Influence of management and genetic merit for milk yield on the oxidative status of plasma in heifers

This study was part of a larger study that addressed whether milk production levels affect health risks in dairy cows as influenced by genetic merit for milk yield and management factors. Plasma samples were collected from 80 Holstein Friesian heifers at 2 weeks pre-partum and at 4 and 8 weeks post-partum in a 2 × 2 × 2 factorial arrangement design with the factors breeding value for milk production (high or low), milking frequency (2 or 3 times a day) and feed energy density (high or low). The following parameters indicative of the oxidative status were measured in plasma: ferric reducing ability of plasma (FRAP), a-tocopherol level, glutathione peroxidase activity (GSH-Px), superoxide dismutase activity (SOD), thiobarbituric acid reactive substances (TBARS) concentration and paraoxonase activity (PON). There was a significant effect of time for FRAP, a-tocopherol, GSH-Px and SOD, indicating changes in the plasma oxidative status around parturition. A high merit for milk yield, three-times-daily milking and especially feeding the high energy feed all stimulated milk production level. However, the influence on oxidative status parameters was minimal. Only the FRAP value was significantly lower in the high compared to the low energy group. Cows seem to undergo some oxidative stress around parturition, which can make them more susceptible to disorders. However, there were no clear indications that breeding value, milk frequency or feed energy level jeopardizes heifers in a way oxidative stress became critica

The effect of <i>Artemia</i> -supplementation of dry foods on growth and survival of <i>Clarias gariepinus</i> (Burchell 1822) larvae

Two experiments were performed in order to determine the effect of supplementation of dry foods with live Artemia nauplii on the growth, survival, rate of cannibalism, and length-weight relationships of Clarias gariepinus larvae. It was found that Artemia -supplementation resulted in a significantly higher growth rate. The "condition", expressed as a length-weight relationship, was likewise altered after supplementation. The survival and rate of cannibalism were not influenced by supplementation. Artemia -supplementation of dry foods was compared with other approaches which are based on the concept of the 'adaptation weight'

Carbon footprint of five pig diets using three land use change accounting methods

The aim of our study was to estimate the carbon footprint (CFP) of five diets for fattening pigs in Europe, using three land use change accounting methods: (i) reference CFP excluding emissions from land use change (LUC); (ii) CFP taking into account emissions from direct LUC and (iii) CFP including total LUC risk. Total LUC risk comprises all emissions from land use change caused by commercial agriculture worldwide, allocated to products based on their land use. We compared a standard feed composition (STAND) with four alternative diets directed at reducing the CFP: in CROP diet we assumed an improved crop production through 10% increased crop yields or 10% decreased fertilizer use; in EU diet we excluded soybean products and used European grown feed ingredients only; in BY-P diet we maximized the use of by-products from food and bio-energy industry; and in N-LOW diet we limited crude protein content to 13% while adding synthetic amino acids. Our analysis showed that the method chosen to account for LUC has a major impact on the CFP of each diet and, therefore, affects mutual comparison of diets. Based on the reference CFP, CROP diet showed the lowest CFP, i.e. -6% compared to STAND. When accounting for direct LUC, EU diet had the lowest CFP, i.e. -15% compared to STAND, by avoiding soybean products. When accounting for total LUC risk, N-LOW diet had the lowest CFP, i.e. -9% compared to STAND. We discussed that each of the considered land use change accounting methods has specific strengths and limitations. As a result, we proposed two decision rules when formulating low CFP diets, i.e.: (1) avoid direct land use change as much as possible; and (2) within this precondition, minimize carbon footprint including total land use change risk to encourage the formulation of diets that combine a low reference carbon footprint with low land use requirements

Potential of life cycle assessment to support environmental decision making at commercial dairy farms

In this paper, we evaluate the potential of life cycle assessment (LCA) to support environmental decision making at commercial dairy farms. To achieve this, we follow a four-step method that allows converting environmental assessment results using LCA into case-specific advice for farmers. This is illustrated in a case-study involving 20 specialized Flemish dairy farms. Calculated LCA indicators are normalized into scores between 0 and 100, whereby a score of 100 is assumed optimal, to allow for a mutual comparison of indicators for different environmental impact categories. Next, major farm and management characteristics affecting environmental performance are identified using multiple regression and correlation analyses. Finally, comparing specific farm and management characteristics with those of best performing farms identifies farm-specific optimization strategies. We conclude that this approach complies with most of the identified critical success factors for the successful implementation of LCA as a decision support system for farmers. Key aspects herein are (i) the flexibility and accessibility of the model, (ii) the use of readily available farm data, (iii) farm advisors being intended model users, (iv) the identification of key farm and management characteristics affecting environmental performance and (v) the organization of discussion sessions involving farmers and farm advisors. However, attention should be paid (i) to provide sufficient training and guidance for farm advisors on the use of the applied LCA model and the interpretation of results, (ii) to evaluate the correctness of the used data and (iii) to keep the model up-to-date according to new scientific insights and knowledge concerning LCA methodology. Keywords Life cycle assessment; Dairy farms; Decision support system; MOTIF

Potential of life cycle assessment to support environmental decision making at commercial dairy farms

In this paper, we evaluate the potential of life cycle assessment (LCA) to support environmental decision making at commercial dairy farms. To achieve this, we follow a four-step method that allows converting environmental assessment results using LCA into case-specific advice for farmers. This is illustrated in a case-study involving 20 specialized Flemish dairy farms. Calculated LCA indicators are normalized into scores between 0 and 100, whereby a score of 100 is assumed optimal, to allow for a mutual comparison of indicators for different environmental impact categories. Next, major farm and management characteristics affecting environmental performance are identified using multiple regression and correlation analyses. Finally, comparing specific farm and management characteristics with those of best performing farms identifies farm-specific optimization strategies. We conclude that this approach complies with most of the identified critical success factors for the successful implementation of LCA as a decision support system for farmers. Key aspects herein are (i) the flexibility and accessibility of the model, (ii) the use of readily available farm data, (iii) farm advisors being intended model users, (iv) the identification of key farm and management characteristics affecting environmental performance and (v) the organization of discussion sessions involving farmers and farm advisors. However, attention should be paid (i) to provide sufficient training and guidance for farm advisors on the use of the applied LCA model and the interpretation of results, (ii) to evaluate the correctness of the used data and (iii) to keep the model up-to-date according to new scientific insights and knowledge concerning LCA methodology. Keywords Life cycle assessment; Dairy farms; Decision support system; MOTIF

Hydrolysate preparation and comparative amino acid determination by cation-exchange and gas-liquid chromatography in diet ingredients

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