Efeitos de diferentes sistemas de cultivo in vitro sobre o crescimento de folículos pré-antrais isolados de ovários de fetos bovinos

The objective of this study is to use different in vitro culture systems of preantral follicles from Nelore breed bovine fetuses in the last gestation quarter. The evaluation of treatments considered the time of growth of isolated follicles. Preantral follicles were mechanically isolated and submitted to the individual culture, for 9 days, in media no supplemented or supplemented with fetal calf serum (FCS), bovine serum albumin (BSA) or synthetic defined supplement substitute of serum KnockoutSR (KNO). We have also evaluated the effects of collagen gel or fetal calf fibroblast monolayer as substratum for in vitro cultures. The increase on the follicular diameter was followed in the first day (0 h), at the 72 h, 144 h and 216 h. Considering cultures of isolated follicles, the results have shown that the association between media supplemented with FCS and collagen gel was significantly more efficient on the increase of the follicular diameter than other treatments. It is not still established a system of appropriate cultivation that sustains the differentiation and multiplication of the granular cells and that maintains the contact of the same ones with the oocyte to provide molecules and factors that supply the metabolic demand. We also understand that our results also represent another promising step on the search for the ultimate system of in vitro culture of preantral follicles from bovines.

Morfogênese do testículo de embriões e fetos de vacas da raça nelore (Bos taurus indicus)

The aim of this study was to accompany the process of testicular development from the non-differentiable phase to its complete formation. Embryos and fetuses of Nelore breed cows (Bos Taurus indicus) were obtained in slaughterhouses near the Uberlandia city, Minas Gerais. The gonads and the embryos were fixed in Bouin's fixative and afterwards processed for conventional optical microscopy. The gonadal was observed firstly in a 1.0 cm long embryo. In 2.5 cm long embryos the presence of the albuginea allows the sex identification. The mean thickness of the albuginea ranged from 29.08 to 558.45 mm. Gradually increase of vascularization of the albuginea and parenchyma is observed. The mediastinum is located centrally. There was a decrease in the space occupied by the testicular cords, from 63.71 to 41.99% of the total testes volume. Its diameter ranged from 31.68 to 48.80 mm. The diameter of germinal cells (and their nuclei) was from 12.27 (6.65) to 16.95 914.21) mm. The quantity of germinal cells by cross section of cord decreased from a maximum of 2.80 to 0.76. The total number of germinal cells was from 16 at the beginning of colonization of the gonad to 18.32 x 106 at the end of the study. The number of Sertoli's cells by cross section of cord ranged from 10.00 to 16.25. The results obtained show that the origin and formation of testes in embryos and fetuses from Nelore breed cows (Bos taurus indicus) does occur in a very similar way to what is described for Bos taurus taurus.

Desempenho ponderal de novilhas mestiças Holandês x Zebu submetidas a duas estratégias de suplementação mineral

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Profitability measures of dairy cows

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Propriedades tensiométricas comparadas entre fragmentos do centro tendíneo do diafragma, pericárdio fibroso e peritônio parietal de bovinos não conservados e conservados em glicerina

The behaviour of the non conserved and 98% glycerin conserved specimens for periods of 30, 60 and 90 days of bovine diaphragma's tendinous center, fibrous pericardium and parietal peritoneum submitted to mechanical tests of traction, was observed in ten bovines between 30 months and 36 months of age, crossbreeds, males and females, collecting fragments of these aforesaid membranes in each animal. The diaphragma's tendinous center and parietal peritoneum did not suffered significant modification (p>0.05) in the values of tension when compared to the resistance tests of traction of non conserved and 98% glycerin conserved membranes. However, all the evaluated tissues showed significant increase (p£0.05) of the elongation values when conserved in 98% glycerin for until 90 days. It was also observed that fibrous pericardium is the one which supports greaters tensions. So, it to was concluded, that glycerin is efficient to the conservation of biological membranes besides modifying its mechanical properties.

