Assessment of Brix refractometry to estimate immunoglobulin G concentration in beef cow colostrum.

BACKGROUND: Brix refractometry can be used to assess colostral immunoglobulin G (IgG) concentration, but studies identifying Brix percentages to detect high- and low-IgG colostrum are lacking for beef cows and interlaboratory agreement is unknown. OBJECTIVES: Evaluate Brix refractometer performance and interlaboratory agreement for assessing beef cow colostrum IgG concentration, including determination of thresholds to identify colostrum containing IgG concentrations <100 g/L and ≥150 g/L. ANIMALS: Beef cows (n = 416) from 11 cow-calf operations in Alberta, Canada. METHODS: Colostral IgG concentrations were measured using radial immunodiffusion (RID) and estimated by Brix refractometry for this retrospective study. Spearman correlation coefficients were assessed between RID and Brix refractometry. Likelihood ratios and misclassification cost-term analysis were used to determine optimal Brix percentages for detecting colostrum containing IgG concentrations <100 g/L and ≥150 g/L. Concordance correlation coefficient (CCC) and Bland-Altman analyses were performed for Brix percentages obtained at 3 different laboratories. RESULTS: Brix percentages obtained at 3 laboratories were positively correlated with IgG results (r = 0.72, 0.68, and 0.76, respectively). Colostrum Brix percentages of <24% and ≥30% were optimal for indicating IgG concentrations of <100 g/L and ≥150 g/L, respectively. Interlaboratory agreement was substantial, with CCC ranging from 0.89 to 0.96 and Bland-Altman analysis showing small mean differences (-1.2% to 0.09% Brix) and narrow limits of agreements (-4.8% to 2.4% Brix) among laboratories. CONCLUSIONS AND CLINICAL IMPORTANCE: Brix refractometry shows good potential for reliably estimating IgG concentrations in beef cow colostrum across multiple laboratories and can be recommended to aid colostrum management decisions on farms.

Quantitative assessment of German Holstein dairy cattle colostrum and impact of thermal treatment on quality of colostrum viscosity and immunoglobulins.

OBJECTIVE: This study aimed to determine the color, fat, viscosity, IgG concentration, %Brix and refractive index of fresh postpartum colostrum of German Holstein dairy cattle and assess the impact of different thermal treatments on the visual and dynamic viscosity, in association to IgG concentration, of colostrum that can be used for pasteurization process. RESULTS: Of the total 40 fresh postpartum colostrum, the color of colostrum (ranging from white-pale yellow to yellow and dark-yellowish), fat (1.4-8.2 100 g-1), IgG (4-116 mg mL-1), %Brix (8.5-35.4%), refractive index (1.3454-1.3905 nD), visual (ranging from watery to liquid and thick) and dynamic (4.9-219 cp) viscosity, were recorded. Statistical analysis between visual and dynamic viscosity of fresh colostrum showed significant correlation coefficients (rs = 634). Moreover, a significant correlation between viscosity and three IgG concentrations was also observed. Heat-treated colostrum showed dynamic viscosity ranged from 25 to 3066 cP, where dynamic viscosity of colostrum before- and after heat-treatment showed no significant correlation. Treated colostrum at 60 °C/60 min and 63.5 °C/30 min containing IgG concentration ≤ 80 mg mL-1 and ≤ 68 mg mL-1 showed no significant change in the viscosity and can successfully be applied for pasteurization of first postpartum colostrum.

[Measurement of IgG concentration in bovine colostrum by immunoturbidimetric assay in comparison to ELISA-based assessment]. / Messung der IgG-Konzentration in Rinderkolostrum mit einem immunturbidimetrischen Schnelltest im Vergleich zum ELISA.

