Protection of the nursing pig against experimentally induced enteric colibacillosis by vaccination of dam with fimbrial antigens of E coli (K88, K99 and 987P)

Pregnant gilts were vaccinated with two doses of alhydrogel adsorbed fimbrial antigens of Escherichia coli (K88ab, K88ac, K99 and 987P) supplemented with beta toxoid of Clostridium perfringens type C. Their piglets, and piglets of nonvaccinated gilts, were subsequently orogastrically challenged with one or other of the four fimbrial types of enteropathogenic E coli. Some of the vaccinated animals were reinjected with a single dose of the vaccine during second gestation and their piglets, and piglets of non-vaccinated sows, were challenged the same way as were litters of gilts. Blood serum and colostra were examined for antibodies to the four fimbrial antigens of E coli and for antitoxin to beta toxin of C perfringens type C. It was found that: (1) a highly significant reduction in mortality and morbidity was achieved in vaccinated litters against all four challenge strains of E coli; (2) excretion of K88ab and K88ac but not of K99 and 987P challenge strains was significantly reduced; (3) revaccination of sows by a single dose of the vaccine during second gestation conferred complete protection against mortality and highly significant protection against morbidity; (4) no correlation was noted between colostral or seroagglutinins to fimbrial antigens of E coli and mortality rates in litters challenged with homologous fimbrial types of E coli, but good correlation was found between colostral precipitins to K88 antigens and mortality rates in litters; (5) antitoxin value in 97 per cent of colostrum of vaccinated sows was 10 iu equivalent of C perfringens type C toxin or more per ml of colostrum.     

A longitudinal study of rotavirus antibody titers in swine in a closed specific pathogen-free herd.

In a newly established closed specific pathogen-free (SPF) swine herd, gilt/sow suckling and weaned pig rotavirus specific antibody titers were followed for three lactations by enzyme-linked immunosorbent assay (ELISA) to gain insight into the dynamics of herd antibody titers to group A rotavirus. Among gilts/sows, serum antirotavirus IgG titers increased during each lactation with a subsequent drop in titer between farrowings. Serum antirotavirus IgM titers declined during each lactation and with subsequent parity. Serum antirotavirus IgA titers remained constant during lactations and among parities. In colostrum and milk, antirotavirus IgA antibody was abundant. Differences in titer were not noticed between gilts and second litter sows but third litter sows had significantly higher titers than the first two groups. Antirotavirus IgG was high in colostrum but nearly nonexistent in milk. This titer did not vary significantly within or among parities. There was a linear regression in the titers of baby pig serum antirotavirus IgG from the post colostral sample through to seven weeks old, after which titer began to increase. No difference in baby pig serum antirotavirus IgG was noted among the three litters. Serum antirotavirus IgA and IgM were undetectable in baby pig sera after 2-3 weeks of age. Coproantibody to rotavirus was sporadically present in pig feces for 2-3 weeks after birth with highest titers in the IgA fraction. We conclude that although it is probable that age resistance of pigs to rotavirus diarrhea occurs, humoral immunity as measured by ELISA rotavirus antibody titers may not be intimately involved in virus clearance since in our studies baby pigs passively received large amounts of antibody but still excreted pathogenic virus. The finding of increasing levels of serum antirotavirus IgG in gilt/sow serum suggest that exposure to antigen of dams occur without significant increases in antirotavirus IgG titers in either colostrum, milk, or baby pig serum.     

Effect of oral inoculation of Escherichia coli on colostral antibody production in cattle.

Oral inoculation of approximately 1.2 x 10(9) viable Escherichia coli to pregnant cows resulted in increased blood serum and colostral whey titers to the "O" antigen. The antibody titers were more pronounced in colostral whey and were correlated with the inoculum strain of Escherichia coli. There was no correlation between antibody titers of the colostrum ingested and the resulting serum antibody titers of the calves. The incidence of diarrhea in calves did not correlate with the antibody titer in the colostrum. The occurrence of diarrhea was significantly greater in calves that did not ingest colostrum until they were 12 hours old, compared with calves that had free access to their dams and suckled within an hour of birth.     