Respostas produtivas e comportamentais durante a ordenha de vacas Holandesas em início de lactação

Aiming to compare milk yield, residual milk and behavioral responses of Holstein cows during milking, fourteen experimental cows were mechanically milked twice a day, and evaluated during the first six weeks of lactation. Milk yield was measured daily, and residual milk volume weekly. Body (ribs region), udder and teat temperatures and respiratory frequency were measured twice a week. Animal behavior at the milking parlor was registered using ethograms and interviews with the milkers. During the first weeks of lactation, a higher percentage of kicks, over-steps, milking cups being knocked down, urinations and vocalizations in primiparous cows (p < 0.05) was observed, which were also considered more reactive by the parlors compared to multiparous cows. Multiparous cows produced more milk than primiparous (p < 0.05). However, there were no significant differences in residual milk percentage (p > 0.05), which suggests adaptation of both groups to the milking environment.

Reproductive technology in domestic carnivorous

Background: The delay in development of artificial reproduction techniques on carnivorous could be due to countless reasons, but the lack of commercial interest is probably the most important one. The majority of canines are small structures, canidae are extremely fertile and a great number of species are adapted to domestication or captivity. Finally, the canine gamete physiology presents a difficult adaptation of technology knowledge obtained from other species. Furthermore, domestic felines are animals of company and there is no interest in reproducing them in a large scale, as it has been observed in other domestic animals, however, besides of being a valuable model for the development of in vitro techniques, the domestic cat is also used as an embryo receptor for different species of small wild felines due to physiological similarities among them, in vitro embrionary development, Review: It was reviewed the main insights about the reproductive physiology in female dogs, in vitro oocytary maturation (IVM), pregnancy and conception rate with dogs' frozen/unfrozen semen and PIV in domestic cats. The majority of mammal oocytes restart meiosis spontaneously after ovulation and reaches MII in artificial environment; in an in vitro maturation system in bovines, around 90% of oocytes complete their maturation, although its development capacity can be reduced subsequently. The success of IVM in canidae have been limited, with maturation rate varying from 0 to 58%, usually around 20%. The greatest difficulties include oocyte quality, hormonal environment, protein supplementation, cumulus / oocyte cell interaction, donor breed and age, culture systems, oxygen tension, amino acids, growth factor and sequential means. The freezing process reduces the quality of the semen, firstly because it reduces the number of living sperms and secondly because freezing produces cell modifications that could alter the sperm motility, longevity, integrity of membranes and its fertilizing capacity. Conclusion: Nowadays, several researches are being performed with the aim of increasing viability after dogs' and cats' semen is unfrozen, using extenders, cryoprotectors, freezing and unfreezing curves, addition of antioxidant substances. The aim of this text is to inform about the improvements obtained on the artificial reproduction techniques, emphasizing the oocytary maturation in female dogs, semen cryopreservation and artificial insemination in domestic dogs and cats.

Influência da raça do touro (Bos indicus x Bos taurus) na tolerância ao estresse térmico calórico de embriões bovinos produzidos in vitro

To better understand the differences related to HS resistance between Bos indicus and Bos taurus, we aim to verify if the HS tolerance is due mostly to the genetic contribution from the oocyte, spermatozoa or both. Oocytes from Nelore and crossbreed Holstein cows (cHST) were collected, matured and fertilized with semen from Nelore (N), Angus (An), Brahman (Bra) and Gir (Gir) bulls. Nine six hours post insemination (hpi), ≥ 16 cells embryos were separated in two groups: control and HS. In control group, embryos were cultured at 39°C, whereas in the HS group, embryos were subjected to 41°C for 12 h, and then returned to 39°C. There was no effect of HS on blastocyst and hatched blastocyst rates in all breeds analyzed. The percentage of oocytes that cleaved and reached morula stage was significantly lower (p < 0.05) in cHST x Gir as compared to the other breeds. Additionally, blastocyst rates was higher in cHST x N than in cHST x An and cHST x Gir (p < 0.05). It was concluded that the oocyte is more important than the spermatozoa for the development of thermotolerance, since the breed of the bull did not influence embryo development after HS.

