This study aimed to determine the effect of antral follicle count (AFC), and pubertal status on the fertility of beef heifers. In this study, 230 Nelore heifers, 20±2 months of age, were subjected to an estradiol progesterone-based timed artificial insemination (TAI) program. On Day 0 of the TAI protocol, the heifers were examined by transrectal ultrasound to record videos of the ovaries. Later, in the darkroom of the laboratory of images, the videos were analyzed for AFC (≥ 3 mm) of each ovary. Females who failed the first TAI were resynchronized with the same hormonal protocol. The pregnancy status was evaluated by ultrasonography 30 days after each FTAI. The general mean of the AFC was 22.0 follicles. Thus, the heifers were divided into 2 groups according to AFC: Low AFC (˂ 22 follicles, n = 114), and High AFC (≥ 22 follicles, n = 116). No differences (P > 0.05) in the pregnancy per AI (P/AI) were observed between the Low and High AFC groups, and between pubertal and prepubertal categories. The P/AI was not different between heifers that displayed or did not estrus (P = 0.2). However, considering the estrus response of each AFC group, High AFC heifers that displayed estrus had greater P/AI (P = 0.01) than High AFC heifers that did not display estrus. In summary, AFC and pubertalstatus did not affect the fertility of Nelore heifers. In contrast, the P/AI of heifers that did not display estrus was lower than heifers observed in estrus only in the High AFC group.

Considering the lack of information about livestock diseases on Brazilian oceanic islands, the occurrence of bovine brucellosis was investigated on the island of Fernando de Noronha, state of Pernambuco, Brazil. Serum samples were collected in October 2009, from all the 105 cows raised on the island at that time. These were examined concurrently using the Rose Bengal test and the Complement Fixation Test. All the samples were negative in both tests, indicating that the cows on the island were likely free from infection by smooth forms of Brucella. These results can partly be explained by the prohibition of introduction and importation of both small and large-sized animals that had been implemented through District Decree 19 of February 28, 2004.

We characterized the network of cattle movements in Mato Grosso, Brazil—a state responsible for a significant amount of Brazilian beef exports. In this analysis, we were particularly interested in the importance of slaughterhouses in the network of cattle movements, in the characteristics of the trade for different purposes (especially for reproduction, fattening, and slaughter), and about the importance of the main traders. We found that the median distance of all movements was 79.0 km, with an interquartile range between 37.2 and 163.2 km, which suggests a relatively short-range trade pattern; roughly 20% of the premises purchasing more animals were responsible for 95% of the animals purchased and 20% of the premises selling more animals were responsible for 86% of the animals sold, indicating the importance of the cattle trade hubs. Fitting the degree distribution using a power-law distribution, we obtained a scaling parameter of 2.59, indicating that the cattle movement network of Mato Grosso is less dense than other observed cattle movement networks. The networks for fattening, reproduction, and slaughtering only comprised 73%, 56%, and 25% of all nodes and 52%, 30%, and 17% of all edges, respectively; and slaughterhouses had the highest in-degrees and total degrees, followed by markets and farms, playing the role of main cattle trade hubs. Therefore, slaughterhouses are potentially useful as surveillance points to detect cases, and controlling important trader premises may optimize the use of resources for controlling diseases.

Universidade Federal de Minas Gerais, Escola de Veterinária, Departamento de Medicina Veterinária Preventiva, Laboratório de Bacteriologia AplicadaSusceptibility pattern of 45 Campylobacter spp.isolates – 16 C. jejuni, eight C. coli, and 21 C. fetus isolated from different animal species in Brazil – to twelve antimicrobial agents was determined. All Campylobacter spp. isolates were susceptible to gentamicin, sulfadiazine, and sulfamethoxazole. C. jejuni and C. coli were also sensitive to chloramphenicol, whereas all C. fetus strains were susceptible to kanamycin. Cefoperazone showed the highest percentage of resistance among C. jejuni (68.75%), followed by nalidixic acid (31.25%), ampicillin (37.50%), tetracycline (37.50%), erythromycin (12.50%), and kanamycin (6.25%). Likewise, cefoperazone exhibited the highest percentage of resistance among C. coli (75.00%), followed by nalidixic acid (50.00%), tetracycline (50.00%), erythromycin (37.50%), ampicillin (12.50%), and kanamycin (12.50%). Among C. fetus strains, nalidixic acid showed the highest resistance rate (85.71%), followed by cefoperazone (71.43%), tetracycline (42.86%), ampicillin (19.05%), chloramphenicol (9.52%), and erythromycin (4.76%). Therefore, it was found that the majority of Campylobacter spp. isolated from animals was sensitive to gentamycin, chloramphenicol, kanamacyn, and sulfonamides; however, a high proportion of the strains showed reduced susceptibility to nalidixic acid, ampicillin, cefoperazone, and tetracycline. Moreover, C. coli and C. fetus isolates showed a high percentage of multidrug resistant strains.

