Uterine tone: A neglected criterion for the selection of bovine embryo transfer recipients.

This study evaluated the relationship between CL features assessed by ultrasound (luteal tissue area and blood flow, BF) or rectal palpation (size), uterine tone (UT), plasma progesterone (P4) concentration on Day 7 (D7) and subsequent pregnancy outcomes in bovine embryo recipients. A total of 163 cows and heifers were included in this study. The expected day of ovulation after the synchronization protocol was designated as D0. On D7, ovaries and uterus were examined by ultrasonography and rectal palpation, and subjective scores (1-3 scale) were assigned for CL size, area and BF, and for UT. Blood samples were collected for further P4 analysis. Each embryo recipient then received a grade I frozen-thawed in vivo-produced blastocyst, which was transferred to the uterine horn ipsilateral to the CL. Pregnancy diagnosis was performed on D35, and the results were retrospectively compared with the assigned scores for CL and UT. We observed a significant (p < .02) interaction between CL size and UT, with a progressive increase in the likelihood of pregnancy for recipients bearing a large CL among those with turgid UT. Ultrasound scoring of the CL using B-mode and Doppler-mode did not significantly predict pregnancy rates on D35 (p < .6 and p < .5, respectively). However, logistic regression analysis revealed a trend towards a quadratic effect (p < .08 and p < .06) indicating that the probability of pregnancy varied according to the area of luteal tissue and P4 concentrations, respectively. No significant (p > .05) association was found between the probability of pregnancy and the BF area of the CL. In summary, UT before embryo transfer may reflect successful recipient synchronization. Elevated P4 levels, assessed by CL size, may offset uterine contractility, mitigating adverse effects. Additionally, the CL area may be more important than its vascularization area when evaluating recipients D7 after ovulation.

Superovulating cattle with corifollitropin-alpha, a long-acting recombinant human FSH (rhFSH): Dose-response, half-life, effects on the ovaries, and embryo outcomes.

The aim of this study was to evaluate the superestimulatory and superovulatory responses of cattle treated with corifollitropin-alpha, a long-acting human recombinant FSH (rhFSH). In the first and second experiments, we used Nelore (Bos indicus) heifers previously submitted to follicular wave suppression by active immunization against GnRH. In Experiment 1 (a dose-response study), heifers (n = 20) were randomly allocated into five groups, which received placebo (saline) or a single sc dose of 7.5, 15.0, 22.5 or 30.0 µg rhFSH. The heifers were subjected to daily ovarian scan and blood sampling during 11 days. We observed group, time, and group x time effects (P<0.0001) for both average follicle size and circulating FSH concentrations, with a strong correlation (R = 0.82, P<0.0001) between the area under curve (AUC) for both parameters. The peak concentration of FSH 24h after treatment and average follicle size at all timepoints, however, were similar (P>0.05) between groups 22.5 and 30.0 µg. In Experiment 2, heifers (n = 18) were allocated into three groups, which received (0h) either placebo (control), 25 µg rhFSH or 130 mg pFSH (Folltropin). There was no difference (P>0.05) in average follicle size at any moment, as well as in intrafollicular E2 at 120h or in plasma P4 seven days later between groups rhFSH and pFSH. In Experiment 3, cycling Nelore heifers (n = 20) were subjected to a wave synchronization protocol and superovulated (day 0) using a standard pFSH protocol (120 mg split in eight decreasing im doses) or with a single sc injection of 20 µg rhFSH. The number of follicles >7 mm on day 4 did not differ (P=0.4370). Heifers receiving rhFSH had greater average follicle size on day 4 (P=0.0005), ovulation rate (P<0.0001), and number of CL (P=0.0155), as well as a trend towards a greater number of ova (P=0.07) and viable embryos (P=0.0590). In Experiment 4, superovulation was induced with a single sc injection of 25 µg rhFSH in Girolando and Nelore cows and heifers (n = 20). None of the embryo yield endpoints differed between the two breeds (P>0.05). In conclusion, cattle superstimulation and superovulation can be successfully induced with a single dose of a long-acting rhFSH (corifollitropin-alpha).

Active immunization against GnRH as an alternative therapeutic approach for the management of Bos indicus oocyte donors diagnosed with chronic cystic ovarian disease.

