Passive Immunity Status Research Articles

Failure of Passive Immunity Transfer Is Not a Risk Factor for Omphalitis in Beef Calves.

Omphalitis is the third most frequent disease in newborn calves after neonatal diarrhea and bovine respiratory disease (BRD), but limited data on the prevalence and risk factors are available in the literature. Failure of passive immunity transfer (FPIT) is recognized as a major risk factor for diseases and mortality in calves. However, the association between omphalitis and FPIT remains poorly described. To assess this association, 964 suckler beef calves from 22 farms were included in a longitudinal cohort study for 5 months. Each calf was examined twice (mean ages: 4.4 and 11.1 days old) to diagnose omphalitis through clinical examination and ultrasonographic evaluation (USE) if necessary. Measurements of the total solids percentage (TS-%Brix) and total protein (TP) were performed on the serum during the first visit to evaluate the calves' passive immunity status. FPIT (fair and poor) was defined as serum %Brix < 8.1 or TP < 5.1 g/dL; among calves with omphalitis, 14% had FPIT and among calves without omphalitis 12% had FPIT. The omphalitis prevalence was 32.3% in calves without any other disease (overall prevalence of 30.9%). No statistical association between the prevalence of omphalitis and FPIT was observed. Further research is needed to identify the risk factors and promote the prevention measures for omphalitis in cow-calf systems, such as calving difficulty, hygiene of housing, and navel disinfection.

A randomized controlled trial investigating the effect of transport duration and age at transport on surplus dairy calves: Part II. Impact on hematological variables

Surplus dairy calves often arrive at veal and dairy-beef rearing facilities with health and blood metabolite level abnormalities, which can affect their welfare and performance, predisposing them to future health challenges. The objective of this randomized controlled trial was to investigate the effects of transport duration and age at the time of transport on blood parameters in surplus dairy calves following 6, 12, or 16 h of continuous road transportation. All surplus calves from 5 commercial dairy farms in Ontario were enrolled and examined daily before transport (n = 175). On the day of transportation, calves were weighed, blood sampled, and randomly assigned to 6, 12, or 16 h of transportation. Blood samples were then collected immediately after transportation, as well as 24, 48, and 72 h thereafter. Serum was analyzed at a provincial diagnostic laboratory for nonesterified fatty acids (NEFA), β-hydroxybutyric acid (BHBA), creatine kinase (CK), cholesterol, and haptoglobin. In addition, blood gas and electrolyte values were also assessed at the time of sample collection. Mixed models with repeated measures were used to assess the effects of transport duration, breed, sex, transfer of passive immunity status, weight before transportation, and age at transportation on blood parameters. Immediately following transportation, NEFA and BHBA were greater for calves transported for 12 h (Δ = 0.22 mmol/L NEFA, 95% CI = 0.15 to 0.30; Δ = 0.04 mmol/L BHBA, 95% CI = 0.02 to 0.06) and 16 h (Δ = 0.35 mmol/L NEFA, 95% CI = 0.27 to 0.42; Δ = 0.10 mmol/L BHBA, 95% CI = 0.08 to 0.11) compared with calves transported for 6 h. Glucose was lower immediately following transportation in calves transported for 16 h compared with 6 h (Δ = -15.54 mg/dL, 95% CI = -21.54 to -9.54). In addition, pH and HCO3- were lower in calves transported for 12 (Δ = -0.09 pH, 95% CI = -0.13 to -0.05; Δ = -1.59 mmol/L HCO3-, 95% CI = -2.61 to -0.56) and 16 h (Δ = -0.07 pH, 95% CI = -0.12 to -0.03; Δ = -1.95 mmol/L HCO3-, 95% CI = -2.95 to -0.95) compared with calves transported for 6 h. Calves transported between 15 and 19 d of age had a higher concentration of cholesterol and CK (Δ = 0.27 mmol/L cholesterol; 37.18 U/L CK) compared with 2- to 6-d-old calves, and calves 12 to 14 d old had greater reduction in HCO3- (Δ = -0.92 mmol/L) compared with 2- to 6-d-old calves. These findings show that transporting calves for long distances results in lower glucose concentration and suboptimal energy status, and that this effect varies based on the calf's age.

