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Estradiol benzoate (EB), estradiol cypionate (EC), and gonadotrophin releasing hormone (GnRH) were evaluated as ovulation inducers for TAI of crossbred lactating cows. In experiment I (n = 45), the follicular dynamics was evaluated, while in experiment II (n = 171) the reproductive efficiency was evaluated. All females were submitted to a synchronization protocol: insertion on day 0 (D0) of intravaginal progesterone -release intravaginal device (PRID; 1g) plus administration of EB 2mg; D8, PRID removal, administration of 0.150mg PGF2α and 400 IU of eCG, and cows were allocated into three treatments: 1) TEB9 - IM administration of 1mg EB on D9 and AI performed 52 hours after PRID removal; 2) TEC - IM administration of 1mg EC on D8 and AI performed 48 hours after withdrawal of PRID; and 3) TGnRH - administration of 100pg GnRH on D10 and AI performed 52 hours after removal of PRID. The follicular growth rate was lower in the EC group (p 0.05). The use of EB, EC, and GnRH as ovulation inducers in the TAI protocol did not show marked differences in the evaluated patterns of follicular dynamics and pregnancy. RESUMO Benzoato de estradiol (EB), cipionato de estradiol (EC) e hormônio liberador de gonadotrofinas (GnRH) foram avaliados como indutores da ovulação na IATF em vacas mestiças em lactação. No experimento I (n=45) a dinâmica folicular foi avaliada, enquanto no experimento II (n=171) a eficiência reprodutiva foi avaliada. Todas as fêmeas foram submetidas a um protocolo de sincronização: inserção no dia 0 (D0) de dispositivo intravaginal de liberação de progesterona (PRID; 1g) mais administração de EB 2mg; D8, remoção de PRID, administração de 0,150mg de PGF2α e 400 UI de eCG, e as vacas foram alocadas em três tratamentos: 1) TEB9 - administração IM de 1mg EB em D9 e AI realizada 52 horas após a remoção PRID; 2) TEC - administração IM de 1mg EC em D8 e AI realizada 48 horas após a remoção de PRID; e 3) TGnRH - administração de 100μg GnRH em D10 e AI realizada 52 horas após a remoção de PRID. A taxa de crescimento folicular foi menor no grupo EC (p 0,05). O uso de EB, EC e GnRH como indutores de ovulação em protocolos de IATF não mostrou diferenças marcantes nos padrões avaliados de dinâmica folicular e prenhez.

Aim: The aim of this study was to evaluate the effects of the administration of recombinant bovine somatotropin (rbST) at the moment of implementation of the timed artificial insemination protocol, on follicular dynamics and pregnancy rate in crossbred cows. Materials and Methods: A total of 346 cows were used in two experiments with a factorial 2×2 design. The cycling cows (Tcycling) and the anestrous cows (Tanestrous) were considered as factor 1 and the administration of rbST (TrbST) or not (Tcontrol) as factor 2. The experimental protocol: (1) Tcontrol – day 0 (D0), insertion of a progesterone-release intravaginal device (PRID) plus 2 mg of estradiol benzoate (EB); D8, PRID removal, plus 0.150 mg of prostaglandin F2α, and 400 IU of equine chorionic gonadotropin; D9, 1 mg of EB; and with artificial insemination at day 10; (2) TrbST – similar to Tcontrol plus 500 mg of rbST on D0. In experiment I, ultrasound examinations were performed in all treatments. In experiment II, the cows' pregnancy rate was evaluated. Data were analyzed with 5% probability. Results: There was no effect of the protocols on cows cyclicity or follicular growth rate (p>0.05). There was no interaction of the effects, administration of rbST, and the cyclicity of cows on the pregnancy rate. The total pregnancy rate observed was 49.0%. The pregnancy rate in cows receiving rbST was lower for anestrous compared with cycling cows (p

