Colostral Immunoglobulin Research Articles

Pre-foaling period in Trotter mares – 2: variations of protein fractions in pre-colostrum secretion

RiassuntoIl pre-parto in fattrici di razza Trottatore – 2: variazioni delle frazioni proteiche nella secrezione pre-colostrale. Sono state valutate le frazioni proteiche del pre-colostro e colostro in fattrici di razza Trottatore. I campioni sono stati raccolti dal 6° giorno precedente il parto fino al giorno successivo la nascita del puledro, e sottoposti ad SDS-Page. L’elettroforesi ha evidenziato una specifica dinamica nelle variazioni delle varie frazioni proteiche ed in particolare delle Immunoglobuline che, dal 6° giorno precedente il parto, aumentano in maniera significativa fino alla nascita del puledro. In particolare per le immunoglobuline l’aumento più considerevole è stato registrato tra il 4° ed il 2° giorno precedenti il parto. Inoltre è stata riscontrata una correlazione negativa tra il contenuto ematico di β-globuline e γ-globuline ed il contenuto pre-colostrale e colostrale di Ig (r=-0,33 e -0,34 rispettivamente).

Colostral immunoglobulins absorption in Canchim and Nelore calves

The efficiency of absorption of colostral immunoglobulins was evaluated in five Canchim and seven Nelore calves. They received colostrum pools with concentration of 70.20 ± 6.14 mg/mL through esofageal feeder at 2, 12, 24 and 36 hours after birth. The immunoglobulins concentrations of the pools were estimated through specific gravity and measured by radial immunodifusion. In the blood collection at birth and during the first 70 days of life, the total protein was assayed by biuret method and the immunoglobulins were assayed by radial immunodifusion. Data were analysed as a randomized split-plot statistical model. The highest concentrations of serum immunoglobulins and total protein were observed at 24 hours of age. No significant differences (P>0.5484) were observed for immunoglobulins concentration at 24 hours, with concentrations of 28.80 ± 7.24 mg/mL for Canchim and 27.32 ± 9.54 mg/mL for Nelore. The efficiency for immunoglobulins absorption was not significantly different (P>0.8715) between breeds, 64.04 ± 7.74% for Canchim and 62.30 ± 6.93% for Nelore. The lack of statistical significance persisted until the fourtieth day of life, period of maternal immunoglobulin predominance in the calves blood circulation. In the following period, from 40 to 70 days of age, phase of establishment of the endogenous production of immunoglobulin, differences in the IgG concentrations between the two groups were detected refflecting a possible breed effect difference. The process of colostral IgG absorption by the newborn calves was not affected by breed. The differences between breeds in the calves serum IgG were related to the phase of endogenous production of antibodies.

Minerał bioplex supplementation of diets for cows affects colostrum quality and immunoglobulins in calf blood serum

1. The influence of colostral immunoglobulin concentration in heifer calves’ serum on their health and growth K. Furman-Fratczak, A. Rzasa, T. Stefaniak Journal of Dairy Science CrossRef

Destruction of Mycobacterium paratuberculosis, Salmonella spp., and Mycoplasma spp. in raw milk by a commercial on-farm high-temperature, short-time pasteurizer.

The 2002 NAHM's Dairy Survey indicated that 87.2% of dairy farms in the United States feed waste milk to their neonatal calves. Although cost-effective, this practice can lead to increased calf morbidity and mortality due to ingestion of pathogenic agents. In an effort to reduce the risk of infection, dairy producers are implementing on-farm pasteurization of the waste milk as a control procedure before feeding the milk to calves. In the present study, the efficacy of a commercial high-temperature, short-time (HTST) on-farm pasteurizer unit to destroy Mycobacterium paratuberculosis, Salmonella enterica spp., and Mycoplasma spp. in raw milk was evaluated. Replicate experiments were run for 3 isolates of M. paratuberculosis, 3 serovars of Salmonella (derby, dublin, typhimurium); and 4 species of Mycoplasma (bovis, californicum, canadense, serogroup 7) at 2 different levels of experimental inoculation. In addition, HTST pasteurization experiments were performed on colostrum experimentally inoculated with M. paratuberculosis. After culture of the pasteurized milk samples, no viable M. paratuberculosis, Salmonella, or Mycoplasma were recovered, regardless of species, strain, or isolate. Pasteurization of colostrum was also effective in the destruction of M. paratuberculosis but resulted in an average 25% reduction in colostral immunoglobulin. These results suggest that HTST pasteurization is effective in generating a safer product to feed to young calves.

