The article discusses the results of comprehensive studies histomorphological signs of skin and hair of sheep (Degeress) of various stripes, especially the thickness of the skin and its layers that are commonly identified indicators. Studies allow to bring the scientific basis for the proper development of activities aimed at increasing production of wool, quantity and quality of which skin microstructure largely depends on. Sheep of different colors have a specific feature on the histological structure of the skin, which is essential for the development of effective methods of selection that enhance productivity of sheep wool. The researches have established that brown suit sheep has thickened skin as compared to red and gray color (p is less than 0.01). In turn, pilar layer of the skin is also much thicker at brown coloration sheep (2029.7 ×10E-6 m) than in sheep red (1850.6×10E-6 m) and sulfur (1773.7×10E-6 m) suits, the difference is statistically highly significant (p is less than 0.001). The thickness of the pilar layer is up to 70% of the dermis, which varies depending on sheep lear ranging from 1773.7×10E-6 m to 2029.7×10E-6 m. Reticular layer thickness varies depending on sheep lear ranging from 743.5×10E-6 m to 826.4×10E-6 m.

Nowadays the demand for fast and easy-to-make meals is ever increasing. This type of food is an essential dietary component of a large section of people in developed countries. Given the economic importance of ready-to-eat meals there is a need for a better understanding of the factors that determine their consumption. The aim of this research was to determine consumer attitudes towards the introduction of ready-to-eat meal (MRE) sets in the Latvian market. A survey was performed to determine the Latvian citizens’ attitudes towards the introduction of this type of quick-tomake, ready-to-eat products into the market of Latvia. The survey included a total of 800 respondents who answered 14 questions which were related to the interest in MRE sets that can be prepared (warmed up etc.) in less than 10 minutes and taste like home-cooked food, and the types of MRE sets these consumers would like to purchase. The demand forecast for MRE sets in the Latvian market is rather high as 67% of the respondents expressed a desire to purchase these products; the development and implementation of MRE sets is topical. The results show that the highest rated MRE set the respondents, a total of 77.1%, expressed a desire to purchase, was chicken fillet with vegetables. No significant differences in terms of liking were observed between chicken fillet with vegetables and chicken fillet with rice, the second highest rated MRE set by 73.9% of the respondents (p is greater than 0.05).

The objective of the study was to investigate the microbiological content of cow (Bos primigenius) milk in Latvian organic farms according to season and herd size with a purpose to detect their impact on the distribution of mastitis causing pathogens in milk. Samples were collected in 14 organic dairy farms of Latvia, 4 times through 2012: in winter, autumn, spring and summer period. Raw milk samples (n=564) obtained from cow composite milk were studied. The samples were divided into three groups in accordance with the number of cows in the cow-shed: A (3-30), B (31-60) and C (61-124). The total colony count (TTC) and the isolation of mastitis causing bacteria were analysed using standard methods. Bacterial growth occurred in 90.4% of samples. Isolated microorganisms belonged to 35 species, and the following bacteria were the most prevalent agent, including Coagulase negative staphylococci in 29.4%, Staphylococcus aureus in 24.1%, Kocuria kristinae in 12.9%, and Enterobacteriaceae spp. in 10.3% out of 564 milk samples. Depending on the season, the average number of TCC was the lowest in summer (4.66 ± 4.01 log10 CFU mLE-1), moderately higher in spring and winter (4.72 ± 4.18 and 4.82 ± 3.54 log10 CFU mLE-1, respectively), but significantly higher in autumn (5.43 ± 4.80 log10 CFU mL-E1). Coliforms were not isolated from group A herds instead of B (3.1%) and C (4.6%). Occurrence of Staphylococcus aureus was noticeably higher in B (19.1%) and C (20.8%) than in A (12.6%) herds. Most of group A herds met the milk quality requirements, while group C herds produced more contaminated milk.

Antibiotic resistance of Staphylococcus is increasing worldwide. New antibiotics are used in big amounts in the meat production more and more. As a zoonosis, Staphylococcus aureus (S. aureus) is found in various species of animals and people, especially in those, who are working on commercial swine farms and slaughterhouses. The aim of the study was to find out the occurrence of S. aureus in different age groups of pigs on commercial swine farms in Latvia. Microbiological samples (n=702) including nasal, rectal, milk and air samples were collected during October 2013 from three closed farms of different sizes and several age groups of pigs and investigated with microbiological standard methods. S. aureus was found in all swine farms. The occurrence of S. aureus in Latvian pig farms was 41% and the highest occurrence of S. aureus was among 3-3.5 month old piglets. S. aureus was 1.8 times more frequently found in nasal than in rectal samples, and only in 28.38% of pigs S. aureus was in both - nasal and rectal samples. S. aureus was found also in sow milk in 13% of samples and in 3 samples of air (n=23).

The changes of areas of eight tree species in Lithuania during the past century were analysed. Aiming to apply the different approaches in forest studies, the Exponential smoothing method for forecasting the changes of the tree areas for the 25 years was used. The data dating from 1922 was analyzed as a time series. The descending trend was identified for Scots pine (Pinus sylvestris L.) and European ash (Fraxinus excelsior L.) and increasing trend – for Norway spruce (Picea abies (L.) H. Karst.), common oak (Quercus robur L.), birch species (Betula pubescens Ehrh. and Betula pendula Roth), black alder (Alnus glutinosa (L.) Gaertn.), European aspen (Populus tremula L.) and grey alder (Alnus incana (L.) Moench). The Exponential Trend with Multiplicative Seasonality (ET-MS) model was fitted for almost all investigated tree species with exception of European ash. For the latter species, the Damped Trend with Multiplicative Seasonality (DT-MS) model was chosen. Mean absolute percentage error of the model in all cases did not exceed 2%.

