Caracterização do gene do choque térmico (HSP-70. 1) e sua relação com características de produção em bovinos leiteiros criados no semiárido brasileiro / Characterization of the thermal shock gene (HSP-70. 1) and its relationship with production characteristics in dairy cattle reared in the Brazilian semiarid

Objetivou-se com este trabalho avaliar a diversidade genética do gene HSP-70.1 e associar os polimorfismos encontrados com a performance de vacas leiteiras das raças Holandesa, Girolando (5/8H-G) e Sindi criadas em região do semiárido brasileiro. Os polimorfismos foram identificados e avaliados pela técnica de PCR-RFLP, usando-se a enzima de restrição EcoRII. Avaliou-se a variabilidade genética por meio do índice de diversidade padrão e da análise de variância molecular (AMOVA). Os polimorfismos identificados foram avaliados sobre as características de produção de leite. Foram identificados sete alelos, os quais demonstraram que houve polimorfismo para a região gênica analisada, e alguns alelos foram compartilhados entre os rebanhos. As raças bovinas Holandesa e Sindi foram similares geneticamente para o gene analisado. A AMOVA demonstrou que há variação genética entre os rebanhos e dentro deles, com a maior parte da variação ocorrendo dentro dos rebanhos para todos os grupos avaliados. Houve efeito dos alelos identificados sobre a produção de leite dos rebanhos das raças Holandesa (P<0,0001) e Girolando (P<0,0117). O gene HSP-70.1 foi polimórfico na população de bovinos leiteiros estudada, sendo, portanto, um marcador molecular promissor para avaliar a produção de leite de raças criadas em região semiárida.(AU)

The objective of this work was to evaluate the genetic diversity of the HSP-70.1 gene and to associate the polymorphisms found with the performance of Holstein, Girolando (5/8H-G) and Sindi dairy cows raised in region of the Brazilian semiarid. Polymorphisms were identified and evaluated using the PCR-RFLP technique using the EcoRII restriction enzyme. Genetic variability was evaluated using the standard diversity index and molecular variance analysis (AMOVA). The identified polymorphisms were evaluated on the characteristics of milk production. They were identified from the seven alleles, demonstrating that there was polymorphism for the analyzed gene region and some alleles were shared among the herds. The Holstein and Sindi bovine breeds were genetically like the analyzed gene. AMOVA demonstrated that there is genetic variation between and within the herds, with most of the variation occurring within the herds for all groups evaluated. There was effect of the alleles identified on the production of milk herds of Holstein and (P<0.0001) Girolando (P<0.0117) breeds. The HSP-70.1 gene was polymorphic in the population of dairy cattle studied, and therefore a promising molecular marker to evaluate milk production of breeds created in semiarid regions.(AU)

The use of steroid hormones in superovulation of Nelore donors at different stages of estrous cycle.

The objective of the present study was to evaluate the superovulatory response and ova/embryo recovery from Nelore donors following treatment with a controlled internal drug releasing device and estradiol benzoate (CIDR-B program) at different stages of the estrous cycle. The control group (TI; n=40) received a standard superovulation protocol with females of this group being between days 9 and 12 of the estrous cycle (estrus = day 0). The donors that received a CIDR-B program containing 1.9 g progesterone and an intramuscular injection of estradiol benzoate (2 mg) were at day 0 (TII; n=30), between days 2 and 6 (TIII; n=30), days 7 and 12 (TIV; n=30), days 13 and 16 (TV; n=30) and days 17 and 20 (TVI; n=30) of the estrous cycle. Superovulation was induced with 400 IU of p-FSH, divided into eight decreasing doses (80/80; 60/60; 40/40; 20/20) at intervals of 12h. The donors received PGF2alpha (Cloprostenol) 48 h after beginning the treatment and CIDRs were removed 12h later. Artificial inseminations (AI) were performed 12 and 22 h after the initiation of estrus and embryos were collected 7 days after AI. The mean numbers (+/-S.E.M.) of total ova and embryos, viable (transferable) and degenerated embryos were 14.2+/-11.3, 7.4+/-6.9 and 3.2+/-3.5 (TI), 13.3+/-10.4, 7.1+/-6.2 and 3.3+/-4.3 (TII), 13.5+/-7.0, 8.1+/-6.7 and 2.3+/-3.0 (TIII), 17.4+/-9.9, 9.4+/-6.9 and 4.0+/-4.4 (TIV), 16.9+/-8.8, 9.8+/-8.1 and 2.7+/-2.5 (TV) and 13.0+/-7.8, 7.2+/-6.9 and 2.3+/-2.5 (TVI), with no significant differences (P>/=0.05) among groups. Pregnancy rates of 67.1% (TI; n=86/128), 60.8% (TII; n=59/97), 62.5% (TIII; n=73/115), 64.1% (TIV; n=84/131), 72.3% (TV; n=81/112) and 60.6% (TVI; n=63/104) were obtained with embryos transferred from these collections and did not differ significantly (P>/=0.05) among groups. The results of the present study allow us to conclude that a combination of steroid hormones may be used prior to superovulation in Nelore donors, at any stage of the estrous cycle without affecting the efficiency of embryo transfer programs.