OBJECTIVE: The aim of the presented study was to compare the results of IgG measurements using a turbidimetric immunoassay (TIA), a newly developed laboratory-independent method for direct immunoglobulin determination in colostrum, with measurements obtained via enzyme-linked immunosorbent assay (ELISA). MATERIAL AND METHODS: In colostrum samples from 59 cows, IgG concentration was measured using TIA and ELISA. RESULTS: Correlation analysis according to Pearson revealed a correlation coefficient of r = 0.74 (p < 0.0001) between the 2 methods. The Bland-Altman analysis showed that measurement by TIA resulted in significantly lower mean IgG levels than the ELISA-based quantification. This difference was more pronounced in high IgG concentration ranges. By means of a double-logarithmized data transformation it was calculated that the TIA-determined IgG-values on average amounted to 66.4 % of the IgG-values measured by ELISA. Although colostrum with low IgG concentration could be quantified with satisfactory reliability (sensitivity 100 %), high-quality colostrum was not sufficiently assessed in the TIA-based IgG measurements (specificity 40.4 %). CONCLUSION AND CLINICAL RELEVANCE: Based on the results of the presented study, IgG measurement by TIA cannot be recommended. In comparison to ELISA-based assessment, this technique does not exhibit higher correlations than established indirect rapid evaluation methods (density and viscosity determination).

Assessment of the safety and efficacy of an attenuated live vaccine based on highly virulent genotype 2b porcine epidemic diarrhea virus in nursing piglets.

We have previously reported the generation of the attenuated KNU-141112-S DEL5/ORF3 virus by continuous propagation of highly virulent G2b porcine epidemic diarrhea virus (PEDV) in Vero cells. The present study aimed to assess the safety of S DEL5/ORF3 and to evaluate its effectiveness as a live vaccine for prime-booster vaccinations. Reversion to virulence experiments revealed that the S DEL5/ORF3 strain retains its attenuated phenotype and genetic stability after five successive passages in susceptible piglets. Pregnant sows were primed orally with an S DEL5/ORF3 live vaccine and boosted intramuscularly twice with a commercial killed vaccine at 2-week intervals prior to parturition. This sow vaccination regimen completely protected nursing piglets against virulent G2b challenge, as evidenced by the increase in survival rate from 0% to 100% and the significant reduction in diarrhea intensity, including the amount and duration of PEDV fecal shedding. In addition, despite a 2-3 day period of weight loss in piglets from vaccinated sows after challenge, their daily weight gain was recovered at 7 days post-challenge and became similar to that of unchallenged pigs from unvaccinated sows over the course of the experiment. Furthermore, strong antibody responses to PEDV were verified in the sera and colostrum of immunized sows with the prime-boost treatment and their offspring. Altogether, our data demonstrated that the attenuated S DEL5/ORF3 strain guarantees the safety to host animals with no reversion to virulence and is suitable as an effective primary live vaccine providing durable maternal lactogenic immunity for passive piglet protection.

[Determination of the immunoglobulin G supply in the newborn calf]. / Bestimmung der Immunglobulin-G-Versorgung beim neugeborenen Kalb.

A sufficient supply of colostral antibodies within the first hours of life is crucial for the development and the health status in young calves. It is rational to examine the immunoglobulin uptake of single animals, but particularly on a herd basis, during herd controls and consultations. This enables economical calf rearing in accordance with animal welfare. Because of the costly, laboratory-dependent and in part time-consuming direct measurement of the absorbed immunoglobulins using radial immunodiffusion (RID) or ELISA, multiple studies attempted to develop indirect methods, which would be affordable and operational in the field. These aim to draw an inference for the absorbed quantity of colostral antibodies based on other correlated parameters. Multiple validations showed in part significant differences between various methods concerning specificity and sensitivity in comparison to the direct methods. In addition to RID and ELISA, this article presents the measurement of the γ-glutamyltransferase (GGT) activity, the determination of the total serum protein concentration using refractometry and the zinc sulphate turbidity test, and describes the advantages and disadvantages of their application. Refractory measurement and determination of the GGT activity represent a valuable alternative to a laboratory-dependent immunoglobulin G measurement. Nevertheless, there is no ideal rapid test method, such that several influencing factors have to be considered.

Defining health standards through economic optimisation: The example of colostrum management in beef and dairy production.

