Colostral Antibodies Research Articles

Analysis of colostral antibodies to herpesvirus 1 and 5 in Murrah buffalo calves

Familiar agriculture is predominant in the production of milk buffaloes in São Paulo southwest, Brazil. The production of buffaloes’ milk is sold almost exclusively to cheese production inside and out São Paulo State. This search was done in a proprerty located in Alambari, São Paulo, specialized in the production of Murrah buffaloes, with 21 animals, born between March and May in the year 2017. Blood was collected at 24 to 48 h from the birth, every 15 days and at the completetion of weaning (91 days of age). The samples were collected in vaccum tubes of 10 mL with coagulum activator, by a puncture of the jugular vein. With the application of the virus neutralization tests, we could see 90.47% reagent animals for BoHV-5 and or BoHV-1 in the first two days of life. The geometric medium titles (GMT) of antibodies reduced significantly from the time 0 (1.4563) to the time 6 (05721) (P=0.0001), showing adequate transference of passive immunity through the ingestion of colostrum by buffalo calves, with the persistence of antibodies until 3 months old. Considering that most buffalo calves were reagents after sucking the colostrum, it is possible to conclude that there is a great occurrence of BoHV-5 and or BoHV-1 once there is a crossed reaction among these and the cattle with no historic of vaccination for the agents.

The genetic resistance of sows to Escherichia coli F4 adhesion reduces their response to a vaccine containing F4 fimbriae but does not affect the preweaning performance of their susceptible piglets.

Pigs without intestinal receptors for F4 fimbriae are congenitally resistant to F4 fimbriae-bearing enterotoxigenic Escherichia coli (ETEC F4). In general, 50 % and 100 % of piglets born to resistant (RR) sows crossed with hetero- or homozygous susceptible (SR, SS) boars, respectively, are susceptible but do not receive colostral antibodies against F4 fimbriae unless the sows have been vaccinated. The question arises as to whether resistant sows produce protective amounts of F4 antifimbrial antibodies after vaccination. The serum and colostrum antibody titres of 12 resistant and 12 susceptible vaccinated gilts were compared. The effect of the receptor status of the dam and sire on the preweaning performance of 5027 piglets was evaluated using Agroscope's recordings. The sows of the experimental herd, where ETEC F4 was circulating, were vaccinated against ETEC twice during the first pregnancy and once during each following pregnancy. The log2 transformed F4 antibody titres in the serum obtained after the second vaccine injection as well as in the colostrum of the 12 resistant animals were lower than the titres of the susceptible animals (serum: F4ab 11,19 ± 1,44 vs. 12,18 ± 1,33, P = 0,096; F4ac 10,03 ± 1,58 vs. 11,59 ± 1,43, P = 0,019; colostrum: F4ab 12,20 ± 2,41 vs. 14,02 ± 1,31, P = 0,033; F4ac 10,93 ± 2,46 vs. 13,03 ± 5,21, P = 0,006). The heat labile enterotoxin (LT) antibody titres after vaccination did not differ between susceptible and resistant animals (p > 0,10). Preweaning mortality in the offspring of RR sows × SS boars was slightly lower than in the offspring of SS sows × RR boars (P = 0,04), suggesting that the disease risk of susceptible piglets born to vaccinated resistant sows was not increased, even though they received colostrum with a slightly reduced content of antibody against F4 fimbriae.

Vertical transmission of Trypanosoma evansi in a dromedary camel calf that spontaneously recovered after colostrum consumption

AbstractA weak dromedary calf with signs of prematurity was born in April of 2023 to a healthy multiparous camel with a good body condition. The calf was diagnosed strongly positive to Trypanosoma evansi by haematocrit centrifugation technique (immediately after birth). The mother at that time was asymptomatic and negative by haematocrit centrifugation technique and PCR of blood. Indirect ELISA of the calf's serum before colostrum ingestion showed negligible levels of antibodies. However, 12 hours after colostrum ingestion and without any treatment, the levels of antibodies increased significantly, which coincided with negative haematocrit centrifugation technique. This indicates a possible role of colostral antibodies in neutralising the trypanosomes in the calf's blood. Examination of the placenta showed placentitis, and PCR confirmed a positive result for Trypanosoma nucleic acid. The importance of vertical transmission in maintaining the infection in a herd is discussed, as well as the role of colostrum in decreasing calf mortalities due to trypanosomosis.

