Oxidative stress in cows according to calving season: passive calf immunity and its relationship with colostrum quality.

This study details the relationship between maternal plasma oxidant-antioxidant enzymes with colostrum quality, serum gamma glutamyl transferase (GGT), immunoglobulin G (IgG) and IgM concentrations of calves in the different calving seasons. Holstein breed cows between two and eight lactations and their calves were enrolled in the study. Holstein cows calving in winter (n=45) and their calves (n=45) were assigned to the winter group, while cows calving in summer (n=45) and their calves (n=45) were assigned to the summer group. Samples for malondialdehyde (MDA) and glutathione peroxidase (GSH-Px) were collected on day -21±3 before expected calving and also on calving day (Day 0). IgG and the specific gravity of the colostrum were determined after calving. Serum GGT and IgG and IgM were measured before the feeding, with colostrum, of calves (0 hours) and also in the 24th hour following the feeding of colostrum. Plasma MDA levels at -21±3 and 0 days in the summer cows were determined to be higher. GSH-Px activity was higher in the winter cows. IgG levels and the specific gravity of the colos- trum were also higher in the winter cows. Calf IgG levels at the 24th hour of life were higher in the winter cows. In the winter group, IgM levels at 0 and 24 hours were also higher. While MDA was negatively correlated with IgG, IgM, GGT, IgG and the specific gravity of colostrum, GSH-Px activity had a positive correlation with IgG, IgM, GGT, IgG and the specific gravity of colostrum. The observed differences in plasma MDA, GSH-Px, calf serum IgG and IgM levels, and colostrum quality between both groups suggest a possible seasonal effect. The relationship between maternal oxidant-antioxidant enzymes, colostrum quality, and passive calf immunity revealed that these enzymes could be used as indicators in the evaluation of calf health and colos- trum quality.

Does increased immune response at early postpartum period have a relationship with metabolic markers and subsequent fertility?

The aim of the present study was to investigate blood parameters and subsequent fertility in cows with or without increased postpartum polymorphonuclear neutrophil activity. The study was conducted with 15 Brown Swiss cows between 1-3 lactations. Polymorphonuclear neutrophil activities were assessed at 10±4 days before and after parturition. The cows which maintained their phagocytic and oxidative burst activites compared to the prepartum period were classified as control (CON), and cows which increased phagocytic and oxidative burst activites were defined as increased cellular immune response (ICIR) cows. Energy, protein metabolism markers, hepatic enzymes, blood mineral levels and body condition scores were measured at -10±4, 3±2, 10±4 days relative to parturition. Pregnancy rates, the number of inseminations, and calving to pregnancy intervals were evaluated. The mean non-esterified fatty acid (NEFA) and beta- -hydroxybutyric acid (BHB) concentrations were lower in ICIR cows. Mean serum calcium (Ca) concentrations were in subclinical hypocalcemia level at day 3±2, 10±4 days postpartum in CON cows. Postpartum immune cell functions and NEFA, BHB concentrations were negatively cor- related. The calving to pregnancy interval were longer in the control cows. However, total preg- nancy rates and the number of insemination in both groups were similar. In conclusion, postpar- tum polymorphonuclear neutrophil activity is affected by periparturient metabolic status. Postpartum energy metabolites negatively affected the postpartum cellular immune response. The increased postpartum polymorphonuclear neutrophil activity at early postpartum period is positively related with subsequent fertility in dairy cows.

Characterization of transforming growth factor beta superfamily, growth factors, transcriptional factors, and lipopolysaccharide in bovine cystic ovarian follicles.

The process of transformation of growing bovine follicles into cysts is still a mystery. Local expression of proteins or factors, including transforming growth factor ß, growth factors, and transcription factors, plays a central role in mammals. Therefore, in abattoir-derived cystic ovarian follicles and follicular fluid, the role of some transforming growth factor ß superfamily proteins, insulinlike growth factor-1 (IGF-1) and GATA-4 and GATA-6, were investigated. The relationship between intrafollicular lipopolysaccharide (LPS) and etiopathogenesis of ovarian cysts was also assessed. Data on the preovulatory follicle and the largest follicle (F1) were compared. The number of intrafollicular LPS-positive samples and LPS concentrations were higher in cysts. Immunohistochemical staining was mildly positive for IGF-1, inhibin alpha, and GATA-4 in thecal cells. Staining for anti-Müllerian hormone (AMH), growth differentiation factor-9, bone morphogenetic protein-6 (BMP-6), and GATA-6 was insufficient for their quantitation, and oocytes could not be stained for any of the proteins tested in the cystic follicles. Expression of BMP-6, inhibin alpha, and IGF-1 was moderately higher in granulosa cells of F1 follicles, and all the proteins were moderately expressed in granulosa cells in preovulatory follicles. However, loss of GATA-6 staining was significant in F1 follicles. Intrafollicular progesterone, IGF-1, and AMH concentrations in cysts and F1 follicles were significantly higher than those in preovulatory follicles. Western blot analyses revealed that follicular fluid inhibin-α was strongly expressed, whereas expression of growth differentiation factor-9, BMP-6, GATA-4 and GATA-6 was lower in cysts than in preovulatory follicles. Also, high intrafollicular AMH concentration and low BMP-6 expression were closely associated with cystic degeneration and atresia. In conclusion, immunohistochemical loss of BMP-6 and GATA-6 in the granulosa cells together with high intrafollicular LPS levels may play important roles in disruption of the ovulatory mechanism and steroidogenic reactions in type 2 cyst. Also, high intrafollicular AMH concentration along with low BMP-6 expression may be used as indicators of the bovine degenarative ovarian follicles.