Avaliação do fornecimento adicional de colostro para bezerros

A imunidade adquirida pelos recém-nascidos depende, no caso de ruminantes, da ingestão e absorção de quantidades adequadas de imunoglobulinas do colostro. A suplementação adicional de colostro pode ser um procedimento que determine a correção de possíveis falhas de manejo. O objetivo do presente trabalho foi avaliar o efeito da suplementação de colostro de superior qualidade imunológica às 12 horas de vida sobre os níveis séricos de proteína total e de imunoglobulinas G, em bezerros recém-nascidos. Foram amostrados 45 bezerros recém-nascidos, distribuídos em dois tratamentos: Tratamento 1 - colostro suplementar após 12 horas de nascimento (10% peso vivo) e Tratamento 2 - controle. Posteriormente, de acordo com a concentração de imunoglobulina G (IgG) sérica adquirida até o momento da suplementação, os animais foram subdivididos em grupos: Grupo 1 (baixo suplementado) IgG< 20 mg/mL; Grupo 2 (alto suplementado) IgG > 20 mg/mL; Grupo 3 (baixo controle) IgG< 20 mg/mL e Grupo 4 (alto controle) IgG> 20 mg/mL. A concentração média de IgG dos "pools" de colostro foi de 68,49 ± 4,21 mg/mL. Nos animais com níveis adequados de anticorpos, independentemente da suplementação, as concentrações foram semelhantes, não sendo verificadas diferenças significativas. Já para os animais com baixa aquisição inicial de anticorpos, verificou-se um processo de compensação em que os animais alcançaram níveis compatíveis aos animais com níveis iniciais normais de anticorpos séricos.

Uptake of Passive Immunity by the Compromized Newborn Animal

Circulating immunoglobulins constitute a key element in the host defence against environmental antigens. Before birth, the fetus is well protected from antigens by the protective barrier of the placenta. Just after birth, the newborn must be able to respond immunologically to a massive invasion of potentially harmful antigens and microorganisms from the surrounding environment. However, the innate immune defence is immature at the time of birth and some passive immunization from the mother is required until an active immune system is developed. Humans and certain other species are born with passive immunity in the form of maternal immunoglobulins transferred across the placenta before birth. In the large farm animals, the placenta does not allow transfer of maternal immunoglobulins before birth. The newborns from these species therefore depend entirely on the transmission of immunoglobulins from mother s colostrum transported across the small intestine immediately after birth. In the large farm animals, intestinal immunoglobulin absorption occurs mainly by a non-specific endocytosis of macromolecules, but the details of the absorption process and its cessation after 1-2 days of colostrum exposure ('intestinal closure') remains poorly understood. Little is known about both the feed and animal factors affecting the macromolecule absorptive capacity of the small intestine. This knowledge is important because a poor absorption of immunoglobulins from colostrum is known to increase neonatal disease susceptibility and mortality. The aim of this review is to provide information about the ability of the 'compromised newborn farm animal' to absorp colostral immunoglobulins. Stressful delivery, premature birth, fetal growth retardation and in vitro embryo production are factors that potentially lead to a compromised newborn animal. The available literature indicates that the ability of the small intestine to absorb macromolecules is severely reduced in response to premature birth and also negatively affected by some forms of metabolic and environmental stress after birth. The ability to take up immunoglobulins is also severely impaired, in both premature and term animals, if immunoglobulins are absorbed from diets other than mother's colostrum. On the other hand, fetal growth retardation, in vitro embryo production, or the birth process does not reduce the ability of the newborn intestine to absorb immunoglobulins from colostrum. Knowledge about both the dietand animal-related factors which influence intestinal immunoglobulin uptake is important to improve the clinical care for both the normal and the 'compromized' newborn farm animal.

Uptake of colostral immunoglobulins by the compromised newborn farm animal.