There is extensive literature addressing acceptable practices of colostrum distribution to new-born calves; however, no economic analyses are available concerning the profitability of this practice. Moreover, the health standards associated with colostrum management have been defined through the observation of reference farms without explicit reference to economic assessments. The objective of the current study was to evaluate the profitability of farm colostrum management and to define the optimal economic situations for given livestock systems and farm situations. The herd-level net value was calculated using the value of calf products, the cost of passive transfer failure and the cost of prevention. This value was determined for various beef and dairy scenarios and the various time periods spent managing colostrum. The maximal net values defined the optimal economic situations and enabled the determination of the optimal times for colostrum management and respective health standards (i.e., the prevalence of disorders at optimum). The results showed that the optimal time farmers should spend on colostrum management is approximately 15 min per calf. Furthermore, farmers should err on the side of spending too much time (> 15 min) on colostrum management rather than not enough, unless the cost of labour is high. This is all the more true that potential long term consequences of passive transfer failure on milk yields were not accounted for here due to scarcity of data, leading to consider this time threshold (15 min) as a minimal recommendation. This potential underestimation may arise from the greater nutrient content and bioactive compounds identified in colostrum although the passive immune transfer is here defined through immunoglobulins only. The present results show that for small farms that cannot hire colostrum managers, this work can be performed by the farmer after subcontracting other tasks. Moreover, the method proposed here-the definition of health standards through economic optimisation-is a promising approach to analysing health conventions in the cattle industry.

Rotavirus specific maternal antibodies and immune response to RV3-BB neonatal rotavirus vaccine in New Zealand.

BACKGROUND: Maternal antibodies, acquired passively via placenta and/or breast milk, may contribute to the reduced efficacy of oral rotavirus vaccines observed in children in developing countries. This study aimed to investigate the effect of rotavirus specific maternal antibodies on the serum IgA response or stool excretion of vaccine virus after any dose of an oral rotavirus vaccine, RV3-BB, in parallel to a Phase IIa clinical trial conducted at Dunedin Hospital, New Zealand. At the time of the study rotavirus vaccines had not been introduced in New Zealand and the burden of rotavirus disease was evident. METHODS: Rotavirus specific IgG and serum neutralizing antibody (SNA) levels in cord blood and IgA levels in colostrum and breast milk samples collected ∼4 weeks, ∼20 weeks and ∼28 weeks after birth were measured. Infants were randomized to receive the first dose of vaccine at 0-5 d (neonatal schedule) or 8 weeks (infant schedule). Breast feeding was with-held for 30 minutes before and after vaccine administration. The relationship between rotavirus specific IgG and SNA levels in cord blood and IgA in colostrum and breast milk at the time of first active dose of RV3-BB vaccine and level of IgA response and stool excretion after 3 doses of vaccine was assessed using linear and logistic regression. RESULTS: Forty infants received 3 doses of RV3-BB rotavirus vaccine and were included in the analysis of the neonatal and infant groups. Rotavirus specific IgA in colostrum (neonatal schedule group) and breast milk at 4 weeks (infant schedule group) was identified in 14/21 (67%) and 14/17 (82%) of infants respectively. There was little evidence of an association between IgA in colostrum or breast milk IgA at 4 weeks, or between cord IgG or SNA level, and IgA response or stool excretion after 3 doses of RV3-BB, or after one dose (neonatal schedule) (all p>0.05). CONCLUSIONS: The level of IgA in colostrum or breast milk and level of placental IgG and SNA did not impact on the serum IgA response or stool excretion following 3 doses of RV3-BB Rotavirus Vaccine administered using either a neonatal or infant schedule in New Zealand infants.

Assessment of different methods to estimate bovine colostrum quality on farm.