Adsorptive effects of di-tri-octahedral smectite on Clostridium perfringens alpha, beta, and beta-2 exotoxins and equine colostral antibodies

OBJECTIVE: To determine the adsorptive capability of di-tri-octahedral smectite (DTOS) on Clostridium perfringens alpha, beta, and beta-2 exotoxins and equine colostral antibodies. SAMPLE POPULATION: 3 C perfringens exotoxins and 9 colostral samples. PROCEDURES: Alpha, beta, and beta-2 exotoxins were individually co-incubated with serial dilutions of DTOS or bismuth subsalicylate, and the amount of toxin remaining after incubation was determined via toxin-specific ELISAs. Colostral samples from healthy mares were individually co-incubated with serial dilutions of DTOS, and colostral IgG concentrations were determined via single radial immunodiffusion assay. RESULTS: Di-tri-octahedral smectite decreased the amount of each C perfringens exotoxin in co-incubated samples in a dose-dependent manner and was more effective than bismuth subsalicylate at reducing exotoxins in vitro. Decreases in the concentration of IgG were detected in samples of colostrum that were combined with DTOS at 1:4 through 1:16 dilutions, whereas no significant decrease was evident with DTOS at the 1:32 dilution. CONCLUSIONS AND CLINICAL RELEVANCE: Di-tri-octahedral smectite effectively adsorbed C perfringens exotoxins in vitro and had a dose-dependent effect on the availability of equine colostral antibodies. Results suggested that DTOS may be an appropriate adjunctive treatment in the management of neonatal clostridiosis in horses. In vivo studies are necessary to fully assess the clinical efficacy of DTOS treatment.     

Quantification of bovine IgG, IgM and IgA antibodies to Clostridium perfringens B-toxin by enzyme immunoassay I. Preparturient immunization for enhancement of passive transfer of immunity

A quantitative competitive binding "triple-sandwich" enzyme immunoassay was developed and used to evaluated pathogen/class-specific antibody responses in Holstein-Friesian cows vaccinated against Clostridium perfringens B-toxin. Vaccination of cows at six weeks and again at two weeks prepartum increased pathogen-specific IgG levels in each dam's colostrum and respective calf's serum. Pathogen-specific IgG and IgM concentrations in dams' sera and colostra were related to subsequent pathogen-specific IgG and IgM neonatal sera concentrations. Only pathogen-specific IgA in dams' colostra was correlated to neonatal levels, possibly owing to a different origin and role of this immunoglobulin class. All class-specific colostral immunoglobulin levels were related to subsequent neonatal concentrations. Isotypic antibody responses against C. perfringens B-toxin were found with pathogen-specific IgM predominant in dams' sera and pathogen-specific IgA predominant in colostra and neonatal sera.     

Passive immunity to Pasteurella haemolytica A1 in dairy calves: effects of preparturient vaccination of the dams.

Dairy cows from five herds were assigned to receive a commercial Pasteurella haemolytica vaccine or no vaccine at all, administered at six and three weeks before parturition. Vaccination was associated with increased leukotoxin neutralizing serum antibody titers in the dams (p < 0.001), and with increased titers in colostrum (p < 0.001). Vaccination of dams also had a significant association with increased passive leukotoxin neutralizing antibody titers in their calves (p < 0.001). Vaccination was also associated with increased indirect agglutinating antibody titers in serum of the dams (p < 0.001). In the analysis of agglutinating antibody titers in colostral whey the interaction "vaccination*herd" was found to be significant (p < 0.001), indicating that the effects of vaccination on colostral titers were not consistent from herd to herd. The analysis was repeated, stratifying by herd. Vaccination was associated with increased agglutinating antibody titers in colostrum (p < 0.05) in three herds of the five in the study. In two of these three herds there were significant increases in passive neonatal titers associated with vaccination. In the remaining herd the mean IgG1 level in the calves was consistent with failure of passive transfer of immunoglobulins (IgG1 < 8.0 g/L). These results suggest that preparturient vaccination of dairy cows can induce modest increases in passive antibody titers to antigens of Pasteurella haemolytica in their calves, but the antigen of interest and the population being studied can affect the outcome.     