A randomized controlled trial investigating the effect of transport duration and age at transport on surplus dairy calves: Part I. Impact on health and growth

Calves arriving to veal and dairy-beef facilities in poor condition are at risk of future health challenges and reduced growth rates, and limited knowledge is available on how time in transit affects subsequent health and growth of these animals. The objective of this randomized controlled trial was to understand the effects of transport duration on diarrhea, respiratory disease, and growth of surplus calves destined for veal production following 6, 12, or 16 h of continuous road transport. Surplus dairy calves (n = 175; 7 transport cohorts) from 5 commercial dairy farms in Ontario, Canada, were enrolled on the day of birth. These calves were clinically examined daily on the source farms until the day before transport and on a daily basis for the first 14 d at the veal farm. On the day of transport, they were randomly assigned to 6, 12, or 16 h of transport to a veal farm. A blood sample was collected between 24 and 48 h of birth to assess transfer of passive immunity status. Calves were weighed at birth, before and immediately after transport, as well as 24, 48, and 72 h after unloading. Calves were also weighed 14 and 50 d after transport. Health exams were conducted daily at the source farm, immediately before and after transport, and once daily for 14 d thereafter to evaluate clinical signs of diarrhea, respiratory disease, dehydration, and navel inflammation. Mixed effects Poisson regression models were used to evaluate variables associated with the number of days with abnormal respiratory and fecal scores, whereas mixed logistic regression models with repeated measures were built to assess the probability of a calf having abnormal respiratory scores, abnormal fecal scores, or dehydration by day after arrival to the facility. A mixed model with repeated measures was used to evaluate calf weight at each time point at which body weight was measured after transport, whereas a mixed linear regression model was used to evaluate factors associated with average daily gain (ADG) in the 50 d after transport. Calves transported for 16 h had greater incidence of abnormal fecal scores compared with 6 h in the 14 d after transport. In addition, an interaction between age and duration of transport on the number of days with abnormal respiratory scores was identified, where calves older than 7 d of age had reduced incidence of abnormal respiratory score compared with calves 2 to 6 d old, even when transported for 16 h. As for growth, age at transport was positively associated with ADG in the 50 d of observation; however, no differences were observed between transport duration groups. These findings highlight that transporting calves for a longer duration negatively affects subsequent health, and calves greater than 1 wk of age experience improved health and growth after transport compared with their younger counterparts.

An Assessment of the Accuracy of Digital and Optical Brix Refractometers for Estimating Passive Immunity in Beef Calves

This study was aimed at determining and comparing the diagnostic accuracy of digital and optical Brix refractometers (D-Brix and O-Brix, respectively) for the estimation of passive immunity status (

Changes in serum total protein and immunoglobulin G concentrations and Brix percentages in neonatal Arabian foals from birth up to 21 days of age

The aim of this study was to evaluate changes in the serum immunoglobulin G (IgG) and serum total protein (STP) concentrations and serum Brix percentages of neonatal Arabian foals during first 3 weeks of life. Blood samples were collected from 12 apparently healthy foals by jugular venipuncture at birth and at 12-hours, 24-hours, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15 and 21 days of age. Serum IgG and STP concentrations and Brix percentages were measured by the radial immunodiffusion assay, and digital STP and Brix refractometers, respectively. Based on the serum IgG concentrations measured at 24 h, two foals were diagnosed with failure of transfer of passive immunity (FTPI). While IgG concentrations were determined using the data of foals with adequate transfer of passive immunity, other calculations were made using the data of all foals. The mean IgG concentration of the foals increased from birth (<200 mg/dl) to 12 (2068.5 mg/dl) and 24 h (2184.7 mg/dl), and progressively decreased up to 21 days of age (1318.5 mg/dl). The serum IgG concentrations at 12 h were highly correlated with each of the IgG concentrations measured over the 21-day period. The serum IgG and STP concentrations and Brix percentages of the foals diagnosed with FTPI at 12 h did not reach the adequate strata over time. These results suggest that foals can be reliably tested for passive immunity status at 12 h after birth.

Diagnostic accuracy of refractometry methods for estimating passive immunity status in neonatal beef calves.

