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In vivo- and in vitro-produced bovine embryos have different metabolic profiles and differences in gene transcription patterns. These embryos also have a distinct ability to establish and sustain early pregnancies. Small extracellular vesicles (sEVs) are secreted by embryos and carry bioactive molecules, such as miRNAs. We hypothesize that in vivo or in vitro-produced bovine hatched blastocysts on Day 9 and the sEVs secreted by them have different miRNA profiles. To address this hypothesis, embryos of both groups were placed in in vitro culture on Day 7. After 48 h, hatched embryos and hatched embryo-conditioned media (eCM) of both groups were collected. A total of 210 miRNAs were detected in embryos of both groups, of these 6 miRNAs were downregulated, while 7 miRNAs were upregulated in vitro group when compared to in vivo group. sEVs were isolated from eCM to determine miRNA profile. A total of 106 miRNAs were detected in both groups, including 14 miRNAs upregulated in sEVs from in vivo-eCM, and 2 miRNAs upregulated in sEVs from in vitro-eCM. These miRNAs express in embryos and sEVs secreted by them regulate early embryonic developmental and endometrial pathways, which can modify embryo-maternal communication during early pregnancy and consequently affect pregnancy establishment.

The use of assisted reproductive technologies, such as superovulation and in vivo embryo production and in vitro embryo production (IVEP), has increased rapidly in recent years and is now applied worldwide for genetic improvement in beef and dairy buffaloes. Although in vivo embryo production has been shown to be feasible in buffalo, low efficiency and limited commercial application has been documented. These results could be associated with low antral follicle populations, high levels of follicular atresia and/or failures of the oocyte to enter the oviduct after superovulation. Additionally, IVEP technology has been shown to be an important tool for multiplying genetic material from donors of superior merit, and promising results have been achieved with the use of ovum pick-up (OPU) along with IVEP in buffalo. However, several factors appear to be critical for successful OPU/IVEP, including circulating levels of anti-Müllerian hormone, antral follicle populations, sizes of the follicles available for the OPU, reproductive seasonality, semen (sire) used for IVEP, donor category and farm. Furthermore, technologies applied to control follicular wave emergence and ovulation at predetermined times, without the need for estrus detection in recipients, has facilitated management and improved the efficiency of embryo transfer programs in buffalo herds. Conclusively, with the considerable evidence of poor results with in vivo embryo production in buffaloes, the association of OPU with IVEP represents a new alternative for the exploitation of buffalo genetics.

The purpose of this study was to evaluate the functional morphology of the spermatogenesis of Gir bulls, with emphasis on the testicular biometry and testicular parenchyma histomorphometry. Testicular fragments from eight Gir bulls were used. The fragments were fixed by tissue perfusion with Karnovsck’s solution, and inclusion was subsequently performed using glycol methacrylate. Histological sections of 4 μm were made and stained with a 1% toluidine blue-sodium borate solution. The mean age of the bulls was 8.0 ± 1.3 years and the mean body weight was 467.5 ± 26.7 kg. Testicular weight was 289.2 ± 30.5 g on average, and the average gonadosomatic index was 0.12% ± 0.02%. The seminiferous tubules, Leydig cells, stroma, and intertubular tissue composed 80.9% ± 1.7%, 5.4% ± 1.3%, 13.7% ± 1.1%, and 19.1% ± 1.7% of the total testicular weight, respectively. The mean length of the seminiferous tubule per gram of testicle was 17 ± 0.8 m. Losses during spermatogonia mitosis averaged 75.5% ± 3.22%, while losses were 30.6% ± 8.17% during the meiotic phase, which resulted in an average total loss of 81.49% ± 2.58% of cells during the entire process of spermatogenesis. The average daily sperm production per gram of parenchyma was 28.0 × 106 cells. It was concluded that the histometric measurements of testicular parameters in the Gir breed are within the averages reported for other zebu cattle breeds.