Sarcoptes scabiei var. suis in a closed pig breeding and fattening herd and control possibilities after treatment

On an Austrian pig breeding and finishing farm containing 13,000 pigs a mange prevalence of 38.7% according to the results of the skin scraping and 28.2% based on serology was determined. Due to the insufficient treatment (single treatment of the sows using Phoxim [Sebacil pour on]), sustainable control was impossible. That could be confirmed by the high number of mange positive gilts and finishing pigs. Before eradication started the following prevalences of mange could be found: sows 6.74% (skin scrapings), respectively 6.18% (serologically), gilts 18.18% resp 28.67%, finishing pigs 54.35% and 38.58%. The breeding stock for eradication was treated with doramectin (Dectomax) injectable solution and the finishing pigs with Ivomec-praemix, both applied twice. The success of treatment of the different farm units and of different age groups was controlled for the following ten months by combined diagnostic methods. In addition to skin scrapings, serum and colostral samples were carried out using a commercially available ELISA licensed for investigation of blood serum and colostrum. After treatment antibodies in the serum of the sows and gilts and Sarcoptes mites in their skin scrapings were detectable for up to four months after treatment. In serum samples of piglets and colostrum samples antibodies against Sarcoptes mites were detectable up to five months after final treatment. Due to the higher level and longer verifiability of antibodies in blood samples of piglets for five months after treatment and high prevalences their use as a diagnostic tool can be recommended. In contrast the use of colostral samples for routine diagnosis should be investigated more thoroughly. The comparison of the results of different diagnostic methods showed that for reliable mange diagnosis combined methods are recommended.     

Protection against enteric colibacillosis in pigs suckling orally vaccinated dams: evidence for pili as protective antigens

Pregnant gilts were vaccinated orally with Escherichia coli that produced pilus antigens K99 or 987P. The vaccines were live or dead enterotoxigenic E coli (ETEC) or a liver rough non-ETEC strain which has little ability to colonize pig intestine. Pigs born to the gilts were challenge exposed orally with K99+ or 987P+ ETEC, which did not produce heat-labile enterotoxin or flagella and which produced somatic and capsular antigens different from those of the vaccine strains. Control gilts had low titers of serum and colostral antibodies against pilus antigens, and their suckling pigs frequently had fatal diarrhea after challenge exposure. Serum antibody titers against pilus antigens of the vaccine strains increased in the gilts after vaccination with liver ETEC, and the colostral antibody titers of these gilts were higher than those of controls. Pigs suckling such vaccinated gilts were more resistant than controls to challenge strains were of different pilus types, and it could not be attributed to enterotoxin neutralization by colostrum. In contrast to the live ETEC vaccines given to the pregnant gilts, the liver rough non-ETEC and dead ETEC vaccines stimulated little or no production of antibody against pilu, and the pigs born of these vaccinated gilts remained highly susceptible to challenge exposure. The results support the hypothesis that pilu can be protective antigens in oral ETEC vaccines. It was indicated that in the system reported, protection depended on living bacteria for the production of pilus antigens in vivo or for the transport of pilus antigens across intestinal epithelium.     