Assessing the inadequate transfer of passive immunity (ITPI) in beef calves is crucial because calves with ITPI are at high risk for morbidity and mortality. The aim of this study was to determine the accuracy of digital Brix (D-BRIX) and digital serum total protein (D-STP) refractometers to estimate different passive immunity status in beef calves and to determine the robustness of thresholds. Blood samples were collected from 202 (1-7 days old) beef calves. Serum total solid percentages, total protein concentrations, and IgG concentrations were measured with the D-BRIX refractometer, D-STP refractometer, and gold standard radial immunodiffusion (RID) assay, respectively. Data were analyzed using diagnostic test accuracy, areas under the receiver operating characteristics curve, Cohen's kappa coefficient, and misclassification costs analysis to estimate IgG concentrations <10, <16, and <24 mg/mL. For the prediction of serum IgG concentrations <10, <16 and <24 mg/mL, the optimal cut-off values were determined to be <8.5% (Se: 100.0% (95% CI: 87.9-100.0); Sp: 94.2% [95% CI: 89.6-97.2]), <8.5% (Se: 92.1% [95% CI: 78.6-98.2]; Sp: 97.6% [95% CI: 93.9-99.3]), and <10.1% (Se: 88.8% [95% CI: 79.7-94.7]; Sp: 67.2% [95% CI: 58.1-75.4]), respectively, for the D-BRIX refractometer; and <5.2g/dL (Se: 100.0% [95% CI: 87.9-100.0]; Sp: 93.6% [95% CI: 88.9-96.8]), <5.2g/dL (Se: 92.1% [95% CI: 78.6-98.2]; Sp: 97.0% [95% CI: 93.0-99.0]), and <6.4g/dL (Se: 87.5% [95% CI: 78.2-93.8]; Sp: 69.7% [95% CI: 60.7-77.7]), respectively, for the D-STP refractometer. The digital Brix and digital serum total protein refractometers can be used as monitoring tools for assessing passive immunity transfer in neonatal beef calves.

Evaluation of 2 refractometers to estimate different passive immunity status in Simmental dairy calves

Inadequate transfer of passive immunity (ITPI) is major risk for mortality, morbidity and decreased growth performance in dairy and beef calves. Refractometry method is used in estimating ITPI in dairy and beef calves but studies evaluating refractometers for Simmental dairy calves are limited. The objectives of this study were determining the accuracy of digital serum total protein refractometer (STP-REF) and digital Brix refractometer (BRIX-REF) in the estimating of different passive immunity status (<10, <18, <25 and <32 g/L) in Simmental dairy calves. Serum samples were collected from apparently healthy Simmental dairy calves aged 1–8 days (n = 291). Serum total solid percentages were measured using BRIX-REF, serum total protein concentrations were measured using STP-REF and serum IgG concentrations were measured using radial immunodiffusion (RID) assay as a reference test. Correlation coefficients were calculated between RID test and refractometers results, and each other. The diagnostic test performance of the refractometers at IgG concentrations of < 10, < 18, < 25 and < 32 g/L was measured by performing a receiver operating characteristics (ROC) analysis. The optimal thresholds of the refractometers were determined based on Youden's J statistics and after accounting for different costs between false positive and false negative cases using misclassification cost term analysis. The overall test performance and the agreement of the refractometers were assessed using area under the ROC curve and Cohen's kappa analysis. Optimal thresholds were determined as < 7.9, < 8.3, < 8.7, < 9.4% for the BRIX-REF, and < 4.6, < 5.2, < 5.4, < 5.8 g/dL for the STP-REF in estimating IgG concentrations of < 10, < 18, < 25, < 32 g/L, respectively. Se and Sp of BRIX-REF were 88.8% and 89.1% for < 7.9% Brix, 81.6% and 94.2% for < 8.3% Brix, 77.9% and 97.4% for < 8.7% Brix and 81.7% and 91.2% for < 9.4% Brix, respectively. Se and Sp of STP-REF 92.5% and 88.2% for < 4.6 g/dL; 92.1% and 87.1% for < 5.2 g/dL; 81.7% and 93.6% for < 5.4 g/dL; 79.0% and 94.1% for < 5.8 g/dL, respectively. Both, digital Brix and STP refractometers performed well to estimate the status of passive immunity in dairy Simmental calves.