Since buffaloes are a seasonal, polyestrous species, optimizing reproduction during the non-breeding season is a key factor in increasing the reproductive and productive efficiency of herds. Ovum pick-up associated with in vitro embryo production and embryo cryopreservation is an alternative to reduce seasonal impacts. We studied the effects of seasonality in buffalo oocyte donors and embryo recipients during the favorable and non-favorable breeding seasons. Donors were evaluated for oocyte recovery and blastocyst production rate as dFBS (donors in favorable breeding season) or dNBS (donors in non-favorable breeding season). Embryos produced from dFBS or dNBS were cryopreserved by vitrification or the slow-freeze method for direct transfer and transferred to recipients in the favorable (rFBS) or non-favorable breeding season (rNBS). The heifers or cows were subjected to a fixed-time embryo transfer protocol and conception rates were determined on day 30 and on day 60. The oocyte recovery was lower in dFBS than in dNBS (7.6 vs. 10.0 oocyte/OPU, p = 0.0262); while no difference was found comparing blastocyst production rate (23.7% vs. 30.9% of blastocysts, respectively). Embryos from dFBS resulted in greater (p = 0.0013) conception rates on day 30 compared to dNBS (46.5% vs. 22.4%, respectively), despite the breeding season. The rFBS and rNBS treatments had similar (p = 0.6714) conception rates on day 30 (38.0% vs. 33.0%, respectively), indicating similar uterine receptivity. However, heifers on FBS had higher (p = 0.0003) conception rates on day 30 than cows (73.9% vs. 13.3%, respectively) when receiving embryos from dFBS. Vitrification and direct transfer had similar (p = 0.1698) conception rates on day 30 (30.4% vs. 41.4%, respectively). In conclusion, in vitro-produced embryos derived from dFBS were more competent in establishing pregnancy than dNBS counterparts, independent of recipients' reproductive seasonality. Heifers achieved better conception rates than cows during the favorable breeding season when the embryo came from dFBS. Cryopreserved in vitro produced embryos represent a reliable alternative to reduce seasonal variations in buffalo reproduction. The data elucidate the seasonal effects on embryo competence and on recipients’ uterine receptivity, affording new strategies to implement ovum pick-up associated with in vitro embryo production programs in buffalo herds.

The use of tail chalk and estrus/heat expression scores (HEATSC) evaluation is instrumental in identifying cows with greater estrus expression and greater artificial insemination pregnancy rates (P/AI) in cows submitted to timed artificial insemination (TAI), and cows with low or no estrus expression present lower P/AI. It was intended in this study to improve the pregnancy rates in TAI for Bos indicus beef cows, and gonadotrophin-releasing hormone (GnRH) injection was hypothesized to increase pregnancy rates in a TAI program for cows submitted to progesterone–estradiol-based protocols with low or no estrus expression, evaluated by HEATSC. Cows (n= 2284) received a progesterone device and 2 mg estradiol benzoate, after 8 days the device was removed and 1 mg estradiol cypionate, 150 μg of d-cloprostenol and 300 IU equine chorionic gonadotropin was administered. All cows were marked with chalk and HEATSC evaluated (scales 1 to 3) at TAI performed on day 10. Animals with HEATSC1 and HEATSC2 (n= 937) received 100 μg de gonadorelin (GNRH group; n= 470), or 1 ml saline (Control group; n= 467), and cows with HEATSC3 (named HEAT group; n= 1347) received no additional treatment. The larger dominant follicle, evaluated on day 8and at TAI (day 10), was greater in HEAT group (P= 0.0145 and P