Avaliou-se a eficiência de dois indutores da ovulação: cipionato de estradiol (CE) e benzoatode estradiol (BE), na inseminação artificial em tempo fixo (IATF). Foram utilizadas 128novilhas. Todos os animais foram submetidos ao mesmo protocolo de sincronização, a partirdo dia 8 os animais foram distribuídos em dois tratamentos: Tratamento com CE no dia 8 (64novilhas) e tratamento com BE no dia 9 (64 novilhas). Quanto ao número de folículos, sóobservou-se diferença significativa entre os tratamentos no dia 8. Não houve diferença(p>0,05) para taxa de crescimento folicular, diâmetro do folículo dominante (10,97 ± 1,24 e9,77 ± 1,36 mm), e intervalo da ovulação à inseminação artificial (13,20 ± 3,79 e 23,00 ±14,28 horas) entre os tratamentos. A retirada do dispositivo de progesterona à ovulação, emhoras, foi de 60,60±3,69 e 74,75±15,17 horas, respectivamente para CE e BE (p

In order to evaluate whether ovarian volume, presence and diameter of the corpus luteum (CL) have effects on the number and quality of bovine recovered oocytes, 110 ovaries were obtained from the slaughterhouse. Cumulus oocytes complex were aspirated and evaluated under stereomicroscope. Oocytes were counted and classified according to their quality (Grades I, II, III and IV). Ovarian volume was weakly correlated to the number of good quality oocytes (P < 0.05). Ovaries with CL showed greater numbers of good quality oocytes than ovaries without CL (P < 0.05). Further, presence of CL and its diameter positively influenced the probability of recovering good quality oocytes (P < 0.05). In conclusion, ovarian volume is not a good parameter itself to predict important ovarian characteristics; moreover, analysis of CL, its presence and diameter, may be a good tool to improve efficiency on in vitro embryo production programs.

Made available in DSpace on 2014-09-30T18:18:34Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-03-01Bitstream added on 2014-10-01T14:03:16Z : No. of bitstreams: 1 S1809-68912014000100014.pdf: 184291 bytes, checksum: 01d77e25b758479e023dbc703d721dbd (MD5) O objetivo do trabalho foi avaliar o efeito da associação entre crioprotetores ainda pouco estudados no Brasil como a dimetilformamida e a trealose em meio diluidor, por meio de protocolos de descongelamento rápido e lento. Foram utilizados três cães machos, adultos, sadios da raça Labrador do Retrievier, que foram submetidos a uma coleta de sêmen semanal durante o período de cinco semanas. Os três meios diluentes utilizados neste estudo foram: (D1)-tris-citrato, acrescido de 3% de dimetilformamida + 3% de glicerol, (D2)-3% de dimetilformamida e de trealose e (D3)-4% de glicerol. No descongelamento, metade das amostras de cada meio diluente foi descongelada pelo método rápido, em banho-maria a 75ºC por sete segundos, seguido de nova imersão a 37 ºC por 1 minuto. A outra metade foi descongelada pelo método lento, em banho-maria à 37 ºC por 1 minuto. O sêmen foi avaliado quanto à motilidade progressiva, vigor espermáticos e integridade de membrana. Pra isso, as amostras foram submetidas aos testes hipo-osmótico e de integridade da membrana plasmática e do acrossoma (fluorescência). Os resultados indicam que o uso do glicerol como crioprotetor em diluidor TRIS proporciona maior eficácia na criopreservação dos espermatozoides da espécie canina, quando comparados com a dimetilformamida associada ao glicerol ou trealose. The aim of this study was to evaluate the association between cryoprotectants little studied in Brazil such as dimethylformamide and trehalose amid thinner, using protocols of fast and slow defrosting. Three adult Labrador Retrievier male, healthy dogs, weekly submitted to one semen collection during five-weeks period, were used. The base diluent medium used in this study was tris-citrate added with 3% of dimethylformamide + 3% glycerol (D1), 3% dimethylformamide and trehalose (D2) and 4% glycerol (D3). At defrosting, half of the semen samples from each diluent medium was defrosted by rapid method in water-bath at 75 °C for seven minutes, followed by a new immersion at 37 °C for 1 minute. The other half of the samples was defrosted by slow method, in water-bath at 37 °C for 1 minute. The semen was evaluated for sperm progressive motility and vigor, besides membrane integrity. For this, the semen samples were submitted to either hyposmotic and membrane integrity tests of the plasmatic membrane and acrosome (fluorescence). The results indicated that the use of glycerol as cryoprotector in TRIS diluter provides greater efficacy in cryopreserving spermatozoa of the canine species, when compared to dimethylformamide associated with trehalose or glycerol. UNESP Faculdade de Ciências Agrárias e Veterinárias Universidade Federal de Viçosa Universidade de Rio Verde UNESP Faculdade de Ciências Agrárias e Veterinárias

