The objective of this research was to evaluate the influence of cells from colostrum on the health of neonate calves. Animals were distributed in 2 groups: COL+ (n=9) which received fresh colostrum from their own damns; and COL- (n=10) which received frozen colostrums from donors. Heifers were assessed before colostrum intake - D0; D2; D7; D14; D21 and D28. Heifers were monitored by clinical examination, hematological profile and serum iron. COL- had a higher diarrhea intensity score (typically 3) on D7. Moreover, a single case each of bronchopneumonia and navel inflammation were observed in COL- calves. COL- had fewer red blood cells (RBC) (6.5±0.8×10/μL) and less hemoglobin (Hgb) (8.3±1.4g/dL) than COL+ (RBC=7.2±0.8×10/μL; Hgb=9.6±1.3g/dL) at D14 (P≤0.05). COL- had more anemia on D21 (P=0.03) and on D28 (P=0.02). Iron was lower in COL- (5.6±2.7μM/L) than COL+ (10.7±6.2μM/L) (P=0.03) on D7. Lymphocytes was lower in COL- than COL+ on D7 (3.8±1.0×10/μL COL+ and 5.4±2.2×10/μL COL-, P=0.02). COL- calves had more anemia and lower serum iron concomitant with diarrhea on D7. The number of leukocytes was relatively consistent in the COL+ calves, while COL- calves showed an increasing number of of lymphocytes starting on D7.

Communications via quorum sensing (QS) between non-aureus staphylococci (NAS) and Staphylococcus (S.) aureus in the bovine mammary gland remains largely unexplored. We determined whether 34 S. chromogenes, 11 S. epidermidis, and 14 S. simulans isolates originating from bovine milk samples and teat apices were able to regulate the QS of S. aureus, and if so, how in vitro growth inhibition of S. aureus by NAS, or NAS metabolites, or NAS cells themselves play a role in this process. In co-culture with S. aureus we observed that these 3 NAS species in general downregulated the expression of rnaIII, the effector molecule of the QS system, but this effect was more pronounced in S. chromogenes and S. simulans isolates than in S. epidermidis isolates. In vitro growth inhibition of S. aureus by NAS resulted in a small underestimation of the downregulating effect of NAS on rnaIII expression of S. aureus. Additionally, the culture supernatant of these NAS isolates and supernatant treated with proteinase K expressed greater regulatory activity over S. aureus virulence genes rnaIII, hla, and spa than washed NAS cells suspended in sterile water. These microbial interactions may influence S. aureus virulence and pathogenesis within the host. Isolation and identification of NAS metabolites affecting the QS system of S. aureus might help to develop alternative strategies for treatment and control of S. aureus mastitis.

The detection of Bovine Viral Diarrhea virus (BVDV) infection, especially among persistently infected calves (PI), should be performed earlier in order to eliminate the source of the infection and to prevent the spread of the disease in the herd. However, colostrum intake can influence the results of some of the tests used to diagnose the BVDV infection. Therefore, this study evaluated the efficacy of serum neutralization (SN) test in conjunction with reverse transcription-polymerase chain reaction (RT-PCR) for the diagnosis of BVDV infection before colostrum intake. The deliveries of the animals were assisted to select 52 newborn Holstein calves for inclusion in the study. Initially, the whole blood and serum samples were collected from the calves before (T0) and after (T1) the colostrum intake. The calves that were RT-PCR positive at any of the time-points were retested on the 30 th day post birth (T2). The presence of specific antibodies for BVDV was evaluated by SN, and that of viral RNA by the RT-PCR. The BVDV-specific antibodies were observed in the serum of 13.46% (7/52) of the calves at T0 because of fetal infection. At T1, seroconversion was observed in 100% (52/52) of the calves. The geometric mean titers (GMT) of the antibodies for BVDV increased significantly from T0 (14.52) to T1 (2490) (P = 0.0001). Of the four calves that were RT-PCR positive before colostrum intake (T0), two were seronegative and two, seropositive. Of the forty-eight RT-PCR negative calves, five were seropositive. After 30 days post birth, all of the animals tested negative by RT-PCR, thus excluding the possibility of persistent infection. The association observed between the results of the SN and RT-PCR assays at T0 (P = 0.025) could not be observed at T1 (P > 0.05). The SN test before the colostrum intake allowed the detection of fetal infection in the herd; however, this test was ineffective as a diagnostic method after the transfer of passive immunity. The confirmation of the results of the SN assay by those of the RT-PCR was essential for the identification of the infected calves before colostrum intake. Key words: Bovine viral diarrhea. Passive immunity. Persistent infection. Polymerase chain reaction. Serum neutralization. ResumoInfecção causada pelo BVDV, especialmente bezerras persistentemente infectadas (PI), deve ser detectada precocemente para eliminação da fonte de infecção e disseminação da doença no rebanho. No entanto, a mamada de colostro interfere em alguns testes adotados para o diagnóstico da Diarréia Viral Bovina. Assim, esta pesquisa avaliou o uso da soroneutralização (SN) em associação com a reação em cadeia de polimerase precedida da transcrição reversa (RT-PCR) para diagnóstico da infecção pelo BVDV antes da mamada de colostro. Partos foram acompanhados para seleção de 52 bezerras da raça Holandesa. Inicialmente foram coletadas amostras de sangue total e soro de todos os animais antes (T0) e após a mamada do colostro (T1). Os animais positivos no RT-PCR em qualquer momento foram retestados aos 30 ...