AIMS: To evaluate two different hydrometers and an optical and a digital Brix refractometer for the assessment of bovine colostrum quality, in terms of accuracy and precision compared with the measurement of IgG concentrations using radial immunodiffusion (RID), and to evaluate the reliability and repeatability of the Brix refractometers. METHODS: To determine reliability and repeatability, 145 colostrum samples were tested by two independent observers twice, using the optical and digital Brix refractometers. A further 193 colostrum samples from Holstein cows were collected on one commercial dairy farm at first milking and tested with two hydrometers and an optical and digital Brix refractometer. An aliquot of each sample was frozen for RID measurement of IgG concentrations and samples were classified as poor (≤50 g IgG/L) or good (>50 g IgG/L) quality colostrum. Intraclass correlation coefficients (ICC) were used to determine inter- and intra-observer reliability and repeatability. Optimised cut-off values for the four devices were determined using receiver operating characteristics (ROC) analysis with the RID results as the reference. Using these cut-offs, sensitivities and specificities for determining good quality colostrum were calculated. RESULTS: The ICC for inter-observer reliability was 0.98 for the optical Brix refractometer, and for intra-observer repeatability was 0.97 and 0.98 for the optical and the digital Brix refractometers, respectively. For the 193 colostrum samples, 67 (34.7%) had concentrations of IgG ≤50 g/L determined by RID. Optimised cut-off values evaluated by ROC analysis were higher for all devices compared with manufacturer reference or previously published values. Using these values, the sensitivities for the two hydrometers, and the optical and the digital Brix refractometers were 0.73, 0.71, 0.56 and 0.79, respectively; specificities were 0.72, 0.61, 0.90 and 0.69, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: The Brix refractometers provided the most accurate assessment of colostrum quality of the devices evaluated, and demonstrated excellent precision in terms of repeatability. To provide optimal health for newborn calves, a sufficient intake of good quality colostrum is essential. The Brix refractometers provide rapid, convenient tools for classification of colostrum quality.

Failure of Passive Immune Transfer in Calves: A Meta-Analysis on the Consequences and Assessment of the Economic Impact.

Low colostrum intake at birth results in the failure of passive transfer (FPT) due to the inadequate ingestion of colostral immunoglobulins (Ig). FPT is associated with an increased risk of mortality and decreased health and longevity. Despite the known management practices associated with low FPT, it remains an important issue in the field. Neither a quantitative analysis of FPT consequences nor an assessment of its total cost are available. To address this point, a meta-analysis on the adjusted associations between FPT and its outcomes was first performed. Then, the total costs of FPT in European systems were calculated using a stochastic method with adjusted values as the input parameters. The adjusted risks (and 95% confidence intervals) for mortality, bovine respiratory disease, diarrhoea and overall morbidity in the case of FPT were 2.12 (1.43-3.13), 1.75 (1.50-2.03), 1.51 (1.05-2.17) and 1.91 (1.63-2.24), respectively. The mean (and 95% prediction interval) total costs per calf with FPT were estimated to be €60 (€10-109) and €80 (€20-139) for dairy and beef, respectively. As a result of the double-step stochastic method, the proposed economic estimation constitutes the first estimate available for FPT. The results are presented in a way that facilitates their use in the field and, with limited effort, combines the cost of each contributor to increase the applicability of the economic assessment to the situations farm-advisors may face. The present economic estimates are also an important tool to evaluate the profitability of measures that aim to improve colostrum intake and FPT prevention.

Characterization, quantification, and assessment of immune protection potential of secretory immunoglobulin A in colostrum samples from Saudi women.

OBJECTIVE: To characterize, quantify, and assess the function of colostral secretory immunoglobulin A (sIgA) in Saudi women. METHODS: This prospective study was performed between March 2009 and February 2010 at King Khalid University Hospital, Riyadh, Saudi Arabia. Twenty milliliters of colostrum sample was collected from each of 23 healthy Saudi women (mean age 26+/-4 years) included in the study within 48 hours postpartum. Levels of sIgA and sIgM were determined by enzyme-linked immunosorbent assay (ELISA) and purification of secretory antibodies from pooled clarified sample was performed by thiophilic-gel chromatography, Jacalin-agarose chromatography, and Sephacryl S-300 gel filtration. Antibody induced respiratory burst in peripheral blood neutrophils and monocytes was assessed by chemiluminescence. RESULTS: The median concentration of sIgA1 was 0.053 mg/ml, sIgA2 0.047 mg/ml and sIgM 0.067 mg/ml with interquartile ranges of 0.308, 0.158 and 0.150. The levels of antibodies were no different. Whereas, 60% of IgA1 was present in dimeric and 30% in trimeric form; the major bulk of sIgA2 (85%) were comprised of the dimeric form. Both sIgA and serum IgA were able to induce effective and almost identical respiratory bursts in neutrophils and monocytes. CONCLUSION: Dimeric forms of sIgA were the predominant antibodies in colostrum samples and sIgA antibodies exhibited functional similarity with serum IgA.