Neonatal mortality is very high in farm animals (approximately 10%) and disease resistance is greatly influenced by an adequate passive immunisation just after birth. In piglets, foals, calves and lambs, the intestinal absorption of immunoglobulins from their mother's colostrum occurs mainly by a non-specific endocytosis of macromolecules, but the details of the absorption process, and the mechanisms regulating its cessation after 1-2 days of colostrum exposure, remain poorly understood. In both normal and 'compromised' (premature, growth-retarded, hypoxic, lethargic) newborn farm animals, the intestinal capacity to absorb macromolecules is influenced by both diet- and animal-related factors. Thus, macromolecule uptake is severely reduced in response to premature birth and when macromolecules are to be absorbed from diets other than species-specific colostrum. On the other hand, fetal growth retardation, in vitro embryo production, or a stressful birth process are unlikely to reduce the ability of the intestine to absorb immunoglobulins from colostrum. More knowledge about the diet- and animal-related factors affecting intestinal immunoglobulin uptake will improve the clinical care of 'compromised' newborn farm animals. The present text gives a brief introduction to the process of intestinal immunoglobulin absorption in large farm animals and describe some recent results from the author's own studies in pigs, calves and lambs.

Screening of the T- and B-cell antigenicity in neonatal calves of the His-tagged Cryptosporidium parvum antigens CP15, CP15/60, P23 and TRAP-C1.

Cryptosporidium parvum Tyzzer, 1912 is the most commonly found enteropathogen during the first weeks of the life of calves, lambs and goat kids and is considered to be an important agent in the aetiology of the neonatal diarrhoea syndrome. Because of the limited availability of effective drugs, hygienic measures and good management are the most effective disease control measures (de Graaf D.C., Vanopdenbosch E., Ortega-Mora L.M., Abbassi H., Peeters J.E. 1999: Int. J. Parasitol. 29: 1269-1287). Immunoprophylactic control of Cryptosporidium infection is still under development and most studies focused on the passive transfer of colostral immunoglobulins from immunized dams to susceptible neonates, with sporozoite surface and microneme antigens being the target molecules of choice (de Graaf D.C., Spano F., Petry F., Sagodira S., Bonnin A. 1999: Int. J. Parasitol. 29: 1289-1306). Although the key position of CD4 T-cell dependent interferon-gamma (IFN-γ) in acquired immunity against C. parvum (Ungar B.L., Kao T.C., Burris J.A., Finkelman F.D. 1991: J. Immunol. 147: 1014-1022) and C. muris (McDonald V., Robinson H.A., Kelly J.P., Bancroft G.J. 1994: Infect. Immun. 62: 2289-2294) is well documented, the development of a T-cell vaccine to be administered to the newborns themselves has so far received only little attention. In previous papers we described the specificity of the IFN-γ response in the Cryptosporidium-infected bovine host (de Graaf D.C., Peeters J.E. 1997: Int. J. Parasitol. 27: 131-134) and the involvement of CD4 T-cells and a low molecular mass antigen preparation (de Graaf D.C., Walravens K., Godfroid J., Peeters J.E. 1998: Int. J. Parasitol. 28: 1875-1880). Further efforts to identify and purify a single parasite-derived antigen that evokes this immune response failed because of the limitations and constraints of the biochemical approach. Here we report the cloning of four known C. parvum surface or microneme antigens in a pBADTOPO-TA expression vector (Invitrogen, Carlsbad, CA, USA) and the evaluation of their Tand B-cell antigenicity in the bovine host. Cryptosporidium parvum oocysts were purified from faeces of infected calves by biphasic diethyl ether/phosphate buffered saline (PBS) extraction and differential centrifugation on Percol. Sporozoites were liberated in prewarmed excystation fluid (37°C) consisting of 0.75% (w/v in PBS) sodium taurocholate with 0.25% bovine trypsine. Cryptosporidium sporozoite DNA was prepared according to a method optimized for the preparation of genomic DNA from bacteria (Ausubel F.M., Brent R., Kingston R.E., Moore D., Seidman J.G., Smith J.A., Struhl K. 1990: Current Protocols in Molecular Biology. Greene Publishing Associates, Brooklyn). PCR primers were designed for the amplification of the complete coding region (stop codon excluded) of the known C. parvum proteins CP15, CP15/60, P23 and TRAPC1 (see Table 1). Amplification was performed in a PerkinElmer model 9600 thermocycler by 30 cycles of denaturation at 94°C for 60 s, annealing at 51°C for 60 s and extension at 72°C for 4 min, with a supplementary annealing step at 72°C for 20 min after the last cycle to ensure that all PCR products were full length and 3’ adenylated. The resulting amplicons had the expected lengths and were subsequently cloned in pBAD-TOPO-TA according to manufacturer’s instructions. Cloning was confirmed by DNA sequence analyses of the retained pBAD-CP15, pBAD-CP15/60, pBAD-P23 and pBAD-TRAP-C1 clones. Indeed, we found a perfect match

Redistribution of the sheep neonatal Fc receptor in the mammary gland around the time of parturition in ewes and its localization in the small intestine of neonatal lambs.

