TOWARDS THE USE OF NEW TECHNOLOGIES FOR NUTRITIONAL SAFETY

In this thesis five experimental studies were reported with the objective to improve the knowledge and provide new solutions for different and important aspects of dairy cow nutrition. The first trial was performed to examine the relationships between blood concentrations of fatty acids (NEFA), β-hydroxybutyrate (BHB) and α-tocopherol during the periparturient period in dairy cows. For the study 131 cows from 4 different farms, 2 in Italy and 2 in Greece were used. We determined blood concentrations of NEFA, BHB, and α- tocopherol at dry-off, at calving, and 30d postpartum. We found a weak correlation between NEFA and BHB throughout the periparturient period. Negative correlations between NEFA and α-tocopherol were highly significant at 30d postpartum and approached the level of significance at dry-off. However, both correlations became nonsignificant following the adjustment of α-tocopherol with cholesterol, indicating that the correlations were a reflection of changes in lipid transport. We found significant negative correlations between BHB and α- tocopherol after adjustment with cholesterol. The aims of the second research presented was to understand the effects of lactic acid bacteria (LAB) inoculation on fermentation products and quality of alfalfa and ryegrass silage and the use of thermal camera and electronic nose to evaluate the silage quality. Wilted ryegrass and alfalfa silage were inoculated with a commercial product containing Lactobacillus Rhamnosus and Lactobacillus Farciminis and stored in triplicate micro fermenters for each treatment. The silos were opened after 2, 5, 30, 60, 90 and 120 days and silages were collected and analyzed. The results obtained showed better acidification of treated silages with pH value lower in both alfalfa and ryegrass silages (P≤0.01). Alfalfa silage has had higher content of lactic acid (P≤0.01) with unexpected higher values of NH4 (P≤0.01). In ryegrass silage the LAB concentration was lower in treated compared to control silage (P≤0.01). Instead no significant difference of LAB concentration was observed between control and treated alfalfa silages. Strong negative correlation between pH and lactic acid 97% (P≤0.01) and positive correlation between pH and LAB concentration 93% (P≤0.01) were observed in alfalfa silage. The LAB concentration was positive correlated with pH value 94% (P≤0.01). Significant but not strong negative correlation was observed between pH and NH4 33% (P≤0.05). Probably due to the good quality of both treated and control silages no differences of temperature were observed. Although, different results were obtained between ryegrass and silage analysis the electronic nose showed promising ability to evaluate the silage quality but further studies will be needed to understand his ability to evaluate the silage quality. In the third experimental trial the combined use of thermal camera and electronic nose was evaluated for rapid assessment of unfavorable fermentations that can occur in a corn silage mass. From April to September, five sampling times were performed to collect silage samples. The thermal camera was used to detect the temperature. For all samples chemical analysis were performed to evaluate the silage quality and was used electronic nose to perform the off-flavors analysis. The silage quality remained constant and no differences were observed throughout the trial. Significant statistical differences were observed between samples with normal temperature and that with higher temperature for pH value (P<0.01), lactic acid (P<0.05). The off-flavors analysis showed the ability of electronic nose to distinguish the strong wrong fermentation. The results obtained showed that the use thermal camera and electronic nose can provide an indication of silage quality in short time and with low cost. Further studies aimed to study the accuracy of both instruments are necessary. The aim of the fourth experimental study was to investigate the physical quality of a selected lot of twenty animal feed samples collected in Italy and Serbia. The samples belonged to different categories and analyzed to assess the flowability, particle size distribution, hardness and durability. Granulation of cattle and pig feed was finer in Italian than in Serbian samples. Flowability of samples from both countries in mash form were rated from fair to good (angle of repose >30°) while granulated samples (pellets and extrudates) had improved flowability (angle of repose < 20°). Extruded products had higher hardness (>10 kg) than pelleted products (<8 kg). Durability of most of the extruded and pelleted products was higher tha 95%. Most of the physical characteristics of the samples responded to recommendations, which showed that the similar practices are in use in both countries. The last research reported in this thesis had the aim to determine the influence of filling level, cutting and mixing time on homogeneity and particle size distribution of a dairy cow total mixed ration (TMR). The mixing wagon was loaded to 40%, 70% and 100% of maximum nominal load (21m3). The cutting time and mixing time were 4, 5 and 6 minutes. Samples of TMR were collected at the beginning, in the middle and at the end of the feeding alley and analysed to evaluate the dry matter (DM), ether extract (EE), crude protein (CP), neutral detergent fibre (NDF), and ash content. At the same time TMR particle size distribution was determined in triplicate for each sampling point by Penn State Particle Separator. The coefficient of variation (CV %) of DM, CP, NDF and EE was used to evaluate the multiple effect of filling level, cutting and mixing time on ration uniformity and differences between the theoretical ration formulated and that provided to dairy cattle. The filling level was the main factor affecting uniformity and differences from theoretical ration, the best results were obtained to 70%. The mixing time had less and different effects uniformity and ration composition. The cutting time showed no effects.