Hyperimmune bovine colostrum as a low-cost, large-scale source of antibodies with broad neutralizing activity for HIV-1 envelope with potential use in microbicides.

Bovine colostrum (first milk) contains very high concentrations of IgG, and on average 1 kg (500 g/liter) of IgG can be harvested from each immunized cow immediately after calving. We used a modified vaccination strategy together with established production systems from the dairy food industry for the large-scale manufacture of broadly neutralizing HIV-1 IgG. This approach provides a low-cost mucosal HIV preventive agent potentially suitable for a topical microbicide. Four cows were vaccinated pre- and/or postconception with recombinant HIV-1 gp140 envelope (Env) oligomers of clade B or A, B, and C. Colostrum and purified colostrum IgG were assessed for cross-clade binding and neutralization against a panel of 27 Env-pseudotyped reporter viruses. Vaccination elicited high anti-gp140 IgG titers in serum and colostrum with reciprocal endpoint titers of up to 1 × 10(5). While nonimmune colostrum showed some intrinsic neutralizing activity, colostrum from 2 cows receiving a longer-duration vaccination regimen demonstrated broad HIV-1-neutralizing activity. Colostrum-purified polyclonal IgG retained gp140 reactivity and neutralization activity and blocked the binding of the b12 monoclonal antibody to gp140, showing specificity for the CD4 binding site. Colostrum-derived anti-HIV antibodies offer a cost-effective option for preparing the substantial quantities of broadly neutralizing antibodies that would be needed in a low-cost topical combination HIV-1 microbicide.

Prevention of flu episodes with colostrum and Bifivir compared with vaccination: an epidemiological, registry study.

The aim of this study was to evaluate the efficacy of colostrum (ARD Colostrum) in association with the immunomodulator Bifivir in the prevention of flu episodes compared with anti-flu vaccination. The registry groups included no prevention, vaccination, vaccination+immunomodulators, and immunomodulators only. Groups were comparable for age and sex distribution. In the group without prevention there were 8 major episodes and 12 minor episodes out of 34 subjects (8-12/34); in the vaccination group the respective figures were 8-13/38; in the group treated with a combination of vaccination and immunomodulators (ARD Colostrum + Bifivir) the figures were 4-9/33; and in the group treated with immunomodulators only there were 11 viral episodes (3-8) in 36 subjects. The episodes in the vaccination+immunomodulators and immunomodulators only groups were significantly lower compared with the other two groups (P<0.05). The number of episodes registered with the immunnomodulators was significantly lower than those observed in patients using vaccination or no prevention (P<0.05). The number of days of disease was higher in untreated controls compared to the groups treated with immunomodulators (P<0.05) and 2 times higher in the vaccination group compared to the same groups (P<0.05). The average relative costs were significantly lower (2.3 times) in the immunomodulators groups in comparison with the other groups (P<0.05). No problems concerning tolerability or side effects were observed during the study. Compliance was very good. In conclusion, the administration of immunomodulators is very cost effective and appears to be more effective than vaccination to prevent flu.

Prevalence of failure of passive transfer of immunity in newborn heifer calves and associated management practices on US dairy operations.

