclusion, extending the duration of the VWP from 60 to 88 d numerically increased profitability of primiparous cows and reduced profitability of multiparous cows. Such an effect depended mostly on the herd replacement dynamics and milk production efficiency.
Asunto(s)
Bovinos/fisiología , Industria Lechera/economía , Inseminación Artificial/veterinaria , Reproducción/fisiología , Animales , Industria Lechera/métodos , Dinoprost , Estro , Sincronización del Estro/fisiología , Femenino , Hormona Liberadora de Gonadotropina , Inseminación Artificial/métodos , Lactancia/fisiología , Paridad , Embarazo , Progesterona , Factores de TiempoRESUMEN
To better understand the impact of ovarian superstimulation on bovine follicular microenvironment, Nelore cows (Bos taurus indicus) were subjected to ovarian superstimulation with follicle stimulating hormone (FSH, nâ¯=â¯10; P-36 protocol) or FSH combined with eCG (nâ¯=â¯10; P-36/eCG protocol). Follicular fluid was analyzed for cholesterol concentration. Granulosa cells were analyzed by RT-qPCR to assess the expression of genes involved in steroidogenic and ovulatory and expression of microRNAs involved in final follicular development and luteinizing hormone/choriogonadotropin receptor (LHCGR) expression. Plasma concentration of estradiol was also measured. Follicular fluid from the P-36 group showed higher concentration of cholesterol than that of control (non-superstimulated) cows. Plasma concentration of estradiol was higher in the P-36/eCG group. Abundance of STAR and FSHR mRNAs were lower in granulosa cells from the P-36/eCG group. In contrast, LHCGR mRNA abundance was higher in superstimulated granulosa cells from the P-36 group and showed a pattern opposite to that of miR-222 expression. Ovarian superstimulation did not affect the expression of other markers (mmu-miR-202-5p, has-miR-873, has-miR-144, and their target genes, CREB, TGFBR2, and ATG7) of antral follicle development. However, the mRNA expression of VEGF pathway components was modulated by P-36 treatment. Taken together, these results demonstrate that superstimulatory protocols modify steroidogenic capacity, increase plasma estradiol, and regulate the abundance of VEGF system, LHCGR mRNA and suppress the expression of miR-222 in bovine granulosa cells.
Asunto(s)
Bovinos/genética , Hormonas Esteroides Gonadales/biosíntesis , MicroARNs/genética , Ovulación/genética , Superovulación/genética , Animales , Sincronización del Estro/fisiología , Femenino , Expresión Génica , Redes y Vías Metabólicas/genética , Inducción de la Ovulación/métodos , Inducción de la Ovulación/veterinaria , Superovulación/fisiologíaRESUMEN
Two experiments were performed to test the hypothesis that administering PGF2α concurrent with timed artificial insemination (AI) in lactating dairy cows would enhance pregnancy per AI (P/AI). In experiment 1, lactating Holstein cows (nâ¯=â¯289) in one herd were enrolled after a non-pregnancy diagnosis (30-36â¯d after AI) to synchronize subsequent ovulation before AI. Cows were assigned randomly to receive (im) 10â¯mg of PGF2α concurrent with timed AI (Day 0; treatment) or no injection (control). Blood samples were collected on Days -3, 0, and 13 to determine serum concentrations of progesterone. Ovaries were scanned via transrectal ultrasonography to determine follicle diameters (Day -3), subsequent ovulation risk (Day 13), and total volume of luteal tissue (Day 13). Diagnosis of pregnancy occurred on Days 32 and 80 after AI. Ovulation risk post-AI exceeded 90% and did not differ between treatments. In addition, PGF2α treatment only numerically increased progesterone (5.7⯱â¯0.3 vs. 6.2⯱â¯0.3â¯ng/mL) or luteal tissue volume (8.9⯱â¯0.4 vs. 9.8⯱â¯0.5â¯ng/mL) on Day 13 by 8.8% (Pâ¯=â¯.206) or 10.1% (Pâ¯=â¯.134) in control and treated cows, respectively. Pregnancy per AI at Days 32 (Pâ¯=â¯.50) and 80 (Pâ¯=â¯.33) did not differ between treatments. Cows with progesterone >0.5â¯ng/mL at timed AI had reduced (Pâ¯<â¯.001) ovulation risk but risk was unaffected by treatment. In experiment 2, lactating dairy cows (nâ¯=â¯1828) in two commercial dairy herds were enrolled at time of insemination (Day 0), and assigned randomly to treatment or control as described in experiment 1. Initial (Days 32-35) and confirmed (Days 63-68) pregnancy diagnosis revealed no differences in P/AI or pregnancy loss. Pregnancy diagnosis on Days 32-35 produced percentage increases in P/AI for primiparous compared with multiparous cows (20.8%; Pâ¯=â¯.002), for first-service compared with repeat-service cows (26%; Pâ¯=â¯.001), and cows in one herd compared with the second herd (36%; Pâ¯<â¯.001). Pregnancy loss was greater (Pâ¯=â¯.001) for cows inseminated at first (10.0%) vs. later services (5.3%) but was unaffected by treatment. Cows treated with PGF2α in one herd produced more twins than control cows (11.7 vs. 3.2%), whereas no treatment difference was detected in the second herd (5.6 vs. 5.6%), respectively. We conclude that im treatment of lactating dairy cows with 10â¯mg of PGF2α concurrent with timed AI did not improve P/AI or embryo survival, but increased twinning in one herd.
