G. M. Bragança

Use of two doses of cloprostenol in different intervals for estrus synchronization in hair sheep under tropical conditions

This study evaluated the effect of two doses of prostaglandin at different intervals on reproductive parameters of crossbred ewes. In Experiment 1, 30 ewes received two doses of 120xa0μg cloprostenol at 7 (G7xa0days), 9 (G9xa0days), or 11.5 (G11.5xa0days) days apart. Ultrasound assessments were performed from the first and second cloprostenol administration for 5xa0days or ovulation detection. Estrus signs were checked by a teaser male. Plasma progesterone concentration was measured before each cloprostenol dose. In Experiment 2, 95 ewes were allocated into the same treatments and after the second dose, ewes in estrus were mated. At 30xa0days after breeding, pregnancy diagnosis was conducted and prolificacy was evaluated at lambing. In Experiment 1, at the first cloprostenol administration, 50% of ewes had an active CL and all showed estrus. At the second administration, 66.7% of ewes had an active CL and one did not present estrus. There was no difference (Pxa0>xa00.05) after the second dose for as follows: overall estrous response (90%), interval from cloprostenol administration to estrous onset (42.0xa0±xa04.9xa0h), estrus duration (31.5xa0±xa02.1xa0h), ovulation rate (100.0%), and number of ovulations (1.5xa0±xa00.3). In Experiment 2, both pregnancy and prolificacy rates were similar (Pxa0>xa00.05) for G7xa0days (73.3; 145%), G9xa0days (75.9; 125%), or G11.5xa0days (75.9; 145%), leading to an overall pregnancy rate of 75.0% (66/88) and prolificacy rate of 137%. Therefore, the three treatments proposed were able to promote high pregnancy and prolificacy rates in crossbred ewes.

Early pregnancy diagnosis in ewes by subjective assessment of luteal vascularisation using colour Doppler ultrasonography

This study was designed to evaluate early pregnancy diagnosis using colour Doppler ultrasonography (US) for luteal vascularisation assessment. In Study 1, 28 ewes were artificially inseminated (Day 0), and luteal vascularisation was assessed from Day 12 to Day 19 by two evaluators using colour Doppler US, categorising the corpus luteum (CL) on a subjective scale ranging from 1 to 4. Females bearing a CL with score 2 or greater were presumably considered pregnant. Pregnancy was confirmed on Day 30 by B-Mode US. In Study 2, a predictive pregnancy diagnosis was performed on Day 17 in 197 ewes based on the criteria described in Study 1. Pregnancy was confirmed by B-mode US on Day 45. Agreement between evaluators was verified by an intraclass correlation coefficient (ICC) and Kappa index (κ). Performance of colour Doppler US for early pregnancy diagnosis was evaluated calculating sensitivity (Sens), specificity (Spec), negative predictive values (NPV), positive predictive values (PPV) and accuracy (Ac). In Study 1, luteal vascularisation assessment was unable to predict non-pregnant animals between 12 and 14 days after insemination, as all animals still had vascularised CL, and thus were considered pregnant. The colour Doppler US performance improved progressively until Day 17, when it reached maximum values (Sensxa0=xa0100%, Specxa0=xa076%, PPVxa0=xa073%, NPVxa0=xa0100% and Acxa0=xa086%). The subjective scale for luteal irrigation assessment showed medium to good agreement among evaluators on Day 12 and Day 13 (ICCxa0=xa00.66 and 0.68, respectively), and excellent agreement from Day 14 to Day 19 (ICCxa0=xa00.90, 0.80, 0.80, 0.84, 0.95 and 0.93, respectively). Agreement was almost perfect for score 1 CLs (κxa0=xa00.87), and moderate for scores 2, 3 and 4 CLs (κxa0=xa00.54, 0.48 and 0.41, respectively). In Study 2, performance of colour Doppler US as a tool to predict pregnancy status in ewes on Day 17 post-insemination was as follows: Sensxa0=xa093.5%, Specxa0=xa080.8%, PPVxa0=xa085.6%, NPVxa0=xa091.1% and Acxa0=xa087.8%. Subjective luteal vascularisation assessment using colour Doppler US to distinguish between pregnant and non-pregnant animals was considered a reliable tool which was highly efficient beginning 17 days after breeding.