Failure of passive transfer of immunity (FPT) in dairy replacement calves has been linked to increased neonatal morbidity and mortality and long-term decreases in productivity. The purpose of this study was to estimate the prevalence of FPT in US dairy heifer calves in 2007 and to use nationally representative data to investigate associations of FPT with colostrum and calf management practices. A cross-sectional study was conducted by the USDA's National Animal Health Monitoring System between January and August 2007. Producers from 394 operations in 17 states completed survey questions about colostrum and calf management practices, and serum samples were collected from 1,816 healthy heifer calves on those operations. Serum immunoglobulin G (IgG) levels were determined by radial immunodiffusion, and calves were classified as having FPT if the IgG concentration was less than 10 mg/mL. To investigate associations between FPT and management practices, a multivariable analysis was completed using a weighted logistic regression model. The estimated prevalence of FPT in US dairy heifer calves was 19.2%. The odds of FPT were higher for calves on operations that pooled colostrum [odds ratio (OR = 2.2)], allowed nursing (OR = 2.4), or hand fed colostrum more than 4 h after birth (OR = 2.7). The odds of FPT were also higher for calves on operations that did not provide a source of heat during cold weather for calves experiencing a dystocia (OR = 1.6), would not seek veterinary assistance when unable to correctly position a calf for delivery (OR = 2.6), or did not routinely monitor serum proteins in calves as a measure of passive transfer (OR = 13.8). The prevalence of FPT in dairy heifer calves has decreased in the last 15 yr, so progress has been made in this important area of calf management. This study identified several management practices associated with FPT that could be targeted for educational campaigns or further research.

Passive transfer of immunoglobulin G and preweaning health in Holstein calves fed a commercial colostrum replacer.

The objective of this study was to describe passive transfer of IgG and preweaning health in newborn calves fed a commercially available plasma-derived colostrum replacement (CR) product or maternal colostrum (MC). Twelve commercial Holstein dairy farms enrolled singleton newborn heifer calves to be fed fresh MC (n = 239 calves) or one dose of CR containing 125 g of Ig (n = 218 calves) as the first colostrum feeding. For 7 of these farms that routinely provided a second feeding of 1.9 L of MC to their calves 8 to 12 h after the first colostrum feeding, calves assigned to the CR treatment group were offered a second feeding consisting of 1.9 L of commercial milk replacer supplemented with one dose of a commercially available plasma-derived colostrum supplement, containing 45 g of Ig per dose, 8 to 12 h after the first colostrum feeding. A blood sample was collected from all calves between 1 to 8 d of age for serum IgG and total protein (TP) determination, and records of all treatment and mortality events were collected until weaning. Serum IgG and TP concentrations were significantly higher in calves fed MC (IgG = 14.8 +/- 7.0 mg/mL; TP = 5.5 +/- 0.7 g/dL) compared with calves fed CR (IgG = 5.8 +/- 3.2 mg/mL; TP = 4.6 +/- 0.5 g/dL). The proportion of calves with failure of passive transfer (serum IgG <10.0 mg/mL) was 28.0 and 93.1% in the MC and CR treatment groups, respectively. Though a trend was present, the proportion of calves treated for illness was not statistically different for calves fed MC (51.9%) vs. CR (59.6%). Total number of days treated per calf (MC = 1.7; CR = 2.0), treatment costs per calf (MC = $10.84; CR = $11.88), and proportion of calves dying (MC = 10.0%; CR = 12.4%) was not different between the 2 colostrum treatment groups. The mean serum total protein concentration predictive of successful passive transfer (serum IgG = 10 mg/mL) was 5.0 g/dL in calves fed MC or CR. Long-term follow-up of these calves (to maturity) is ongoing to describe the effects of feeding CR on longevity, productivity, risk for Johne's disease, and economics.

Prevention of influenza episodes with colostrum compared with vaccination in healthy and high-risk cardiovascular subjects: the epidemiologic study in San Valentino.

The efficacy of a 2-month treatment with oral colostrum in the prevention of flu episodes compared with antiinfluenza vaccination was evaluated. Groups included healthy subjects without prophylaxis and those receiving both vaccination and colostrum. After 3 months of follow-up, the number of days with flu was 3 times higher in the non-colostrum subjects. The colostrum group had 13 episodes versus 14 in the colostrum + vaccination group, 41 in the group without prophylaxis, and 57 in nontreated subjects. Part 2 of the study had a similar protocol with 65 very high-risk cardiovascular subjects, all of whom had prophylaxis. The incidence of complications and hospital admission was higher in the group that received only a vaccination compared with the colostrum groups. Colostrum, both in healthy subjects and high-risk cardiovascular patients, is at least 3 times more effective than vaccination to prevent flu and is very cost-effective.

Assessment and promotion of judicious antibiotic use on dairy farms in Washington State.