PSX-B-9 A Nanotechnology Base Immunity Measurement (D2Dx) Compared with Total Serum Protein Concentration Using Neonatal Holstein Bull Calves

Abstract The D2Dx immunity test (Nano Discovery Inc.) is a nanotechnology-based assay for quantifying the immune responses to foreign pathogens. In contrast, the measurement of total serum protein (TSP) concentration is used to determine the passive immunity status of neonatal calves. Inadequate colostrum feeding increases the risk of calves having increase disease challenges thereby reducing growth performance and possibly death. Our operation routinely sources 2- to 5-day old Holstein bull calves from numerous Wisconsin sale barns for evaluating nutritional programs and feed additives. The study objective was to compare the D2Dx immunity test with TSP concentration for evaluating the immunity and status of passive immunity of calves. Two 2021 calf studies conducted during summer and fall consisting of 160 total calves (80 calves per study) had 8-10 mL blood samples collected via jugular puncture within 1 day of arrival. Blood serum was immediately analyzed for TSP concentrations using a digital refractometer. Samples were then frozen and later thawed to room temperature for collecting D2Dx measurements. Pearson correlation coefficients were calculated using SAS version 9.4. The D2Dx test was highly correlated with TSP concentrations (r = 0.61, P &amp;lt; 0.01) across both studies indicating the D2Dx test can be used to assess status of passive immunity. The correlation coefficient did vary by study ranging from r = 0.54 (P &amp;lt; 0.01) for summer sourced calves to r = 0.65 (P &amp;lt; 0.01) for fall sourced calves. Average daily gains (ADG) were less (P &amp;lt; 0.01) for summer compared with fall sourced calves (0.692 and 0.853 kg/d for summer and fall, respectively). There was little correlation between passive immunity measurements (D2Dx and TSP) with ADG (r = &amp;lt; -0.04, P &amp;gt; 0.10). The D2Dx test can be used to assess transfer success or failure of passive immunity in neonatal Holstein bull calves.

Evaluation of refractometry methods for estimating passive immunity status in neonatal foals

The objective of this cross-sectional study was to determine the accuracy of the digital Brix and serum total protein (TP) refractometers for estimating different passive immunity status in neonatal foals. In total, 18- to 40-h old purebred Arabian foals (n=185) were used. Serum TP concentrations, total solid percentages and IgG concentrations were measured with a digital serum TP refractometer, digital Brix refractometer and the gold standard radial immunodiffusion (RID) assay, respectively. Correlation coefficients were calculated between the refractometer and RID assay results. A receiver operating characteristic analysis was used to select the optimal cut-offs for both refractometers. Test performance and agreement were evaluated using diagnostic test characteristics at optimal thresholds and areas under the ROC curve, and by calculating Cohen's kappa coefficient. The sensitivity and specificity of the digital Brix refractometer at optimal cut-offs (≤7.8%, ≤7.9%, ≤8.2%, ≤8.3%, ≤9.0%) were 100 and 69.3%; 100% and 68.5%; 70.5% and 71.0%; 88.3% and 85.5%; 88.1% and 76% to estimate RID-IgG of <400mg/dL, <800mg/dL, <1500mg/dL, <2500mg/dL and<3000mg/dL, respectively. The sensitivity and specificity of the digital serum TP refractometer at optimal cut-off (≤4.6g/dL, ≤4.6g/dL, ≤4.8g/dL, ≤5.0g/dL, ≤5.4g/dL) were 100 and 69.3%; 100% and 72.8%; 90% and 72.8%; 72.9% and 83.9%; 84.4% and 88% to estimate RID-IgG of <400mg/dL, <800mg/dL, <1500mg/dL, <2500mg/dL and<3000mg/dL, respectively. In conclusion, the refractometers showed a good potential as screening tools for the estimation of different IgG concentrations in neonatal foals.