The aim of this study was to evaluate the effect of active immunization against GnRH in Nelore (Bos indicus) cows repeatedly used as oocyte donors that developed chronic cystic ovarian disease (COD). In the first experiment, ovarian and uterine features were first compared between COD cows (n = 15) and healthy cows (n = 22, cycling control group) from the same breed and herd. Cows with COD had a greater number of large (P < 0.0001) and medium follicles (P < 0.01) but lesser small follicles (P < 0.05) than cycling controls. Mucometra was diagnosed in 73.3% of COD cows, but in none of the controls. No difference in average thickness of the endometrium was detected between groups; however, endometrial thickness and mucometra score were negatively correlated (R = -0.73, P = 0.0029) in COD cows. In the second experiment, COD cows were randomly allocated into two experimental groups, which received two 1.0 mL SC injections of either an anti-GnRH vaccine (COD immunized group, n = 8) or saline (COD control group, n = 7), given 28 days apart. Cows were examined weekly by transrectal ultrasonography during nine consecutive weeks after the first injection to evaluate the number and distribution of follicles among size classes, endometrial thickness, and presence of clinical mucometra. Vaccination against GnRH resulted in a progressive suppression of follicle growth and a reduction in the average size of the largest follicle, as well as in the number of large follicles (P < 0.01) in COD immunized cows compared with COD controls from week 7 onwards. Conversely, the number of small follicles in the COD immunized group increased after week 5 and was greater (P = 0.0023) than controls on week 9. Endometrial thickness and mucometra score were not affected (P > 0.05) by immunization against GnRH. In the third experiment, the COD immunized cows with effective suppression of follicle growth four weeks after the 2nd injection (n = 6) were submitted to three consecutive ovum pick-up (OPU) sessions (weeks 10, 11, and 12) for in vitro embryo production (IVEP). Cumulus-oocyte complexes (COC) collected from slaughterhouse ovaries were used as controls for IVEP. COD cows with produced 25.0 ± 3.8 COC per OPU session with no apparent detrimental effect of anti-GnRH vaccine on oocyte developmental potential in vitro, i.e., we observed similar cleavage rate (P = 0.5914) and greater blastocyst rate (P = 0.0177) in immunized cows compared with COC from slaughterhouse controls. Finally, in the fourth experiment wave emergence and follicular dynamics after follicle ablation were compared between COD immunized cows with effective suppression of follicle growth and a subset (n = 6) of the cycling, control group. No follicles grew beyond 4 mm diameter after follicle ablation in the COD immunized group, whereas a normal follicular wave emergence occurred in cycling controls. Antral follicle count was similar between cycling controls and COD immunized groups at 24 h and 96 h post-follicle ablation (P > 0.05), but greater in cycling controls at 48 h and 72 h post-follicle ablation (P < 0.05). In summary, our results suggest that active immunization against GnRH is effective to induce the regression of follicular cysts as well as increase the number of small follicles growing on the ovaries, in oocyte donors diagnosed with chronic COD, with no apparent negative effect on oocyte developmental potential in vitro.

Use of two new formulations as bovine embryo manipulation solution.

This study aimed to evaluate the effect of two Embryo Manipulation Solutions (EMS and EMS supplemented) in maintenance of the viability of embryos, initially using structures derived from mice (first phase). Next, the efficiency of these solutions in routines of bovine embryo transfer was evaluated (second stage). Mice embryos were used in the stages of early blastocyst, and compact morula grades I and II. These embryos were initially randomly distributed and maintained for four hours in three solutions: Modified phosphate buffered saline (PBS; Control); EMS (treatment 1), and EMS supplemented (treatment 2). Subsequently, they were cultured in TCM 199 medium and evaluated in terms of total number of cells, morphometric characteristics, ultra structural aspects, detection of cell apoptosis, and quantification of Hsp70.3 gene expression. In the second phase, these same solutions were tested in the transfer of quality I and II bovine embryos (excellent and good). These embryos were transferred fresh to 58 recipients. The results showed that the total number of cells in embryos expanded blastocyst (ExB), the number of apoptotic cells, the cell, nuclear, nucleolar diameter and the nucleus/nucleolus ratio was similar among the treatments. The pregnancy rate shown on second phase was also similar. However, the EMS supplemented expressed more Hsp70.3 than EMS. The expression of Hsp70.3 was also greater for embryos in EMS than that of EMS supplemented. The McII embryos, EMS and EMS supplemented samples also expressed more Hsp70.3 compared to control embryos. In conclusion, the tested solutions can be used in routine embryo transfer techniques, replacing modified PBS solution as an effective media in maintaining embryo viability.

Safety of vaccination against brucellosis with the rough strain in pregnant cattle.

Brucellosis is an infectious and contagious disease that profoundly impacts public health. However, in many countries, disease prevention is restricted to the vaccination of calves, and there is no prophylactic strategy for pregnant heifers and cows. The aim of this study was to evaluate the safety of the rough strain vaccine against brucellosis in pregnant cattle. Crossbred cows (N = 96) at three gestational periods (early, mid, or late pregnancy) were randomly allocated into the vaccine treatment group or to the control group. We then compared the percentage of pregnancies reaching full term, live calves 60 days after delivery, and seropositive calves. There was no effect of vaccination in any of the gestational periods on the evaluation endpoints. In conclusion, vaccination against brucellosis with the rough strain is safe for pregnant cattle at all gestational periods.