The quality of oocytes is more critical for the success of bovine in vitro embryo production (IVP) than the conditions of in vitro culture of these structures. Despite knowledge about bovine follicular development, especially gonadotropin-dependent phase, be considerably wide, knowledge about effects of the estrous cycle phase, follicular or luteal, on recovery Mini -review Article

The objective of this work was to evaluate the effects of protein and/or starch supplementation on the nutritional performance of cattle grazing on low-quality tropical forage. Five crossbred steers (Holstein × Gyr) with an average body weight (BW) of 397 kg that were fitted with ruminal and abomasal cannulae were used. The animals were kept in individual signal-grass (Bracharia decumbens) paddocks. Five treatments were evaluated: 1 - control (without supplementation); 2 - supplementation with 1 g of crude protein (CP) per kg of BW; 3 - supplementation with 2.5 g of starch per kg of BW; 4 - supplementation with CP and starch as described for treatments 2 and 3; and 5 - supplementation as described for treatment 4 but replacing the corn starch with a mixture of corn starch and nitrogenous compounds, thereby resulting in an energy supplement of 150 g CP/kg of dry matter. The experiment was performed according to a 5 × 5 Latin square design in a 2 × 2 + 1 factorial arrangement. The forage intake was not affected by any of the factors evaluated in this study. The production of microbial nitrogen in the rumen was not affected by nitrogen or starch supplementation. The apparent nitrogen balance was only increased when both starch and nitrogen were supplied. Supplementation with both starch and nitrogenous compounds for cattle grazing on low-quality tropical forage is characterized by an interactive metabolic effect that increases nitrogen accretion by the animals.

Avaliaram-se as dinâmicas de trânsito e degradação da fibra em detergente neutro (FDN) em bovinos alimentados com forragem tropical de baixa qualidade e compostos nitrogenados. Foram utilizadas cinco novilhas Holandês x Zebu fistuladas no rúmen. A alimentação volumosa basal dos animais foi constituída por feno de capim-braquiária (Brachiaria decumbens Stapf.), com 5,08% de proteína bruta (PB), com base na matéria seca (MS), fornecido ad libitum. Os cinco tratamentos avaliados foram definidos de acordo com o nível de suplementação proteica (0, 3, 5, 7 e 9 pontos percentuais acima do nível de PB da forragem). Como fonte de compostos nitrogenados, empregou-se mistura de ureia:sulfato de amônia:albumina (4,5:0,5:1,0). O experimento foi estruturado segundo delineamento em quadrado latino 5 x 5. Os níveis médios de PB nas dietas foram de 5,28; 8,08; 9,82; 11,87 e 13,63%, com base na MS. Verificou-se elevação linear (P

