The aim of this research was to evaluate the influence of maternal cells from colostrum on the development and function of the innate immune response in Holstein calves. Calves were divided into 2 groups: COL+ (n=10) received fresh colostrum; and COL- (n=10) which received frozen colostrum containing no viable cells. The calves were assessed before colostrum intake (D0), 48h of age (D2), and weekly from D7 up to D28. Blood samples were collected for analysis of the distribution of leukocytes, cellular phenotype and in vitro granulocyte function. COL+ calves tended to have a high number of neutrophils on D7 (p=0.073). COL- calves took up significantly more Escherichia coli (measured as MFI) on D7 (p=0.034). Endogenous production of radicals (as percentage of cells) tended to be higher in COL- calves on D14 (p=0.061). The intensity of endogenous reactive oxygen species (ROS) produced by granulocytes tended to be higher in COL+ calves on D21 (p=0.094). Overall, ROS production (percent of cells, and MFI) induced by Staphylococcus aureus and Escherichia coli were higher in COL+ calves than COL- calves. It was our observation that COL+ calves developed an innate immune response more quickly and efficiently after natural exposure to pathogens after birth. In contrast, COL- calves mounted an innate response more slowly that yielded a persistent inflammatory response after natural exposure to these bacteria agents. This research provides evidence of an advantage to the calf of receiving fresh colostrum on the development and function of the innate immune system.

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.

No abstract

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 ...

The objective of this study was to evaluate the influence of viable cells from colostrum on immune development in dairy heifer calves during the first 28 days of life. The animals were distributed between 2 groups: COL+ (n=9) receiving fresh whole colostrum from their own damns; and COL-(n=10) receiving pooled frozen colostrum, containing no viable cells, from a pool of donor cows. These calves were assessed before colostrum intake (D0), 48 hours of age (D2), and weekly from D7 to D28. The development of immunity was evaluated by assessment of the phenotype of blood leukocyte subsets, and induced cytokine production after 72 hours of stimulation in culture with concanavalin A (ConA), killed Staphylococcus aureus (S.aureus) and killed Escherichia coli (E. coli) by peripheral blood mononuclear cell (PBMC). The clinical history of these calves was marked by a high frequency of diarrhea in both groups. However, COL-had greater diarrhea intensity scores (fecal score~3 of 4), and rectal temperature on D7 than COL+ calves. Moreover, bronchopneumonia (n=1) and navel inflammation were observed only in COL-calves. COL-had a lower concentration of serum iron, and a higher absolute number of lymphocytes on D7 than COL+. COL-also had a higher percentage of anemic calves than the COL+ calves on D21 and D28. In general, the percent of cells within each subset of leukocytes was similar between the groups over the experiment, except on week 1 when COL-calves had a higher percentage of lymphocytes expressing CD45RO + (P=0.07). A steady increase in CD45RO + and concomitant decline in CD45RO -leukocytes was observed over the course of the study, indicating the development of immune memory. The proportion of CD14MHCII + leukocytes increased with age (P≤0.05). The median background cytokine production by PBMC that were not stimulated was below the level of detection of the assays used for both groups. The PBMC from COL+ calves stimulated with ConA secreted a larger quantity of IL-17 week 2 (COL+=2060.0pg/mL and COL-=0.0pg/mL, P=0.00). PBMC from COL+ calves stimulated with killed S. aureus whole cell antigen (P=0.05) and killed E. coli whole cell antigen (P=0.05) also secreted higher levels of IL17 than COL-calves at week 4. Clear production of IL17 was observed in PBML from COL+ calves at week 2, but the difference was not statistical different between groups. In conclusion, calves fed fresh and frozen colostrum showed no difference in cells subset profile overall. The increased percentage of leukocytes expressing the memory CD45RO + or CD14MHCII + over the course of the experiment indicated a maturation of the adaptive immune response after natural exposure to pathogens in the + aumentou de acordo com a idade (P≤0.05). As medianas das citocinas produzidas a partir do PBMC não estimuladas apresentaram valores abaixo do nível de detecção em ambos os grupos. O PBMC do COL+ estimulado com ConA secretou elevada concentração de IL17 na semana 2 (COL+=2060.0pg/mL e COL-=0.0pg/ml, P=0.00). PBMC do COL+ estimuladas com S. aureus inativado (P...

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

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.

SUMMARY The aim of this study was to evaluate the effects of additional consumption of immuneglobulins associated with high quality colostrum in health and performance of dairy calves. After birth, 80 females were randomly assigned to two treatments: MC) high quality colostrum, supplied in a volume corresponding to 15% of birth weight; and MC+S) high quality colostrum (15% of birth weight) + colostrum supplement. Blood parameters were not affected by the additional supply of immune globulins (Ig) by colostrum supplement feeding. The concentrate and total dry matter intakes were not affected by the administration of colostrum supplementation. The additional intake of Ig through the colostrum supplement did not affect the performance or feed efficiency of calves; however, animals doubled their birth weight at the end of the period, as occurred with MC fed calves. Regarding the health, additional supply of Ig did not affect the number of days with diarrhea, days with fever or medicated days. The additional intake of Ig via colostrum supplement in combination with high quality maternal colostrum have not improved immunity or affected the performance and health of dairy calves.