Effect of the first and next calvings of cows and their milk production level on the relationship between dry period length and milk yield and its composition in the subsequent lactation

The effect cow age and milk production level was analized on the relationship between dry period length and milk yield and composition in the subsequent lactation. The GLM and CORR PEARSON procedures of the SAS package were used in the statistical calculations. It is shown that in terms of milk yield in the subsequent lactation, a dry period of 40–60 days was the most favourable. In particular in primiparous cows it was found that in terms of milk yield, shortening the dry period is less favourable than extending it beyond the 41- to 60-day standard. A dry period of 21–40 days can be offered to multiparous cows without significant milk losses in the subsequent lactation. Eliminating or shortening the dry period should exclude cows after first calving. It seems that a dry period of 21–40 days can also be offered to high-producing cows (≥ 8 000 kg milk) because their milk yield, in relation to cows dried for 41–60 days, was lower by 3.5 %. Shortening the dry period has a positive effect on the concentration of basic milk components such as fat and protein, causing them to increase. Dry period length had no effect on milk lactose content

A VEGF-A splice variant defective for heparan sulfate and neuropilin-1 binding shows attenuated signaling through VEGFR-2

Abstract.: The development of functional blood and lymphatic vessels requires spatio-temporal coordination of the production and release of growth factors such as vascular endothelial growth factors (VEGFs). VEGF family proteins are produced in multiple isoforms with distinct biological properties and bind to three types of VEGF receptors. A VEGF-A splice variant, VEGF-A165b, has recently been isolated from kidney epithelial cells. This variant is identical to VEGF-A165 except for the last six amino acids encoded by an alternative exon. VEGF-A165b and VEGF-A165 bind VEGF receptors 1 and 2 with similar affinity. VEGF-A165b elicits drastically reduced activity in angiogenesis assays and even counteracts signaling by VEGF-A165. VEGF-A165b weakly binds to heparan sulfate and does not interact with neuropilin-1, a coreceptor for VEGF receptor 2. To determine the molecular basis for altered signaling by VEGF-A165b we measured VEGF receptor 2 and ERK kinase activity in endothelial cells in culture. VEGF-A165 induced strong and sustained activation of VEGF receptor 2 and ERK-1 and −2, while activation by VEGF-A165b was only weak and transient. Taken together these data show that VEGF-A165b has attenuated signaling potential through VEGF receptor 2 defining this new member of the VEGF family as a partial receptor agonis