The aim of this study was to evaluate the effects of vitamin E associated with rapid thawing on cryopreserved goat semen. Two bucks were used and eight ejaculates per animal were collected using artificial vagina. Semen was diluted with the following treatments: BIOXCELL (control), BIOXCELL + Equex (sodium lauryl sulphate) and BIOXCELL + vitamin E 100 μM. Semen was packaged into 0.25 mL straws and cooled at 5°C for 1 hour. Freezing was performed in liquid nitrogen vapor (−155°C) during 15 minutes. Then, the straws were immersed in liquid nitrogen (−196°C). Straws were thawed at 38°C/60 seconds or at 60°C/7 seconds with immediate sperm analysis. Hypoosmotic swelling test was performed adding a 20 μL aliquot of thawed semen to 1 mL of hypoosmotic solution (100 mOsm·Kg−1) followed by incubation during 60 minutes in water bath (38°C). Vitamin E did not affect any studied parameters (P>0.05). Nevertheless, defrosting rate of 60°C/7 seconds improved sperm membrane functional integrity (P<0.05). Current knowledge about goat semen cryopreservation is not sufficient to ensure high post-thawing recovery rates; thus, this study brings important data about using antioxidants and different thawing rates on cryopreservation process.

In order to evaluate whether ovarian volume, presence and diameter of the corpus luteum (CL) have effects on the number and quality of bovine recovered oocytes, 110 ovaries were obtained from the slaughterhouse. Cumulus oocytes complex were aspirated and evaluated under stereomicroscope. Oocytes were counted and classified according to their quality (Grades I, II, III and IV). Ovarian volume was weakly correlated to the number of good quality oocytes (P0.05). Ovaries with CL showed greater numbers of good quality oocytes than ovaries without CL (P0.05). Further, presence of CL and its diameter positively influenced the probability of recovering good quality oocytes (P0.05). In conclusion, ovarian volume is not a good parameter itself to predict important ovarian characteristics; moreover, analysis of CL, its presence and diameter, may be a good tool to improve efficiency on in vitro embryo production programs.

Objetivou-se avaliar os efeitos de compostos nitrogenados suplementares sobre o consumo, a digestibilidade e a síntese de proteína microbiana em bovinos alimentados com forragem tropical de baixa qualidade. Foram utilizadas cinco novilhas mestiças Holandês × Zebu, com peso vivo médio de 209 kg, fistuladas no rúmen. O volumoso consistiu de feno de capim-braquiária (Brachiaria decumbens Stapf.) (5,08% de proteína bruta (PB), com base na matéria seca), fornecido à vontade. Os cinco tratamentos avaliados foram definidos de acordo com o nível de suplementação proteica (0, 3, 5, 7 e 9 pontos percentuais acima do nível de PB da forragem). Como fonte de compostos nitrogenados, empregou-se mistura de ureia, sulfato de amônia e albumina, nas proporções de 4,5:0,5:1,0, respectivamente. O experimento constou de cinco períodos experimentais, segundo delineamento em quadrado latino 5 × 5. Os níveis médios de PB observados nas dietas foram de 5,28; 8,08; 9,82; 11,87 e 13,63%, com base na matéria seca (MS). Verificou-se efeito quadrático dos níveis de PB na dieta sobre os consumos de MS, matéria orgânica (MO) e fibra em detergente neutro (FDN) (kg/dia), com respostas máximas nos níveis de 10,83%, 10,78% e 10,37% de PB, respectivamente. Os coeficientes de digestibilidade da MO e FDN apresentaram relação do tipo linear-response-plateau com os níveis de PB na dieta com início de platô (resposta máxima) em 7,93 e 7,55% de PB, respectivamente. A concentração média diária de nitrogênio amoniacal ruminal apresentou comportamento linear crescente em função dos níveis de PB da dieta, com valor estimado de 15,33 mg/dL, equivalente ao máximo consumo de MS. A avaliação da relação entre consumo de nitrogênio e fluxo intestinal de nitrogênio microbiano indica que as estimativas dessas variáveis tornam-se equivalentes no nível de 7,13% de PB na dieta. The objective of this study was to evaluate the effects of supplementation with nitrogenous compounds on intake, digestibility, and rumen microbial synthesis in cattle fed low-quality tropical forage. Five crossbred heifers, averaging 209 kg and fitted with ruminal fistulla, were used. The animals were fed ad libitum with signal grass (Brachiaria decumbens Stapf.) hay, which had crude protein (CP) content of 5.08%, as dry matter (DM) basis. The five treatments were defined according to the increasing level of CP in the diet (0, 3, 5, 7, and 9 percentile points above the forage CP level). The supplement consisted of the following nitrogen sources: urea, ammonium sulfate and albumin (4.5:0.5:1.0, respectively). The experiment was carried out according to a 5 × 5 Latin square design, with five experimental periods. The average CP levels in the diets were: 5.28, 8.08, 9.82, 11.87, and 13.63% on DM basis. The intakes of DM, organic matter (OM), and neutral detergent fiber (NDF) showed a quadratic response according to CP levels in the diet, with maximum responses at 10.83%, 10.78%, and 10.37% CP, respectively. The digestibility coefficients of OM and NDF showed a linear-response-plateau response according to CP levels, with the plateau beginning (maximum response) at 7.93% and 7.55% CP, respectively. The average daily concentration of rumen ammonia nitrogen (RAN) was positively related with CP levels. The RAN estimate associated with the maximum DM intake was 15.33 mg/dL. It was observed that intestinal flow of microbial nitrogenous compounds and nitrogen intake became equivalent to each other at 7.13% of CP.

