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Abstract

Objective—To determine whether passively acquired antibodies prevent development of a protective immune response to live virus in calves.

Procedures—18 calves.

Procedure—Calves were caught immediately after birth and tested free of bovine viral diarrhea virus (BVDV) and serum antibodies against BVDV. Within 48 hours, 12 calves were fed colostrum that contained antibodies against BVDV and 6 calves received BVDV antibody free milk replacer. Three milk replacer fed and 6 colostrum fed calves were exposed to virulent BVDV2-1373 at 2 to 5 weeks of life when passively acquired serum antibody titers were high. After serum antibody titers against BVDV had decayed to undetectable concentrations (at 7 to 9 months of age), the 3 remaining milk replacer fed calves, 6 colostrum fed calves previously exposed to BVDV2-1373, and 6 colostrum fed calves that had not been exposed to the virus were inoculated with BVDV2-1373.

Results—Passively acquired antibodies prevented clinical disease in inoculated colostrum fed calves at 2 to 5 weeks of life. Serum antibody titers did not increase in these calves following virus inoculation, and serum antibody titers decayed at the same rate as in noninoculated colostrum fed calves. Inoculated colostrum fed calves were still protected from clinical disease after serum antibody titers had decayed to nondetectable concentrations. Same age colostrum fed calves that had not been previously exposed to the virus were not protected.

Conclusion and Clinical Relevance—A protective immune response was mounted in calves with passive immunity, but was not reflected by serum antibodies titers. This finding has implications for evaluating vaccine efficacy and immune status. (Am J Vet Res 2003;64:65–69)

Full access
in American Journal of Veterinary Research

Summary

Effects of farm management, breed, mare age, gestation duration, and climatologic factors on colostral specific gravity, colostral IgG concentration, and foal serum IgG concentration were evaluated. Climatologic variables measured were daily maximal, minimal, and mean air temperature, precipitation, average relative humidity, and total solar radiation. Presuckle, postpartum colostrum samples were collected from 140 Standardbred, 94 Thoroughbred, and 59 Arabian mares from January through June during 1985 and 1986. Thoroughbred (farm A, n = 61; farm B, n = 33) and Arabian (farm C, n = 45; farm D, n = 14) mares were located in Ocala, Fla; Standardbred mares (farm E) were in Montgomery, NY. Mares from farms A, B, D, and E foaled in box stalls, and mares from farm C foaled in sand paddocks. Mares with premature lactation >12 hours were not included in the study. Foals were clinically normal at birth and suckled colostrum without assistance within 2 hours of parturition. Specific gravity of presuckle colostrum samples was measured by use of an equine colostrometer. Blood samples were collected 18 hours after parturition from 253 of the 293 foals (n = 45, 25, 32, 13, 138 on farms A through E, respectively) to determine serum concentration of IgG. The IgG concentrations in colostrum and serum were measured by single radial immunodiffusion. Data were analyzed by multiple regression or Χ2 analysis.

The most important determinants of foal serum IgG concentration were the IgG content and specific gravity of presuckle colostrum samples (P < 0.0001). Colostral IgG concentration was highest in mares 3 to 10 years old, and mean values were higher in Thoroughbred and Arabian mares than in Standardbred mares (P < 0.01). Failure of passive transfer (serum IgG concentration <400 mg/dl) was observed in 13% of the foals, and highest prevalence was in foals that suckled mares >15 years old (P < 0.001). Seventy percent of foals whose dams were <15 years old had serum IgG concentration >800 mg/dl, whereas only 45% of foals whose dams were >15 years old had serum IgG concentration >800 mg/dl. Farm management affected passive transfer of IgG; mares from farm D had the highest mean colostral specific gravity, but their foals had the lowest mean serum IgG concentration (P < 0.01). Arabian foals born between 335 and 345 days of gestation had the highest mean serum IgG concentration; values decreased in bell-shape fashion as gestation duration increased or decreased. Similar pattern was observed for colostral specific gravity and IgG concentration of Arabian and Thoroughbred mares. Total solar radiation was the only climatologic variable that affected IgG concentration in colostrum or foal serum. Only horses on farm E (temperate environment) were affected. As total solar radiation increased, IgG concentration in colostrum and foal serum increased. These results indicate that foals from dams >15 years old, foals whose dams have a colostral specific gravity <1.06, and foals born in cold, wet environments may need supplemental colostrum to prevent failure of passive transfer. Farm management, premature birth, and birth after day 345 of gestation may adversely affect absorption of colostral IgG in foals.

Free access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine the effects of porcine mammary secretions on polymorphonuclear (PMN) leukocyte function and to relate concentrations of estradiol-17β and cortisol in mammary secretions to PMN cell function.

Sample Population—Mammary secretions from 10 healthy sows and blood PMN leukocytes from 27 healthy sows.

Procedure—Mammary secretions were collected within 24 hours after parturition (colostrum) and 12 to 13 days later (milk). Chemoattractant properties were assessed by use of a cell migration assay. Phagocytic capacity of PMN cells in colostrum and milk was assessed by recording chemiluminescence following phagocytosis of Escherichia coli or zymosan. Estradiol-17β and cortisol concentrations were determined by use of radioimmunoassays.