Passive immunity in lambs: Colostral and serum γ-glutamyltransferase as a predictor of IgG concentration and related to the diseases from birth to 12 weeks of life

The main goal of this study was to find a link between colostrum and the 1-day-old lamb serum γ-glutamyltransferase (GGT) activity and immunoglobulin G (IgG) concentration and their relation with neonatal diseases and beyond. Further, to set a linear relationship between the serum GGT activity (SGGTA) and the IgG concentration (SIgGC) in different days of the neonatal period, thereby determining the feasibility of the GGT activity in the prediction of the colostrum quality and passive immunity and to define a cut-off point for the SGGTA associated with an increased risk of illness or death in lambs. For this purpose, blood samples were obtained from the lambs before the colostrum intake (day 0) and on different days (1, 2, 4, 7, 14 and 28) in the neonatal period. The colostrum was collected from the respective ewes (n = 254) related to the lambs. The most accurate (R&lt;sup&gt;2&lt;/sup&gt; = 0.652) model for predicting the SIgGC or passive immune status was the multiple regression model developed to calculate ln[IgG] from ln[GGT] in healthy neonatal lambs using the serum GGT and IgG values of day 0, 1, 2, 4, 7, 14 and 28. The In[GGT] activity at 24 h after birth in lambs that died or became ill during the neonatal period accounted for approximately 77% and 88% of the variation in the ln[IgG] concentration at 24 h after birth, respectively. The study revealed that SGGTA-24 &amp;gt; 500 IU may be considered as a critical cut-off point for the adequate colostral passive transfer. This study also disclosed that the colostral GGT activity might be used as an indicator to determine the colostrum quality.

Post-natal transition of serum biochemical profiles in calves of adequate and inadequate passive immunity status

Adequate amount of colostrum intake increase serum IgG concentration after birth and its level of 10 mg/ml is an indicator to sufficient passive immunity transfer in neonatal calves. Present study aimed at comparative assessment of changes in serum biochemical profiles of calves having adequate and inadequate levels of passive immunity after colostrum intake. Total 65 calves were divided into two groups i.e. failure of transfer of passive immunity (FTPI) calves had 10 mg/ml of serum IgG level. The incidence of FTPI rate was 26.15% in this study. FTPI calves had significantly (p<0.05) lower serum total protein (STP) concentration (4.13±0.05 g/dl vs. 4.31±0.04 g/dl) and lower serum albumin level (2.48±0.04 g/dl vs. 2.61±0.02 g/dl) compared to ATPI calves at ‘0’ hr i.e. before colostrum intake. At initial age, ATPI and FTPI calves had similar serum globulin concentration and albumin: globulin (A:G) ratio. At 48 hr after colostrum intake, STP and globulin concentration were also significantly lesser in FTPI (5.10±0.07 g/dl and 3.54±0.10 g/dl) than ATPI calves (6.26±0.11 g/dl and 4.06±0.13 g/dl). The A: G ratio was higher in FTPI (p<0.05) as compare to ATPI calves at 48 hr age. From 0 hr to 48 hr of age STP level increased by 47% in ATPI calves, that was significantly (p<0.05) higher in comparison to FTPI calves (21.79%). In ATPI calves, increment of globulin from 0 hr to 48 hr age was 2.54±0.12 g/dl, significantly higher than that of FTPI calves (1.57±0.09 g/dl). Glucose, Urea and BUN did not vary significantly between ATPI and FTPI calves before colostrum intake, whereas glucose level significantly increased in ATPI at 48 hr compared to FTPI calves. The study concluded that to avoid the incidence of FTPI, calves serum IgG level must increase by at least 9 folds during 0 to 48 hr of age and attainment of passive immunity levels after colostrum feeding had direct impacts on post-natal transition of biochemical and metabolic profiles in crossbred Jersey calves.

The effect of dystocia on passive immune status, oxidative stress, venous blood gas and acid-base balance in lambs

The aim of this study was to research the effect of dystocia in lambs on passive immune status, oxidative stress, venous blood gas and acid-base balance. The study involved 20 lambs of both sexes. The lambs were divided into two groups, normal (n = 10) and dystocia (n = 10) births. Blood samples for blood gas, MDA, GSH, GSH-Px and IgG were collected at 0 h and at periodic intervals of 1, 3, 6, 24 and 48 h. Both groups’ 0 h pH and glucose levels were under normal values and their pCO2 and lactate levels were above normal values. The blood pH increased in both groups in the 1st, 3rd, 6th, 24th and 48th hours at a significant rate when compared to 0 h and the pCO2 level decreased at a significant rate. Moreover, the blood pH of the dystotic lambs was found to be low according to the normal birth group in 0 h and the 1st, 3rd, 6th and 48th hours, but no statistical difference was determined. When it was compared to the normal birth group, the pO2 and O2 saturation in dystotic lambs was low at all hours but a statistical difference was determined only in the 48th hour. Lactate levels decreased in both groups. When the oxidative stress parameters were analysed, no statistical difference was determined although the malondialdehyde (MDA) level of the dystotic lambs was found to be higher than the normal birth group and its glutation (GSH) and glutation peroxidase (GSH-Px) levels were lower. When the IgG levels of the lambs at the postnatal 48th hour were examined, no difference was found between the two groups. In conclusion, it was deduced that dystocia caused negative effects on the oxidative stress and blood gases but the changes in the lambs’ passive immunity, oxidative stress, blood gases and vital functions could be reduced to a minimum level with early intervention in dystocia.