O objetivo neste trabalho foi avaliar os efeitos da dimetil-formamida na criopreservação de sêmen caprino, por meio de testes in vitro. As partidas de sêmen foram congeladas com os diluidores leite desnatado-gema, associado a diferentes crioprotetores e concentrações: 7% de glicerol (T1); 3,5% de glicerol e 3,5% de dimetil-formamida (T2) e 5% de dimetil-formamida (T3). O sêmen foi centrifugado e envasado em palhetas de 0,5 mL, sendo resfriado por 40 minutos, atingindo 5,0°C e permanecendo nesta temperatura por mais 1 hora e 20 minutos. Os parâmetros avaliados in vitro foram a motilidade progressiva e o vigor espermático, a integridade acrossômica, a integridade da membrana plasmática (HO) e a reação acrossômica. Observou-se perda de 30,0% da motilidade inicial quando as amostras foram submetidas aos procedimentos de criopreservação. A perda de integridade da membrana plasmática, avaliada pelo teste hiposmótico (HO) foi de 19%. As lesões de acrossoma aumentaram em 3% durante o teste de termo-resistência (TTR) lento. Não houve diferença entre os tratamentos quanto aos aspectos de motilidade nos tempos de 0,00; 0,05; e 1,00 horas do TTR e vigor em todos os tempos. No tempo de 2,00 horas do TTR, registrou-se diferença entre os tratamentos 1 e 2, de modo que a motilidade no tratamento 2 foi superior às demais. Os valores de integridade de membrana plasmática, integridade acrossômica e reação acrossômica pós-descongelamento não diferiram entre os tratamentos, indicando que a dimetil-formamida não foi superior ao glicerol na manutenção da qualidade espermática após a criopreservação. The objective of this trial was to evaluate the efficiency of dimethylformamide on cryopreservation of goat semen using semen physical analyses and complementary tests. Alpine and Saanen bucks from the Dairy Goat Experimental Station- DZO were used. Semen samples were frozen with a yolk-skimmed milk diluent and cryoprotectors with different concentrations as follows: 7% glycerol (T1), 3.5% glycerol plus 3.5% dimethylformamide (T2) or 5% dimethylformamide (T3). Semen was centrifuged, diluted, and bottled in 0.5 mL straws followed by cooling for 40 minutes until reach 5.0°C and kept at this temperature for additional 80 minutes. Samples were then exposed to liquid nitrogen vapor for 15 minutes and finally frozen. Thawing was done in a waterbath at 37°C for 50 seconds. The following variables were evaluated in vitro: sperm progressive motility and vigor, acrosomal integrity and reaction, and plasmatic membrane integrity. The cryopreservation procedures reduced 30.0% of the initial motility and 19% of plasmatic membrane integrity that was evaluated using the hyposmotic swelling test (HOST). It was observed an increaseof 3% in acrosomal lesions when samples were submitted to a slow thermoresistance test (TRT). No significant differences in sperm motility were observed among treatments at 0, 5, and 60 minutes of TRT as well as in sperm vigor at all TRT times. However, at 120 minutes of TRT a significant difference in sperm motility was found comparing T1 and T2 while T3 was intermediate. There were no significant differences on plasmatic membrane integrity, acrosomal integrity, and post-thawing acrossomal reaction across treatments. It can be concluded that dimethylformamide can be a viable alternative for goat semen cryopreservation used alone or in association with glycerol.