Anti-Müllerian hormone and antral follicle count are more effective for selecting ewes with good potential for in vivo embryo production than the presence of FecG E mutation or eCG pre-selection tests

This study aims to compare four different methods for selecting high responding sheep donors for inxa0vivo embryo production. These methods include a pre-selection eCG test (eCG), antral follicle count (AFC), plasma anti-Müllerian hormone measurement (AMH) and genotyping for the presence of the FecGE mutation (a polymorphism in the GDF9 gene associated with increased ovulation rate). Santa Ines ewe lambs (nu202f=u202f25) underwent superovulation (SOV) with 800 IU equine chorionic gonadotropin (eCG) and the corpus luteum (CL) count was recorded by laparoscopy after eight days. At the D0eCG, blood samples for AMH and genotyping analysis were collected. Twenty-one days after the end of the eCG test, the same animals underwent SOV with 200u202fmg of FSH, administered in six decreasing doses, and then naturally mated. Immediately before the beginning of the FSH protocol (D0FSH), and at the moment of the first FSH dose (D9FSH), the AFC was assessed. Plasma AMH was again determined at the D9FSH. After each screening process, animals were classified as having a high (HR), or low (LR), potential of response (using specific thresholds for each method). Then, the ewes response to SOV and embryo yield for each screening method, classified as HR or LR, were compared. Animals classified as HR by AFC (HRAFC) and by AMH concentration (HRAMH) at the D9FSH, produced more viable embryos than those classified as LRAFC and LRAMH (HRAFC 6.2u202f±u202f3.2 vs LRAFC 2.8u202f±u202f3.0 and HRAMH 6.6u202f±u202f3.6 vs LRAMH 3.0u202f±u202f2.9). Pre-selection tests with eCG and different FecGE genotypes, either heterozygous (+/E) or wild type (+/+), were unable to discriminate HR or LR animals. A tendency (Pxa0=xa00.06) to have lower plasma AMH was observed in heterozygous FecGE (+/E) ewes. In conclusion, both AFC and plasma AMH can be used to select donor ewes with a higher potential of response for inxa0vivo embryo production.

Supplementation of 17β-estradiol and progesterone in the co-culture medium of bovine oviductal epithelial cells and ovine spermatozoa reduces the sperm kinematics and capacitation

This study investigated the effect that bovine oviductal epithelial cell (BOEC) and ovine spermatozoa co-culture exposed to different hormonal environments had on ram sperm function over the course of a 24-h incubation period. Ram cooled-stored spermatozoa were selected by swim-up and then co-cultured separately for 24u2009h at 38.5u2009°C under 5% CO2 with either: (1) Fert-TALP medium (positive control [POSControl]), (2) Fert-TALP medium supplemented with 17β-estradiol (E2) and progesterone (P4) at concentrations similar to follicular phase (Follicular NEGControl), (3) Fert-TALP medium supplemented with E2 and P4 concentrations similar to luteal phase (Luteal NEGControl), (4) BOEC cultured in the same medium as that of the Follicular NEGControl group (Follicular BOEC group), or (5) BOEC cultured in the same medium as that of the Luteal NEGControl group (Luteal BOEC group). The sperm kinematics, capacitation status, and plasma membrane (PM) integrity were evaluated at different intervals. Sperm PM integrity was not affected (P ˃ 0.05) by BOEC co-culture, regardless of the phase of the estrous cycle. After 4u2009h of incubation, the Luteal BOEC group presented lower (Pu2009<u2009 0.05) progressive motility and total motility than the Luteal NEGControl group while the Follicular BOEC group showed lower (Pu2009<u2009 0.05) velocimetric parameters and progressive motility than the Follicular NEGControl group. Throughout the incubation period, both BOEC co-culture groups showed a decrease (Pu2009<u2009 0.05) in their capacitation rate in comparison to the POSControl group. Conversely, the Luteal BOEC group presented a higher (Pu2009<u2009 0.05) non-capacitated rate than both the POSControl and Luteal NEGControl groups. In conclusion, BOEC co-culture with ovine spermatozoa at either the follicular or luteal phase decreases sperm kinematics and delays sperm capacitation.