Comparing colostral bovine rotavirus and bovine coronavirus antibodies in primiparous and multiparous cows vaccinated pre-partum with two different multivalent vaccines

Neonatal calf diarrhea (NCD) is a prevalent problem globally and in the U.S., data from NAHMS indicates that 50% of pre-weaned dairy heifer deaths are due to NCD. Bovine rotavirus (BoRV) and coronavirus (BoCV) are common viral causes of NCD. Dry cows are frequently vaccinated against these pathogens to enhance colostral antibody content. Studies have shown that vaccinating cows increases colostral antibodies but few published studies exist comparing different vaccines in this regard. The objective of this trial was to compare colostral antibody titers from cows given one of 2 commonly used multivalent vaccines compared to cows that were left as unvaccinated controls.

The influence of passive colostrum transfer on humoral immunity to selected antigens of Mannheimia haemolytica in calves

The aim of the study was to evaluate the effectiveness of colostral immunity against aetiological agents of bovine respiratory disease complex (BRDC), to assess the suppressive effect of colostral antibodies against Mannheimia haemolytica on immunity, and to analyse acute phase proteins in calves. Holstein-Friesian and Simmental cows and calves were immunized with M. haemolytica leukotoxin (Lkt) and outer membrane proteins (OMPs) at 6 and 4 weeks before parturition. Sera and colostrum were collected from the cows directly after calving. Sera from calves were obtained before colostrum intake and 48 h after birth. Calves from vaccinated and unvaccinated cows were placed in the feedlot and immunized with Lkt or OMP on days 10 and 24. Calves were tested for serum antibodies against respiratory viruses. Trachea and lung samples were collected for bacteriological examination from all calves that had died with BRDC. The results indicated high colostrum values and IgG transfer in calves at 48 h (> 12.5 g/l) and a high concentration of anti-BVD antibodies in calves at 48 h (> 33–45 mg/ml). Similar values were observed for bovine herpes virus BHV-1 and bovine respiratory sycytil virus BRSV. Immunoglobulin concentrations were highest for antibodies specific to parainfluenza PI-3 and adenoviruses. The lowest antibody levels were detected against M. haemolytica antigens in all experimental groups of calves (< 50 mg/ml in calves of cows vaccinated with M. haemolytica antigens and < 25 mg/ml in calves of unvaccinated cows). The findings indicate the need for early immunization of calves, which is often precluded by stress associated with transport and adaptation to the new conditions in the feedlot.

Local and Systemic Antibody Responses in Beef Calves Vaccinated with a Modified-Live Virus Bovine Respiratory Syncytial Virus (BRSV) Vaccine at Birth following BRSV Infection.

Maternal antibodies interfere with BRSV vaccine responses and efficacy in young calves. The objective of this study was to determine if vaccination before the complete absorption of colostral antibodies results in adequate immune priming and clinical protection of beef calves. Within 6 h of life, calves were randomly assigned to 2 different treatment groups. Group Vacc (n = 25) received a single dose of a modified-live virus (MLV) BRSV vaccine intranasally (IN) and group Control (n = 25) received 2 mL of 0.9% saline IN. At approximately 3 months of age, all calves were experimentally challenged with BRSV. Serum and nasal secretion samples were collected before and after challenge for BRSV real-time RT-PCR and antibody testing. Respiratory signs were not observed before challenge. After challenge, respiratory scores were similar between groups. On the challenge day, >40% of calves in each group were febrile. The mean serum and nasal BRSV-specific antibody titers indicated natural BRSV exposure before the experimental challenge in both groups. All calves tested positive for BRSV and had a similar duration of shedding after challenge. Based on these results, vaccination at birth does not offer advantages for immune priming or clinical protection for beef calves in BRSV-endemic cow-calf herds.

A Single-Dose Intramuscular Nanoparticle Vaccine With or Without Prior Intrauterine Priming Triggers Specific Uterine and Colostral Mucosal Antibodies and Systemic Immunity in Gilts but Not Passive Protection for Suckling Piglets.