Relationship among transmissible gastroenteritis virus antibody titers in serum, colostrum, and milk from vaccinated sows, and protection in their suckling pigs

We studied the antibody responses to transmissible gastroenteritis (TGE) in serum, colostrum, and milk from sows vaccinated with 2 attenuated (1 IM and 1 oral-IM) and 1 nonattenuated live vaccines and the relationship of these responses with the survivability of the sow's suckling pigs after challenge exposure with virulent TGE virus. Contrary to previous studies, the anti-TGE virus-neutralizing geometric mean titers (GMT) in the milk of sows vaccinated with attenuated vaccines at 3 and 5 days of lactation were similar to that found in the colostrum. Colostral and serum antibody titers were highest in sows given 2 injections of the IM attenuated vaccine. Half of the sows given the oral-IM attenuated vaccine did not seroconvert after 2 oral doses. Only sows vaccinated with the nonattenuated live vaccine had milk GMT that remained high for 21 days after farrowing. The linear relationship between colostral GMT and percentage of survivability of suckling pigs challenge exposed at 3 days of age was significant (P less than 0.05), although the relationship between serum GMT and percentage of survivability and the relationship between milk GMT and percentage of survivability were not significant (P greater than 0.10). The linear relationship between colostral (P less than 0.10) or pre-challenge exposure milk (P less than 0.05) GMT and percentage of survivability of suckling pigs challenge exposed at 5 days of age was significant.(ABSTRACT TRUNCATED AT 250 WORDS)     

Relationships among serum immunoglobulin concentration in foals, colostral specific gravity, and colostral immunoglobulin concentration

Postpartum, presuckle, colostrum samples were collected from 100 mares. Colostral specific gravities significantly correlated (r = 0.9) with colostral immunoglobulin (Ig)G concentrations. Foal serum IgG concentrations highly correlated (r = 0.82) with specific gravities of the colostrum each foal ingested. Eight of 48 foals (17%) had serum IgG concentrations less than 400 mg/dl. The dams of these 8 foals had colostral sp gr less than 1.06 and colostral IgG concentrations less than 3,000 mg/dl. Foals had serum IgG concentrations greater than 520 mg/dl 24 hours after parturition, when the colostral specific gravity of the dam was greater than or equal to 1.06. Effects of breed on colostral specific gravity, colostral IgG concentrations, foal serum IgG concentrations, and mare serum IgG concentrations were not significant.     

Passive transfer of antibodies to Shiga toxin-producing Escherichia coli O26, O111 and O157 antigens in neonatal calves by feeding colostrum

To study whether or not passive immunity of neonatal calves against Shiga toxin-producing Escherichia coli (STEC) O26, O111, and O157 was obtained by colostrum administration, serum antibodies in calves after the feeding were determined by enzyme-linked immunosorbent assay (ELISA) in comparison with antibodies in colostrum and sera from donor dams. The highest antibody titers to STEC in colostrum from dams were detected soon after parturition. The antibody titers were found to be elevated in sera of neonatal calves (4-9 hr after birth) orally administered with colostrum with high antibody titers, suggesting that passive immunity of neonatal calves to STEC infection may be obtained by feeding colostrum. These results suggest that colostrum administration to neonatal calves may play an important role in elevating serum antibodies against STEC in neonatal calves.     

Antibody responses in protein-energy restricted beef cows and their cold stressed progeny.

Antibody titers were measured in serum and colostral whey of pregnant beef cows immunized with tetanus toxoid and chicken red blood cells while being fed diets either restricted or nonrestricted in protein and/or metabolizable energy during the last 150 days of gestation. Serum antibody titers were also measured in the colostrum-fed, cold and noncold stressed progeny that were actively immunized with dinitrophenol conjugated to keyhole limpet hemocyanin. In general, there were no major or sustained differences in humoral immune responses to injection of tetanus toxoid or chicken red blood cells between cows fed diets that were adequate or restricted in protein or metabolizable energy. In the few cases where serum antibody titers to tetanus toxoid or chicken red blood cells differed (P less than 0.05) between adequately fed or restricted cows, the differences were no greater than twofold. Anti-chicken red blood cell titers were uniformly low (P less than 0.05) by a magnitude of two to threefold in colostral whey of cows restricted in protein and/or metabolizable energy when compared to titers in cows fed adequate amounts of protein and metabolizable energy. With one exception, neither maternal dietary restriction nor cold exposure had a major effect on the ability of the calves to absorb antitetanus toxoid and chicken red blood cell antibodies from colostrum. The humoral immune responses of all calves to injection of keyhole limpet hemocyanin and dinitrophenol were similar in magnitude.     