Association between passive immunity and health status of dairy calves under 30 days of age

Calves are highly susceptible to disease and mortality occurrence within the first month of life. Even if failed transfer of passive immunity (FTPI) is commonly recognized as a main factor affecting calf health and survival, conflicting results are reported in literature about the association between passive immunity (PI) and calf health, especially regarding enteric diseases. Therefore, a prospective cohort study was conducted on 78 calves of three Italian dairy farms during winters of years 2014–2016, with the specific aim of evaluating the association between PI and health status of calves within 30 days of age under field conditions. Blood samples were collected between 1 and 5 days of age from each calf included in the study, and disease and mortality occurrence was monitored throughout the first month of life. Additionally, fecal samples were collected from calves with scours before treatment. Blood serum samples were tested by an electrophoretic method for the assessment of immunoglobulin (Ig) concentration, whereas fecal samples were submitted to ELISA test for positivity to Escherichia coli K99, rotavirus, coronavirus, and Cryptosporidium spp. Only enteric diseases occurred in calves of this study. Calves that suffered from diarrhea or died within the first month of life had lower serum Ig concentrations than those that remained healthy or survived (P < .05). Even if not significantly (P = .127), lower serum Ig concentrations were observed in sick calves that had been treated with antibiotics compared to those that had not been treated. The odds of disease and mortality occurrence were 24 (95% CI = 3–231) and 11 (95% CI = 1–111) times higher, respectively, for calves with FTPI (serum Ig concentration <10.0 g/L) than for those with an adequate PI transfer (P < .05). Calves with adequate PI transfer had also a 6-day delay in the age at first disease onset compared to those with FTPI (P < .01). Even if estimated on a small number of calves, those with FTPI had higher risks of enteric infections by rotavirus (odds ratio = 12; 95% CI = 1–137) and Cryptosporidium spp. (odds ratio = 9; 95% CI = 1–72) (P < .05). In this study, the PI level influenced the occurrence of enteric diseases and mortality in calves under one month of age, confirming the importance of a proper colostrum provision to calf health and, consequently, to the reduction of antimicrobial use in dairy farming. However, further investigations are needed, particularly focusing on the relationship between PI and specific enteropathogen infections in calves.

Impact of passive immunity induced by maternal vaccination on subsequent immunization and disease-sparing in early-weaned beef calves challenged with highly virulent BVDV

Vaccination programs have been developed to limit disease associated with bovine viral diarrhea virus (BVDV) infection. The ultimate goal of BVDV vaccination is to induce immunity that prevents viral replication after infection; however, passively acquired BVDV-specific neutralizing antibodies can impact immunity and vaccine responses in the young calf. The purpose of this study was to examine the impact of passively-derived antibody on vaccine response and mitigation of disease in early weaned beef calves whose passive immune status was documented, and when vaccination and challenge were separated by only 5 days.

Disease screening profiles and colostrum management practices on 16 Irish suckler beef farms.

