Lydia Bommelé

Effect of Vegetable, Fruit And Garden (VFG) Waste Compost on Soil Physical Properties

Compost and other organic amendments have been proven to improve the soil physical quality. In Flanders, vegetable, fruit and garden (VFG) wastes are collected selectively and composted. We studied the effects of the combined application of three different doses of VFG compost and cattle slurry and one treatment with only mineral N applied, during 9 years on a range of soil physical properties: aggregate stability, saturated hydraulic conductivity, bulk density, total pore volume and soil moisture retention. The organic amendments had a significantly beneficial impact (p<0.05) on all soil physical properties, except for the soil moisture retention which was hardly influenced by any of the treatments. The combined application of VFG compost and cattle slurry resulted in the best soil physical conditions. No significant differences were found in soil physical parameters between the unfertilized plots and plots that were fertilized with mineral N.

Pathways of the dominant follicle after exposure to sub-luteal circulating progesterone concentrations are different in lactating dairy cows versus non-lactating heifers.

With the increased use of different synchronization programs in cattle, attention is given to the progesterone concentration during development of the ovulatory follicle. It has been shown that low peripheral progesterone concentrations during follicular development may lead to decreased fertility. To investigate the effect of low progesterone concentrations on the fate of the dominant follicle, a study was conducted where cycles of dairy cows and heifers were manipulated to induce the development of the first dominant follicle without progesterone (PLACEBO) or under sub-luteal progesterone concentrations from a progesterone releasing intravaginal device (PRID Delta(®)). After insertion of the devices, daily follow up was performed by transrectal ultrasonography to identify and measure follicular development and blood samples were taken to determine the circulating progesterone concentration. Follow up was continued until the ovulation of a follicle occurred. After ovulation, the fate of the first dominant follicle was identified as arrested, atretic or ovulatory. Arrest was defined as persistence of the dominant follicle followed by ovulation whereas atresia was defined as regression of the dominant follicle and subsequent growth and ovulation of a new follicle. During PLACEBO treatment, heifers ovulated earlier and smaller follicles in comparison to cows. During PRID Delta(®) treatment, heifers had greater progesterone concentrations compared to cows and arrest of the dominant follicle occurred more in cows in comparison to heifers. In cycles where the dominant follicle was arrested, the ovulatory follicle was larger in comparison to cycles where the dominant follicle was atretic.