Results—Chemoattractant properties of colostrum and milk were significantly greater than that of zymosan-activated serum. However, chemoattractant properties did not differ significantly between the 2 types of secretions. The capacity of PMN cells in colostrum to phagocytose either zymosan or E coli was less, compared with cells in milk, and the ability of cells in either type of mammary secretion to phagocytose E coli was greater than the ability to phagocytose zymosan. Concentrations of estradiol-17β and cortisol were greater in colostrum, compared with milk. No clear relation was evident between PMN cell activity and hormone concentrations in mammary secretions.

Conclusions and Clinical Relevance—Although chemoattractant properties of colostrum and milk did not differ, the phagocytic capacity of PMN cells in colostrum was significantly less than that of cells in milk. This may predispose sows to coliform mastitis during the early postparturient period. (Am J Vet Res 2001;62:1250–1254)

Full access
in American Journal of Veterinary Research

at birth and fed 1.5 L of pooled frozen bovine colostrum that had been screened by ELISA for minimal antibodies against BRSV. Ingestion of this colostrum ensured that the calves were seronegative for BRSV at the time of first vaccination, but had

Full access
in Journal of the American Veterinary Medical Association

. Materials and Methods Animals —Colostrum-deprived Holstein bull calves were procured from a local dairy at birth. Calves were raised for the first 2 weeks after birth in individual crates. Calves were fed a commercial infant formula a for the first 48

Full access
in American Journal of Veterinary Research

Summary

Chicken egg yolk IgG can be absorbed and transferred as efficiently as colostral antibodies in the blood of neonatal pigs. Egg yolk IgG has a half-life of 1.85 days in newborn pig serum. This is shorter than the reported half-life (12 to 14 days) of homologous IgG in serum of pigs. Similar to colostral antibodies, egg yolk IgG absorption from intestine ceased at about 34 hours of age, after a logarithmic decrease in absorption rate from birth. Egg yolk IgG absorption inhibition time in the gastrointestinal tract took 1.73 hours to decrease by half. Egg yolk IgG was protective against experimentally induced diarrhea in pigs when it was administered at high dose, and multiple dosing was instituted. Adverse effects were not observed when chicken egg yolk IgG was administered orally to pigs.

Free access
in American Journal of Veterinary Research

Abstract

Objective—To determine concentrations of IgA and IgG subclasses in serum, colostrum, milk, and nasal wash samples of adult horses and foals.

Animals—Seven 2-year-old Welsh ponies, 27 adult mixed-breed horses, and 5 Quarter Horse mares and their foals.

Procedure—Serum was obtained from ponies and adult horses. Colostrum and milk were obtained from mares and serum and nasal wash samples from their foals immediately after parturition and on days 1, 7, 14, 28, 42, and 63. Nasal wash samples were also obtained from 23 adult horses. Concentrations of immunoglobulins were determined by use of inhibition ELISA. To determine transfer of maternal isotypes to foals, concentrations in colostrum and milk were compared with those in foal serum. Serum half-lives of isotypes in foals were also determined.

Results—IgGb was the most abundant isotype in serum and colostrum from adult horses, whereas IgA was the predominant isotype in milk. The major isotype in nasal secretions of adult horses and foals ≥ 28 days old was IgA, but IgGa and IgGb were the major isotypes in nasal secretions of foals ≤ 14 days old. Serum half lives of IgGa, IgGb, IgG(T), and IgA in foals were 17.6, 32, 21, and 3.4 days, respectively.

Conclusions and Clinical Relevance—The early immunoglobulin repertoire of neonatal foals comprised IgGa, IgG(T), and IgA; endogenous synthesis of IgGb could not be detected until 63 days after birth. The restricted repertoire of immunoglobulins in foals may influence humoral immune responses to vaccination. (Am J Vet Res 2000;61:1099–1105)

Full access
in American Journal of Veterinary Research

Abstract

Objective

To confirm that ivermectin fed for 7 days to pregnant sows controls transmission of Strongyloides ransomi larvae to pigs via the colostrum or milk.

Animals

24 mixed-breed sows.

Procedure

The sows were infected with 250,000 S ransomi larvae on 3 occasions (days 63, 64, or 65, days 71 or 73, and days 78, 79, or 80 of gestation). Eight sows received ivermectin at a dosage of 100 μg of ivermectin/kg of body weight/d from days 92 to 99 of gestation, and 8 sows were treated from days 103 to 110 of gestation; 8 remaining sows received unmedicated vehicle. Numbers of S ransomi larvae were counted in samples of colostrum or milk collected 1, 2, and 7 days after parturition. At 7 and 14 days after parturition, fecal samples were collected from each sow and from 4 pigs from each litter for determination of nematode egg counts; at the latter date, pigs were euthanatized and necropsied for worm counting.

