The research was performed at the Faculty of Veterinary Medicine of the Latvia University of Agriculture. At the moment the research in veterinary anaesthesia is in its infancy stage. The aim of this study was to determine the effects of the acepromazine maleate on intraocular pressure (IOP) and horizontal pupil diameter (HPD) in a dog's eye. Ten adult dogs of different age, breed and sex were examined clinically and ophthalmologically. All animals were clinically and ophthalmologically healthy. Animals received acepromazine intramuscularly. IOP and HPD were measured every 5 minutes for the total period of 60 minutes. It was established that the acepromazine maleate intramuscular injection causes an IOP decrease in booth eyes. A significant IOP decrease was observed from 35 till 60 minutes after the acepromazine injection. The pupil contraction was observed 5 minutes after the treatment and continued to contract till the end of the research. As acepromazine maleate causes a significant decrease of intraocular pressure, it is not contraindicated to be used in the case of corneal trauma, perforation, glaucoma and corneal ulcers.

The investigation was carried out from 2006 to 2008 with the aim of observing the stability of morphological traits in Latgale's melon (Cucumis melo L.) lines in the Tukums region of Latvia. Four lines of Latgale's melons ('8', '14', '5(2)', and '4(3)') were grown in high plastic tunnels: five plants from each line. The following parameters were measured to determine stability of morphological traits in melons: fruit petiole and flower scar diameters (cm), length and wide of melon fruit (cm), and thickness of flesh (cm). Results showed that there was a significant difference in fruit petiole scar diameter between the years 2006 and 2007 for all lines. The melon line '14' was stable in all parameters from 2006 till 2008 except fruit flower scar diameter. The melon line '4(3)' was less stable in all parameters between all melon lines in all years of investigation.

After a 16-m high dam was constructed and a 297-ha pond was arranged in the River Šušvė nearby Angiriai in 1980, the previous natural flow regime of the river has changed: 15500000 m3 of water accumulated above the dam is not discharged via a natural bed, but through two 1.5x1.5 m bottom orifices, and flood discharges (up to Q1% = 296 m3 sE-1) are directed into the lower reach through a 16-m high shaft spillway of floods. Such arrangement of the Angiriai dam ensured it to become an essential obstacle for migrating fish. In 2000, after the arrangement and operation of Angiriai hydro-electric power station, the water regime downstream the dam has been changed and new hydrological pulses as well as ecosystem biodiversity are to be adapted. Thus, the operation of Angiriai HPS on the River Šušvė generating hydroelectric power can have adverse effect on the river habitats and hydro ecological connectivity. To evaluate the effect, the eco-hydraulic water regime measurements in 2005 in a lower stretch with and without turbines operating were made. The study results showed that artificial water levels fluctuation (≈ 4 m hrE-1) induced by Angiriai hydro-electric power station as well as the discharge flowing through the bottom orifices due to high velocities (13–14 m sE-1) and temperature differences could create stressful situations for young fish in the lower bank. According to the data of soil texture of the Šušvė River, the bed armoring process is going on below the Angiriai HPS is quasistable and no impact of HPS operation is found.

The aim of this research is to work out the graphic method for the calculation of the maximum rain intensity with a different guarantee in Riga. In order to develop this method analysis as regards the rainfall rates having a different probability was carried out. The measurement data of maximum rainfall minute intensity (mm minE-1) 3 and 9 hours as well as daily common rainfall from the accessible archive materials in the period 1954-2006 have been studied in this research and treated with the mathematical statistics methods. After the data collection and calculations, the final results are shown in a graphical way in which it is easy to determine which guarantee percent and repetition probability the rain intensity in Riga may be foreseen. In order to determine which module of one factor regression is the most accurate, five different modules were investigated. From the modules studied the most adequate one for data analyses was the logarithmic module having the accuracy up to 92%. The analysis of the rainfall data as well as the research of the situation of the location place can help to choose the system of rain accumulation and infiltration for each building location thus improving the operation of the total sewerage system. The calculations may be useful in practice to calculate the runoff rates from the areas of different covering. If necessary, using the graphic, it is possible to work out a mathematical expression for the calculation of the maximum rain intensity having any necessary probability. The accessibility and application of a wide range of materials for modern surfaces or infiltration buildings in the world present a wider range of their practical use for separate modern solutions in Riga.

Climatic changes are shifting the potential tree distribution limits of many tree species northwards. One of such species is Fagus sylvatica, currently represented in Latvia only by a few stands. In order to increase knowledge on its potential use in the forest management, the aim of our study was to characterize the growth of beech in a young stand in the central part of Latvia. The stand of beech and spruce, mixed in rows with an initial spacing of 2.5 x 2.5 m in Oxalidosa forest type was assessed. Survival of European beech in clear cutting was similar to that observed for the native Norway spruce (73% and 79%, respectively), but both height and diameter were notably and significantly superior for wildlings at the mean age of 15 ± 2 years, reaching on average 7.4 ± 0.30 m and 8.9 ± 0.69 cm, respectively. Increasing ring width with increasing tree age for both tree species was observed until the last four years, when large and increasing superiority of beech over spruce, coinciding with reduction of ring width of spruce, was noted. It was most likely caused by intensified competition due to very wide crowns formed by young beech trees in the plantation with wide spacing: average crown radius reached 2.4 ± 0.16 m, for few trees exceeding even 4 m.