An effective single-dose vaccine that protects the dam and her suckling offspring against infectious disease would be widely beneficial to livestock animals. We assessed whether a single-dose intramuscular (i.m.) porcine epidemic diarrhea virus (PEDV) vaccine administered to the gilt 30 days post-breeding could generate mucosal and systemic immunity and sufficient colostral and mature milk antibodies to protect suckling piglets against infectious challenge. The vaccine was comprised of polymeric poly-(lactide-co-glycolide) (PGLA)-nanoparticle (NP) encapsulating recombinant PEDV spike protein 1 (PEDVS1) associated with ARC4 and ARC7 adjuvants, a muramyl dipeptide analog and a monophosphoryl lipid A (MPLA) analog, respectively (NP-PEDVS1). To establish whether prior mucosal exposure could augment the i.m. immune response and/or contribute to mucosal tolerance, gilts were immunized with the NP-PEDVS1 vaccine via the intrauterine route at breeding, followed by the i.m. vaccine 30 days later. Archived colostrum from gilts that were challenged with low-dose PEDV plus alum was used as positive reference samples for neutralizing antibodies and passive protection. On day 100 of gestation (70 days post i.m. immunization), both vaccinated groups showed significant PEDVS1-specific IgG and IgA in the serum, as well as in uterine tissue collected on the day of euthanasia. Anti-PEDVS1 colostral IgG antibody titers collected at farrowing were significantly higher relative to the negative control gilts indicating that the NP vaccine was effective in contributing to the colostral antibodies. The PEDVS1-specific colostral IgA and anti-PEDVS1 IgG and IgA antibodies in the mature milk collected 6 days after farrowing were low for both vaccinated groups. No statistical differences between the vaccinated groups were observed, suggesting that the i.u. priming vaccine did not induce mucosal tolerance. Piglets born to either group of vaccinated gilts did not receive sufficient neutralizing antibodies to protect them against infectious PEDV at 3 days of age. In summary, a single i.m. NP vaccine administered 30 days after breeding and a joint i.u./i.m. vaccine administered at breeding and 30 days post-breeding induced significant anti-PEDVS1 immunity in systemic and mucosal sites but did not provide passive protection in suckling offspring.

Comparison of testing for failure of passive transfer in calf serum using four different testing methods

Failure of passive transfer (FPT) in calves is defined as failure to absorb colostral antibodies sufficient to achieve a serum immunoglobulin G (IgG) concentration of > 10 g/L within the first week of life. The aim of this study was to compare four different tests to diagnose FPT in a convenience sample of 1–7 day old dairy calves in Scotland. Published cutpoints for Brix and total protein (TP) refractometry and zinc sulphate turbidity (ZST) were compared with the reference test radial immunodiffusion (RID) for suitability to detect FPT. In addition, the current commercial RID reference test offered in Scotland was validated.FPT prevalence was estimated to be 14.17% (95% confidence intervals, 10.58–17.75) based on RID test results. There was moderate agreement between the reference (RID) and indirect tests (kappa=0.28 for Brix; 0.34 for TP; 0.24 for ZST). Brix and TP refractometry underestimated IgG concentration, resulting in an overestimation of FPT prevalence (40.54% and 29.46%, respectively). Similarly, ZST overestimated the prevalence of FPT (46.29%), but the variability was more consistent across all IgG concentrations. The performance of all three indirect methods was improved by lowering test cutpoints (to 5 g/dL for TP; 8.2% for Brix; 15 units for ZST) which improved test specificity and accuracy of these screening tests.

Evidence for transfer of maternal antigen specific cellular immunity against Mycobacterium avium ssp. paratuberculosis via colostrum in a goat twin model

