Milking procedures, milk flow curves and somatic cell count in dairy cows

Recent availability of electronic mobile milk flow meters allows to study in details milk flow patterns during milking. A normal milk flow profile is characterized by an incline phase, with increasing milk flow, a plateau phase, with steady milk flow, and a decline phase. In these phases milk flow is influenced by many factors: genetic characteristics of the cows, regulation of milking machine and milking routine

Environmental impact of the typical heavy pig production in Italy

The Italian pig sector is mainly focused on the production of heavy pigs used for the traditional dry-cured hams. At slaughter a minimum of 160 kg and 9 months age are required to comply with the production specifications of the ham consortia. Advancing livestock age and increasing fat deposition negatively affect feed conversion ratio, which is one of the main determinants of meat production environmental impact. The aim of the study was to provide a first evaluation of the environmental impact potentials of heavy pig production in Italy through a Life Cycle Assessment approach. Additional objectives were to identify the main hot spots and the most important data gaps in the analysis. A cradle to farm gate Life Cycle Assessment was performed in 6 intensive pig farms located in Northern Italy. Key parameters concerning on-farm activities, inputs and outputs were collected through personal interviews with farmers. The functional unit was 1 kg live weight. Direct land use change was considered in the emissions of imported soybean. The average pig slaughter live weight was 168.7 \ub1 33.3 kg. Environmental impacts per kg live weight were generally higher than those generated in the production of pigs slaughtered at lower weight. The global warming potential was on average 4.25 \ub1 1.03 kg CO2 eq/kg live weight. Feed chain (crop production at farm and purchased feed) was the major source of impact for all the categories and the most important hotspot of heavy pig production. Farm size and reproductive efficiency appeared important factors in the environmental burden of heavy pig production: the largest and most efficient farm (as live weight produced per sow) had impact potentials per kg live weight much lower than those generated in the less efficient farm and similar to the ones reported on pigs slaughtered at a lower weight. The wide range of impact values within farms reveals opportunities for environmental improvements in the production of the traditional heavy pig. There is a need for further data and models on methane enteric emissions and nitrogen excretions above 100 kg of live weight

Milking procedures and milk ejection in Italian Brown cows

The aim of the study was to describe, on the basis of field data, the traits of milk flow curves of Italian Brown cows and to investigate some sources of variation. A total of 1,450 milk flow curves of the whole udder were collected in 81 Italian Brown dairy herds in Lombardy, Italy, using electronic mobile milk flow meters. Parity order and days in milk affected most milk flow traits. Milk flow curves showed some defects dependent on milking management practices: very long machine-on time, long duration of overmilking phase, high percentage of stripping and moderate percentage of bimodality

Milk ejection during automatic milking in dairy cows

Tactile stimulation (manual or mechanical) of the mammary gland causes alveolar milk ejection through a neuro-endocrine reflex arc (Dzidic et al., 2004). Oxytocin is the hormone that induces the contraction of the myoepitelial cells surrounding the alveoli

Effect of season and cow cleanliness on teat apex score and milk somatic cell count

Teat end tissue could change after repeated milkings, resulting in the development of a callous ring around the teat orifice. Factors affecting teat hyperkeratosis include: teat end shape, production level, stage of lactation, lactation number, milking management (especially slow milking and over-milking). Also harsh weather conditions or sudden weather changes can affect the level of teat hyperkeratosis. Somatic cells count in milk is an indicator of udder safety and is influenced by stage and number of lactation, milking procedure, hygiene condition of cubicles and udder, seasonal variations. The aim of the study was to investigate the effects of season and cow cleanliness on teat end condition and somatic cell count (SCC). A sample of 16 dairy farms (80 cows on average) were visited during winter, summer and intermediate seasons (autumn or spring) at evening milking. Hygiene score (Schreiner and Ruegg, 2003) and teat score (Mein et al., 2001) were assessed for each milking cows. Individual SCC and milk quality were obtained from AIA database. Records were Linear Score (LS) per cell count, average Udder hygiene Score (US) and average Teat Score (TS). Two classes of observations were defined on US basis: 642 or >2 score. All data (2161 observations) were analyzed using analysis of variance (proc GLM, SAS). LS showed very low values but with high variability (2.9\ub11.7 on average); TS was very good (1.8\ub10.62). Season had a significant effect (P < 0.001) on milk quality (fat and protein) with higher values during winter in comparison with other season; unexpected no effect was obtained on LS. Season also affected TS with higher value during intermediate seasons. US was significantly higher (P<0.05) during winter in comparison with other seasons. TS were significantly lower (P<0.02) in the first class (based on US) compared to the second one. The study confirmed the great effect of season on milk quality and teat conditions and showed that udder cleanliness had a positive consequence on teat apex condition

CFD Simulation of Mass Transfer Phenomena in Spacer Filled Channels for Reverse Electrodialysis Applications

