Fecal Microbial Communities of Nellore and Crossbred Beef Calves Raised at Pasture.

This study aimed to investigate the effect of age and genetics on the fecal microbiota of beef calves. Ten purebred Nellore (Bos taurus indicus) and ten crossbreed 50% Nellore-50% European breed (Bos taurus taurus) calves co-habiting on the same pasture paddock had fecal samples collected on days five (5 d), 14 d, 28 d, 60 d, 90 d, 180 d, 245 d (weaning) and 260 d after birth. All calves were kept with their mothers, and six Nellore dams were also sampled at weaning. Microbiota analysis was carried out by amplification of the V4 region of the 16S rRNA gene following high-throughput sequencing with a MiSeq Illumina platform. Results revealed that bacterial richness increased with age and became more similar to adults near weaning. Differences in microbiota membership between breeds were found at 60 d and 90 d and for structure at 60 d, 90 d, 245 d, and 260 d (p < 0.05). In addition, crossbreed calves presented less variability in their microbiota. In conclusion, the genetic composition significantly impacted the distal gut microbiota of calves co-habiting in the same environment, and further studies investigating food intake can reveal possible associations between microbiota composition and performance.

Blood and milk polymorphonuclear leukocyte and monocyte/macrophage functions in naturally caprine arthritis encephalitis virus infection in dairy goats.

The exact influence of caprine arthritis encephalitis virus (CAEV) infection on blood and milk polymorphonuclear leukocytes (PMNLs) and monocyte/macrophages of goats remains unclear. Thus, the present study sought to explore the blood and milk PMNL and monocyte/macrophage functions in naturally CAEV-infected goats. The present study used 18 healthy Saanen goats that were segregated according to sera test outcomes into serologically CAEV negative (n=8; 14 halves) and positive (n=10; 14 halves) groups. All milk samples from mammary halves with milk bacteriologically positive outcomes, somatic cell count ≥2×106cellsmL-1, and abnormal secretions in the strip cup test were excluded. We evaluated the percentage of blood and milk PMNLs and monocyte/macrophages, the viability of PMNLs and monocyte/macrophages, the levels of intracellular reactive oxygen species (ROS) and the nonopsonized phagocytosis of Staphylococcus aureus and Escherichia coli by flow cytometry. In the present study, a higher percentage of milk macrophages (CD14+) and milk polymorphonuclear leukocytes undergoing late apoptosis or necrosis (Annexin-V+/Propidium iodide+) was observed in CAEV-infected goats; we did not find any further alterations in blood and milk PMNL and monocyte/macrophage functions. Thus, regarding our results, the goats naturally infected with CAEV did not reveal pronounced dysfunctions in blood and milk polymorphonuclear leukocytes and monocytes/macrophages.

Effects of bovine leukemia virus infection on milk neutrophil function and the milk lymphocyte profile.

The effects of bovine leukemia virus (BLV) on the immune response have been extensively investigated; however, its effects on mammary gland immunity are only speculative. Although BLV has a tropism for B cells, it can affect both adaptive and innate immunities because these systems share many effector mechanisms. This scenario is the basis of this investigation of the effects of BLV on mammary gland immunity, which is largely dependent upon neutrophilic functions. Thus, the present study sought to examine neutrophilic functions and the lymphocyte profile in the milk of naturally BLV-infected cows. The viability of the milk neutrophils and the percentage of milk neutrophils that produced reactive oxygen species (ROS) or phagocytosed Staphylococcus aureus were similar between BLV-infected and BLV-uninfected dairy cows. Furthermore, the expression of CD62L and CD11b by the milk neutrophils and the percentage of milk neutrophils (CH138+ cells) that were obtained from the udder quarters of the BLV-infected cows were not altered. Conversely, the median fluorescence intensity (MFI) representing intracellular ROS production and the phagocytosis of S. aureus, the expression of CD44 by the milk neutrophils and the percentage of apoptotic B cells were lower in the milk cells from BLV-infected dairy cows, particularly those from animals with persistent lymphocytosis (PL). The lymphocyte subsets were not different among the groups, with the exception of the percentage of CD5-/CD11b- B cells, which was higher in the milk cells from BLV-infected cows, particularly those with PL. Thus, the present study provides novel insight into the implications of BLV infection for mammary gland immunity.

Efeitos do estresse da orquiectomia na citologia broncoalveolar de bezerros da raça Holandesa / Effects of the stress of orchectomy on bronchoalveolar citology of Holstein Calves

A identificação do impacto que certas formas de estresse causam ao bem estar animal e equilíbrio orgânico, representa um desafio á adoção de boas práticas de criação. Assim, a presente pesquisa verificou o impacto de um desafio doloroso rotineiro dos bovinos na imunidade pulmonar e sistêmica. Avaliou-se hemograma e cortisol, em quatro momentos, sendo M1, M6, M7 e M8 (respectivamente sete dias antes e um, três e oito dias depois do desafio doloroso) e citologia broncolaveolar, obtida por broncoscopia, nos momentos M1, M6 e M8. Houve uma redução dos valores do eritrograma no primeiro dia após o desafio, compatível com anaplasmose e agravada pela perda de sangue durante a cirurgia e um influxo de leucócitos para a região pulmonar. Oito dias após o desafio, evidenciou-se aumento de cortisol, gerando uma leucocitose por neutrofilia e monocitose no sangue com provável redução de quimiotaxia para o pulmão, tornando o trato respiratório potencialmente mais susceptível a infecções, sugerindo que esta prática de manejo, mesmo acompanhado de protocolo analgésico, pode ser considerada um fator de risco a penumonias afetando o bem estar animal.

The recognition of the impact of certains forms of stress in the animal well being and organic equilibrium, represents a challenge to the adoption of good practices. Thus, this research verified the impact of a painful rotine of the cattle husbandry can cause on pulmonary and systemic immunity. Was evaluated hemogram and cortisol, in four moments, being M1, M6, M7 e M8 (respectively seven days before and one, three and eight days after the painful challenge) and bronchoalveolar cytology,obtained by bronchoscopy, in the moments of M1, M6 e M8. There was a reduction of the erythrogram values in the first day after the challenge, compatible with the anaplasmosis and aggravated by the blood loss during the surgery and an influx of leukocytes to the pulmonary region. Eight days after the challenge, became evident the cortisol increase, enerating leukocytosis by neutrophilia and monocytosis in the blood with a probable reduction of chemotaxis to the lungs, turning the respiratory tract potentially more susceptible to infections, suggesting that this practice, even accompanied by analgesic protocol, increases the risk of pneumonia, affecting the animal well-being.