Colostrum intake is one of the most important factors in neonatal health in ruminants, mainly because of its unique immunological properties. Both in practice as well as in research, the attention of lactogenic immunity is focused on the importance of colostral antibodies and less attention is given to the functional role of maternal cells in colostrum. Here we study the transfer of maternal leukocytes via colostrum and the functionality in goat kids. In experiment 1, twenty twin pairs of goat kids from dams previously immunized with an inactivated Mycobacterium avium subsp. paratuberculosis (MAP) vaccine were fed maternal colostrum from their dam (kid 1) or pasteurized and frozen/thawed bovine colostrum (kid 2). The presence of cell mediated immune response (CMIR) against Mycobacterium avium antigens in the kids was assessed using intradermal skin testing with PPD-A tuberculin. Linear mixed effect models showed an increase in skin thickness in response to intradermal PPD-A injection in maternal colostrum fed kids compared to bovine colostrum fed kids. After intradermal PPD-A application, serum concentration of MAP specific antibodies increased in kids fed maternal colostrum, indicating antigen specific activation of the adaptive immune system. We did not detect a similar increase in antibodies in the kids fed bovine colostrum.In experiment 2, a more reductionistic approach was applied to specifically study the effects of the transfer of maternal colostral leukocytes on CMIR in goat kids. Similar to experiment 1, twin kids from MAP immunized dams were randomly divided over two groups. The experimental group received colostrum replacer supplemented with fluorescently labelled colostral cells of the dam and the control group received colostrum replacer only. No difference in skin response following intradermal PPD-A injection was observed between both groups of kids. Histologic examination of the skin at the intradermal injection site did not show fluorescently labelled cells.In conclusion, in our initial experiment we observed an antigen specific CMIR in goat kids fed fresh colostrum with colostral leukocytes from vaccinated dams. The lack of a DTH response in kids fed colostrum replacer supplemented with maternal colostrum derived leukocytes indicated that the complete colostral matrix is probably required for colostrum leukocytes to transfer across the intestinal epithelial barrier and modulate the neonatal immune response. In line with earlier studies, our results indicate that caprine maternal leukocytes present in colostrum can functionally contribute to the newborns’ early adaptive immune responses adding to the importance of colostrum feeding in ruminant neonates.

Dynamics of natural infection by Toxoplasma gondii in goat herds in the semiarid region of northeastern Brazil: transitional antibody observation.

This study aimed to describe the transmission of T. gondii in naturally infected goats in the semiarid region of northeastern Brazil, through evaluating the serological status of these animals from one to 12 months of age. Seven goat farms were selected. During the first visit, an epidemiological questionnaire was applied. Blood samples were collected from pregnant goats and from their female offspring every month, to monitor them for anti-T. gondii antibodies, using the indirect fluorescence antibody test (IFAT). Out of 66 pregnant goats evaluated, 47% (31/66) (95% CI: 34.6% - 59.7%) were positive and out of 93 female offspring, 61.3% (57/93) (95% CI: 52.4% - 69.2%) were positive, in at least one month during the evaluation period. Among the positive female offspring, 43.3% (27/57) (95% CI: 39.7% - 56.9%) presented environmental infection and 56.7% (30/57) (95% CI: 43.4% - 66.3 %) probably had only colostral antibodies or vertical transmission. It was observed that 92,6% (25/27) from environmental infections occurred until reproductive age (six months) (p<0.0001). It was also noted that there is a correlation between the titration of mothers and offspring, until four months of age (p<0.0001). Large fluctuations in the presence of antibodies were observed among the animals over the months monitored. It can be concluded that the prevalence of anti-T. gondii antibodies within the herds was greater than what has been expressed in specific prevalence studies and that most goat become infected up to the six months of life in the studied area.

Ewe colostrum quality on commercial Welsh sheep farms

In advance of the 2020 lambing season, 147 Welsh farmers were engaged in active colostrum management through training and discussion groups. Sixty-four of these farmers returned data on 1295 ewes, including ewe age, breed, body condition score (BCS), number of live and dead lambs born, a description of udder condition, colour of colostrum and a Brix reading. Flock numbers were available from 43 farmers and information on late pregnancy ration from 30 farms. Results were analysed using a Brix reading cut-off of 26.5% and showed that 76% of samples exceeded this level and were considered of good quality. With an average of 20 ewe colostrum samples returned per flock, the greatest variation was found to be at the flock level with ewe nutrition considered to be the greatest driver. Concentrate feed space, silage crude protein and the supplementation of concentrates to twin and triplet-bearing ewes were all factors that indicated a potential flock level role in determining the colostrum quality. Individual level ewe factors appeared to have a much smaller role in determining the quality of the colostrum, with the ease of stripping being the main significant factors. Colostrum quality was more likely to be inadequate if the ewe was reported to be hard to strip (OR 0.56). While not significant in the final regression model, other ewe factors appeared to have an impact on the colostrum quality, such as the BCS and number of lambs born; however, lack of significance in the model may mean they are not significant or that they reflect differences in management between different flocks. As UK sheep farmers prepare for lambing 2022, and continue to optimise colostrum management and reduce levels of antibiotic given to neonatal lambs, this practical study has demonstrated how sheep farmers can be actively motivated to measure colostrum quality to determine how to optimally manage colostral antibody delivery to individual lambs.