Protection against progressive atrophic rhinitis by vaccination with Pasteurella multocida toxin purified by monoclonal antibodies

Pasteurella multocida toxin was purified by affinity chromatography and inactivated by treatment with formaldehyde before use as a single component vaccine against progressive atrophic rhinitis in pigs. Twenty pregnant gilts which were vaccinated twice before farrowing with either low or high doses of the purified toxoid, developed dose-dependent positive serum and colostrum titres to the toxin and, unlike the progeny of 10 untreated control gilts, the offspring of the vaccinated gilts also had serum titres. These titres could be measured in blood samples taken for more than eight weeks from birth for most pigs born to gilts vaccinated with low doses and more than 12 weeks for pigs born to gilts vaccinated with high doses of the vaccine. All the piglets were inoculated intranasally with Bordetella bronchiseptica and toxigenic P multocida. The clinical and post mortem examinations of snouts revealed a significant reduction in the frequency and degree of conchal atrophy in the two groups of pigs from the vaccinated gilts compared with the pigs from control gilts. Clinically 90 per cent of the snouts of pigs born to vaccinated gilts appeared normal whereas only 28 per cent of the snouts of control pigs were not shortened or deviated at eight weeks of age. At slaughter 11 per cent of the pigs born to vaccinated gilts and 81 per cent of the control pigs had severe turbinate atrophy.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of the ingestion of whole colostrum or cell-free colostrum on the capacity of leukocytes in newborn calves to stimulate or respond in one-way mixed leukocyte cultures

OBJECTIVE: To evaluate effects of colostral cells on the ability of neonatal leukocytes to respond in a mixed leukocyte response (MLR) as a means of evaluating specific immune responsiveness. ANIMALS: 10 Holstein calves, their respective dams, and 10 unrelated adult Holstein cows. PROCEDURE: Soon after birth, their calves were fed maternal whole colostrum or colostrum after cells were removed by centrifugation. Responses for leukocytes obtained from calves during the first 5 weeks after birth, their dams, and unrelated cows were measured by use of 1-way MLR as an indicator of immune development. An internal control treatment, proliferation of lymphocytes stimulated with Staphylococcus enterotoxin B (SEB), was also measured. RESULTS: Transfer of colostral leukocytes had a significant effect on the MLR and SEB-induced response in calves. Calves receiving whole colostrum had enhanced responses to maternal and unrelated leukocytes 24 hours after ingestion of colostrum. These responses decreased quickly, indicating direct modulation of the neonatal immune response. Calves receiving whole colostrum effectively stimulated the MLR by 24 hours after ingestion of colostrum. In contrast, calves receiving acellular colostrum did not effectively stimulate the MLR until 2 to 3 weeks after birth. CONCLUSIONS AND CLINICAL RELEVANCE: Ingestion of maternal colostral leukocytes immediately after birth stimulates development of the neonatal immune system. These maternal leukocytes enhance development of antigen-presenting capacity as indicated by their ability to stimulate the MLR and SEB response. The influence of ingested maternal cells on neonatal immunity was also indicated by a reduction in reactivity of neonatal cells to maternal alloantigens.     

Bovine leukemia virus: Duration of BLV colostral antibodies in calves from commercial dairy herds

A study was conducted to determine the duration of colostral antibodies to bovine leukemia virus (BLV) in diary calves from commercial dairy farms. Sera of pregnant dams from four different dairy farms and sera of the calves of these dams were analyzed for BLV antibodies using the agar gel immunodiffusion (AGID) test. Precolostral serum samples were collected from the female calves of known BLV serologically positive dams. Postcolostral serum samples of the same calves were collected on Day 2 and biweekly until 2 consecutively negative AGID tests performed 4 weeks apart were obtained. Subsequently, the biweekly serum samples from each calf were analyzed quantitatively for BLV antibodies with the AGID test. End-point titers were determined using phosphate buffered saline to make two-fold dilutions. A logarithmic transformation of the inverse of the end-point titer was used to determine the regression line of antibody decay for each calf. Estimated weighted regression analysis was used to determine the least-squares regression line for 27 of the 38 calves sampled. The duration of colostral antibodies was calculated as 71 days using the prediction equation. The minium and maximum durations of colostral antibodies were 14 days and 147 days, respectively. The half-life of the antibodies was 36.05 days. Factors affecting the duration of BLV colostral antibodies and the practical applicability of this study were discussed.     