Latvia is one of the forest-richest countries in Europe. Very often in young forest stands of spruce admixture of coniferous or deciduous trees are taking place. During the growth trees suffer from influence of different risk factors. Damages in mixed stands depend on chosen mode and intensity of economic activities. Forest management cannot be imagined without creating the infrastructure (roads, ditches, etc.). However, the development of infrastructure may cause an effect of fragmentation and lead to changes in the forest structure. The aim of the research is to analyze influence of forest spatial features on the sanitary state of mixed stands of spruce. In 2011 and 2012 mixed stands of spruce younger than 40 years were investigated in all regions of Latvia. Nineteen stands were measured and surveyed and 80 sample plots were arranged. With the help of Geographical Information System (GIS) data base of the State Forest Service of Latvia the forms of forest plots (regular or irregular), as well as location of neighbouring infrastructural objects and location of mixed stands in forests were stated. In unnaturally created regular form plots damages of risk factors usually tend to be larger than in those, which have been created naturally. With the credibility of 95%, linear connection between occurrence of damages caused by browsing and intensity is relevant (r=0.937 is greater than r0.05=0.575), as well as occurrence and intensity of damages caused by Lophophacidium hyperboreum Lagerb. (r=0.999 is greater than r0.05=0.575).

Climate in Latvia has been changing in last decades, and it is predicted to continue changing; therefore, it is important for forestry sector to understand how these climatic changes might affect tree growth and survival. In order to assess climate suitability effect on Scots pine (Pinus sylvestris L.) provenances in Latvia, height and survival data from a Scots pine provenance trial located in three geographically distant places in Latvia were analysed together with several climatic indices. Provenances in the corresponding trial originated from Latvia, Poland, Germany, Belarus, Russia and Ukraine. Thirty year average climate data values from 1961 – 1990 for the 64 origins of provenances were acquired from the WorldClim project. Correlation analysis between provenance average values for height and survival and climate index values for the origins of the provenances confirm that there is a relation between these amounts, and the relation differs between the three site locations, indicating that suitability of climate is an important factor affecting the results of provenance trials. Cluster analysis confirmed that provenances from distant origins might have a very similar growth and survival rates; therefore, geographical location of the provenance origins cannot be considered as the only influential factor on these rates and the results from provenance trials have to be analysed together with climate data in order to make conclusions about the suitability of the provenances.

In Latvia, Picea abies and Pinus sylvestris as the commercially most valuable species make more than half of all woodlands. It has been found that about 23% of spruce stands are infected by root rot, caused predominantly by fungal pathogen Heterobasidion annosum s.l. To restrict the spread of root rot in coniferous forests of Latvia, the Joint Stock Company ''Latvijas valsts meži'' collaborated with Latvian State Forest Research Institute ''Silava'' in 2006 and launched a project for testing the Rotstop biological preparation, containing a suspension of Phlebiopsis gigantea spores. This project had a general task to accomplish Rotstop using technology approbation in Latvia and develop control system. Starting with the year 2008, preparation was used for stump treatment during thinning operations. When analysing the field data, a conclusion made in other studies was confirmed - P. gigantea colonizes pinewood more intensively even in case of improper stump treatment. It implies that the quality of stump treatment is decisive when using Rotstop for rot control in spruce stands.

Invention of light weight cellular wood material (CWM) with a trade mark of Dendrolight is one of the most important innovations in wood industry of the last decade. Currently CWM has been used as core material for sandwichpanels. These three layer panels are used in furniture industry and have wide non-structural applications. The aim of the research was to define the thermal properties of CWM and evaluate various wall envelopes where solid wood cellular material is used. There were 4 specimens of cellular wood material manufactured with nominal dimensions thickness 120 mm, length and with 600 mm to determine thermal conductivity and thermal transmittance according to standard EN 12667:2002. The specimens were manufactured of four layer 112 mm thick Scots pine (Pinus sylvestris L.) CWM double faced with 4 mm thick high-density fiberboard (HDF). Adhesive used in the bonding process was polivinilacetate Cascol 3353. Each direction (parallel, perpendicular) was represented by two specimens. Common procedure to evaluate the energy efficiency of building envelope is to calculate thermal transmittance in static conditions. The influence of the cellular material orientation to its thermal properties was investigated. Coefficient of thermal conductivity was determined for both material directions of CWM (l0 =0.0977 W∙m-1∙K-1 l90=0.148 W∙m-1∙K-1), combining the test method of EN 12667:2002 and calculation method of standard EN 6946:2008. To calculate thermal transmittance of various wall envelopes calculation software in JavaScript environment was created. Various compositions of external walls were assessed, thermal transmittance of these structures were calculated according to standard EN 6946:2008.

When the measurements of power consumed by cutting mechanism electromotor are made, the mechanical cutting power cannot be obtained, because they are different physical processes. However, determination of electricity power is relatively simpler. Therefore, both powers are determined in the study, in order to evaluate coherence between them. Computer numerical control machine was used for climb-sawing of aspen (Populus tremula L.) wood with a circular saw. Mechanical cutting power was calculated from measurements of cutting force, but the electric ones – from measurements of current and voltage. As a result, changes of both powers and of specific cutting work, on what the analytical calculation of cutting power is based, were obtained depending on length of the cutting trajectory. It is found out, that mechanical cutting power is greater than electric power, and it is useful to use for the analytical calculation, based on determination of the specific cutting work, wear coefficient of the cutter that depends not only on the duration of work of cutter, but also on feed speed and the length of the cutting trajectory.