Optimization of rabies (Rhabdoviridae: Lyssavirus) dog vaccination schedule using a mathematical model

Most cases of human rabies are caused by dog (Canis lupus familiaris) bites. Therefore, the implementation of vaccination programs of these animals is one of the urgent tasks.The work aims to identify the factors influencing the production of antirabies virus-neutralizing antibodies (VNAs) in vaccinated dogs, and to formulate recommendations for adjusting the vaccination schedule using mathematical modeling (MM). We used a fixed-effects modeling procedure to estimate the two-compartment model parameters using log-transformed data (obtained by RFFIT, rapid fluorescent focus inhibition test; and FAVN, fluorescent antibody virus-neutralization test) on the VNAs levels in the serum of vaccinated dogs. More vigorous immune response after a two-dose primary vaccination is formed in juvenile dogs at the age of 3 months to 1 year compared to the adult dogs. Following the primary vaccination and revaccination 1 year after, VNAs were produced more intensively in adult stray dogs than in domestic dogs. The short-term immune response observed in dogs aged up to 3 months is due to the presence of colostral antibodies and the active growth of the organism at this age. The results of our study confirm that most of the dogs have a level of antirabies VNAs of ≥0.5 IU/ml up to two or more years following immunization. However, only regular annual revaccination ensures the protective VNAs level in animals that responded poorly to vaccination due to various factors. The following antirabies vaccination schedule is recommended: primary vaccination of the dog at the age of 3 months up to 1 year with 1-2 month intervals, then revaccination annually. This work also demonstrates the possibility of a wider application of MM methods for solving problems of vaccine prevention.

Intrauterine immunizations trigger antigen-specific mucosal and systemic immunity in pigs and passive protection in suckling piglets

We assessed whether vaccines administered to the uterus at breeding can lead to sufficient colostral antibodies to protect suckling piglets against Porcine Endemic Diarrhea Virus (PEDV). An antigen from Lawsonia intracellularis, a disease that impacts weanling intestinal health, was also included because we have extensive knowledge on the pig immune response to this antigen. Gilts were mock-bred at 2nd estrus with killed sperm including an intrauterine (i.u.) vaccine comprised of recombinant (r) PEDV Spike protein (rPEDVS1) and L. intracellularis flagellin (rFliC) formulated with poly I:C, host defense peptide, and polyphosphazene (TriAdj). Gilts returned to estrus within 3 weeks and they were inseminated with killed sperm (3rd estrus) or live sperm (4th estrus) with rPEDVS1-TriAdj vaccine. They also received an i.m. injection of rFliC-TriAdj at 3rd and 4th estrus to establish whether i.u. vaccination primes systemic immunity without inducing mucosal tolerance. Control gilts were administered semen alone at 2nd estrus which allowed us to compare litter weights and sizes to industry standards. Colostrum from gilts challenged with low dose PEDV plus alum was used as positive reference samples for neutralizing antibodies and passive protection. Thirteen weeks later, the i.u.-vaccinated gilts showed significant PEDVS1-specific serum, colostral, and uterine antibody titers and colostral PEDVS1-neutralizing antibodies but poor cell-mediated immunity. Piglets born to i.u. vaccinated gilts received partial passive protection from PEDV infection 3 days after birth but eventually succumbed to the disease. Immunization by the i.u./i.m. route triggered significant anti-FliC cell-mediated immunity and colostral FliC antibodies that remained high in weaned piglet serum. This trial and a repeat trial wherein gilts were immunized at 1st estrus without semen and at 2nd estrus with live semen showed that intrauterine immunization did not impact fertility, number of live births or piglet growth kinetics. Further optimization is needed to promote robust passive protection in suckling offspring.

Schmallenberg virus infection suspected in a calf born to an imported heifer.

Schmallenberg virus infection suspected in a calf born to an imported heifer.

Innate and acquired immune responses of colostrum-fed neonatal Holstein calves following intranasal vaccination with two commercially available modified-live virus vaccines.