The aims of this study were to describe antibiotic use and biosecurity practices among Washington State dairy producers and to evaluate the effectiveness of a collaborative approach to promoting judicious antibiotic use on dairy farms. In collaboration with a statewide industry group, Washington State dairy producers participated in a written, self-administered survey in 2003. They were then provided several educational interventions followed by a second written survey in 2005. Sixty-five percent (381) of dairy producers completed the 2003 survey. The most commonly cited drugs used for disease treatment were penicillin, ceftiofur, and oxytetracycline. Participants also indicated significant preventive uses with 28% using medicated milk replacer. Most producers appeared to consider intramammary infusion at dry-off to be a treatment rather than a preventative practice. Twenty-three percent of initial respondents indicated at least one extra-label use of antibiotics, yet only half routinely consulted with a veterinarian when doing so. Most agreed that using written protocols for disease treatment could reduce errors, but less than one-third had protocols. After the educational intervention there was a tendency toward reduced use of antibiotic medicated milk replacer: 51% of producers who originally reported using medicated milk replacer discontinued this practice, whereas 12% of producers began using medicated milk replacer between the 2003 and 2005 surveys. Most reported that the resources and educational materials were useful. Areas where additional work is needed include reducing the use of medicated milk replacer, increasing veterinary involvement in antibiotic use decisions, implementing treatment protocols, enhancing biosecurity, and ensuring optimal cow and calf immunity.

Imunidade passiva, morbidade neonatal e desempenho de cabritos em diferentes manejos de colostro / Passive immunity, neonatal morbidity and performance of kids in different colostrum management

Objetivando determinar o manejo de colostro que permitisse a melhor aquisição de imunidade passiva em cabritos e avaliar possíveis relações entre imunidade, morbidade e desempenho, amostras de sangue foram obtidas de 58 cabritos da raça Saanen antes e 30 horas após a primeira ingestão de colostro. Os cabritos foram distribuídos em cinco grupos experimentais. No Tratamento 1 (T1) o colostro foi ingerido ad libitum durante 24 horas. Nos demais tratamentos o colostro foi fornecido em mamadeira; os cabritos do T2 ingeriram 200mL de colostro após o parto; do T3, ingeriram 400mL de colostro sendo 200mL após o parto e 200mL após 8 horas; do T4, ingeriram também 400mL de colostro, sendo 200mL após o parto, 200mL após 14 horas; e os do T5 ingeriram 600mL de colostro, 200mL após o parto, 200mL as 12 e 200mL as 24 horas. Os valores séricos de gamaglobulinas foram avaliados por eletroforese. O ganho de peso diário foi utilizado para avaliação do desempenho no período de aleitamento. A ocorrência de doenças foi registrada do nascimento até 28 dias. A menor concentração de gamaglobulinas foi encontrada nos animais do Grupo 2 (1,65g/dL) e a maior concentração foi observada no Grupo 3 (2,60g/dL). Foi observado no Grupo 3 mais animais com diarréia, porém não foram encontradas diferenças estatísticas significativas ao nível de 5 por cento. Os diferentes manejos de colostro não estiveram associados com o desempenho dos cabritos até o final do período neonatal.

Assessment of the opsonic activity of purified bovine sIgA following intramammary immunization of cows with Staphylococcus aureus.

The phagocytosis of Staphylococcus aureus by bovine polymorphonuclear neutrophils (PMN) requires the presence of antibodies. Among the major isotypes of bovine antibodies, IgG2 and IgM are considered opsonic for bovine PMN. However, the role of purified bovine secretory IgA (sIgA) as an opsonin has not been assessed. In the present study, IgG2 were obtained from serum and sIgA, IgG1, and IgM were purified from the colostrums of three cows intramammarily immunized with heat-killed Staphylococcus aureus. The Ig preparations were assayed for specific antibodies, and the opsonic capacity of every isotype was investigated. Despite the presence of antibodies, we observed no distinct chemiluminescence response of PMN stimulated with sIgA- or IgG1-opsonized S. aureus, whereas IgM or IgG2 bound to bacteria induced a marked chemiluminescence response. Moreover, the counting of internalized bacteria per PMN after phagocytosis revealed a low uptake of S. aureus opsonized with sIgA or IgG1, in contrast to IgM or IgG2, which triggered efficient ingestion of bacteria. Priming of neutrophils by TNF-alpha, IFN-gamma, or C5adesArg did not promote an oxidative burst or uptake of sIgA-opsonized S. aureus to a greater extent than with IgG1-opsonized bacteria. Furthermore, analysis of uningested bacteria by flow cytometry after incubation with PMN showed a preferential uptake of IgM-opsonized S. aureus by PMN and only few sIgA-positive stained bacteria were PMN-associated. These experiments indicate that sIgA, like IgG1 and unlike IgM or IgG2, could not be considered as a major opsonin for phagocytosis of S. aureus by bovine blood PMN.