Testicular Histomorphometric Evaluation of Zebu Bull Breeds

The objective of this study was to evaluate the quantitative histology and testicular biometrics in zebu bulls of different breeds. Testicular fragments of Nelore (n=10), Polled Nelore (n=6), Gir (n=5), Guzerat (n=5) and Tabapuã bulls (n=5) were used. The fragments were perfusion-fixed in Karnovsky solution, embedded in glycol methacrylate and stained with toluidine blue-1% sodium borate. The Nelore animals had a higher tubular volumetric proportion (85.2%) and greater height of the seminiferous epithelium (73.2 µm) than the Gir, Guzerat and Tabapuã breeds. The Nelore animals also had a higher volumetric proportion of Leydig cells (5.2%) than the Guzerat and Tabapuã breeds. There was no significant difference for any of these parameters between the Nelore and Polled Nelore breeds. The gonadosomatic index, seminiferous tubule diameter, cross-sectional area of the seminiferous tubule and tubule length (total length and length per gram of testicular parenchyma) did not vary among the breeds studied. The morphometric parameters evaluated suggested that the genetic selection applied to the Nelore and Polled Nelore breeds improved the efficiency of spermatogenesis in these breeders.

Uso do cloprostenol para tratamento de infecção uterina em vacas sem corpo lúteos / Use of cloprostenol for treatment of uterine infections in cows without corpus luteum

Os objetivos da pesquisa foram caracterizar a ocorrência de infecções uterinas pós-puerperais em vacas leiteiras e avaliara eficiência do cloprostenol sódico para tratamento de infecções uterinas pós-puerperais em vacas leiteiras, sem atividade ovariana luteal. Foram usadas 111 vacas de diferentes rebanhos com infecção uterina, associada ao útero totalmente involuído.O diagnóstico e classificação das endometrites foram baseados na característica da descarga vaginal por vaginoscopia. A mesma medida foi utilizada para avaliação da evolução do processo e eficiência do tratamento. De acordo com o grau de infecção, os animais foram divididos aleatoriamente em quatro grupos e receberam via IM os seguintes tratamentos. T1 (n=15): 2 ml de solução salina; T2 (n=32): uma dose de 0,530mg de Cloprostenol; T3 (n=32): duas doses de 0,530mg de Cloprostenol com 24 horas de intervalo e T4 (n=32) duas doses de 0,530mg de Cloprostenol com 48 horas de intervalo. As vacas foram novamente avaliadas por vaginoscopia 15 a 20 dias mais tarde. A eficiência dos tratamentos foi comparada pelo teste de qui-quadrado (χ2). A eficiência geral dos tratamentos, considerada a cura dos sinais clínicos foi de 6,67; 31,25; 50,00 e 37,50% para os grupos T1, T2, T3 e T4, respectivamente, sendo que todos os tratamentos foram igualmente eficientes (P<0,05) em relação ao controle. Os resultados mostram que o cloprostenol pode ser utilizado no tratamento de infecções uterinas pós-puerperais em vacas sem corpo lúteo,estimulando diretamente a imunidade uterina.

The research aims to characterize the occurrence of uterine post-puerperal infections in dairy cows and evaluate the efficiency ofprotocols of Cloprostenol administration for the treatment of clinical post puerperal uterine infections in dairy cows with and without luteal ovarian activity. 111 cows of different herds were used, all presenting clinical endometritis, associated with an involuted uterus. The diagnosis and classification of the endometritis was based on vaginal discharge characteristic by vaginoscopy. The same measure was used to evaluate the evolution of the process and efficiency of treatment. According to the infection degree the animals had been randomized in four groups, and received IM treatments: T1 (n=15): 2ml of saline solution; T2 (n=32): only onedose of 0.530mg of Cloprostenol; T3 (n=32): 2 doses of 0.530mg of Cloprostenol 24 hours apart and T4 (n=32): 2 doses 0.530mg of Cloprostenol with interval of 48 hours. The cows were evaluated by vaginoscopy 15 to 20 days later. The treatments efficiency was compared by the chi-square test (χ2). The general efficiency of treatments regarded as the healing of clinical signs was 6.67;31.25; 50.00 e 37.50 for groups T1, T2, T3 and T4, respectively. In relation to the Control group T1 (not treated), all groups were more efficient (P<0.05). The Cloprostenol can act in a direct way, in this case of animals without corpora lutea stimulating the uterine immunity. The results demonstrate that cloprostenol can be used in post puerperal uterine infections treatment in cows with absence of corpus luteum, directly stimulating uterine immunity.