Expression of estrus near timed artificial insemination (TAI) is associated with greater fertility, and estrus detection could improve TAI fertility or direct TAI management, although accurate estrus detection can be difficult and time-consuming using traditional methods. The aim of this study is to evaluate influence of estrus on pregnancy (artificial insemination pregnancy rates (P/AI)) and to validate an alternative method to classify estrus/heat expression using tail chalking (HEATSC) in postpartum Bos indicus cows subjected to TAI in progesterone–estrogen-based protocols. In experiment 1 (Exp. 1), cows (5491) were subjected to visual observation of estrus after progesterone device removal, before TAI, and P/AI was evaluated according to estrus and body condition score (BCS). Cows received a progesterone device and 2 mg estradiol benzoate (EB). After 8 days, the device was removed and 150 μg of d-cloprostenol and 300 IU equine chorionic gonadotrophin was given. Later, animals in Exp. 1 received 1 mg EB and TAI 44 to 48 h. In the Exp. 2 – 3830 cows using similar protocol, received different ovulation inducers: 1 mg EB (n=1624) or 1 mg estradiol cypionate (EC; n=2206) on day 8 (D8). Cows were then marked with chalk, and HEATSC evaluated at TAI on D10 (HEATSC1 – no chalk removal=no estrus expression; HEATSC2 – partial chalk removal=low estrus expression; HEATSC3 – near complete/complete chalk removal=high estrus expression). In Exp. 1, cows showing estrus presented greater P/AI (48.4% v. 40.2%, P

The intensive use of Doppler ultrasonography in several studies in the last decade allowed the characterization of vascular perfusion and the estimation of function of the reproductive organs and tissues along the estrous cycle and pregnancy in cattle. We aim to discuss the possibility of using Doppler imaging and to explore the potential of its inclusion in reproductive programs in cattle industry. Recent studies in dairy and beef cows indicated a high accuracy and sensitivity when Doppler ultrasonography is used to evaluate corpus luteum function and to diagnosis pregnancy between days 20 and 22. Moreover, resynchronization programs starting 5 to 7 days after timed embryo transfer (FTET) coupled with early pregnancy diagnosis were developed for beef cattle, and have been implemented in commercial embryo transfer programs. These strategies allow a reduction in the interval between two FTET from ≈ 40 to 24 days and may improve the gains in reproductive efficiency when compared to traditional programs than begin resynchronization after the pregnancy diagnosis at 30 days. A second alternative to use Doppler imaging is the evaluation of luteal blood perfusion at the time of embryo transfer for selection of recipients with greater receptivity potential. This may increases fertility in FTET, as embryos would not be transferred to females with non-functional CL, and in cases with recipients surplus, females with higher receptivity would be prioritized.

This study aimed to determine the amount of plasma nitric oxide in clinically stable dogs at different stages of chronic kidney disease (CKD). Five groups of dogs were studied, aged from 4 to 18, comprising of a control group composed of healthy animals (control n=17), group CKD stage 1 (DRC-1, n=12), group CKD stage 2 (CKD-2, n=10) group, CKD stages 3 (CRD-3, n=13) and Group CKD stage 4 (DRC-4, n=10). Dogs with CKD were clinically stable and received no treatment. Two blood samples were collected at 24 hours intervals (repeated measures) to obtain serum and plasma. The serum creatinine values were used to classify dogs as CG, CKD-1, CKD-2, CKD-3 and CKD-4, and were (1.02±0.02mg/dL), (1.07±0.04mg/dL), (1.81±0.03mg/dL), (3.40±0.15mg/dL) and (6.00±0.20mg/dL) respectively. The determination of nitric oxide (NO) was performed by dosing nitrate/nitrite indirectly, and used for measurement of nitrate according to the NO/ozone chemiluminescence. The data were submitted to ANOVA for nonparametric analysis(Kruskal-Wallis) (P