BackgroundCalf output is a key element in determining the profitability of a suckler beef enterprise. Infectious agents such as Bovine Virus Diarrhoea (BVD) virus, colostrum management and parasitic challenge can all affect calf output. Prior to the national BVD eradication programme, there was little published information on either the prevalence or effect of BVD in Irish beef herds. There is little published information on colostrum management practices in Irish commercial beef herds and there have also been few studies published on the prevalence of liver fluke or rumen fluke infection in Irish beef herds. Sixteen farms participating in the Teagasc/Farmers Journal BETTER farm beef programme were used in this study. Fourteen herds were screened for the presence of BVD virus in 2010 using RT-PCR. In 13 herds, blood samples were collected from calves (2–14 days of age) in November 2011 - April 2012 to determine their passive immune status using the zinc sulphate turbidity (ZST) test, while in 12 herds, blood and faecal samples were taken in order to determine the level of exposure to gastrointestinal and hepatic helminths.ResultsThe overall prevalence of BVD virus-positive cattle was 0.98% (range 0 - 3% per herd, range 0.6 - 3.0% per positive herd). Eighteen of the 82 calves (22%) sampled had ZST values less than 20 units (herd mean range 17.0 – 38.5 units) indicating a failure of passive transfer. The overall animal-level (herd-level) prevalence of liver fluke and rumen fluke infection in these herds was 40.5% (100%) and 20.8% (75%), respectively.ConclusionsThe potential costs associated with the presence of animals persistently infected with BVD virus through the increased use of antibiotics; the rate of failure of passive transfer of colostral immunoglobulins and the high prevalence of liver fluke infection in these herds highlight that some Irish suckler beef farms may not be realizing their economic potential due to a range of herd health issues. The use of farm-specific herd health plans should be further encouraged on Irish suckler beef farms.

Studies on Vitamin Mineral Interactions in Relation to Passive Transfer of Immunoglobulins in Buffalo Calves

Status of blood minerals and their absorption by neonate calves as influenced by fat soluble vitamins supplementation in their respective mothers, mineral supplementation in calves themselves has been evaluated. The objective was to know the impact of antioxidant vitamin supplementation to advance pregnant buffaloes, on enhanced acquired immunity during first few hours after birth, in relation to weight gain in buffalo calves. Advance pregnant buffaloes (n = 30) consisting of average body weight of 550±15 kg and of 4- 6 parity were fed on 25 kg green (green Jawar-Sorghum bicolor), 2-3 kg wheat straw and 3-4 kg concentrate mixture individually per day. Intramuscular injections of vitamin triplex A D3 E consisting of -2,500,000 IU of vit A -Palmitate; 2,500,000 IU of vitamin D3 and 1,000 IU of vit E (dl-alpha tocopherol acetate) were given per dose, a month prior to parturition, twice at 15 days interval to 15 dams. Rest of the 15 pregnant buffaloes served as negative controls. Secretion of immune proteins, immunoglobulin (Ig) enhanced by 80% in colostrum. The blood serum levels of Zn, Cu, Ca, Mg were measured from birth to 90 days in calves. A significant (p<0.05) difference between the blood serum Zn levels of calves born to vitamin supplemented and non-supplemented dams was measured and a positive correlation between blood serum Zn levels and injections of vitamins was identified. Association of Zn and Cu with passive immunity status has been identified in these calves. A significant positive correlation between Zn and Cu was also identified which showed a change under the impact of vitamin supplementation in buffaloes. The study signifies the role of micronutrients supplementation in dams prior to parturition, in calf immunity development. The study indicates significant mineral - vitamins interactions during this process. (Asian-Aust. J. Anim. Sci. 2006. Vol 19, No. 6 : 825-830)

Foal-related risk factors associated with development of Rhodococcus equi pneumonia on farms with endemic infection.

To identify foal-related risk factors associated with development of Rhodococcus equi pneumonia among foals on farms with endemic R. equi infection. Prospective case-control study. 220 foals at 2 equine breeding farms in Texas during a 2-year period. Information collected for each dam included age, time housed on the farm prior to parturition, whether there were any peripartum illnesses, parity, and health of previous foals. Information collected for each foal included breed, sex, gestational age, month and year of birth, location of birth, type of flooring and bedding in stall, postpartum management and preventive health care, passive immunity status, supplementation of immunoglobulins, exposure to other farms or foals affected with R. equi pneumonia, stall and pasture exposure, commingling with other mare-foal pairs, age at weaning, and whether the foal developed R. equi pneumonia. 32 of the 220 (15%) foals developed R. equi pneumonia, of which 4 (13%) died. Foals at 1 of the 2 farms and foals born during the second year of the study were more likely to develop R. equi pneumonia. Foal-related factors that were examined were not significantly associated with risk of R. equi pneumonia in multivariate analyses. Results suggest that there are farm- and year-related effects on the risk that foals will develop R. equi pneumonia. Other foal-related factors significantly associated with R. equi pneumonia were not identified.

Role of passive and adaptive immunity in influencing enterocyte-specific gene expression.