Embryo transfer (ET) in cattle speeds up genetic gains, but its use is limited by cost-benefit analysis. In addition other techniques can be developed, such as sexing and bipartition of embryos. An alternative to improve the economic viability of ET in cattle would be to bipartition embryos in order to increase the yield of the technique. The aim of this study was to investigate the operational viability of embryo bipartition technique in an ET program in cattle and to study aspects related to the viability and development of bovine hemi-embryos (HE) compared with intact ones. The embryos were collected by nonsurgical technique 7 days after the onset of oestrus. Viable structures (130) from 49 embryo collections from 25 Aberdeen and Simmental donor cows and heifers were used. Only embryos in compact morula, early blastocyst and blastocyst stage, with a morphological range from excellent to good grade (IETS Grade 1), were split. The embryos, split (78) or not (52), were transferred into the uterine horn ipsilateral to the corpus luteum of the recipients 7 days after oestrus. The treatment groups evaluated were T1 (intact embryo, n = 52), T2 (1 HE, n = 27) and T3 (2 HE, n = 51). Crossbred heifers were used as recipients and pregnancy diagnosis was done at 60 to 80 days of gestation. The embryos of T1, T2 and T3 were classified morphologically as excellent or good and by developmental stage as morula, early blastocyst, or blastocyst, distributed as follows: T1: 30, 22 and 16, 17 and 19; T2: 15, 12 and 7, 9 and 11; and T3: 29, 22 and 15, 15 and 21, respectively. The birth rate per original embryos was greater for T2 than for T1 and T3 (Table 1). The pregnancy rates for excellent and good embryos and morulae, early blastocysts and blastocysts were not different (P > 0.05). The T1, T2 and T3 twin births were 0, 1 and 5, respectively. It is concluded that embryo bipartition technique applied in a commercial ET program is a viable operational technique. Table 1.Pregnancy at 60 to 80 days and birth rate per original embryos used Supported by CAPES, CNPq, FAPEMIG and BIOTRAN.