Results

Pigs born to ivermectin-treated sows had significantly (P < 0.01) fewer adult S ransomi than did those born to control sows; efficacy was 100%. Treated sows had significantly (P < 0.05) fewer S ransomi larvae in colostrum/milk samples taken 1, 2, and 7 days after parturition than did control sows; efficacy was 100%, with the exception of 1 S ransomi larva found in a milk sample from 1 treated sow at 2 days after parturition.

Conclusion and Clinical Relevance

Ivermectin fed to sows during the last third of gestation at a dosage of 100 μg/kg/d for 7 consecutive days is highly efficacious for control of transmission of infective S ransomi larvae to pigs via colostrum or milk. (Am J Vet Res 1998;59:277–279)

Free access
in American Journal of Veterinary Research

Summary

Serum interleukin-6 (il-6) concentration was measured in 11 colostrum-fed (cf) and 8 colostrum-deprived (cd) 2- to 3-day-old foals after foals were infused with lipopolysaccharide (lps; Escherichia coli O55:B5 endotoxin, 0.5 µ.g/kg of body weight in sterile saline [0.9% NaCl] solution). Four cf and 2 cd foals were given saline solution alone. Serum il-6 concentration was estimated by use of an in vitro proliferative bioassay, using the IL-6 dependent B.13.29 clone 9 cells. Interleukin-6 concentration increased in all lps-infused foals, and geometric mean serum il- 6 concentration was significantly higher in cf than cd foals 30 and 90 minutes after infusion. Both lps- infused groups had multiple spikes of mean il-6 concentration that peaked at 120 minutes in cf foals and 150 minutes in cd foals. Results indicated that il-6 is produced in neonatal foals in response to lps infusion. Furthermore, colostrum deprivation resulted in longer times to peak mean serum il-6 concentration and tended to reduce serum il-6 concentration in neonatal foals.

Free access
in American Journal of Veterinary Research

Abstract

Passive protection provided by sows inoculated with the virulent Miller strain of transmissible gastroenteritis virus (tgev), or the isu-1 strain of porcine respiratory coronavirus (prcv), or both was evaluated in nursing pigs challenge exposed with virulent tgev. Four sows (group B) were inoculated with prcv oro- nasally twice at 4 and 2 weeks before parturition; 1 sow (group C) was inoculated similarly, but in 2 subsequent pregnancies; and 2 sows (group D) were oronasally primed with prcv at 4 weeks before parturition, and 2 weeks later were administered a booster inoculation of virulent tgev. Two additional sows (group E) remained uninoculated and served as seronegative controls, and 1 sow (group A) that had been naturally infected with tgev served as a seropositive control. The degree of passive immunity transferred by these sows to their litters was assessed by challenge exposing the pigs of sows in groups BE (only the second litter of group C) with virulent tgev at 3 to 5 days of age. After challenge exposure, clinical signs of infection and mortality were noted and fecal and nasal shedding of virus was assessed by EUSA. The IgA, IgG, and IgM antibody titers to tgev were quantified in colostrum and milk of the sows by use of an isotype-specific monoclonal antibody-capture ELISA, using biotinylated monoclonal antibodies against each porcine isotype as detecting reagents. A plaque-reduction assay was used to quantify neutralizing antibody titers in serum, colostrum, milk, and fractionated whey (IgG and IgA/ IgM). In the sow naturally infected with tgev (group A), there was a pronounced decrease in IgG antibody titers to tgev in the transition from colostrum to milk, and IgA tgev antibodies became predominant, with high titers maintained throughout lactation. The 4 group-B sows partially protected their pigs after tgev challenge exposure; mean mortality was 67%, compared with 100% in pigs suckling the 2 tgev seronegative control sows (group-E fitters). Although IgA tgev antibodies were detected in colostrum and milk of group-B sows, IgG tgev antibodies were the most abundant. The sow of group C had a marked increase in IgA tgev antibody titers in colostrum and milk after reinoculation with prcv during the second pregnancy, before tgev challenge exposure of the fitter. Its pigs were passively protected to a high degree after tgev challenge exposure (27% litter mortality). The sows in group D, primed with prcv and boosted with tgev, provided the best passive protection after tgev challenge exposure of their pigs. Not only fitter mortality (27%) but also morbidity was reduced, compared with those factors for the other challenge- exposed fitters, and the sows did not become ill. In these swine, the high degree of passive protection observed could not be associated with the presence of only IgA tgev antibodies in the milk, but high IgM tgev antibody titers also were detected in colostrum and milk. Results of this study suggest that prcv- inoculated sows are able to partially protect their pigs from tgev challenge exposure and, on the basis of preliminary data, the degree of protection may increase after multiple prcv exposures or after secondary exposure to tgev during pregnancy. Also, an IgA respiratory tract-mammary gland link may exist as evident by the low titer of IgA tgev antibodies in the milk of prcv-inoculated sows, but may not be as efficient in inducing lactogenic IgA immunity as is the gastrointestinal tract-mammary gland link.

Free access
in American Journal of Veterinary Research