Maternal immunity is mediated exclusively by colostral immunoglobulins in ruminants. As the neonatal Fc receptor (FcRn) is suggested to be involved in the transport of immunoglobulin G (IgG) in the mammary gland, we cloned this receptor from sheep and analysed its expression in the mammary gland around the time of parturition and also in the small intestine from the newborn lamb. FcRn heavy-chain mRNA was detected (by using in situ hybridization) exclusively in the acinar and ductal epithelial cells in mammary gland biopsies both before and after parturition. Immunohistochemistry revealed that the cytoplasm of the epithelial cells of the acini and ducts in the mammary gland biopsies stained homogeneously before parturition. A remarkable difference was observed in the pattern after lambing, where the apical side of the cells was strongly stained. The presence of the FcRn in the acinar and ductal epithelial cells of the mammary gland, and the obvious change in distribution before and after parturition, indicate that the FcRn plays an important role in the transport of IgG during colostrum formation in ruminants. Immunohistochemical analysis detected a strong apical and a weak basal FcRn signal in the duodenal crypt cells of a neonatal lamb, which have been previously demonstrated to secrete IgG1 in newborn ruminants. The FcRn was not detected in the duodenal enterocytes, which absorb intact IgG from the colostrum in a non-specific manner. These data suggest that FcRn is involved in IgG1 secretion in ruminant epithelial cells.

Bovine Anti- Helicobacter pylori Antibodies for Oral Immunotherapy

Background: Passive immunization with orally administered antibodies against specific pathogens has previously been successfully used therapeutically in both animal and human studies. We employed a similar strategy for experimental treatment of mice infected with the gastric pathogen Helicobacter pylori. Methods: An anti- H. pylori bovine colostral hyperimmune immunoglobulin preparation (BIC) was generated and its efficacy was tested in different in vitro experiments, such as binding to the Lewis b blood group antigen, inhibition of adherence of H. pylori to human gastric mucosa tissue sections in situ and in a haemagglutination assay. The BIC preparation was also given in the drinking water to H. pylori -infected mice. Results: An inhibition of 95% of the binding of H. pylori to Lewis b glycoconjugate was observed in vitro. Furthermore, a blocking activity of almost 90% was observed when the BIC was preincubated with H. pylori bacteria. Finally, the BIC preparation inhibited the haemagglutination of H. pylori and human red blood cells. Seven of 40 (17.5%) mice remained infected in the treatment group as compared with 25 of 45 (55.5%) in the control group. Hence, the cure rate was 66%, P = < 0.001. The mean number of colonies in the antibody-treated mice where eradication was not successful was also reduced ( P < 0.05). In trials using FVB/N transgenic Lewis b expressing mice, a cure rate of 50%-66% was observed. Conclusion: Bovine colostral antibodies against H. pylori can be generated in high titres, inhibit binding in vitro and can eradicate or reduce the number of bacteria in infected mice.

Serum levels of insulin like growth factor-l and total protein in newborn calves offered different amounts of colostrums

The aim of this investigation was to determine the concentrations of insulin like growth factor-I (IGF-I) and total protein in blood serum from calves consuming different amounts of colostrum during the first 32 h of postnatal life, as well as at 7 days old. The experiment involved two groups of calves. The first group was offered the standard amount of colostrum while the second group received half the recommended amount. At birth serum concentration of IGF-I was in the range from 5 to 13 nmol/L. Compared to the initial level there was a marked decrease of mean IGF-I concentration in both groups of calves at 2 h after the first intake of colostrum. Thereafter, the level gradually increased until 20 h of age, more markedly in the group which received the full ration of colostrum. The highest mean IGF-I concentrations were recorded at 20 h in both groups (11.81 nmol/L for group one and 8.96 nmol/L for group two), and were significantly higher than values recorded 2h after the first intake of colostrum. Two hours after the third intake of colostrum, serum concentration of IGF-I dropped in both groups, compared with the value recorded at 20 h. During the time period from 4hto32h after birth, the calves that received the standard amount of colostrum had a significantly higher mean concentration of serum IGF-I than the calves which received an insufficient amount. Calves were born with serum concentrations of total proteins, which were lower than those found for adult animals. Serum protein concentrations in the calves that consumed normal amounts of colostrum increased more rapidly than in the calves that received insufficient amounts of colostrum. Presumably, total protein concentrations increased as a consequence of colostral immunoglobulin absorption. Thus our results indicate that the amounts of colostrum received during the first 32 h of postnatal life had strong effects on the serum concentrations of IGF-I and total proteins. The differences in IGF-I concentrations between the two groups of calves may have been a consequence of greater colostral IGF-I absorption and/or the result of greater absorption of other colostral components, which stimulate endogenous synthesis of this bioactive substance in the tissues of neonatal calves.

