Soil compaction is the compression of soil particles in a lower volume as a consequence of the reduction of the spaces existing among the particles themselves. This phenomenon is caused by natural forces and, above all, human ones. In order to estimate the field damages that can be caused by the traffic of agricultural machines, the load and the mean pressure applied by the tyres onto the soil can be measured. The research aim is to determine the pressure applied by each considered tractor onto the soil, in order to evaluate the effect of the traffic of tractors onto the soil itself. A total of 783 wheeled tractors manufactured and marketed in the last 35 years (1979-2014) were investigated. Data like construction year, manufacturer, model, power, total weight, weight (load) on the front and rear axle, wheelbase, front and rear type of tyres, as well as the tyre specifications, were collected. The mean pressure applied by each tractor onto the soil was computed by dividing the load applied on each tyre by its contact area. In order to reduce the pressure applied by agricultural machines onto the soil, the vehicle mass and, therefore weight, has to be reduced, or the tyre contact area on the soil has to be increased. Farmers can easily increase the tyre contact area, by decreasing the tyre inflation pressure or increasing the tyre width, i.e. mounting tyres having a larger section width, or Terra Tyres, or twin-tyres. Over the last 40 years: the mean power of mechanical four wheel drive (MFWD) tractors and four wheel drive (4WD) (isodiametric tyres) tractors increased, while that of two wheel drive (2WD) tractors remained constant; the power and the total weight increased, while the weight-power ratio decreased. Practically the reduction of the mean pressure on the soil resulted rather limited, meaning that tractor manufacturers have not bore in mind soil compaction.

EU countries agreed upon increasing the use of renewable energy, which strongly stimulates usage of biofuels. Biomass ash is generated as a residue product in large volumes as a result of biomass combustion. Heavy metal content in the ashes is the main hinder for further ash utilization in agriculture, forestry and construction sector. Aim of this study was to assess potential of biomass ash to be used as pavement base, also to evaluate risks associated with heavy metals contained in ash as well as their leaching possibility. Ash elemental analysis showed that biomass was burned efficiently, and organic carbon content in ash samples was below 2%. The limiting trace element was cadmium, which concentration in ash exceeded maximum permissible value, restricting ash recycling in forestry or agriculture. Leaching test showed that there is no threat to the environment when such waste material is used in road construction as base layer. All leaching values were below permissible concentrations or even below ICP detection limits. Compaction tests of layers made from gravel/ash mixtures revealed that biomass ash could be successfully used in road construction industry. Results showed that the strongest mixed layer was from 80% gravel and 20% ash. The compaction of this mixture was the highest, only the second best result showed pure 100% gravel, while the least compacted was 50% ash and 50% gravel mixture.

Many abandoned (term "hostless" by 2010) hydraulic structures have been exploited for over 30 years, so due to the aging of materials, the probability of failures and accidents increases. Due to the insufficient exploitation in several dams the breakdowns occurred, some ponds in damaged dams have been emptied. It is known that no comprehensive research on technical state evaluation of abandoned hydraulic structures in Lithuania has been carried out. It becomes clear that practical, scientifically based algorithms for the technical state evaluation of abandoned hydraulic structures are needed in order to assess the impact of environmental factors on the technical state, safety, reliability and durability of structures. This paper focuses on the presentation of investigation results of technical state evaluation of 4 abandoned hydroschemes in Raseiniai distr. Due to the noticed significant defects and deteriorations all 4 hydroschemes are in critical state, the pond in Gyliai IV is emptied, the demolition of reinforced concrete structures should be applied in this object.

peer reviewed | The pig sector annually contributes about 78 % of the total meat production in Vietnam. The government of Vietnam has implemented numerous policies to promote the development of the pig industry. It strongly emphasizes the production with little attention paid to marketing. Bac Giang is one of the provinces with the highest pig population in Vietnam. Pig production contributes up to 52% of the gross output of the livestock sector of the province. One of emerging problems is the majority of pig farmers are limited in market power and there is low income from pig production. This study aimed to analyse the pig value chain in Bac Giang province, identify main factors affecting farmers‟ market power and income in the chain, and propose relevant policy implications to enhance farmers‟ market power and income. It was found that pig collectors and pork retailers are the dominant players in the chain in terms of their strong influence on prices due to their coordination role in directing supply of pigs and carcass to market. Numerous factors affecting farmer‟s market power and income are weak collective action of farmers in production, lack of collective marketing, volatility of pig price, lack of formal contract farming, consumers‟ food safety concern, high price of feed and animal disease. Enhancing farmers‟ market power depends on farmers and public authority‟s involvement in the various strategies of implementation. Some policy implications focus on the improvement of farmer collective action and government actions related to supporting farmer collective action.

peer reviewed | Un dosage sérologique des glycoprotéines associées à la gestation chez les caprins (caPAG), par la technique ELISA "sandwich" a été mis au point pour le diagnostic précoce de la gestation chez la chèvre naine de Guinée. Des anticorps anti-caPAG produits chez les lapins ont été biotinylés et titrés pour permettre ce dosage dans le sérum de chèvres. Des échantillons de sang ont été collectés tous les 7 jours chez 6 chèvres après induction et synchronisation des chaleurs puis saillie pour doser la caPAG sérique. Les densités optiques ont été lues à 492 nm sur un lecteur automatique ELISA pour établie le profil de la caPAG. Le taux de caPAG augmente rapidement pendant le premier tiers de gestation pour atteindre un pic (117 ng/ml) vers le 91e jour puis baisse pour atteindre environ 50 ng/ml le 121ème jour et reste plus ou moins stable jusqu’à la parturition où il chute progressivement pour atteindre environ 12,5 ng/ml trois semaines après. Cependant ce taux reste encore élevé dans la circulation maternelle 3 semaines après la parturition. La PAG caprine est détectable dans le sérum par cette technique à partir du 28ème jour de gestation avec une sensibilité de 100 %. Le 21ème jour, la sensibilité est faible (66,7 %). Ce test offre donc une alternative pratique au laboratoire, précoce et fiable pour le diagnostic de la gestation à partir du jour 28 après insémination chez la chèvre naine de Guinée.