espanolRESUMEN El objetivo de este estudio fue evaluar la ecotextura testicular de los toros Nelore y correlacionarlo con los parametros de espermatogenesis. Para este proposito, 41 toros de edades de 3-5 anos y con pesos corporales en el intervalo de 510,2 ± 21,61 kg fueron seleccionados para el estudio. Los toros se sometieron a ecografia, utilizando un dispositivo portatil junto con un transductor lineal a una frecuencia de 7,5 MHz. Inmediatamente despues, los animales fueron castrados, y el tejido testicular se trato con Karnovsky fijador. Los fragmentos testiculares se incluyeron en metacrilato de glicol y se tineron con una solucion de borato de sodio-azul de toluidina al 1%. La intensidad media de pixeles en el parenquima testicular se determino para secciones de superficie de 1.600 mm2. Los El area entre los dos testiculos derecho e izquierdo dieron lugar a la intensidad media de los pixeles de 105,22 ± 13,58, 107,95 ± 12,82 y 106,59 ± 11,43, respectivamente. El coeficiente de eficiencia de la mitosis espermatogonial fue 19,74; Indice meiotico fue 2,63, y el rendimiento global del espermatogenesis alcanzo el 52,0. No se observo correlacion (P>0,05) entre ecotextura testicular y cualquiera de los parametros morfometricos medidos. Estos resultados sugieren que ecotextura testicular no es un metodo viable para el analisis indirecto de la poblacion celular en el epitelio seminifero, el rendimiento de la espermatogenesis intrinseco, o el indice de celulas de Sertoli en toros Nelore. EnglishABSTRACT The objective of this study was to evaluate the testicular echotexture of Nelore bulls and to correlate it with spermatogenic parameters. Forty one bulls aged 3-5 years, with body weight of 510.2 ± 21.61 kg were selected for the study. The animals were subjected to ultrasonography, using a portable device coupled with a linear transducer at a frequency of 7.5 MHz. Immediately afterwards they were castrated and the testicular tissue was treated with Karnovsky fixative. Next, the fragments were embedded in glycol methacrylate and stained with toluidine blue-1% sodium borate solution. The average pixel intensity in the testicular parenchyma was determined for 1,600-mm2 surface sections. The right and left testicles and the area between the two testicles resulted in average pixel intensities of 105.22 ± 13.58, 107.95 ± 12.82, and 106.59 ± 11.43, respectively. The efficiency coefficient of spermatogonial mitosis was 19.74; meiotic index was 2.63, and overall yield of spermatogenesis was 52.0. No correlation (P>0.05) was observed between testicular echotexture and any of the measured morphometric parameters. These results suggest that testicular echotexture was not a viable method for the indirect analysis of cellular population in the seminiferous epithelium, intrinsic spermatogenic performance, or the Sertoli cell index in Nelore bulls.

This paper presents results of friction-taper stud welding applied to super duplex ASTM A890 Gr.6A stainless steel. The input variables were the speed of rotation; the plunge depth and the downward force and they were tested with a specific geometry in a friction welding machine. These variables were applied by the Taguchi method. After the friction welding, the joints were inspected and was not found lacking of filling. The results of both bending test and tensile test were satisfactory. The temperatures of the process were recorded at three different points on the block welding and presented similar characteristic behaviours. The parameter window applied to this work proved to be suitable for welding of stainless steel super duplex ASTM A890 Gr6A.

We aimed to study the association between CL characteristics assessed by color-Doppler ultrasonography (Doppler-US) at the time of embryo transfer (ET) and pregnancy rate (P/ET) in beef recipients. Estrous cycles of crossbred beef recipients were synchronized for timed-ET. On the day of ET (Day 7), CL area, proportion of luteal blood perfusion (BP), and the relationship between the largest dominant follicle (DF) and CL (ipsilateral or contralateral) were determined. Animals (n = 444) received an in vitro produced embryo from Nelore donors, placed in the uterine horn ipsilateral to the CL. Recipients were split retrospectively in three subgroups according to CL area [small ( 4 cm2)] and three subgroups according to luteal signals of BP [low (≤40%), medium (45–50%) or high (≥55%)]. Pregnancy was detected on Days 30–45 by transrectal ultrasonography and P/ET was analyzed considering the effects of cow's category (suckling or non-suckling), CL area, luteal BP and side of DF. P/ET increased along with BP category [low, 45.9%B, (62/135); medium, 54.1%AB (93/172); and high, 58.4%A (80/137)]. When luteal BP was evaluated as a continuous variable, a significant (P 0.1], when CL area was evaluated as a continuous variable, a quadratic effect (P 0.1). In conclusion, Doppler-US is an innovative tool that has the potential to be used for selection of suitable embryo recipients based on luteal BP. Selection of recipients that have a greater chance of maintaining pregnancy will increase the success of timed-ET programs.