How FTAI and FTET impact reproductive efficiency of Brazilian dairy herds

Background: Throughout dairy cows evolution, milk production was always the key point to select the superior animal. Currently, several evidences has shown that high milk production have intensively contributed to the decline of dairy cattle fertility. Beyond milk production, dairy cows have their reproductive performance impaired by another factors, heat stress and repeat-breeding. Methods like fixed time artificial insemination and embryo transfer were developed to minimize the effects of these factors, and improve dairy herds profitability. This review aims to show some key-point experiments conducted to improve the efficiency of the self-appointed protocols for artificial insemination and embryo transfer in Brazil, overcoming several reproductive problems. Our goal is to develop cheap and easy self-appointed programs that facilitate animal handling and maximize their reproductive outcomes all over the year. Review: Failure in estrus detection is the mainly limiting factor for the use of artificial insemination in high-production dairy herd. An excellent alternative to overcome the need of estrus detection is fixed time artificial insemination. Many protocols with and without the use of estradiol have been developed to that end. Among the protocols for fixed time artificial insemination without estradiol, DoubleOvsynch has been extensively used recently in American dairy herds. In Brazil, similar pregnancy rate was obtained compared to progesterone-estradiol based protocols for fixed time artificial insemination. Particularities of progesterone-estradiol based protocols as (1) new progesterone device or devices previously used for eight days; (2) different doses of eCG; and (3) the use of estradiol cypionate for fixed time artificial insemination have been studied in Brazil. The use of self-appointed artificial insemination also enabled the reduction of the interval calving-conception compared to cows inseminated following the standing estrus. Regarding the low fertility of repeat breeders and the effect of heat stress at early pregnancy, other methods like embryo transfer became important tools to enhance reproductive efficiency of Brazilian dairy herds. Protocols were also developed to allow fixed time embryo transfer, eliminating the need of estrus detection and improving the reproductive efficiency of lactating recipients. As well as described for fixed time artificial insemination treatments, there is a large variety of hormone combination for fixed time embryo transfer (with and without estradiol). An experiment conducted in Brazil demonstrated that protocols for fixed time embryo transfer without estradiol can be as good as with estradiol to synchronize high-producing Holstein recipients, essentially during summer. Particularities related to embryos cryopreservation, synchronization of the estrus cycle of donors and recipients and the site of embryo release into the uterine horn were also investigated. Greater conception rates were achieved when fresh embryos were transferred compared to frozen-thawed ones. Also, the tight synchronization between donor and recipient (same day of estrus) resulted more pregnancies than when recipients were one day later or in advantage in relation to donors. Moreover, the site of embryo release into the uterine horn (ipsilateral to the corpus luteum) had no effect on pregnancy rates after in vivo produced embryo transfer. Conclusion: Both fixed time artificial insemination and fixed time embryo transfer are important tools to improve reproductive efficiency of high-producing dairy cows. These biotechnologies help bypassing some of the greatest challenges of dairy cattle reproduction: the difficulties of estrus detection, and the low fertility associated to heat stress and repeat breeding.

Crescimento, comportamento ingestivo e desempenho reprodutivo de novilhas mestiças holandês x zebu, em pastejo, submetidas à suplementação protéica durante a época das águas

The objective of this study was to evaluate the effect of supplemental protein during the rainy season on body growth, ingestive behavior and reproductive performance of crossbred Gir x Holstein dairy heifers, with mean age of 21 ± 4.1 months and average initial body weight of 296.7 ± 57.3 kg, distributed in a completely randomized design with four treatments and six replicates per treatment. Heifers remained on Brachiaria brizantha cv. Marandu pasture, managed according to a rotational grazing system and, as treatment, it was supplemented with protein concentrate (34%, 43%, 56% and 66% BW) and level of supply of 0.30% body weight (BW). The animals were weighed and the mean weight of the lot was used for the calculation of adjustment of the amount of concentrate offered. Heifers that reached 330.0 kg of live weight were artificially inseminated and, 45 days after insemination, pregnancy diagnosis was performed for the calculation of pregnancy rate and age at conception. No significant difference of protein levels was observed on grazing, eating behavior, productive performance and age at conception of dairy heifers on pasture. The average daily weight gain of BW and age at conception were, on average, 0.907 kg/animal and 24.03 months, respectively.