Uptake of colostral leukocytes in the intestinal tract of newborn calves

The role of colostral immunoglobulins for the protection of newborn calves has been studied extensively, but little is known about the importance of colostral leukocytes. To study the uptake of colostral leukocytes in the intestine of calves and to determine preferential sites for this uptake, FITC-labelled colostral cells derived from the respective dams were injected into intestinal loops with/without Peyer’s patches of three male Holstein Frisian calves about 5 h post natum. In adjacent loops, PBS was injected as control. Loops were excised after an exposure of 1.5–2 h. FITC-labelled material and cells were detected by the direct immunoperoxidase method in paraplast sections. Twenty-five consecutive sections were evaluated from each localization. Uptake of labelled material and cells was observed in all three calves in the jejunal Peyer’s patch and in two calves in the ileal Peyer’s patch as well. In the jejunal Peyer’s patch, labelled material and cells were present in epithelium, domes and sinuses around lymphoid follicles, whereas in the ileal Peyer’s patch, they were found in the sinuses only. These findings confirm that uptake of colostral leukocytes through the intestinal barrier is possible and that the preferential route of uptake is through follicle-associated epithelium of Peyer’s patches.

Camelid Immunoglobulins and Their Importance for the New‐Born – A Review

Camelid immunoglobulins differ from all other known antibodies and contradict all common theories on antibody diversity. It was demonstrated that up to 75 % of all serum proteins are immunoglobulin G (IgG) molecules lacking light chains. IgG2and IgG3, which only consist of heavy chains, have a low molecular weight which improves their biodistribution and allows a better tissue penetration. Of special importance is the long complementary determining region (CDR) loop which inserts deep into the active site of an enzyme. This binding property was only observed in experiments to gain structural data and to point out the extraordinary value of heavy chain antibodies as biochemical and pharmacological tools. The acquisition and absorption of adequate amounts of colostral immunoglobulins are essential to the health of the neonate. Pre‐colostrum serum IgG levels in camelids are low, with concentrations of 0.26 ± 0.23 mg/ml. Maximum IgG levels are reached after 24 h and kept at a plateau with concentrations of 24.52 ± 8.8 mg/dl. IgG concentrations above 10 mg/ml indicate a successful passive transfer. IgG levels decline after 2–5 weeks and a marked increase is observed between 1 and 2 months, indicating that the immune system of the neonate has started to mature. A number of different tests are available for the assessment of IgG serum levels. Single radial immunodiffusion (SRID) is the only method that specifically measures serum IgG concentrations. It is a reliable assay to test failure of passive transfer (FPT). FPT is a major factor in neonatal mortality in camelids, but very little has been published so far. Therapeutic administration of colostrum will provide passive protection against infectious diseases for a 2–3‐week period of risk, and the intravenous administration of 20–40 ml of camelid plasma helps to combat FPT.

Camelid immunoglobulins and their importance for the new-born--a review.

Camelid immunoglobulins differ from all other known antibodies and contradict all common theories on antibody diversity. It was demonstrated that up to 75% of all serum proteins are immunoglobulin G (IgG) molecules lacking light chains. IgG2 and IgG3, which only consist of heavy chains, have a low molecular weight which improves their biodistribution and allows a better tissue penetration. Of special importance is the long complementary determining region (CDR) loop which inserts deep into the active site of an enzyme. This binding property was only observed in experiments to gain structural data and to point out the extraordinary value of heavy chain antibodies as biochemical and pharmacological tools. The acquisition and absorption of adequate amounts of colostral immunoglobulins are essential to the health of the neonate. Pre-colostrum serum IgG levels in camelids are low, with concentrations of 0.26 +/- 10.23 mg/ml. Maximum IgG levels are reached after 24 h and kept at a plateau with concentrations of 24.52 +/- 8.8 mg/dl. IgG concentrations above 10 mg/ml indicate a successful passive transfer. IgG levels decline after 2-5 weeks and a marked increase is observed between 1 and 2 months, indicating that the immune system of the neonate has started to mature. A number of different tests are available for the assessment of IgG serum levels. Single radial immunodiffusion (SRID) is the only method that specifically measures serum IgG concentrations. It is a reliable assay to test failure of passive transfer (FPT). FPT is a major factor in neonatal mortality in camelids, but very little has been published so far. Therapeutic administration of colostrum will provide passive protection against infectious diseases for a 2-3-week period of risk, and the intravenous administration of 20-40 ml of camelid plasma helps to combat FPT.

