peer reviewed | The Algerian agricultural sector faces the challenge to meet the food needs of its population despite low agricultural capacity, resulting in increasing pressure on natural resources. This paper aims to inventory the greenhouse gas (GHG) emissions related to livestock sector in the rural area of Chemini (province of Bejaia), taking into account the emissions due to enteric fermentation, in the form of methane, and manure management, in the form of methane and nitrous oxide. Emissions intensity, expressed in CO2- equivalents (CO2-eq) per kg of edible protein, was included in the study. Ruminants contribute to 94% of livestock GHG emissions and to 53% of protein production, with a large share due to cattle. The main part of emissions is related to enteric fermentation. High-producing cattle present the lowest emission intensity of the ruminant category with 24 kg CO2-eq per kg protein. Chickens produce 2.7% of livestock related emissions but provide 47% of animal protein. It results in low emission intensities whereas important difference is noticed between backyard and industrialized systems (around 21 versus 1 kg CO2-eq per kg protein, respectively). Improvement of animal performance should contribute to mitigate the environmental impact of livestock production in Algeria.

Article #83 | absent

International audience | Reproductive performances of the Creole goat, the meat breed of Guadeloupe in the Caribbean, are described from a database generated for 15 years (1973 to 1988) at an experimental farm of the Institut National de la Recherche Agronomique (INRA, Guadeloupe, French West Indies). The data contain information on 599 females, 2259 attempted matings, 2135 achieved matings and 1904 kiddings. Animals were reared under semi-intensive management conditions (on the basis of feeding system, health and culling policy). Main sources of variation were analysed: mating type (buck in permanence or buck effect), mating season (dry, intermediate and humid season) and rank of kidding. The Creole goat is a continuous breeder. On average 94.5 percent of exposed females were mated (defined as mating rate) and 90.5 percent of exposed females achieved a kidding (fertility rate). Their prolificacy reached 1.98 kids/kidding, with only 3.9 percent of kids born dead. These reproductive parameters varied essentially with rank of kidding but very poorly with the mating season. Productivity of these females was regularly high during their whole lifetime production. From the results obtained, it is concluded that Creole goats have very high reproductive performances, provided that animal husbandry and nutrition are adequate.

A study was conducted to determine the productivity and management of indigenous chickens of Kumi district in Eastern Uganda. Eighty households were randomly selected to respond to a standard questionnaire. The average flock size per household was three cocks, six hens and four chicks. Sexual maturity is attained at 5.5 and 6.5 months among male and female chickens respectively, with age at first egg ranging between 5.5-7 months. Egg hatchability varied widely between farmers with an overall mean of 90%. Clutch sizes ranged between 4-19 eggs per clutch, with a mean of 13 eggs. Chickens were acquired through purchase (65.6%), gifts (26.3%), or in exchange for labour. Scavenging was the major feeding system, seasonally supplemented with cereal grain. The majority of the farmers (87.5%) provided birds with drinking water. Death of chicks was prevalent (73%) and was mainly attributed to Newcastle disease (70%), with most of the mortality being observed during the dry season (62%). Survival of chickens was significantly affected (P<0.001) by feeding level, and strongly correlated (r = 0.83) with the housing system. Housing and feeding had significant effects on duration between laying cycles (P<0.001), how chickens were acquired (P<0.01), and the uses to which the chickens were put (P<0.001). Chickens and eggs are mainly used to generate household income and for home consumption. In some households, chickens are exchanged for goats and subsequently, for cattle. Our findings indicate that the indigenous chicken is a major resource in Teso, Uganda. The performance of these indigenous chickens would significantly improve with better feeding, housing and health management. Chicken farmers should be empowered through training and provision of capital credit, the latter of which should be well informed by data on the chicken production cycle.