Própolis no controle da mastite bovina

Bovine mastitis is considered the main disease causing great economic losses in dairy herds. It is usually treated by antimicrobial chemicals that promote drug resistance, residues in food and environmental contamination. However, consumers in different countries requires more natural foods and with higher quality. Thus, the objective was to check the activities of propolis in controlling bovine mastitis. Seventy-two Holstein cows were used. The mastitis was identified by the California Mastitis Test, somatic cell counts and microbiological examination of milk. Four treatments were held: in group EAP1 10ml of a 30% alcoholic propolis extract (EAP) were given orally for seven consecutive days; in group EAP2 the same procedure described for the first group was used, in addition EAP was used for immersion of the teats before and after milking; in group CA alcohol was used for immersion of the teats before and after milking; and in group CT animals were subjected to soaking and disinfection, procedures routinely used by the property. The results were analyzed by the non-parametric variance model for repeated measures complemented by independent groups in multiple comparisons. There was a decrease of the somatic cell count in all groups. The biological activities of propolis provide great prospects; however, under the conditions evaluated, it was not possible to observe differences between treatments. The great diversity in its chemical composition and the complexity of multiple synergistic mechanisms involved in its biological activity require additional clinical trials.

Substituição dos grãos secos de milho pela silagem de grãos úmidos de milho para vacas da raça holandesa em lactação

In order to evaluate the effects of replacement of dried corn (GSM) for silage moisture corn (HMCS) on production and milk composition were used five Holstein cows, primiparous with a mean of 112 days post delivery, confined in Tie Stall, for 70 days. We used five diets according to NRC to 17.5% CP (DM) and 2.4 Mcal / kg DM, the 40:60 ratio of roughage and concentrate containing soybean meal, sugar cane silage and hay and substitution levels of the GSM HMCS the following treatments: a) 0%, 2) 25%, 3) 50%, 4) 75% and 5) 100%. Milk production and dry matter intake (DMI) were recorded daily. The animals were milked daily 6:00 and 18:00 h, and milk samples collected from consecutive milkings of each experimental period of 14 days (four days of collection). The experimental design was a 5x5 Latin square and the data analyzed by the statistical program SAS. Body weight (508 kg), milk (23.6 kg), corrected milk (22.7 kg), DMI (17.13 kg) showed no significant difference, but the intakes of neutral detergent fiber (6.67 kg), and detergent acid (3.39 kg), feed efficiency for the production of milk (milk 1.41 kg / day) urea nitrogen (17.67 mg / dL) differ, thus indicating that HMCS is more efficient than GSM in the diet of dairy cows not alter the production and milk composition.

Random regression models using Legendre polynomials or linear splines for test-day milk yield of dairy Gyr (Bos indicus) cattle

Studies investigating the use of random regression models for genetic evaluation of milk production in Zebu cattle are scarce. In this study, 59,744 test-day milk yield records from 7,810 first lactations of purebred dairy Gyr (Bos indicus) and crossbred (dairy Gyr × Holstein) cows were used to compare random regression models in which additive genetic and permanent environmental effects were modeled using orthogonal Legendre polynomials or linear spline functions. Residual variances were modeled considering 1, 5, or 10 classes of days in milk. Five classes fitted the changes in residual variances over the lactation adequately and were used for model comparison. The model that fitted linear spline functions with 6 knots provided the lowest sum of residual variances across lactation. On the other hand, according to the deviance information criterion (DIC) and Bayesian information criterion (BIC), a model using third-order and fourth-order Legendre polynomials for additive genetic and permanent environmental effects, respectively, provided the best fit. However, the high rank correlation (0.998) between this model and that applying third-order Legendre polynomials for additive genetic and permanent environmental effects, indicates that, in practice, the same bulls would be selected by both models. The last model, which is less parameterized, is a parsimonious option for fitting dairy Gyr breed test-day milk yield records. © 2013 American Dairy Science Association.