Asunto(s)
Bovinos , Industria Lechera/métodos , Dinoprost/administración & dosificación , Sincronización del Estro/efectos de los fármacos , Inseminación Artificial , Lactancia/fisiología , Preñez , Aborto Veterinario/etiología , Animales , Relación Dosis-Respuesta a Droga , Sincronización del Estro/fisiología , Femenino , Inseminación Artificial/veterinaria , Masculino , Inducción de la Ovulación/métodos , Inducción de la Ovulación/veterinaria , Embarazo , Embarazo Múltiple/efectos de los fármacos , Factores de Riesgo , Factores de TiempoRESUMEN
Two experiments were conducted with the aim of determining the effect of equine chorionic gonadotropin (eCG) administration on day 14 after insemination on ovarian response and pregnancy establishment in postpartum anestrous beef cows. In both experiments, cows were subjected to a progesterone- and estradiol-based treatment for fixed-time artificial insemination (FTAI) and were randomly allocated into 4 groups to receive or not receive eCG (400 IU) at the time of device removal and/or at 14 d after FTAI. In experiment 1, from day 14 to 22, daily ultrasonographic determinations were performed to monitor ovarian dynamics, and blood was collected to determine hormone concentrations in 60 cows. In experiment 2, confirmation of pregnancy was performed at 30 and 60 d after FTAI in 1,060 anestrous cows assigned to the same experimental design. Cows that received eCG on day 14 after FTAI showed increases in corpus luteum area (P < 0.01), follicle diameter (P < 0.05), serum progesterone concentrations (P < 0.01), and estradiol-17ß concentrations (P < 0.01), compared with cows that did not receive eCG on day 14. Pregnancy rate on day 30 was greater in those cows that received both eCG treatments (ie, at device removal and 14 d after insemination) than in those that did not receive eCG treatment (P < 0.05). In conclusion, eCG administered on day 14 after FTAI increases serum progesterone concentrations during the critical period of pregnancy in anestrous cows, and this second eCG treatment seems to have a positive effect on achieving pregnancy.
Asunto(s)
Bovinos/fisiología , Cuerpo Lúteo/efectos de los fármacos , Gonadotropinas Equinas/farmacología , Preñez , Animales , Cuerpo Lúteo/fisiología , Sincronización del Estro/fisiología , Femenino , Gonadotropinas Equinas/administración & dosificación , Inseminación Artificial/veterinaria , Periodo Posparto , Embarazo , Preñez/efectos de los fármacosRESUMEN
This study aimed to evaluate the effect of oestrous synchrony between donors and recipients and the embryo quality on the pregnancy rate in beef cow recipients. The experiment was performed over two years at an embryo transfer (ET) centre in Southern Brazil. Ninety Aberdeen Angus cows were subjected to superovulation (SOV) protocols, resulting in the recovery of 1,048 transferable embryos. Eleven groups were formed with intervals of 6 hr, from -30 to +30 hr, with respect to recipient versus donor oestrous detection. Evaluation of embryo quality was according to the IETS guidelines. The overall pregnancy rate was 52%. Effects related to donor and recipient oestrous synchronization on pregnancy rate were observed (p = .01), ranging from 36% to 50%. The embryo quality rate affected the pregnancy rate, where Grade I resulted in 57% and Grade III in 43% of pregnancy (p < .001). The embryonic state (frozen or fresh) showed no (p > .05) effect on pregnancy rate: 53% for fresh embryos and 44% for frozen embryos. The odds ratio for explanatory variables causing pregnancy indicated that Grade III embryos had 31% less chance of conception compared to Grade I. Thus, oestrous synchrony between donor and recipient, considering ±30 hr apart, can affect the pregnancy rate along with embryo quality.