Changes in the composition of colostrum in the peripartum period focused on the neonate's immunity can minimize the response of the mammary gland before natural exposure to mastitis pathogens. This research evaluated the oxidative activity of mononuclear and polymorphonuclear phagocytes of bovine colostrum. Bacteriologically negative (n = 171) bovine colostrum samples of first and second milking postpartum were evaluated. The oxidative activity was assessed by the production of hydrogen peroxide (H 2 O 2 ) released either spontaneously or upon stimulation by enterotoxigenic Escherichia coli (ETEC). For this, three treatments were used: control (C) -only cells; non-opsonized (NO) -cells and ETEC non-opsonized; and opsonized (O) -cells and ETEC opsonized. Median values of concentrations (nmol/10 6 ) of H 2 O 2 produced by cells obtained from the first and second milking treatments C, NO and O were 149.1 and 39.9 (P = 0.0007); 125.5 and 49.1 (P = 0.0007); 102.4 and 54.4 (P = 0.008), respectively. No differences were observed between the treatments at each milking. The amount of H 2 O 2 produced at first milking exceeded the values found thereafter. Furthermore, the presence of bacteria did not determine the increased amount of H 2 O 2 released by phagocytes. Thus, we concluded that the mammary gland's events during the peripartum period have an effect on the proportion and activity of phagocytes, which can cause injuries to the breast parenchyma by the large amount of free radicals produced. The high frequency of bovine mastitis during this period indicates the need for studies of the immunity of the mammary gland and research of susceptibility factors for bacterial infections.

Consumers increasingly demand natural food and absent of toxic waste and medicated. The aim of this study was to evaluate the aqueous extract of dried and in natura stem from pomegranate on the larval inhibition of Haemonchus spp. and Cooperia spp. obtained from cattle. Dried and in natura aqueous extract from pomegranate stem (AEPS), negative control (autoclaved distilled water) and positive control (levamisole hydrochloride 0.05 mg / mL) were evaluated. Four mL of each treatment were used, and the results were evaluated in triplicate by egg counts per gram of feces (EPG), larval culture and counting of the larvae. The mean of the larvae that developed per gram of feces was submitted to logarithimic transformation log. (X + 10). The EPG had an average value of 3.620 eggs, identified in larval culture from Haemonchus spp. and Cooperia spp. Dried AEPS presented, by the reduction of larvae, effectiveness of 92.29% for Haemonchus spp. and 96.97% for Cooperia spp. In natura, this extract showed 80% of efficacy against Cooperia larvae, being considered moderately effective; however, for Haemonchus spp. this extract was not effective. These results are specially important for organic and agroecological systems of production, that not allow the use of chemical parasiticides. In conclusion, the use of dried AEPS showed potential anthelmintic and may represent important natural therapeutic option.

No abstract

RESUMO Esta pesquisa avaliou a TIP e a dinâmica de anticorpos (ACs) específicos em bezerros naturalmente expostos aos agentes causadores da doença respiratória bovina (DRB). Foram selecionados 19 bezerros Holandeses alimentados com colostro proveniente de doadoras vacinadas para DRB. Amostras de soro foram obtidas antes e após a ingestão do colostro (48h) para a soroneutralização (SN). Os valores médios (log2) detectados após colostragem foram de 11,5±1,6 (BVDV), 8,8±1,3 (BoHV-1), 5,5±1,6 (BRSV) e 8,4±1,5 (BPIV-3). Cinco bezerros foram criados do nascimento aos 240 dias de vida, observando-se decréscimo nos títulos de ACs para BVDV, BoHV-1 e BPIV-3 ao longo do tempo (P≤0,001). As taxas de infecções detectadas entre o D14 e o D240 foram de 40% (2/5), 20% (1/5), 80% (4/5), e 60% (3/5), respectivamente, para BVDV, BoHV-1, BRSV e BPIV-3. A maioria dos bezerros manifestou broncopneumonia após as infecções virais. Os bezerros apresentaram ACs para todas as viroses às 48 horas de vida, porém os títulos adquiridos para o BRSV foram baixos. A susceptibilidade para as infecções variou de acordo com os níveis e a duração dos títulos de ACs maternos.

Background: Newborn calves are agammaglobulinemic, immunosuppressed and immunologically immature at birth. The passive immune transfer is fundamental to protect calves against pathogens. The decay of maternal antibodies precedes the immune maturation at puberty enhancing the susceptibility of calves to infections caused by BVDV. Then, the objective of this research was to evaluate the interface between passive and active immunity for Bovine Viral Diarrhea Virus (BVDV) in Holstein dairy heifers in the first 13 months of age to detect susceptibility periods and establish prophylactic measures on prevention of Bovine Viral Diarrhea. Materials, Methods & Results: Sera were analyzed from 585 heifers by serum neutralization (SN) and enzyme linked immunosorbent assay (ELISA) for the p80 protein of BVDV. Heifers were categorized according to their age by the month of life. Heifers were seropositive (100%) from 1 st to 13