peer reviewed | Hays of graminaceous species (I. cylindrica and S. palidefusca) of low quality (30g/kg dry matter (DM) Crude Protein (CP) was offered to 16 goats (8 males, 8 females), alone or with one of three tropical leguminous plants (153g/kg, 104g/kg and 305,6g/kg DM respectively). The supplementation increased total DM, energy and CP intakes and consequently allowed the weight of the goats to increase. The fodder of L. leucocephala gave the best results, while that of S. guianensis gave the lowest. Fodder of A. rhomboideus is a potential nitrogen-source supplement for poor fodder in the dry season for ruminants.

peer reviewed | Lactation persistency (LP) has been neglected over time in genetic evaluations of dairy goats. The main reason for this is the difficulty to infer about the lactation curve shape. However, some lactations models such as Wood seem to be appropriate to provide persistency estimates under biological viewpoints. The aim of this study was to fit the Wood lactation model as well as to calculate and evaluate LP as selection criteria in dairy goat breeding programs through genetic parameters estimates. A total of 23,265 first lactation test day milk yield observations from 900 animals were used. The Wood random regression model was primarily fitted to estimate the lactation curve parameters (a, b and c), and then LP and total milk yield (TMY). Posteriorly, a multi-trait animal model was fitted considering simultaneously LP and TMY. The heritability estimates were 0.31 and 0.04 for TMY and LP, respectively. Based on the low LP heritability, selection based only on this trait might be inefficient. In conclusion, the results of this study suggests that selecting for high milk yields might result in high persistency since the genetic correlation between LP and TMY was moderate (0.39).

peer reviewed | In genetic breeding programs, body weight is measured overtime, and is historically the main source of information from animals. Random Regression Models (RRM) have been frequently used in beef cattle evaluations, but can significantly contribute to genetic progress in all species of economic importance. To our knowledge, there are no scientific studies using RRM to evaluate Polled Nellore. We aimed to estimate genetic parameters by using RRM as a way to provide basis for guidelines development of growth of this breed. The models included direct genetic and maternal genetic, permanent environmental and maternal permanent environmental as random, contemporary groups as fixed and cow age at calving as covariate effects. The residual variances were modeled from homogeneous to six heterogeneous classes. The model of orders 4, 2, 2 and 2 for direct additive genetic, maternal additive genetic, maternal permanent environmental and permanent environmental had greater performance according to statistical criteria (smaller AIC and BIC values). Estimates of direct additive genetic increased over time (range 0-5,000 Kg2) and the heritability estimates were up to 0.73 along the growth curve. Maternal heritability estimates were low, with values close to zero. Genetic correlations between ages ranged from moderate (0.60) to high (0.97). Random regression models may be an alternative to describe the changes in body weight variances throughout lifetime.

peer reviewed | La République Démocratique du Congo (RDC) souffre, à l’instar d’une majorité de pays africains, d’une précarité alimentaire conséquente. Le développement du secteur de l’élevage y est une pièce importante de la stratégie de lutte contre cette insécurité alimentaire, par l’apport de protéines de haute qualité aux populations pauvres ainsi que plus globalement par la création de richesses et la diversification du secteur agricole. A ce titre, le secteur avicole offre incontestablement, par son cycle de production court, une solution rapide et abordable par le plus grand nombre. Cette étude aborde les contraintes à la production de la poule locale au Bas-Congo. Plusieurs facteurs y sont identifiés, tels que les pathologies, l’alimentation, l’habitat et les prédateurs. L’amélioration de la situation économique et nutritionnelle des paysans de la Province du Bas-Congo peut être envisagée en améliorant le potentiel de production des poulets de race locale. Afin d’y arriver, une attention particulière doit être accordée à une alimentation équilibrée et une meilleure conduite générale de l’élevage, incluant un accès aux soins vétérinaires. L’amélioration génétique des races locales est également une voie envisageable, pour autant que l’adéquation entre l’animal et le cadre de son élevage soit respectée.

International audience | This paper deals with designing a cheap and easy-to-attain method to replace weighing for estimating the body mass of goats. Several models on the relationship of heart girth (HG) to live weight (LW) were evaluated using Creole of Guadeloupe goats (376 males and 258 growing females). The best fit was obtained with a Gompertz model: LW = 155 * exp(-7.91 * exp(-0.0215 * HG)), which provided an adjusted R² = 0.98 and a 95% confidence interval of the prediction values below 5% within most of the LW range. The LW of breeding goats (420) was fitted by the following quadratic model taking into account the HG and paunch girth (PG): LW = -28.1 + 0.539 * HG + 0.00221 * PG², which provided an adjusted R² = 0.95 and a 95% confidence interval of the prediction values below 1% within most of the LW range. The first model allows a tape measure graduated in kg to be used on goats except breeding females. The second model allows the building of an abacus to provide the estimated LWs of breeding goats from the HG and PG values. Further correction might be achieved by adding the goat body condition score. Such cheap tools should be very useful for goat farmers, most of whom lack reliable weighing devices.