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To measure the immunoglobulin G (IgG) concentration in colostrum, milk and serum samples, a sandwich enzyme-linked immunosorbent assay (ELISA) detection system was developed. The system provided high reproducibility and sensitivity for routine diagnostic purposes. The period of fluctuating serum concentrations of IgG was monitored in new-born foals and their mares for a period of 6 weeks postnatum and postpartum, respectively. All foals received colostrum from their mares. The mean IgG concentration in the precolostral mare serum was approximately 19.0 mg/ml and decreased significantly to 13.8 mg/ml within the first 24 h postpartum. The IgG value fell to a minimum of 11.2 mg/ml by day 21 and increased to 21.6 mg/ml by day 42 postpartum. Within the first 4 h postpartum, mean IgG concentrations of 54.5 mg/ml were measured in the colostrum. A significant decrease to 10.1 mg IgG/ml colostrum was then noted 9-12 h postpartum. The mean IgG concentrations in foal serum increased from 0.3 mg/ml (precolostral value) to 9.6 mg/ml within 5-8 h postnatum. After 13-16 h postnatum, the highest IgG value of 15.7 mg/ml was reached. Over time the mean IgG concentration decreased significantly to 7.9 mg/ml at day 35. At the end of the observation period (day 42 postnatum) the mean IgG concentration once again increased to 11.2 mg/ml serum. In addition, the possible influence of various parameters on IgG concentration were examined. No significant influences could be shown by the breed, mare age, number of pregnancies, days of gestation, month foaled, foal sex, or the different farms. Finally, the cumulative incidence of failure of passive transfer (FPT) defined as IgG levels < 4 mg/ml foal serum, and partial FPT (PFPT) at levels ranging from 4 to 8 mg/ml foal serum was determined. From a total of 70 foals, 10.0% showed FPT and 18.6% showed PFPT.

In connection with a study on the prophylaxis of infectious diarrhea with specific egg yolk antibodies, the systemic availability of colostral bovine immunoglobulin G (bIgG) and chicken immunoglobulin Y (IgY) after feeding egg powder was investigated on 26 newborn calves from 23 different farms. Blood was sampled daily and at the same day time from these calves in the first 14 days of life. During the feeding of colostrum, the mean bIgG concentration was highest at day 1 post natum with a value of 9.3 mg/ml serum. Thereafter, the mean bIgG level was reduced continuously to a significant lower concentration of 4.9 mg/ml serum at day 12 post natum and remained nearly constant at 5.2 mg/ml till to the end of the observation period. Total protein concentrations in the serum did not change and plateaued at a mean value of 56.2 mg/ml (SD 11.2). The number of colostrum meals had no significant effect on the mean bIgG concentrations during that period. The individual variation of bIgG concentrations was very high on every day of the sampling period. The mean coefficient of variation was at 52.1 % (SD 5.7). After having described the individual bIgG concentration curves mathematically with a regression curve, two groups with significantly different bIgG elimination constants (k) could be obtained. Thus in one group (n = 10) with k-values of < -0.02 a mean half time of serum bIgG of 24.3 days (SD 4.6) was calculated. In the other group of calves (n = 16) with elimination constants of k > -0.02, a mean half time of 68.5 days (SD 36.7) could be calculated, possibly because these calves started earlier with their endogenous bIgG production. Additionally, to 18 of these calves 20 g egg powder with an IgY concentration of 15 mg/g was fed up to day 14. Calves had a maximal mean IgY concentration of 1.9 micrograms/ml serum if egg powder feeding started already during the first 12 hours of life. Starting at a later time resulted in a significant reduction of IgY levels. For example, the mean initial IgY concentration dropped to 0.035 micrograms/ml serum after having had the first egg powder application between 25 and 48 hours post natum. Using the individual IgY elimination constant derived from a regression analysis (r2 = 0.84) of the IgY concentration curve, a mean IgY half time of 5.0 days (SD 2.5) could be calculated. To prevent the absorption of heterologous antibodies and consecutively, also to prevent a possible systemic effect, egg powder for prophylactic purposes in newborn calves should be fed after the first 24, better 48 hour, post natum. Most important for the prophylactic effect of specific antibodies on infectious diarrhea is not their systemic but their high local intestinal availability.

Studying the prophylactic effects of specific yolk antibodies against diarrhea in newborn calves, also the intestinal absorption of unspecific heterogeneous avian antibodies as well as their effects on the uptake of maternal bovine colostral antibodies (bIgG) was investigated. Two groups of newborn calves received egg powder (16 g or 8 g per day) for the first 10 days of their life beginning with the first meal. A third group was kept as a control without any egg powder in their diet. Blood samples (5 to 10 calves per sampling time) were taken from 123 calves at 6, 12, 24, 48, or 96 h postnatally. With both doses the highest chicken IgG (cIgG) levels (3.1 micrograms resp. 1.2 micrograms per ml serum) have been measured 12 h after birth. These concentrations decreased continuously to the levels of 1.1 micrograms resp. 0.2 micrograms cIgG per ml serum at 96 h postnatally. The uptake into blood at 6 h postnatally has roughly been estimated as approximately 23% (bIgG) and 7% resp. 6% (cIgG) of the IgG dosages given with the first meal. The time-course (6 to 96 h) of the bIgG level in blood was quite stable, plateauing already after 6 h at a mean of 5.9 mg per ml serum. Significant differences between the bIgG levels of calves with yolk antibodies in their diet (6.2 resp. 6.1 mg bIgG per ml serum) and those of the control group (5.4 mg per ml serum) could not be observed.(ABSTRACT TRUNCATED AT 250 WORDS)