Early weaning (EW) has been adopted in cattle breeding farms in Pantanal as a strategy to increase the rate of pregnancy in cows. The primary income of these properties is the production of beef calves, and the price of these animals depends on their weight. Therefore, the calves subjected to EW should present weight similar to or higher than those of calves subjected to conventional weaning (CW). This study aimed to evaluate the productive performance of pure (Nellore) calves and crossbred (Nellore/Angus) calves reared in the Pantanal and subjected to either EW or CW. After EW, the calves were supplemented with concentrate at 1 kg/animal/day (low-energy diet) or 1% of live weight (high-energy diet). The weights adjusted to 300 days of age were higher for EW calves fed the high-energy diet (p0.01), and animal weight was 241.17 and 236.27 kg in crossbred calves and 184.44 and 189.78 in Nellore calves, respectively. The EW adopted in this experimental model did not affect the productive performance of calves raised in the Pantanal.

Our expanding knowledge of ovarian function during the buffalo estrous cycle has given new approaches for the precise synchronization of follicular development and ovulation to apply consistently assisted reproductive technologies (ART). Recent synchronization protocols are designed to control both luteal and follicular function and permit fixed-time AI with high pregnancy rates during the breeding (autumn-winter) and nonbreeding (spring- summer) seasons. Additionally, allow the initiation of superstimulatory treatments at a self-appointed time and provide opportunities to do fixed-time AI in donors and fixed-time embryo transfer in recipients. However, due the scarce results of

The objective of this experiment was to evaluate the effects of replacing eCG with FSH or FSH/LH on the diameter of ovulatory follicles (DOF) and the pregnancy rates (PR) of lactating Bos indicus cows subjected to a synchronization of ovulation protocol and fixed-time artificial insemination (FTAI) based on progesterone, estradiol benzoate (EB), PGF2α, and estradiol cypionate (EC). On day 0, primiparous and multiparous Nellore cows (n = 329) at 68 days postpartum were body condition scored (BCS) and received a P4 implant (PRIMER 1.0 g P4) plus 2 mg EB intramuscularly (IM). At day 8, the implant was removed, and 250 μg cloprostenol were injected IM along with 0.5 mg EC. At the time of implant removal, the animals were divided into one of four treatments: cows received (G1) 1 mL of saline solution IM (Control; n = 80); (G2) 300 IU eCG IM (ECG300; n = 84); (G3) 15 mg FSH IM (Folltropin; n = 82); and (G4) 30 IU FSH/LH IM (Pluset; n = 83); all cows were subjected to FTAI 48-54 h after implant removal (day 10). Transrectal ultrasonography was performed to measure the DOF to FTAI and to estimate the pregnancy rate on day 35. A statistical analysis examined the effects of the treatment, technician, semen, BCS, calf age and parity on PR to FTAI. There was no significant difference in PR and DOF among the treatment groups (G1, 41.3%, 13.1 mm; G2, 46.4%, 14.5 mm; G3, 46.3%, 14.2 mm; and G4, 48.2%, 14.3 mm), but PR was higher in multiparous than in primiparous cows. Commercial FSH solutions (Pluset or Folltropin) do not promote increases in PR or DOF of lactating Nellore cows and are equal to eCG in promoting growth in preovulatory follicles and elevating the PR in Nellore cows with a moderate BCS subjected to a progesterone-based FTAI protocol with EC.