The aim of this study was to evaluate the hematological profile of Holstein calves during the first month of life. Blood samples were harvested (n = 208) from 26 calves, from birth until 30 days of life. Hematologic values were determined by an automatic system associated with differential leukocyte count by manual methods. Variations in the erythrogram components were detected from birth up to the 30th day of life, except for hemoglobin (Hb) concentration and Mean Corpuscular Hemoglobin Concentration (MCHC). At birth, higher values were observed for hematocrit, Mean Corpuscular Volume (MCV) and Mean Corpuscular Hemoglobin (MCH) that decreased in subsequent moments. During the first days of life, leukocytosis was found due to neutrophilia and eosinopenia. A gradual increase of lymphocytes with the increase of age was also observed. Finally, the present research showed that the first month of life is a hematological adaptation period. Based on the results, it detected that blood component variations, characterized by hemoconcentration and leukocyte prolife compatible with glucocorticoids response up to the 4th day of life, were responsible for neutrophil lymphocyte ratio > 1.0 at birth.

The bronchopneumonia of calves represents a risk to national supply chain because it is an ecopathy and weakens the more intensive production systems. It is characterized by inflammatory changes in the bronchi, bronchioles, lung parenchyma, and pleura. It is a disease of multifactorial traits called Bovine Respiratory Disease (BRD). The association of infectious agents with host defense and management to which the animal is subjected leads to the emergence of major clinical manifestations of the disease. The clinical evolution of BRD can also have serious secondary changes such as pulmonary edema, sepsis, and pulmonary hypertension, or even be consequent to the involvement of other structures, such as in cases of myocarditis leading to congestive heart failure. Although this report refers to a non-experimental framework, the circumstances that caused the calf to be subjected to a protocol-specific respiratory assessment involving non-routine reviews has made it possible to associate circulatory and respiratory conditions, rarely considered in ruminant clinic. The focus of this report was pulmonary edema. Modern clinical vision requires of the veterinarian work with cost-benefit relation, so that the more accurate and the earlier the clinical diagnosis the less expensive the treatment.

Several factors can affect bovine mammary gland health and although bacterial mastitis is the most studied and reported cause, viral infections may also have negative effects on bovine udder health. Viral infections can indirectly damage the papillary duct of the teat, and induce or exacerbate signs of bovine mastitis due to viral-induced immunosuppressive effects that may lead to a greater susceptibility to bacterial mastitis and even intensify the severity of established bacterial infections. Some viruses (Bovine alphaherpesvirus 2, cowpox, pseudocowpox, foot-and-mouth disease, vesicular stomatitis and papillomavirus) affect the integrity of the udder skin, leading to teat lesions, favoring the entry of mastitis-causing pathogens. It is therefore possible that the association between mastitis and viruses is underestimated and may, for example, be associated with negative bacterial culture results. Few milk samples are tested for the presence of viruses, mainly because of the more laborious and expensive procedures required. Furthermore, samples for virus testing would require specific procedures in terms of collection, handling and storage. Thus, there is a knowledge gap in regard to the actual impact of viruses on bovine udder health. Despite the fact that serum anti-virus antibodies can be detected, there is not enough evidence to confirm or exclude the effect of viruses on udder health. However, any expectation of milk production from healthy animals should consider the possible impact of viral infections in mastitis development and not underestimate the importance of actions to diagnose and control the disease. Therefore, the purpose of this review is to describe the association of diagnosis and control of viral diseases and their effect on bovine udder health.