Caracterização imunoistoquímica de neoplasias de bexigas associadas à hematúria enzoótica bovina

Bovine enzootic hematuria is characterized by the development of hemangiomatous lesions from several types of neoplastic processes, from epithelial and mesenchymal origin. In this research the histogenesis of neoplastic lesions found in bladder of bovines with enzootic hematuria from Caparaó microregion in the state of Espírito Santo, Brazil was determined. To accomplish this objective, immunohistochemical analysis was performed with primary antibodies: anti-vimentin, anti-cytokeratin, anti-CD31 and anti-uroplakin. Neoplasms found included urothelial carcinoma, in situ carcinoma, adenocarcinoma, hemangioma, myxoma e hemangiosarcoma. Immunohistochemical staining of cytokeratin in epithelial neoplasms and vimentin in mesenchymal neoplasms was significant (p<0.05). CD31 was positive in all the vessels of all samples, however, the staining was significant (p<0.05) in the tumor endothelial cells of the vascular mesenchymal neoplasms, as in hemangiomas and hemangiosarcomas. Uroplakin III staining was uneven in several neoplastic types and showed no significant difference (p>0.05). Most neoplasms showed an atypical uroplakin staining on urothelium and, in the case of hemangiosarcomas there was no staining of the urothelium at all. The Spearman statistical analysis revealed a positive correlation (r= 0.63, p= 0.05) between CD31 and vimentin and between cytokeratin and uroplakin (rs= -0.61, p= 0.05). It was concluded that biomarkers anti-cytokeratin, anti-vimentin and anti-CD31 are important for the diagnosis of neoplasms epithelial, mesenchymal and vascular mesenchymal, respectively. It is possible to use vimentin and CD31 in association in vascular mesenchymal neoplasms and cytokeratin and uroplakin in epithelial neoplasms. The uroplakin is an effective marker, not only for tumor diagnosis, but also to evaluate the urothelial integrity.

Short communication: Acute but transient increase in serum insulin reduces messenger RNA expression of hepatic enzymes associated with progesterone catabolism in dairy cows

The objective of this experiment was to evaluate the effects of glucose infusion on serum concentrations of glucose, insulin, and progesterone (P4), as well as mRNA expression of hepatic CYP2C19 and CYP3A4 in nonlactating, ovariectomized cows in adequate nutritional status. Eight Gir × Holstein cows were maintained on a low-quality Brachiaria brizantha pasture with reduced forage availability, but they individually received, on average, 3. kg/cow daily (as fed) of a corn-based concentrate from d -28 to 0 of the experiment. All cows had an intravaginal P4-releasing device inserted on d -14, which remained in cows until the end of the experiment (d 1). On d 0, cows were randomly assigned to receive, in a crossover design containing 2 periods of 24. h each (d 0 and 1), (1) an intravenous glucose infusion (GLUC; 0.5. g of glucose/kg of BW, over a 3-h period) or (2) an intravenous saline infusion (SAL; 0.9%, over a 3-h period). Cows were fasted for 12. h before infusions, and they remained fasted during infusion and sample collections. Blood samples were collected at 0, 3, and 6. h relative to the beginning of infusions. Liver biopsies were performed concurrently with blood collections at 0 and 3. h. After the last blood collection of period 1, cows received concentrate and returned to pasture. Cows gained BW (16.5 ± 3.6. kg) and BCS (0.08 ± 0.06) from d -28 to 0. Cows receiving GLUC had greater serum glucose and insulin concentrations at 3. h compared with SAL cohorts. No treatment effects were detected for serum P4 concentrations, although mRNA expression of CYP2C19 and CYP3A4 after the infusion period was reduced for cows in the GLUC treatment compared with their cohorts in the SAL treatment. In conclusion, hepatic CYP3A4 and CYP2C19 mRNA expression can be promptly modulated by glucose infusion followed by acute increases in circulating insulin, which provides novel insight into the physiological mechanisms associating nutrition and reproductive function in dairy cows. © 2013 American Dairy Science Association.