Numerous genes expressed by intestinal epithelial cells are developmentally regulated, and the influence that adaptive (AI) and passive (PI) immunity have in controlling their expression has not been evaluated. In this study, we tested the hypothesis that both PI and AI influenced enterocyte gene expression by developing a breeding scheme that used T and B cell-deficient recombination-activating gene (RAG) mice. RNA was isolated from the liver and proximal/distal small intestine at various ages, and the steady-state levels of six different transcripts were evaluated by RNase protection assay. In wild-type (WT) pups, all transcripts [Fc receptor of the neonate (FcRn), polymeric IgA receptor (pIgR), GLUT5, lactase-phlorizin hydrolase (lactase), apical sodium-dependent bile acid transporter (ASBT), and Na+/glucose cotransporter (SGLT1)] studied were developmentally regulated at the time of weaning, and all transcripts except ASBT had the highest levels of expression in the proximal small intestine. In WT suckling pups reared in the absence of PI, pIgR mRNA levels were increased 100% during the early phase of development. In mice lacking AI, the expression of pIgR and lactase were significantly attenuated, whereas FcRn and GLUT5 levels were higher compared with WT mice. Finally, in the absence of both passive and active immunity, expression levels of pIgR and lactase were significantly lower than similarly aged WT mice. In summary, we report that the adaptive and passive immune status of mice influences steady-state mRNA levels of several important, developmentally regulated enterocyte genes during the suckling and weaning periods of life.

The incidence and consequences of failure of passive transfer of immunity on a thoroughbred breeding farm.

Circulating IgG concentration was determined between 12 and 24 hours after birth for 323 foals born on a Thoroughbred breeding farm over 3 consecutive years. The incidence of failure of passive transfer (FPT) of maternal immunoglobulins (foal circulating IgG concentration < 8 g/L) was found to be 9.6%. Foals born late in the season (October to December) were found to be at increased risk for the development of FPT. The degree of assistance required at parturition and the presence of a periparturient problem in the mare or foal also significantly influenced the subsequent incidence of FPT. Passive immune status significantly influenced the likelihood of foals developing septic illness (joint ill, septicaemia, pneumonia) in the first month of life, but had no significant effect on the development of diarrhoea or Rhodococcus equi pneumonia. The results of the current study support the value of routine monitoring of passive immune status and the early speculative treatment of foals considered to be at risk for the development of FPT.

Passive immune status at postpartum hour 24 and long-term health and performance of calves

SUMMARY We quantified the effect of passive immune status on pre- and postweaning health and growth performance of calves raised in a beef production environment. Blood samples were collected at postpartum hour 24 from 263 crossbred calves for determination of plasma protein (pp) and serum IgG concentrations. Serum IgG concentration was classified as adequate (&gt; 1,600 mg/dl), marginal (800 to 1,600 mg/dl), or inadequate (&lt; 800 mg/dl). Plasma protein concentration was classified as adequate (≥ 4.8 g/dl) or inadequate (&lt; 4.8 g/dl). Morbidity and mortality events in the study population were monitored from birth to weaning, and after weaning throughout the feeding period. The lowest concentrations of serum IgG and pp were observed among calves that experienced morbidity or mortality prior to weaning. Calves that experienced morbidity in the feedlot had lower 24-hour pp values, but had IgG concentration similar to that in calves that were not observed to be ill during the feeding period. Calves classified as having inadequate IgG concentration were at greater risk of preweaning mortality (odds ratio [or] = 5.4), neonatal morbidity (or = 6.4), and preweaning morbidity (or = 3.2), compared with calves classified as having adequate IgG concentration at 24 hours. Calves classified as having inadequate pp concentration at 24 hours had a greater risk of morbidity (or = 3.0) and respiratory tract morbidity (or = 3.1) while in the feedlot, compared with calves classified as having adequate pp concentration. The effects of 24-hour passive immune status on calf growth were indirect through effects on morbidity outcomes. Morbidity during the first 28 days of life was associated with a 16-kg lower expected weaning weight. Respiratory morbidity in the feedlot resulted in a 0.04-kg lower expected mean daily gain. Thus, passive immune status at postpartum hour 24 was an important determinant of health before and after weaning, and was indirectly associated with calf growth during the same periods.