Dose and administration protocol for FSH used for ovarian stimulation affect gene expression in sheep cumulus–oocyte complexes

The present study evaluated the effect of four ovarian stimulation protocols on the follicular population and molecular status of cumulus-oocyte complexes (COCs). Twelve Santa Inês ewes (in a cross-over design) received 80 or 120mg FSH alone in a multiple-dose (MD80 and MD120) regimen or in combination with 300IU equine chorionic gonadotrophin (eCG) in a one-shot (OS80 and OS120) protocol. The follicular population, COC recovery rate, mean COCs per ewe and the rate of brilliant Cresyl blue-positive (BCB+) COCs were similar among treatments (P>0.05). The expression of markers of oocyte competence (ZAR1, zygote arrest 1; MATER, maternal antigen that embryo requires; GDF9, growth differentiation factor 9; BMP15, bone morphogenetic protein 15; Bcl-2, B-cell lymphoma 2; BAX, Bcl-2 associated X protein) and the steroidogenic pathway (ERα, oestrogen receptor α; LHr, LH receptor; FSHr, FSH receptor; STAR, steroidogenic acute regulatory protein) was affected by stimulation. Specifically, the expression of markers of the steroidogenic pathway was reduced with increasing FSH dose in the OS protocol. FSH at a dose of 80mg reduced the expression of FSHr and ERα in the OS versus MD protocol. Conversely, in MD protocol, only LHr was affected by increasing FSH dose. In conclusion, 80mg FSH in the MD or OS protocol was sufficient to promote the development of multiple follicles and obtain fully grown (BCB+) oocytes. The MD protocol may be more appropriate for the production of better-quality oocytes.

Colour-Doppler ultrasound imaging as a laparoscopy substitute to count corpora lutea in superovulated sheep

This study evaluated colour-Doppler ultrasound imaging (UI) as a substitute for laparoscopy to count the corpora lutea (CL) in superovulated sheep. Twenty-five Santa Ines ewes were superovulated three times at 21-day intervals. Corpora lutea were counted by colour-Doppler UI (CLDOPPLER ) 6xa0days after each superovulation and confirmed by laparoscopy (CLLAP ) 12xa0hr later. The mean number of CL was similar for both techniques (2.1xa0±xa02.5 vs. 2.1xa0±xa02.7 for CLDOPPLER and CLLAP , respectively) with a significant positive correlation (rxa0=xa0.94; r2 =.89). Colour-Doppler UI effectively evaluated the ovarian response in superovulated ewes and efficiently identified animals that did not respond to superovulation.

Uso da somatotropina recombinante bovina em búfalas leiteiras I: produção e composição físico-química do leite

Objetivou-se avaliar a influencia da somatotropina recombinante bovina (rbST) sobre a producao e os constituintes do leite de bufalas entre 63 e 154 dias em lactacao. Foram utilizadas 22 bufalas, distribuidas em dois grupos experimentais: grupo rbST - aplicacao de 500 mg de rbST a cada 14 dias; grupo controle - sem aplicacao de rbST. A cada sete dias, foi aferida a producao de leite de todas as bufalas e coletada uma amostra para analise fisico-quimica. As variaveis produtivas e as oriundas de analises laboratoriais foram avaliadas como medidas repetidas no tempo, utilizando-se o comando Repeated gerado pelo procedimento GLM do SAS. A media dos parâmetros estudados para os grupos rbST e controle foram, respectivamente: producao de leite - 6,54 vs. 6,68 kg; gordura - 6,31 vs. 6,34%; proteina 3,86 vs. 3,81%; lactose - 4,96 vs. 5,02%; solidos totais - 16,05 vs. 16,03%; extrato seco desengordurado - 9,75 vs. 9,74%; contagem de celulas somaticas - 329,90 vs. 171,68 (x 1000/mL); e elecondutividade - 2,87 vs. 2,81mS/cm. A utilizacao de 500mg de rbST administrados quinzenalmente, entre 63 e 154 dias em lactacao nao alterou a producao de leite, a proporcao dos constituintes e a CCS do leite de bufalas leiteiras.