To compare immune responses induced by 2 commercially available vaccines with a bovine herpesvirus type 1 (BHV1) component following intranasal (IN) administration to colostrum-fed calves. 90 male Holstein calves (ages, 5 to 14 days). In a randomized complete block design, each calf received 2 mL (1 mL/nostril) of vaccine A (n = 30), vaccine B (30), or saline (0.9% NaCl) solution (30) on day 0. Blood samples were collected for determination of serum anti-BHV1 IgG titer, and nasal fluid (NF) samples were collected for determination of interferon (IFN)-α and IFN-γ concentrations and for secretory IgA titers against BHV1, Mannheimia haemolytica, and Pasteurella multocida at predetermined times for 42 days after vaccination. All calves were seropositive for anti-BHV1 IgG, and the mean anti-BHV1 IgG titer did not differ significantly among the 3 groups at any time. Both vaccines induced significant transient increases in NF IFN-α and IFN-γ concentrations. On day 5, mean IFN-α concentration and the proportion of calves with detectable IFN-α concentrations for the vaccine A group were significantly greater than those for the vaccine B and control groups. On day 42, the mean NF anti-P multocida IgA titers for both vaccine groups were significantly greater than that of the control group. Both vaccines induced innate and acquired immune responses in calves with colostral antibodies. The magnitude of the IFN-α response and proportion of calves with detectable IFN-α differed between the 2 vaccine groups. Both vaccines appeared to enhance the IgA response against P multocida.

The analysis of the condition of colostral immunity of sows after vaccination against porcine epidemic diarrhea virus

Porcine epidemic diarrhea (PED) is an acute, highly contagious viral disease of pigs of all age groups, but it is manifested by particularly high mortality of newborn piglets and characterized by vomiting, diarrhea, and lack of appetite. Porcine epidemic diarrhea (PED) remains a problem for pig farms in many countries, including Ukraine. Specific prophylaxis PED had proven to be a difficult task and despite many studies, the problem of PED remains unresolved. Since piglets get infected during the first days after birth, their protection can only be provided by colostral antibodies of immuned sows. Therefore, the urgent task of veterinary medicine scientists is to develop effective methods of preventing the disease, which is to use local strains of the pathogen. The article presents the results of studies of colostral immunity of piglets by determining the presence of antibodies against the PED virus in the colostrum of sows who were immunized with a vaccine inactivated against PED from the intestinal virus of artificially infected suckling piglets. Infectious activity of matrix broods of the virus for the production of the preparation was determined by RT-PCR. According to the results of research, material was selected for the manufacture of the vaccine. Subsequently, the drug was monitored according to technological regulations, including the infectious activity of the virus, which ranged from 1.96×10–8 to 3.16×10–9. We conducted a comparative study of the presence of antibodies to the PED virus in the colostrum of sows in the treatment of animals by “back-feeding” and vaccination of sows with inactivated preparation. Samples of colostrum from sows were taken within 1–4 hours after farrowing. The article presents research results that allow us to conclude that both methods of treatment of sows create immunity in newborn piglets. Thus, the presence of antibodies to the PED virus in colostrum in the first hours after birth provide protection against infection and death.

Colostral immunity as an analytical factor in predicting the development of acute respiratory viral infections in calves

To reduce the incidence of acute respiratory viral infections in cattle, routine vaccination of mother cows is carried out. There is a direct dependence of the passive immunity level in calves on the vaccination efficacy in cows. The paper presents the results of a study of colostral immunity in calves and post-vaccination immunity in cows against the agents of acute respiratory viral infections in agricultural facilities located on the territory of the Ural and Volga Federal Districts. In the farms under study (n = 10), cattle are vaccinated with inactivated vaccines: “COMBOVAC” and “COMBOVAC-R” (OOO Vetbiokhim, Russia), “HIPRABOVIS® 4” (Laboratorios Hipra, S. A., Spain). The study of postvaccinal immunity level in cows showed that the levels of antibodies to infectious bovine rhinotracheitis virus (5.3–8.0 log2), bovine viral diarrhea virus (3.5–4.8 log2), bovine parainfluenza-3 virus (6.8–8.5 log2) and bovine respiratory syncytial virus (4.2-4.5 log2) in cattle confer protection. When evaluating the results of serological diagnostics of passive immunity in calves to acute respiratory viral infections, it was found that the level of colostral antibodies in them is lower than the level of post-vaccination antibodies in cows: to infectious bovine rhinotracheitis virus by 34.2–58.8%; to bovine diarrhea virus by 37.5–45.0%; to bovine parainfluenza-3 virus by 14.7–35.4 and to bovine respiratory syncytial virus by 23.5-42.2%. To ensure epizootic favourable situation, it is proposed to adjust the schedules of vaccination against bovine diseases in herds, infected by acute respiratory viral infections for dairy farms under study.