Modulation of the immune system and the response against pathogens with bovine colostrum concentrates.

The growth, development and health conditions for children living under deprived conditions in developing countries are so adverse that immediate public health measures to reduce morbidity and improve nutrition are urgently needed. Preventing and shortening the course of diarrhoeal episodes, eliminating protozoal colonization, and balancing intestinal microflora would all contribute to these goals. The consumption by humans of part of the colostrum produced when a dairy animal gives birth is an established tradition in many traditional societies. Recent advances in food technology in industrial dairying allow for continuous availability of stabilized bovine colostrum concentrate, both natural and hyperimmunized against specific human pathogens. This is safe for the calves of the producers themselves, for laboratory animals, and generally for humans, with the caveat of the milk-allergic. Moreover, substantial amounts of orally ingested bovine colostrum concentrate survive their passage through the stomach to remain intact and active in the lower reaches of the bowel. Studies in animals, human volunteers and naturally infected humans have demonstrated a therapeutic efficacy of oral bovine colostrum with certain infections. Similarly, attempts to prevent gastrointestinal infections in animals, exposed volunteers and at-risk populations have met with limited success with specific pathogens. It is time to begin to assess the feasibility and potential effectiveness and efficiency of employing seasonal or chronic bovine colostrum feeding in populations of deprived infantile populations to reduce the rates of recurrent gastroenteritis and decrease immunostimulation to improve vitality and nutritional status in early life.

Assessment of colostral transfer and systemic availability of immunoglobulin G in new-born foals using a newly developed enzyme-linked immunosorbent assay (ELISA) system.

To measure the immunoglobulin G (IgG) concentration in colostrum, milk and serum samples, a sandwich enzyme-linked immunosorbent assay (ELISA) detection system was developed. The system provided high reproducibility and sensitivity for routine diagnostic purposes. The period of fluctuating serum concentrations of IgG was monitored in new-born foals and their mares for a period of 6 weeks postnatum and postpartum, respectively. All foals received colostrum from their mares. The mean IgG concentration in the precolostral mare serum was approximately 19.0 mg/ml and decreased significantly to 13.8 mg/ml within the first 24 h postpartum. The IgG value fell to a minimum of 11.2 mg/ml by day 21 and increased to 21.6 mg/ml by day 42 postpartum. Within the first 4 h postpartum, mean IgG concentrations of 54.5 mg/ml were measured in the colostrum. A significant decrease to 10.1 mg IgG/ml colostrum was then noted 9-12 h postpartum. The mean IgG concentrations in foal serum increased from 0.3 mg/ml (precolostral value) to 9.6 mg/ml within 5-8 h postnatum. After 13-16 h postnatum, the highest IgG value of 15.7 mg/ml was reached. Over time the mean IgG concentration decreased significantly to 7.9 mg/ml at day 35. At the end of the observation period (day 42 postnatum) the mean IgG concentration once again increased to 11.2 mg/ml serum. In addition, the possible influence of various parameters on IgG concentration were examined. No significant influences could be shown by the breed, mare age, number of pregnancies, days of gestation, month foaled, foal sex, or the different farms. Finally, the cumulative incidence of failure of passive transfer (FPT) defined as IgG levels < 4 mg/ml foal serum, and partial FPT (PFPT) at levels ranging from 4 to 8 mg/ml foal serum was determined. From a total of 70 foals, 10.0% showed FPT and 18.6% showed PFPT.