SummaryStudies on the prophylactic effect of feeding probiotics, pathogen-specific colostrum antibodies or egg yolk antibodies in newborn calves The prophylactic efficacy of feeding probiotics, specific egg yolk antibodies and specific colostrum antibodies on neonatal diarrhoea was investigated in a field trial with calves, grouped (n = 39/40 per group) according to the following treatments: Group I: feeding no additive; Group II: feeding probiotics (5 g powder/day with Bacillus cereus var. toyoi); Group III: feeding egg powder (10 g/day with specific egg yolk antibodies against rotavirus, coronavirus and Escherichia coli F5); Group IV: feeding colostrum antibodies (10 ml/day containing 1 g bovine immunoglobulins with specific antibodies against rotavirus, coronavirus and E. coli antigens); Group V: feeding egg powder together with probiotics (according to group II and III). The additives were given twice daily with the meal from day 2 to day 14 post-natum. The presence of infectious agents was proved in fecal samples of all calves. Intestinal infections with rotavirus (30.8% of the calves) predominated compared to those with coronavirus (7.1%), E. coli F5 (1.5%) and cryptosporidia (24.2%). In contrast to earlier studies, the manifestation of diarrhoea did not differ significantly between the five groups. Only the growth rate of the calves between day 2 and day 14 of life as a measure of their welfare showed treatmentFspecific differences. The control group (I) showed the lowest body weight gain of about 5.8 kg (SD 5.0), whereas in the treated groups it averaged 6.3 kg (SD 4.1, p = 0,60; group II), 6.8 kg (SD 4.3, p = 0.36; group III), 6.9 kg (SD 4.7, p = 0.61; group IV) and 7.7 kg (SD 4.9, p = 0.08; group V). Considering only the rotavirus-positive calves the body weight gain of the control group (I) was 3.5 kg (SD 4.8) and of the treated groups was 3.8 kg (SD 3.3, p = 0.65; II), 5.0 kg (SD 3.5, p = 0.54; III), 6.6 kg (SD 4.5, p = 0.05; IV) and 6.1 kg (SD 5.0, p = 0.13; V). Obviously, the feeding of antibodies from colostrum or from egg powder does increase the mean body weight gain. The feeding of probiotics alone has nearly no effect. However, in the combination with specific egg antibodies probiotics seem to have a synergistic effect. In serum from the 198 newborn calves the IgG concentration averaged 4.9 mg/ml serum (SD 3.3). From 93 dams of these calves a sample of the first colostrum could be obtained showing a mean IgG concentration of 22.0 mg/ml (SD 11.0). IgG levels in the colostrum and in the serum have been positively correlated (r = 0.37, p < 0.05). Calves with a high intensity of diarrhoea had a significantly (p = 0.01) lower mean IgG serum level (3.7 mg/ml; n = 36; SD 2.5) than calves without diarrhoea (5.6 mg/ml; n = 75; SD 4.0). [ABSTRACT FROM AUTHOR]

The time course of serum concentrations of the bovine IgG1 and IgG2 was monitored in 18 newborn colostrum-fed calves from birth to 11 weeks of age. All calves received three 1.5 l meals of a pooled colostrum with IgGl and IgG2 concentrations of 54.9 mg/ml and 4.2 mg/ml during the first 14 h post-natum. The mean IgG concentrations in calf serum increased from 0.15 mg IgG1/ml and 0.06 mg IgG2/ml (precolostral values) to 9.3 mg IgG1/ml and 0.8 mg IgG2/ml 12 h after the third colostrum meal. Thereafter, IgG1 decreased continuously to a minimum level of 4.9 mg/ml (p < 0.05) at day 28 post-natum and increased to 9.0 mg/ml at day 77. Postcolostral mean IgG2 was lowest (0.5 mg/ml) at day 11 and highest (1.2 mg/ml) at day 77. With these postcolostral IgG concentrations the respective body weight-corrected serum IgG pools approximately were calculated. According to that procedure the initially high IgG pool in the serum at day 2 corresponds to 11.3 and 8.7%, respectively, of the ingested colostral IgG1 and IgG2. The time course of these IgG pools in the serum could be characterized by four typical phases. After a rapid increase from 0.45 g to 22.6 g (12 h after the last colostrum meal) in phase I, the total serum IgG decreased to 17.6 g at day 11 post-natum (phase II) and levelled-out until day 28 post-natum at a value of 17.3 g (phase III). In phase IV total serum IgG increased to 49.3 g at the end of the observation period (week 11). Considering these IgG values, which had been standardized by body weight, the endogeneous IgG production seemed to start clearly (at week 1–2 post-natum) before the increase of the IgG concentration in the serum. To measure these IgG1 and IgG2 concentrations in the serum as well as in the colostrum, sandwich ELISA detection systems were developed which specifically quantify these IgG subclasses in cattle. The specific immunoglobulin Y (IgY) could be isolated from the egg yolk of laying hens which have been immunized with bovine IgG1... [ABSTRACT FROM AUTHOR]