Impact of a variety of forestry machine types on soil compaction is evaluated in this study according to the measurement of soil penetration resistance at 0 to 80 cm depth. It is concluded in the study that soils with poor bearing capacity (PBC), comparably small penetration resistance and organic layer thicker than 5 cm are less vulnerable to soil compaction. The use of small-size forwarder Vimek 610 allows to reduce soil compaction to an insignificant level in comparison to the control sites, and most or ruts disappear within a few days in PBC conditions. Whereas John Deere 810E, which belongs to the middle-size class of forwarders, significantly compacts soil through the whole measured depth in similar conditions. Rottne F10B and John Deere 810E forwarders represent the same weight category, and soil compaction due to the use of these machines on soils with moderate bearing capacity (MBC) is similar too; however, on soils with weak (WBC) and good (GBC) conditions results are different, mostly due to a different amount of extracted roundwood in both trials. Tracked forwarder was used only in GBC conditions and the results demonstrated significant compaction only down to 22 cm depth. The trials confirm that the depth of the intensity of impact depends on the weight of the machine and amount of material extracted; however, additional measurement data are necessary to characterize the impact quantitatively in different conditions.

Height at the centre of gravity is a part of mathematical model to interpret risk of lodging used for cereal crops. Because of the anatomical changes during vegetation period, several measured parameters in early milk stage (stem and panicle weight) will differ from over-ripe stage results in their values. The aim of this study was to define approximate values of calculated parameters describing oat (Avena sativa L.) height at the centre of gravity in early milk and over-ripe stages as well as determine connection with lodging risk. The trial was carried out at the State Stende Cereals Breeding Institute in 2013. There were 5 oat cultivars studied. At the investigated growing stages plant samples were taken from a field and in laboratory conditions stem/panicle weight and length measured. The height at the centre of gravity and gravity ratio were calculated using mathematical model by Berry (1998). Results showed that the value of the height at the centre of gravity in over-ripe stage was significantly higher (p is less than 0.01) than in early milk stage, but correlation with risk of lodging remained. Such lodging resistance describing mathematical model can be useful for oat as well as wheat cultivars.

In goats (Capra) the growth and functional development of certain parts of the multi-chambered stomach continue during the first few months after birth. The aim of this research was to clarify morphofunctional changes in the kids abomasa and rumina and live weight gain during the first 8 weeks of life. Research was performed in two parts. In the first part (P1) we used Saanen breed kids which were all kept in the same conditions and in the second part (P2) we used Saanen breed kids which were separated in two groups with different feeding diets. In P1 the stomach contents of the goat kids were collected after slaughter (on day 1, 17, 25 and 30), weighed full and empty. The gastrohromoscopical method proved that in the newborn kids the area where the abomasal pH is 3.0 and lower is about 10% of the surface of the abomasum, but in age of three weeks it is composing 80% of the mucosal surface of the abomasum. In P2 were two groups – in the first group (MMG) kids which were fed with dairy (mother) milk and lived with mothers, the second group (MRG) kids were fed with milk replacer and lived separate from mothers. The stomach contents were collected after slaughter(at day 45 and 60).We confirm that the most important age of stomach development and kids growth in postnatal period are the first 45 days. During this period the most significant differences can be observed. On day 60 there are no significant differences (p is greater than 0.05) between MMG and MRG stomach development.

The paper discusses heat transfer and the step response of a low-power induction motor to no-load mode under fan cooled and naturally cooled conditions. In Latvia University of Agriculture (LUA) in the electric drive laboratory the experimental tests were performed on a 1.1 kW totally enclosed fan cooled three phase induction motor with a fan mounted on a shaft for fan cooled conditions and with a fan taken off for naturally cooled conditions. The transient temperatures are measured in nine points of the stator end windings and in two points of the stator frame using thermocouples. Temperature is measured by using K type thermocouples and Pico-Log TC – 08 data logger. The current and voltage are measured by using Simple Logger II L562 two channel data logger. Measurement data are processed and archived using data loggers Pico-Log Recorder, Simple Logger II and Data View software. The experimental test results show that ventilation plays an essential role in the heating process of small power induction motors. Mathematical and virtual models of induction motor windings heating are represented to simulate the heating process of induction motor under no-load mode and different cooling conditions.

Leaf morphology was assessed in Pajiesys and Seirijai field trials of oaks. Oaks in these trials are the progenies of oak trees (Quercus genus) that grow in the Trakas forest of Seirijai district of Alytus forest enterprise of Lithuania. The aim of the study was to determine the number of hybrid trees between the progenies of the Trakas forest in Pajiesys and Seirijai field trials. 251 oaks belonging to 40 half-sib families were sampled. Twenty three leaf morphological variables were measured on each of 5 leaves collected from each tree and analysed by principal component analysis (PCA) and discriminant analysis (DA). The study concluded that Q. robur and Q. petraea leaves are most clearly identified by six morphological traits. Discriminant function of two traits for oak species separation was proposed. The study has also revealed a high degree of interspecific hybridization in field trials. Study results were compared with earlier reports about hybridization occurring in mixed oak stands in other parts of Europe.