Veterinary session

In the synepitheliochorial placenta of the ruminants newborn calves can only acquire passive immune defense through the colostrum of the dam. The synthesis of the endogenous immunoglobulins in the recent literature begins around one week of age. The immunoglobulin uptake can be well monitored on the field by measuring the refraction of the blood serum. We can highlight the individual animals with higher or lower immunoglobulin blood concentration than the normal average with the direct measurement of the IgG.

We sampled 11 newborn holstein-friesian calves, first in 12 hours after birth, then for 7 days in every 12 hours and then on the 10th and 14th day of life. Altogether we collected 160 blood samples. In the blood samples we measured with ELISA method the common concentration of IgG1 and IgG2 molecules, by measuring duplicates at every measurement, with a commercially available ELISA test. Besides the sampling, we gathered descriptive information about the calves, we measured their body weight right after birth, and the exact timepoint of the first 2 colostrum-feeding.

Even though the immunoglobulin supply of the study group was adequate based on the refraction of the serum, no calf loss was detected in the follow-up period. When measuring IgG concentrations significant individual differences occured between certain calves in their immunoglobulin supply before and after the colostrum-feeding, as well as in the area under curve values based on the measurements of multiple days. As a result of the colostrum feeding according to technology there was no difference in average concentrations of IgG between male and female offsprings in the first 48 hours of life, whereas difference was found between twin and singleton calves. Analyzing our data with linear modell, statistically significant (p<0,001) factors were parity, timepoint of measuring, twin pregnancy, lenght of pregnancy, close-up period length, while gender of the calf was not a significant factor (p>0,05).

Evaluating our results, both the measurements before and after the colostrum-feeding, and the AUC calculation indicate significant individual differences between the animals’ immunoglobulin concentrations. This affects the immune system’s reactions to infections in following life stages, therefore this phenomenon requires further researches. The effect of different variables (sex of the calf, twins, etc.) on the absorption of immunoglobulins requires further analysis including further statistical analysis.