Influence of colostral quality on serum proteins in dairy calves raised in smallholder farms in Thailand

The objective of this study was to analyze the influence of colostral quality on serum proteins in calves. Samples were collected from visited farms in Kasetsart University Veterinary Teaching Hospital at Kamphaeng Saen and Nong Pho Animal Hospital. In total, 35 dairy farms contributed 80 dams and calves’ samples. Colostrum samples from 80 dairy cows and blood samples from their calves were taken to evaluate colostral immunoglobulins (Ig) and immunoglobulin G (IgG), and calf serum protein and IgG. Total colostral Ig, colostral and serum IgG, and serum protein were measured by a colostrometer, single radial immunodiffusion, and refractrometer, respectively. Immunoglobulin G and serum protein concentrations increased in the 1st day after birth, and maximum concentrations were seen in the 2nd day and then decreased in the 7th and 14th days. Average?±?SD total colostral IgG concentrations at calving date and at 1 and 2 days after calving were 93.85?±?33.89, 37.11?±?23.51, and 17.23?±?9.4 mg/mL, respectively. The profile of total Ig and IgG concentrations in colostrum had a similar pattern, with the maximum concentrations obtained in calving date and rapidly decreased thereafter. Low IgG concentrations were seen in the 7th and 14th day after calving. The calves that were fed with high quality colostrum had higher serum protein at 1 day of age, 7.49?±?1.01 g/dL, than calves fed with low quality colostrum, 6.40?±?0.86 g/dL (P?<?0.01). The increase in serum protein after first colostrum feeding of high and low quality colostrum was 1.55?±?1.07 and 0.81?±?0.69 g/dL, respectively (P?=?0.02).     

Epizootiologic investigations of a diarrheic syndrome in fattening pigs

A diarrheic syndrome linked to Clostridium perfringens was observed in fattening pigs. A good correlation was observed between the onset and the severity of diarrhea and the fecal passage of C perfringens enterotoxin. Intestinal fluids from affected pigs had activity comparable with that detected in a purified C perfringens enterotoxin. Seven pigs excreting enterotoxin were shown to develop serum antibodies to C perfringens enterotoxin.     

Effect of chromium tripicolinate supplementation on porcine immune response during the periparturient and neonatal period

A total of 36 gilts were used to assess the effects of Cr tripicolinate supplementation on immune response in sows and their offspring during the periparturient and neonatal period. Gilts were raised from weaning to reproductive age on diets with either 0 (-Cr) or 200 (+Cr) ppb supplemental Cr from CrPic. Subsequently, 22 gilts (9 -Cr and 13 +Cr) in parity 1 and 16 sows in parity 2 (7 -Cr and 9 +Cr) underwent immune status testing. Only sows that completed all procedures in parity 1 were included in parity 2. Sows were immunized with ovalbumin about 3 wk (d 0), and again 14 d later for gilts, prior to anticipated farrowing, and serum was collected on d 0 and at 14-d intervals for a total of four samples. Serum was collected from five to six pigs/litter at 24 h after birth, three or six pigs/litter the day after weaning (25 d of age) in parity 1, and three pigs/litter the day of weaning (20 d of age) in parity 2. Milk was collected at 1 h (colostrum), 6.5 d (early), and 19 d (late) after farrowing. The only effect of Cr on total immunoglobulin (Ig) concentration was on sow serum IgG (21.7 and 24.1 mg/mL for -Cr and +Cr, respectively; P = 0.08) and IgM (11.0 and 12.5 mg/mL; P = 0.06) on d 0. No effect (P > 0.15) of Cr was observed on the IgG antibody response to ovalbumin, but Cr was associated (P < 0.10) with a decreased IgM antibody response to ovalbumin beginning on d 14. In parity 2, colostral total IgG increased (80.6 and 92.4 mg/mL for parity 1 and 2, respectively; P = 0.06), which was reflected in the neonates at 24 h after birth (33.6 and 39.7 mg/mL; P = 0.01) and at weaning (7.3 and 13.3 mg/mL; P < 0.001). Supplementation of Cr tripicolinate had minimal effects on humoral antibody response of the dam or its transfer to the neonate; however, parity greatly influenced the concentrations of immunoglobulins in the milk and their transfer to the neonate.     