Salinity Gradient Power via Reverse Electrodialysis is a topic of primary importance nowadays. It allows to get energy from the \u201ccontrolled\u201d mixing of solutions at different salt concentration. The performance of this technology depends on many factors such as: components properties (i.e. membranes, spacers, electrodes), stack geometry, operating conditions and feeds features. Concentration polarization phenomena may significantly affect the actual membrane potential, thus reducing the gross power produced. On the other hand, C-polarization phenomena may significantly be reduced by suitably choosing the hydrodynamic regime within the stack. Such a choice may in turn significantly require higher pumping power, thus reducing the net power output. In this work, carried out within the EU-FP7 funded REAPower project, CFD simulations were carried out in order to study the fluid flow behaviour and mass transport phenomena within spacer-filled channels for SGP-RE technology. The effect of different parameters (channel geometry, feed flow rate, feed solution concentration and current density) on concentration polarization was assessed. The well known unit cell approach was adopted for the simulations in order to reduce their computational requirements as well as to increase the level of detail. Results show that the electrical potential loss due to polarization phenomena should be regarded as little significant in the case of seawater-brine for the operating conditions and geometrical configurations investigated. Conversely, a great attention should be devoted to such phenomena when very diluted solutions are to be employed (e.g. river water)

Flow and mass transfer in spacer-filled channels for reverse electrodialysis: a CFD parametrical study

In reverse electrodialysis (RED) concentration polarization phenomena and pressure drop affect strongly the power output obtainable; therefore the channel geometry has a crucial impact on the system optimization. Both overlapped and woven spacers are commonly commercialised and adopted for RED experiments; the latter exhibit some potential advantages, such as better mixing and lower shadow effect, but they have been poorly investigated in the literature so far. In this work, computational fluid dynamics was used to predict fluid flow and mass transfer in spacer-filled channels for RED applications. A parametric analysis for different spacer geometries was carried out: woven (w) and overlapped (o) spacers with filaments at 90\ub0 were simulated, and Reynolds number, pitch to height ratio (l/h) and orientation with respect to the main flow (\u3b1=0\ub0 and \u3b1=45\ub0) were made to vary. The filament arrangement was found to be a crucial feature; for any given pumping power, higher Sherwood numbers were provided by the w-arrangement. The influence of flow attack angle and filament spacing depends on Reynolds number and filament arrangement. Only the configuration w-\u3b145 avoids the presence of poorly mixed zones near the wires. Among the cases investigated here, the configuration that provided the best mixing conditions was w, l/h=2, \u3b1=45\ub0

How can farming intensification affect the environmental impact of milk production? 

The intensification process of the livestock sector has been characterized in recent decades by increasing output of product per hectare, increasing stocking rate, including more concentrated feed in the diet, and improving the genetic merit of the breeds. In dairy farming, the effects of intensification on the environmental impact of milk production are not completely clarified. The aim of the current study was to assess the environmental impacts of dairy production by a life cycle approach and to identify relations between farming intensity and environmental performances expressed on milk and land units. A group of 28 dairy farms located in northern Italy was involved in the study; data collected during personal interviews of farmers were analyzed to estimate emissions (global warming potential, acidification, and eutrophication potentials) and nonrenewable source consumption (energy and land use). The environmental impacts of milk production obtained from the life cycle assessment were similar to those of other recent studies and showed high variability among the farms. From a cluster analysis, 3 groups of farms were identified, characterized by different levels of production intensity. Clusters of farms showed similar environmental performances on product basis, despite important differences in terms of intensification level, management, and structural characteristics. Our study pointed out that, from a product perspective, the most environmentally friendly way to produce milk is not clearly identifiable. However, the principal component analysis showed that some characteristics related to farming intensification, such as milk production per cow, dairy efficiency, and stocking density, were negatively related to the impacts per kilogram of product, suggesting a role of these factors in the mitigation strategy of environmental burden of milk production on a global scale. Considering the environmental burden on a local perspective, the impacts per hectare were positively associated with the intensification level

Ionic shortcut currents via manifolds in reverse electrodialysis stacks

Reverse electrodialysis (RED) is a blue energy technology for clean and sustainable electricity harvesting from the mixing entropy of salinity gradients. Recently, many efforts have been devoted to improving the performance of RED units by developing new ion-exchange membranes and by reducing the detrimental phenomena affecting the process. Among these sources of “irreversibility”, the shortcut currents (or parasitic currents) flowing through alternative pathways may affect the process efficiency. Although such phenomena occur in several electrochemical processes (e.g. fuel cells, bipolar plate cells and vanadium redox flow batteries), they have received a poor attention in RED units. In this work, a process simulator with distributed parameters was developed and experimentally validated to characterize the shortcut currents and to assess their impact in RED stack performance under different designs and operating conditions. Results showed that shortcut currents can play a crucial role in stacks with a large number of cell pairs when the electrical resistance of the parasitic pathways is relatively low, e.g. configurations with concentrated brines, high resistance membranes, short channels or large manifolds. Future designs of efficient industrial-scale units cannot ignore these aspects. Finally, the model can be easily adapted for the simulation of electrodialysis and other electromembrane processes