Asunto(s)
Transferencia de Embrión/veterinaria , Embrión de Mamíferos/fisiología , Sincronización del Estro/fisiología , Índice de Embarazo , Animales , Bovinos , Transferencia de Embrión/métodos , Femenino , Congelación , Inseminación Artificial/veterinaria , Embarazo , SuperovulaciónRESUMEN
Approximately 20 to 30% of cows diagnosed not pregnant 32 d after timed artificial insemination (TAI) lack a corpus luteum (CL), and cows submitted to a resynchronization protocol in the absence of a CL have about 10% fewer pregnancies per AI (P/AI) than cows with a CL. An understanding of luteal dynamics after synchronization of ovulation and TAI may help refine strategies for reinseminating cows failing to conceive. Lactating Holstein cows (n = 141) were synchronized for first TAI using a Double-Ovsynch protocol. Thrice weekly from 4 to 32 d after TAI, blood samples were collected for evaluation of plasma progesterone (P4) concentrations, and CL diameter was measured using transrectal ultrasonography. Pregnancy status was determined using transrectal ultrasonography 32 d after TAI. Nonsynchronized cows (n = 4) were removed from the study. For cows diagnosed pregnant 32 d after TAI (n = 57), P4 increased from 4 to 15 d and then remained constant until 32 d after TAI, whereas CL volume increased from 4 to 11 d and then remained constant until 32 d after TAI. For cows diagnosed not pregnant 32 d after TAI (n = 80), P4 profiles were evaluated using statistical cluster analysis based on the day after TAI that P4 decreased to <1 ng/mL, resulting in 5 clusters: (1) CL regression 15 d after TAI (1.3%), (2) CL regression 18 to 22 d after TAI (55.0%), (3) CL regression 25 to 27 d after TAI (17.5%), (4) CL regression 29 to 32 d after TAI (5.0%), and (5) CL maintained until 32 d after TAI (21.3%). Plasma pregnancy-associated glycoprotein (PAG) levels at 25 and 32 d after TAI differed among clusters and were below the cut-off value of the assay for the classification of cows as not pregnant for cows in clusters 2, 3, and 4, whereas more than half of the cows in cluster 5 had increased plasma PAG levels. We conclude that at least half of the nonpregnant cows that maintained their CL until 32 d after TAI were initially pregnant but underwent early pregnancy loss based on increased plasma PAG levels at 25 and 32 d after TAI.
Asunto(s)
Bovinos/fisiología , Cuerpo Lúteo/fisiología , Sincronización del Estro/fisiología , Ovulación/fisiología , Progesterona/sangre , Animales , Femenino , Glicoproteínas/sangre , Inseminación Artificial/veterinaria , Lactancia , Proteínas Gestacionales/sangre , Factores de TiempoRESUMEN
The reproductive performance of postpartum Santa Inês (SI) and Morada Nova (MN) ewes treated with insulin or progesterone hormones in association with ram effect was evaluated. Ewes from SI (n = 69) and MN (n = 69) breeds were randomly allocated to three groups of each breed (T1-ram effect only; T2-ram effect + insulin; T3-ram effect + progesterone). Progesterone concentrations (ηg/ml; mean ± SD) before and after introduction of rams (n = 6) were 0.51 ± 0.22 and 3.78 ± 0.68 (T1), 0.65 ± 0.21 and 3.77 ± 0.78 (T2) and 0.52 ± 0.21 and 3.84 ± 0.84 (T3) in SI ewes and 0.74 ± 0.19 and 3.71 ± 0.56 (T1), 0.70 ± 0.21 and 3.79 ± 0.75 (T2) and 0.81 ± 0.14 and 3.87 ± 0.80 (T3) in MN ewes, respectively. Thus, lower progesterone concentrations were found before the introduction of rams (p < .05). After the introduction of rams, preovulatory peaks of LH (ηg/ml) occurred at 28 (T1), 44 (T2) and 48 (T3) hr in SI ewes and at 64 (T1), 40 (T2) and 44 (T3) hr in MN ewes. The mean number of ovulations was similar between groups (p > .05), was 1.3 ± 0.51 (T1), 1.5 ± 0.54 (T2) and 1.6 ± 0.51 (T3) in SI ewes and 1.3 ± 0.51 (T1), 1.6 ± 0.51 (T2) and 1.6 ± 0.51 (T3) in MN ewes. In conclusion, the ram effect alone is effective at inducing and synchronizing oestrus in sheep under postpartum anoestrus, irrespective of hormone treatments.