Comparison of different protocols used to induce and synchronize estrus cycle of Saanen goats.

The objective of the present study was to determine the efficiency of different protocols in inducing and synchronizing the estrus cycle of Saanen goats by using new or reused synchro-mate-B (SMB) and controlled internal drug release (CIDR) in combination with either equine chorionic gonadotrophin (eCG) or cloprostenol. Female goats (n=120) were divided at random into six groups of 20 animals each. In the T1-SMB group, the females were injected intramuscularly (i.m.) with 2.5mg estradiol valerate+1.5mg norgestomet and received a subcutaneous ear implant containing 2.0mg of norgestomet for 9 days. On the day of implant removal, the animals received 100IU of eCG and 0.05mg of cloprostenol. In the T2-SMB group, the animals were identically treated, except that the ear implant they received had been previously used in cattle. In the T3-SMB group, the treatment was identical to that for T1-SMB, but eCG was not administered. In the T1-CIDR group, the animals were treated for 9 days with an intravaginal device inpregnated with 0.3g of progesterone and injected i.m. with 100IU of eCG and 0.05mg of cloprostenol on the day of implant removal. The animals of the T2-CIDR group were treated like those of the T1-CIDR group, except that the intravaginal implant they received had been previously used in goats. The animals of the T3-CIDR group were treated like those of the T1-CIDR group, but did not receive eCG. The percentages of estrus and fertility were 100/80% (T1-SMB), 90/80% (T2-SMB), 75/75% (T3-SMB), 100/95% (T1-CIDR), 100/100% (T2-CIDR) and 70/65% (T3-CIDR), respectively, with the results for both parameters being lower (P

Determination of the genital tubercle migration period in Morada Nova sheep foetuses by ultrasonography.

The aim of this study was to determine the period of genital tubercle (GT) migration using ultrasonography in Morada Nova sheep foetuses (n = 117) from natural mating (NM) and frozen embryo transfer (ET) to determine the window when foetal sexing can be determined. The examinations were performed using transrectal ultrasonography with a dual-frequency linear transducer (6.0 and 8.0 MHz) from day 30-54 of pregnancy at 48-h intervals. The period of GT migration of foetuses produced by NM varied from 36 to 46 days of pregnancy, resulting in an average of 39.5 +/- 2.9 days. For foetuses derived from ET, GT migration varied from 42 to 52 days of pregnancy with an average of 48.5 +/- 3.3 days, being possible the GT of foetuses from ET start to migrate 96 h later even if they are of the same gender. Migration of the GT occurred earlier (p < 0.05) in foetuses produced by NM and sexing accuracy for triplet pregnancies (77.8%) was significantly inferior (p < 0.05) to single (100%) and twin (92.9%) pregnancies for foetuses derived by NM. The results allow one to conclude that foetal sexing can be done from the 50th day onwards in foetuses produced by NM and from the 55th day onwards in foetuses derived from ET, and that multiple pregnancies compromise the sexing accuracy by ultrasonography.