Macrophage-activating factor of bovine colostrum promotes phagocytic activity of murine macrophages and bovine phagocytes.

Periparturient dairy cows and their newborn calves are highly prone to health complications. Enhancing the innate immune system of these animals is essential to mitigate the transition period stress and promote their health. Macrophage activating factor (MAF) possess immunomodulatory properties and is believed to enhance immune response. In the present study, the impact of different concentrations (10, 50, 100 ng) of MAF on the phagocytic activity (PA) of murine and bovine phagocytoses was explored. MAF synthesized from IgA of cow colostrum was studied for its effect on the phagocytic index (PI) of cow colostrum macrophages (Mφ) and blood neutrophils (sick and healthy calves) under in vitro conditions. Besides, the impact of MAF on the PI of peritoneal Mφ of healthy and immunocompromised mice was studied. PI of healthy Mφ (mice peritoneal and cow colostrum) and healthy neutrophils (blood calf) increased significantly (P < 0.05) after MAF supplementation. MAF also significantly (P < 0.05) increased the PI of neutrophils and Mφ obtained from sick calf and immunocompromised mice, respectively. Results indicate that colostrum MAF can be used as a potential immune modulator to promote immunity and fight infections in dairy animals.

Development of enzyme-linked immunosorbent assay for early pregnancy diagnosis in cattle.

The prerequisite for enhancing reproductive efficacy and successful calving is an early and accurate diagnosis of pregnancy. A highly sensitive enzyme-linked immunosorbent assay (ELISA) utilizing the second antibody coating technique and the horseradish peroxidase conjugate as a label for the determination of Interferon-stimulated protein, 15 kDa (ISG15) in dairy cows was developed. To validate a neutrophil lysate based ELISA for early pregnancy diagnosis, blood samples from healthy multiparous Karan Fries (KF) cows were collected on day 0 (day of AI), 10, 14, 16 and 21 post artificial insemination. The pregnancy and non-pregnancy in cows were confirmed by plasma progesterone assay, ultrasonography and per rectal palpation. The detection range of the assay was 0.312 to 25 ng/ml with a sensitivity of 0.13 ng/ml. The inter-assay and intra-assay coefficient of variation was 12.1% and 10.1%, respectively. The parallelism for measured and expected concentrations had an r2 value of 0.90 and 0.93, respectively. It was observed that ISG15 concentration was greater (P < 0.01) in pregnant as compared to non-pregnant cows, the greatest being 9.36 ± 0.50 ng/ml on day 16 in pregnant cows. With the use of immunocytochemistry, there was a positive staining for ISG15 with greater staining in the neutrophils of day 16 pregnant cows. The study reveals that ISG15 protein in a neutrophil lysate can be utilized as a biomarker for early pregnancy diagnosis in cows.