The importance of serum progesterone (P4) during the first weeks of pregnancy to reduce the embryo mortality in cattle herds has been demonstrated (Mann and Lamming 2001 Reproduction 121, 175-180). Studies show that a P4 peak at the beginning of pregnancy (about 5 days after the natural breeding or AI) helps development of the concept via secretion of interferon-τ (Mann 2002 XXII World Buiatrics Congress 18-23, 300-306). Studies have shown that the administration of gonadotropin-releasing hormone (GnRH) or its agonists after AI may stimulate corpus luteum function, induce the formation of an accessory corpus luteum, or increase of P4 serum concentrations and, therefore, improve embryonic survival (Bartolome et al. 2005 Theriogenology 63, 1026-1037). This work aims to evaluate the effect of GnRH injection 12 d after fixed-time AI(FTAI) on P4 serum levels and pregnancy rate of beef crossbred cows. The cows (Bos taurus indicus × Bos taurus taurus, n = 59), range in body condition (BCS) from 2.5 to 3.5 (scale of 1 to 5), were not previously pregnant. The animals were allocated to 2 treatments: TEB treatment (n = 30) consisted of Day 0 insertion of progesterone intravaginal device (ID) plus 2 mg of estradiol benzoate (EB), i.m. followed on Day 8 by removal of the ID and 300 IU of eCG and 0.15 mg of PGF2α, i.m. on Day 9, 1 mg injection of EB (i.m.) was given, followed by FTAI at 48 to 56 h after the withdrawal of ID. The TEBGnRH12 treatment (n = 29) protocol was similar to TEB, but with administration of 25 μg of GnRH analogue (Lecirelina) 12 d after the FTAI. Transrectal ultrasound was used for pregnancy diagnosis on Day 35 after AI. Blood samples for P4 serum assay were collected from 30% of animals in each treatment, at the time of AI and on Days 5, 12, and 20 after FTAI. For all statistical analysis, we used the program SAS 9.0 (2002; SAS Institute Inc., Cary, NC, USA) at 5% probability. The pregnancy rate was analyzed by logistic regression. The effects of treatment and day in P4 concentration were analyzed in a split plot, with the effect of day in plot, in mixed model, considering the error and repetition as a random effect, and comparison of means by Tukey-Kramer. Pregnancy rate and the concentration of serum P4 on different days was analyzed by Spearman correlation. The pregnancy rate for TEB cows was 53.33% (16/30) for the first service compared with 37.93% (11/29) for TEBGnRH12 cows. The protocol used did not affect the pregnancy rate of crossbred cows (P > 0.05). There were no treatment differences (P > 0.05) between the concentrations of P4 (TEB = 3.88 ng mL-1; TEBGnRH12 = 3.12 ng mL-1). In conclusion, the administration of the analogue of GnRH 12 days after FTAI does not affect the rates of pregnancy or the concentration of P4. Supported by grants from CNPq, FAPEMIG and DZO-UFV.

The objective of this study was to evaluate the administration of the follicle-stimulating hormone (FSH-p) or equine chorionic gonadotropin (eCG) in protocols of ovulation synchronization. One hundred forty-nine crossbred Holstein-Gyr cows were used in 2 properties in Minas Gerais and 3 treatments: TControl (n = 49 cows), Day 0: insert of a progesterone device (Primer®, Tecnopec, São Paulo, Brazil) + 2 mg of estradiol benzoate (RIC-BE®); Day 8: removal of Primer + 112 mg of D-cloprostenol (Prolise®, ARSA SRL, Buenos Aires, Argentina) + 1 mg of estradiol benzoate and fixed-time artificial insemination (FTAI) accomplished 44 h after the removal of Primer; TFSH (n = 50 cows), similar to TControl, but on Day 8, 15 mg of FSH-p (Folltropin®, Bioniche Animal Health) was administered; TeCG (n = 50 cows), similar to TControl, with administration on Day 8 of 300 IU of eCG (Novormon®, Syntex SA, Buenos Aires, Argentina). Cows that returned to estrus 14 to 28 days after the FTAI were inseminated once again. For all statistical analysis, we used the program SAS 9.0 (2002; SAS Institute Inc., Cary, NC, USA) at 5% probability. Quantitative variables (live weight, days postpartum, follicular average per cow) were analyzed by variance, and body condition score by Friedman test. The pregnancy rates were submitted to logistic analysis considering the effect of local experimental factors and were analyzed by Spearman correlation among the variables studied and the pregnancy rate. There was no difference (P > 0.05) between treatment for pregnancy rate in FTAI protocols (TControl = 40.82%; TFSH = 38.00%; TeCG = 26.00%), in the first insemination after FTAI (TControl = 56.25%; TFSH = 70.59%; TeCG = 68.42%), and in FTAI plus first insemination after FTAI (TControl = 59.18%; TFSH =62.00%; TeCG = 52.00%), as well as for the estrus repetition (TControl = 55.17%; TFSH = 54.84%; TeCG = 51.35%) and the correlation (P > 0.05) among the pregnancy rate and postpartum period, milk production, body weight and body condition. No effect was observed on the pregnancy rate by the addition of the hormones FSH and eCG in the protocol of ovulation synchronization in crossbred Holstein-Gyr cows; however, reinsemination in the period from 14 to 28 days after FTAI increased the pregnancy rate. CNPq; FAPEMIG; TECNOPEC/São Paulo, Brazil.