Short Communication: Low Levels of Colostral Immunoglobulins in Some Dairy Cows with Placental Retention

A test with 27 Holstein cows divided in two groups was conducted to evaluate the effects of placental retention (PR) on the colostral components. Fat and total protein content were similar in both groups, but immunoglobulins in cows with PR (7.58±6.72g/L) were significantly lower than in cows without PR (15.13±8.56g/L). In contrast, casein levels were higher in cows with PR (38.61±17.05g/L vs. 27.60±12.71g/L) compared with cows without PR.

Passive Transfer of Colostral Immunoglobulins in Calves

Passive transfer of colostral immunoglobulins has long been accepted as imperative to optimal calf health. Many factors, including timing of colostrum ingestion, the method and volume of colostrum administration, the immunoglobulin concentration of the colostrum ingested, and the age of the dam have been implicated in affecting the optimization of absorption. The practice of colostrum pooling, the breed and presence of the dam, and the presence of respiratory acidosis in the calf also may affect passive transfer. Various tests have been reported to accurately measure passive transfer status in neonatal calves. The radial immunodif‐fusion and the enzyme‐linked immunosorbent assay (ELISA) are the only tests that directly measure serum IgG concentration. All other available tests including serum total solids by refractometry, sodium sulfite turbidity test, zinc sulfate turbidity test, serum γ‐glutamyl transferase activity, and whole blood glutaraldehyde gelation estimate serum IgG concentration based on concentration of total globulins or other proteins whose passive transfer is statistically associated with that of IgG. This paper presents a comprehensive review of the literature of passive transfer in calves including factors that affect passive transfer status, testing modalities, effects of failure of passive transfer on baseline mortality, consequences of failure of passive transfer, and some treatment options. Many previously accepted truisms regarding passive transfer in calves should be rejected based on the results of recent research.

Bovine milk antibodies for health.

The immunoglobulins of bovine colostrum provide the major antimicrobial protection against microbial infections and confer a passive immunity to the newborn calf until its own immune system matures. The concentration in colostrum of specific antibodies against pathogens can be raised by immunising cows with these pathogens or their antigens. Immune milk products are preparations made of such hyperimmune colostrum or antibodies enriched from it. These preparations can be used to give effective specific protection against different enteric diseases in calves and suckling pigs. Colostral immunoglobulin supplements designed for farm animals are commercially available in many countries. Also, some immune milk products containing specific antibodies against certain pathogens have been launched on the market. A number of clinical studies are currently in progress to evaluate the efficacy of immune milks in the prevention and treatment of various human infections, including those caused by antibiotic resistant bacteria. Bovine colostrum-based immune milk products have proven effective in prophylaxis against various infectious diseases in humans. Good results have been obtained with products targeted against rotavirus, Shigella flexneri, Escherichia coli, Clostridium difficile, Streptococcus mutans, Cryptosporidium parvum and Helicobacter pylori. Some successful attempts have been made to use immune milk in balancing gastrointestinal microbial flora. Immune milk products are promising examples of health-promoting functional foods, or nutraceuticals. This review summarises the recent progress in the development of these products and evaluates their potential as dietary supplements and in clinical nutrition.

Effect of pasteurization at 76 and 63 degrees C on the absorption of colostral IgG in calves.