Prostaglandin F2α (PGF2α) determines luteolysis in cattle, and the ability to manipulate its endogenous synthesis is indispensible for large-scale animal breeding. Estradiol (E2) and progesterone (P4) modulate several molecular pathways in endometrial cells, including the synthesis of PGF2α; however, its specific mechanisms are still not totally known. This study investigated the production in vitro and possible modulation of endometrial PGF2α due to a local effect of endogenous E2 in the ipsilateral uterine horn (UH) containing the dominant follicle (DF) or from P4 in ipsilateral horn containing the corpus luteum (CL). The PGF2α stimulators oxytocin (OT) and phorbol 12,13-dibutyrate (PDBu) were incubated with endometrial explants, and PGF2α content was measured. For that, cycling cows were synchronized, the development of DF and CL was examined by ultrasonography and on the seventh day of the estrous cycle, endometrial explants were collected and cultured in medium supplemented with 10-6 M PDBu or 10-6 M OT or non-supplemented. Media samples were collected immediately after treatment and 60 min later. Radioimmunoassay showed that the PGF2α content of the UH ipsilateral to the DF was 49% less than that of the contralateral UH (8.22 ± 0.95 vs. 12.24 ± 0.95 pg/mL/mg tissue, respectively; P < 0.01). However, the PGF2α levels did not differ between the UHs as a function of the CL position (9.46 ± 0.95 vs. 11 ± 0.95 pg/mL/mg; P > 0.05). The cellular stimulators promoted an increase in PGF2α synthesis (P < 0.02), and the effects differed among the animals (P < 0.04). The PGF2a production was higher in the explants treated with PDBu rather than OT (13.68 ± 1.16 vs. 10.01 ± 1.16 pg/mL/mg tissue, respectively; P < 0.05). In conclusion, PGF2α synthesis is modulated by the presence of the DF (local E2) but not the CL (local P4), and both PDBu and OT stimulated PGF2a synthesis.

Although genetic manipulation of farm animals is of great interest for animal production and the pharmaceutical industry, its efficiency remains far from satisfactory. Pronuclear injection, which is the most widely used technique for such modification, mainly in mice, remains limited for this species. Some alternatives have been developed such as sperm mediated gene transfer, in which the spermatozoa are used as vectors for DNA delivery during in vitro fertilization. Mature sperm cells are able to spontaneously bind exogenous DNA molecules which may be internalized into sperm nuclei. Given the potential of sperm mediated gene transfer for livestock animals transgenesis, the aim of this study was to evaluate four methods of DNA uptake for sperm mediated gene transfer in bovine: incubation with DNA, plasma membrane alteration induced by calcium ionophore followed by incubation with DNA, electroporation and lipofection. Spermatozoa not exposed to exogenous DNA were used as control group. Cleavage, blastocyst and hatching rates were recorded at 72 hours post insemination (hpi), days 9 and 12 of embryo culture, respectively. Exogenous DNA-positive embryos were evaluated by PCR. No effect of treatment was observed on cleavage, blastocyst and hatching rates. In addition, percentage of DNA positive blastocysts did not differ among experimental groups. In spite of the low number of positive embryos, our results show that all treatments presented similar efficiencies for DNA delivery during in vitro fertilization. In conclusion, although the development rates were similar and constant in all groups, other factors such as exogenous DNA sequence, size and concentration should be considered to improve sperm mediated gene transfer.

Samanea tubulosa is a plant used for medicinal and feeding purposes. However, ingestion of S. tubulosa pods has been associated with bovine abortion. Thus, the aim of this work was to investigate the effects of diet containing 5% of S. tubulosa pod meal on male and female Wistar rats. Diet was administered to male rats (n = 10) for 60 days before mating. Female rats (n = 10) received the treatment for 30 days, during cohabitation and from gestational day (GD) 0 to GD20. Treated animals were mated with untreated rats. In male rats, plant consumption caused decreased food consumption and 20% fertility index reduction. Litters from treated males presented lower body weight and crown–rump length. Female rats treated with the plant increased water and food intake and body weight. Decreases in fertility, fecundity and gestation indices and increase of placenta weight and mean number of corpora lutea were found. Thus, owing to the possible general and reproductive toxic effects, long-term consumption of S. tubulosa is not recommended for phytotherapic or food purposes.