The feral pig (Sus scrofa sp) also known as Monteiro pig, originated from a domestic pig breed that was introduced into Pantanal region in Brazil in the eighteenth century. Although the feral pig has commercial potential, there are few reports in the literature concerning the reproductive biology of this species. Therefore, the aim of this study was to further describe the feral pig testis parenchyma as well as characterize the stages of the seminiferous epithelium cycle by tubular morphology method, and to evaluate the number of differentiated spermatogonia generations in this species. Eight sexually mature feral pigs were analyzed. Fragments of testes were embedded in plastic resin and used to prepare slides for morphometrical studies. It was concluded that the feral pig has six generations of differentiated spermatogonials (A1, A2, A3, A4, In, B) and that the cellular composition in the eight stages of the seminiferous epithelium cycle of these animals were very similar to those reported in species of suidae and tayssuidae already studied.

Biotecnologias como a Ovum Pick-Up e a Produção In vitro de embriões (OPU-PIVE) tem sido uma importante ferramenta para alcançar o melhoramento genético rápido nos rebanhos, diminuindo o intervalo entre gerações. No Brasil, a PIVE está em fase de crescimento e representa 70,7% de toda a produção in vitro mundial. Contudo a OPU-PIVE é ainda ineficiente em vacas de leite, especialmente devido à sua reduzida população folicular. Muitos estudos têm mostrado um efeito positivo do FSH em gado de leite e corte. Recentemente, a pré-estimulação com FSH mostrou ser capaz de aumentar o diâmetro dos folículos aspirados e a porcentagem de embriões transferíveis. O FSH estimula o recrutamento dos folículos na fase antral, fazendo com que eles possam se desenvolver até o momento em que ocorre a divergência e um ou mais folículos se torne dominante. A hipótese do presente estudo é que o uso de FSH (200 mg), fracionado em 4 ou 6 aplicações, em vacas holandesas não lactantes, com emergência de onda folicular sincronizada, aumenta o número de folículos ovarianos, o número de oócitos viáveis e a quantidade de embriões na produção in vitro. Trinta e seis vacas Holandesas não lactantes foram utilizadas como doadoras de oócitos e distribuídas em três tratamentos: Controle (C), 4 aplicações de FSH (F4) e 6 aplicações de FSH (F6). Todas as vacas foram submetidas ao mesmo protocolo de sincronização de emergência de onda folicular, diferindo apenas pela administração e número de 4 ou 6 doses de FSH, conforme descrito acima. Em dia aleatório do ciclo estral (D0), todas as vacas receberam um dispositivo de P4 (Primer®, Tecnopec-Agener União, São Paulo, SP, Brasil) e 2 mg de benzoato de estradiol (Ric-BE®, Tecnopec-Agener União, São Paulo, SP, Brasil). Três dias após (D3), foi administrado 0,530 mg de Cloprostenol Sódico (Cioprostinn®, Innovare Biotecnologia e Saúde Animal Ltda, Monte Aprazível, SP, Brasil), induzindo a luteólise com a intenção de liberar espaço no estroma ovariano para o crescimento folicular e facilitar a visualização de folículos na OPU. Vacas do grupo C não receberam tratamentos adicionais. Vacas do grupo F4 receberam 200 mg de FSH (Folltropin - Bioniche Anim,al Health, Belleville, ON, Canadá) fracionados em 4 aplicações de equivalentes concentrações em intervalos de 12 h, iniciando no D4 pela manhã. Vacas do grupo F6 receberam 200 mg de FSH fracionados em 6 aplicações de equivalentes concentrações em intervalos aproximados de 12 h, tendo início no D3 pela manhã. No D7, o dispositivo foi removido e a OPU realizada concomitantemente à contagem dos folículos existentes nos ovários. Os oócitos considerados viáveis foram fertilizados in vitro com sêmen sexado de touros da raça Holandesa. Os dados foram analisados pelo PROC GLIMIX do SAS 9.3, utilizando contrastes ortogonais C1 (C x FSH) e C2 (F4 x F6). Não houve efeito de tratamento no número de folículos (C = 53,3 ± 4,9 vs FSH = 51,36 ± 3,1;P = 0,89), número total de oócitos (C = 19,46 ± 1,64 vs FSH = 18,47 ± 1,27; P = 0,55), número