With the advancement of technologies, there are attempts to automate the majority of processes for various reasons, for instance, to improve and optimize production or to perform actions that may cause risk to people’s health, etc. Therefore, the use of mobile autonomous robots is becoming increasingly important as the limits of the potential of the use of autonomous mobile robots in the industry have not yet been reached. The attempts have been made to achieve this by developing optimum trajectory calculation algorithms which enable the robot to move freely in both static and dynamic environments and use an optimum trajectory. Therefore, the subject of study in this article was movement of a mobile robot in an unknown environment using a multi-agent device system and fuzzy logics, and the goal of the study was to prepare the methods for development of intelligent systems for planning mobile robot movement in an unknown environment using multi-agent device and fuzzy logics ensuring the robot will accomplish the planned and adjusted on the go safe trajectory in the environment with unknown obstacles. Based on this, the robot arm model has been developed after calculating in the article the missing parameters of the experimental mobile robot in order to analyze the peculiarities of using the multi-agent device as well as the specifics and challenges of using fuzzy logics. As a result of the study performed in the article, significant data were obtained based on which a method was offered for an intelligent system for planning mobile robot movement in an unknown static environment using a multi-agent system, which was characterized by the use of fuzzy blocks corresponding each agent, and localization of each solution to the task of planning robot movement in each specific situation, which enables to improve the accuracy and efficiency of movement planning.

This study was performed to evaluate use of zeolite &nbsp;for water quality management in cold water recirculating aquaculture system. The system was reared Arctic charr (Salvelinus alpinus) and Hybrid char (Salvelinus fontinalis × Salvelinus alpinus) fry. Fish biomass in the reservoirs was distributed as follows: Arctic charr accounted for 7.32 kg at a density of 23.74 kg∙m-3, and hybrid charr accounted for 7.78 kg at a density of 26.91 kg∙m-3. &nbsp;After increasing the feed rate and documenting water quality studies, a vast increase of ammonium and nitrite concentration was noticed in the rearing tanks. Natural zeolite, known as clinoptilolite with a cation exchange capacity (CEC) of 1.20–1.50 mol.∙kg-1, was used to reduce the amounts of these hazardous substances in the rearing tanks. &nbsp;&nbsp;Zeolite was used to decrease the increased concentration of ammonia and nitrites, which were reduced by 22.7% and 16.7%, respectively, during the study period. These results suggest that zeolite is suitable for water quality management in cold water recirculating aquaculture system with as little of an investment as possible.

The scientific and methodological basis for increasing the efficiency of geothermal ventilation, making it possible to use thermal energy of the Earth’s surface layers for cooling (heating) an incoming air stream are created. Mathematical modeling is performed based on the equations of hydrodynamics, heat transfer and thermal conductivity, along with a computational experiment carried out using the finite volume method.&nbsp; A mathematical model of the process of heat exchange between the flow of air in a heat exchanger and a soil mass is developed. This model describes a relationship between efficiency indicators of the horizontal ground heat exchanger and its performance parameters, and also natural climatic conditions. The determination of thermal fields in incoming cooled air and a soil mass at various depth locations of the horizontal ground heat exchanger is performed. The relationship between thermal efficiency and operation time of the horizontal heat exchanger, located at different depths, is proved. The energy comparison of a horizontal ground heat exchanger, located at different depths, with a vertical one, is made. he depth of the horizontal heat exchanger has been established, for which the loss of thermal energy in comparison with the vertical is insignificant (less than 7.5%). The operating time was determined, starting from which there are practically no differences in the level of thermal energy for all the studied models (&gt; 107 s). The developed mathematical model allows to predict the energy efficiency indicators of a horizontal ground heat exchanger on the basis of its performance parameters and natural climatic conditions, that makes possible determining the economically optimal depth of the heat exchanger location under specific conditions.

Botrytis cinerea, the causal agent of strawberry grey mold, has become a severe problem of horticultural farms due to its genetic variability and growing resistance to frequently used fungicides. Plant disease could induce significant losses of yields and plants thus it is necessary to discover and apply novel approaches to control strawberry pathogens. In addition, chemical plant protection products can leave undesirable residues in fruits and the environment. Plant protection should be more friendly to the environment and human than already used chemical measures. One of the alternatives could be plant-based extracts, produced from aromatic and medicinal herbs, spices, fruits. Therefore, the aim of this study was to determine the in vitro effect of cinnamon bark (Cinnamomum cassia L.) and clove bud (Syzygium aromaticum L.) extracts on B. cinerea colony growth. Experiments were carried out at LAMMC Institute of Horticulture, Lithuania. Both extracts were obtained from dried material by extraction with CO2. For in vitro assay, extracts were separately mixed with potato dextrose agar in concentrations from 200 to 1000 μl/l, poured into Petri dishes, then each dish was inoculated with 6 mm diameter B. cinerea disc and incubated at 22±2 oC in the dark for 7 days. The diameter of the pathogen colony was measured 2, 4 and 7 days after inoculation. Concentrations of the extracts, which demonstrated reduced growth of the pathogen, were considered to have an antifungal effect. The results showed that extracts of cinnamon bark and clove bud had a similar antifungal effect on B. cinerea and suppressed the growth of 100% from 600 μl/l concentrations 4 days after inoculation. At 600-1000 μl/l, no growth of the pathogen was detected for both extracts 7 days after inoculation. However, clove bud extract considered to be more effective, as the diameter of B. cinerea colonies was smaller compared to cinnamon bark extract at 200-400 μl/l concentrations. To conclude, spice extracts of cinnamon bark and clove bud demonstrated antifungal effect on B. cinerea in vitro and could possibly be applied for control of strawberry grey mold.