The timely ingestion and absorption of colostral immunoglobulin is a critical determinant of neonatal calf health. Calves are born without appreciable concentrations of the serum immunoglobulins needed to protect against pathogenic bacteria, viruses and protozoa (Tyler &amp; Parish, 1995). The beneficial effect of passive transfer of colostral immunoglobulin also extends beyond the neonatal period and persists into juvenile and adult life (Robison et al. 1988; Tyler et al. 1998; DeNise et al. 1989). Calves with failure of passive transfer, defined as serum protein &lt; 50 g/l or serum IgG &lt; 10 g/l, have increased mortality risks that persist until 10 weeks of age (Tyler et al. 1998).Several diseases are potentially spread by the ingestion of colostrum, including bovine leukosis and Johne's disease (Perrin &amp; Polack, 1988; Streeter et al. 1995). In one study 22% of latently infected cows were demonstrated to shed Mycobacterium paratuberculosis in their colostrum (Streeter et al. 1995). Optimal programmes to prevent and eradicate these diseases generally include the provision that calves are given colostrum derived from cows of known negative disease status. Pasteurization or heat treatment of colostrum may provide a mechanism whereby calves are provided with protection against neonatal disease without creating undue potential for infection by chronic, economically relevant diseases.Attempts to heat disinfect colostrum are common in goat herds (MacKenzie et al. 1987). Pasteurization has been demonstrated to be effective against the caprine arthritis–encephalomyelitis virus (Adams et al. 1983; MacKenzie et al. 1987). Although Myco. paratuberculosis appears to resist pasteurization, this form of processing has been demonstrated to decrease the likelihood of positive colostral cultures for Myco. paratuberculosis under experimental conditions (Meylan et al. 1996). Sterilizing the milk and colostrum given to calves is a logical and reasonable strategy to prevent transmission of infectious microorganisms. The potential disadvantage of heat treating colostrum is that the immunoglobulins in colostrum may become denatured (Smith &amp; Sherman, 1994). Pasteurization causes only a slight decrease in the colostral concentration of IgG in cattle (Meylan et al. 1996); however, the biological behaviour of these pasteurized immunoglobulins has not been critically examined. Therefore, we cannot be completely confident that immunoglobulin absorption, persistence in serum and biological activity are unchanged by this processing.The goal of this study was to determine the effect of pasteurization at 76 and 63 °C on the absorption of IgG from colostrum. Should these procedures decrease immunoglobulin absorption, the use of pasteurization in disease eradication programmes would require increased efforts to optimize the passive transfer of immunoglobulin.

Operation-management factors associated with early-postnatal mortality of US foals

Of 7320 equine foals reported born alive during 1997 on 1043 operations that had equids on 1 January 1997, and that participated in the United States National Animal Health Monitoring System (NAHMS) Equine 1998 Study, 120 foals were reported to have died (by either euthanasia or natural causes) within the first 2 days of a live birth. The weighted estimate was 1.7% mortality (standard error=0.5) within the first 2 days of live birth for all foals born on operations in the 28 states included in the study. A multivariable logistic-regression model revealed that foals born in the southern region were more likely to have been reported to have died within the first 2 days of live birth than in the western region. In addition, the following operation-level factors were associated with increased odds of a foal dying within the first 2 days of live birth: not routinely testing newborn foals for adequate absorption of colostral immunoglobulins during the first 2 days of life; adding new resident equids to the operation during 1997; having non-resident equids stay on the operation for 1–30 days during 1997; never requiring an official health certificate (for operations that had non-resident equids stay on the operation for 1–30 days); using something other than straw or hay as the predominant bedding type; and feeding equids a vitamin-mineral supplement/premix with forage and/or grain.

Passive transfer of colostral immunoglobulins in calves.

Passive transfer of colostral immunoglobulins has long been accepted as imperative to optimal calf health. Many factors, including timing of colostrum ingestion, the method and volume of colostrum administration, the immunoglobulin concentration of the colostrum ingested, and the age of the dam have been implicated in affecting the optimization of absorption. The practice of colostrum pooling, the breed and presence of the dam, and the presence of respiratory acidosis in the calf also may affect passive transfer. Various tests have been reported to accurately measure passive transfer status in neonatal calves. The radial immunodiffusion and the enzyme-linked immunosorbent assay (ELISA) are the only tests that directly measure serum IgG concentration. All other available tests including serum total solids by refractometry, sodium sulfite turbidity test, zinc sulfate turbidity test, serum gamma-glutamyl transferase activity, and whole blood glutaraldehyde gelation estimate serum IgG concentration based on concentration of total globulins or other proteins whose passive transfer is statistically associated with that of IgG. This paper presents a comprehensive review of the literature of passive transfer in calves including factors that affect passive transfer status, testing modalities, effects of failure of passive transfer on baseline mortality, consequences of failure of passive transfer, and some treatment options. Many previously accepted truisms regarding passive transfer in calves should be rejected based on the results of recent research.