de oócitos viáveis (C = 12,57 ± 1,26 vs FSH = 12,70 ± 1,03; P= 0,606), taxa de recuperação de oócitos (C = 36,5% vs FSH = 36,0%; P = 0,48) e produção de embriões in vitro (C = 4,11 ± 0,52 vs FSH = 4,32 ± 0,46; P = 0,79). Apesar de não ter havido efeito no número de folículos, o tratamento com FSH alterou a distribuição dos mesmos, proporcionando o aumento no número de folículos médios (6 a 10 mm). No entanto, não houve efeito do tratamento com FSH no número de oócitos totais e viáveis recuperados, nem na produção de embriões. Reproductive biotechnologies such as Ovum Pick-Up and in vitro Embryo production (OPU-IVEP) have been widely used as important tools to achieve faster genetic improvement in herds, diminishing the intervals between generations. In Brazil, in vitro Embryo Production (IVEP) is growing in popularity and accounts for 70.7% of all in vitro embryo production worldwide. However, the OPU-IVEP is still poorly efficient in high-producing dairy cattle, especially because of their reduced follicular population. Several studies have shown a positive effect of FSH on OPU-IVEP yeld. Recently, FSH pre-stimulation has shown to be able to increase the diameter of aspirated follicles and the percentage of transferable embryos. The hormone FSH stimulates follicle recruitment in the antral phase, in the way that they develop until the moment of divergence and one or more follicles becomes dominant. The hypothesis of this study is that the use of 200mg FSH split into 6 doses in non-lactating Holstein cows with a synchronized follicular wave emergence increases the number of follicles, the recovery rate and the number of embryos produced in vitro. Thirty six Holstein cows used as oocyte donors were homogenously allocated to one of three treatment groups in a 3x3 Latin square design: Control (C); 4 doses of FHS (FSH4); 6 doses of FSH (F6). All cows were synchronized using the same protocol for synchronization of follicular wave emergence, except for the administration and number of doses of FSH as previously described. At random days of the estrous cycle known as D0, all cows received an intravaginal P4 device (Primer®, Tecnopec-Agener União, São Paulo, Brazil) and 2mg estradiol benzoate (Ric-BE®, Tecnopec-Agener União). Three days after (D3), all cows received 0.530 mg D-Cloprostenol (Cioprostinn®, Innovare Biotecnologia e Saúde Animal Ltda, Monte Aprazível, SP, Brasil). Cows from the Control group received no additional treatment. Cows from group FSH4 were treated with 200 mg of FSH split in 4 doses of similar concentration given approximately 12 h apart, starting on D4 AM. Cows form group FSH6 were treated with 200 mg of FSH split in 6 doses of similar concentration given approximately 12 h apart, starting on D3 AM. On D7, the device was removed and OPU was performed concomitant with antral follicle count in each ovary. The oocytes considered as viable were sent to IVEP. Data was analyzed using the Glimmix of SAS 9.3, with orthogonal contrasts C1 (C x Treatment with FSH) and C2 (FSH4 x F6). There was no effect on the number of antral follicle (C = 53.3 ± 4.9 vs FSH = 51.36 ± 3.1;P = 0.89), number of total oocytes (C = 19.46 ± 1.64 vs FSH = 18.47 ± 1.27; P = 0.55), number of viable oocytes (C = 12.57 ± 1.26 vs FSH = 12.70 ± 1.03; P= 0.61), oocyte recovery rate (C = 36.5% vs FSH = 36.0%; P = 0.48) and number of embryos produced in vitro (C = 4.11 ± 0.52 vs FSH = 4.32 ± 0.46; P = 0.79). Although FSH treatment did not affect the number of follicles, it affected the distribution of them, increasing the number of follicles from 6 to 10 mm. However, FSH treatment did not alter the total number of oocytes and number of viable oocytes or embryo production.

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 Tabapua 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 Tabapua breeds. The Nelore animals also had a higher volumetric proportion of Leydig cells (5.2%) than the Guzerat and Tabapua 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. Key words: cattle, testis, volumetric proportion, seminiferous tubule