Biodegradable and compostable tableware is significantly more environment and nature friendly than disposable tableware and drinkware made of plastic. Tableware made of wheat bran, but also corn and rice bran is already commercially available. It is reasonable to use the by-products of the milling of also other cereals, like rye bran, barley bran and oat bran, for the production of tableware. The aim of this research was to explore the possibilities for the production of tableware and drinkware from the by-products of the milling of wheat and also other cereals like rye and oat bran. In order to achieve the aim, compacts were moulded from rye bran and oat bran and mixtures of bran (wheat bran and rye bran) using various work modes. The moulding of the compacts included different temperatures of the mould, moulding durations and compressive forces. The mechanical properties like density and flexural strength of the compacts were determined and the compostability of the compacts was studied. The test bodies were placed inside a compost bin to check their compostability and to determine the duration of composting.Biodegradable and compostable tableware is significantly more environment and nature friendly than disposable tableware and drinkware made of plastic. Tableware made of wheat bran, but also corn and rice bran is already commercially available. It is reasonable to use the by-products of the milling of also other cereals, like rye bran, barley bran and oat bran, for the production of tableware. The aim of this research was to explore the possibilities for the production of tableware and drinkware from the by-products of the milling of wheat and also other cereals like rye and oat bran. In order to achieve the aim, compacts were moulded from rye bran and oat bran and mixtures of bran (wheat bran and rye bran) using various work modes. The moulding of the compacts included different temperatures of the mould, moulding durations and compressive forces. The mechanical properties like density and flexural strength of the compacts were determined and the compostability of the compacts was studied. The test bodies were placed inside a compost bin to check their compostability and to determine the duration of composting.

Silage for animal feeding can be made from different plants. One of the most important feed crops from which silage is made is maize. Special choppers can be used for cutting and chopping these coarse-stem plants. The most widespread silage preparation is done in trenches, where good quality silage can last for several years, making it one of the best feeds in winter. Incorrect picking and unloading of silage from trenches may result in secondary fermentation and may cause forage losses. Various types of equipment are used for silo unloading from storage. This work researches maize plants, the quality of maize silage and the process of silage making and unloading. The research was carried out in the laboratories of Agriculture Academy of Vytautas Magnus University and in a farmer’s farm. Tests have been performed with three different silo unloaders and a mobile feed mixer. The established average corn plant yield in 2018 was 31.8&nbsp;t&nbsp;ha-1; for silage making, the plants were chopped with the drum chopper. After evaluation of the fractional composition of chopped mass, the chopped maize slices were found to meet the silage production requirements, as even 82.6% of the chopped particles were 3.15-16 mm long. Maize slice moisture was also found to be suitable for silage – 66.12±7.3%. The density of prepared silage was high enough and reached 699.89±19.04&nbsp;kg&nbsp;m-3 or 230.55±6.27 kg m-3 DM (dry matter). Silage unloaders test results showed that one sample of silage could be unloaded in 31–43&nbsp;s. The bucket type device could take the maximum weight sample – 567.8±77.0&nbsp;kg, but the maximum density of the silage sample (30.41±1.95 kg&nbsp;m-3) could be taken by a block-cutting unit. Also, this unloader left the smallest unevenness on the feed surface. Distribution of feed in the farm for the animal was fairly even and this indicated that the silage-unloading device had no significant impact on the quality of feed distribution.&nbsp; &nbsp;