Investigation of causes of neonatal mortality in Bali cattle on Sumbawa Island

There is a desire to increase cattle production on Sumbawa Island but anecdotal reports from farmers indicate that calf mortality can be high. The aim of this paper is to report the occurrence and common causes of calf mortality, as well as to determine if colostral antibody transfer is sufficient in new-born calves. Personal interviews were conducted with 27 farmers. Immunoglobulins were measured in neonatal calves (n=18) using the FASTest IgG Bovine kit. The presence of various pathogens was investigated in fecal samples from calves (n=12) with signs of diarrhea between 1-2 months of age using the FASTest D4T bovine kit and the presence of gastrointestinal parasites was investigated using fecal floatation from pre-weaned calves (3 weeks-3 months of age; n=62). From the questionnaire calf losses ranged from 10–27%, with most losses occurring in older calves. Only one of the 18 calves demonstrated an insufficient concentration of IgG in serum, indicating the possibility of failure of passive transfer from the dam. Of the samples tested from scouring calves, 7 out of 12 samples tested positive for one of the microorganisms causing general diarrhoea in calves. A range of different gastrointestinal nematode parasites were found although very few coccidial oocysts were seen. The results of these studies indicate that calf mortality is high and will be a limitation on the production of beef cattle for slaughter in the Dompu region of Sumbawa Island. Further investigation is required to determine which pathogens are the cause of this calf loss.

Comparison of tests for failure of passive transfer in neonatal calf serum using total protein refractometry and the biuret method

Failure of passive transfer (FPT) is defined as failure to absorb colostral antibodies sufficient to achieve a serum Immunoglobulin G (IgG) concentration >10 g/L. Immunoglobulin G can be measured directly in calf serum using radial immunodiffusion (RID), or indirectly estimated by measuring total protein (TP). Indirect TP measures are usually favoured because of their relatively lower costs. The aim of this work was to compare TP measurements using refractometry and biuret methods against the reference RID test in neonatal dairy calves, and to assess agreement between these indirect measures. Neither the biuret nor the refractometer method provided a high sensitivity for detection of FPT, as defined by RID. There was no systematic difference between the methods in their estimation of TP, although the biuret method was more accurate than the refractometer method when tested against the reference RID test (accuracy = 83.1 % v 69.3 %) and the refractometer was more likely to overestimate the number of calves with FPT. Specificity for the biuret test was 93.9 % compared with the refractometer specificity of 74.4 %. Mean TP as estimated by the biuret method was higher than the mean TP estimated by the refractometer (6.25 g/dL versus 5.52 g/dL), and the Pearson correlation coefficient for the two assays was only moderate, at 0.58. This suggests that the biuret method is preferable to the refractometer for detecting FPT in calves, despite the superior convenience of the refractometer.

The role of colostral immunity in the effectiveness of serological detection of BLV

The purpose of our research was to study the influence of newborn calves colostral antibodies on the efficiency of bovine leukemia virus detection by serological methods. The research was conducted on the basis of agricultural organizations within the territory of the Ural Federal District (Chelyabinsk region). We undertook comprehensive diagnostic studies of calves fed with milk from seropositive and seronegative animals using polymerase chain reaction, ELISA test, and immunodiffusion test. Experimentally it was found that feeding calves with milk from seropositive and seronegative cows led to colostral immunoglobulins persistence for up to 3-3.5 months, in most of the animals, which may be associated with the end of suckling period in calves. At the same time, serological screening of animals during this period is difficult due to the influence of a high concentration of colostral antibodies. The obtained results of laboratory studies indicate the efficiency of PCR diagnostics in detecting a specific locus of the calf leukemia virus in animals at the early stages of the infectious process. PCR diagnostics provides an opportunity to early evaluation of calves with a latent course of BLV, excluding the influence of colostral immunity, thereby reducing the recovery time of enterprises from the leukemia virus by 20%.