Adsorption of colostral antibodies against classical swine fever, persistence of maternal antibodies, and effect on response to vaccination in baby pigs.

OBJECTIVE: To determine kinetics of antibody absorption, persistence of antibody concentrations, and influence of titers on vaccination of baby pigs with a vaccine against classical swine fever (CSF). ANIMALS: 15 sows and their litters. PROCEDURE: Farrowings were supervised. Initial time of suckling was recorded. In the first experiment, blood samples were collected at farrowing, 2 and 4 hours after suckling, and hourly until 10 hours after initial suckling. Samples were assayed for CSF antibodies, using a serum neutralizing (SN) test. A second experiment included 33 baby pigs vaccinated as follows: 10 prior to ingestion of colostrum, 18 between 1 and 4 hours after ingestion of colostrum, and 5 at 12 hours after ingestion of colostrum. Fourteen pigs were vaccinated when 7 weeks old, and 15 pigs were not vaccinated. At 10 weeks of age, pigs were challenge-exposed with virulent CSF virus. Blood samples were collected and assayed for CSF antibodies and p125 antigen and p125 antibodies. RESULTS: CSF antibodies were detected in pigs beginning 2 hours after suckling. Colostral antibodies persisted for > 7 weeks (half-life, 79 days). Vaccination of pigs before suckling provided effective protection from severe disease after challenge-exposure. However, vaccination of neonates with antibody titers was not effective, because 19 of 23 (82%) pigs succumbed after challenge-exposure. All pigs vaccinated when 7 weeks old resisted challenge-exposure, whereas all unvaccinated control pigs succumbed. CONCLUSIONS AND CLINICAL RELEVANCE: Vaccination before ingestion of colostrum conferred good protection against CSF in baby pigs. Vaccination of 7-week-old pigs that had decreasing concentrations of passively acquired antibodies was efficacious.     

Transfer of maternal colostral leukocytes promotes development of the neonatal immune system Part II. Effects on neonatal lymphocytes

It has been established that maternal leukocytes, conditioned by the mammary environment, cross the neonatal gut and circulate in the newborn calf. However, the impact of these cells on the development of neonatal immunity remains to be determined. This study examined the effects of maternal colostral leukocytes on development and maturation of neonatal adaptive immunity by examining the expression of surface markers on neonatal lymphocytes. At birth, neonatal calves were fed whole colostrum, or colostrum that had the maternal cells removed (cell-free colostrum), from their respective dams. Peripheral blood samples were collected at regular intervals over the first 4 weeks of life and lymphocytes were evaluated for surface expression of cellular markers. The results of these studies demonstrated that calves receiving whole colostrum had fewer CD11a positive lymphocytes in circulation during the first 2 weeks of life and this marker was expressed at a lower density than calves receiving cell-free colostrum. In addition, calves receiving whole colostrum also had a higher percentage of lymphocytes expressing the activation markers CD25 and CD26 by 7 days after birth. During the first week of life, lymphocytes from calves receiving whole colostrum had a higher density of MHC class I expression on their surfaces than cells from calves receiving cell-free colostrum. In general, these results indicate that transfer of maternal cells with colostrum allows for more rapid development of lymphocytes and maternal cells appeared to enhance their activation.