Evaluation of fatty acid profile and naturalness of butter marketed in Bulgaria

N. Naydenova

Department of Animal husbandry – Ruminants and Dairy farming, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria

(Manuscript received 5 June 2021; accepted for publication 30 August 2021)

Abstract. The predominant influence on the structural-mechanical characteristics (hardness, brittleness, etc.) and the chemical parameters (acidity, oxidation-reduction potential, etc.) of butter is exerted by its lipid composition. The aim of the study was to establish the fatty acid composition of some Bulgarian brands of butter and those imported from abroad, offered in the trade network of Bulgaria, in connection with their naturalness and health indicators. Five brands of butter produced in Bulgaria and imported from countries in the European Union were tested three times. The content of saturated fatty acids in the studied Bulgarian brands of butter varied from 66.16 to 75.15%, and for brands of butter imported from EU countries they varied in a significantly narrower range – from 67.51 to 72.49%. The amount of short-chain saturated fatty acids is higher for EU-imported butter brands. The data for the identification characteristics of all tested samples from the trade network of the country meet the requirements for naturalness of butter. The atherogenic index of butter varied from 2.56 to 3.26 for the imported brands of butter and from 2.41 to 3.70 for the Bulgarian ones, and the thrombogenic index from 1.49 to 2.36 for the imported brands, and from 1.44 to 2.17 for the Bulgarian ones, respectively.

Bacteria variety causing clinical mastitis in Holstein-Friesian cows in Pelagonia region, North Macedonia

S. Stojanovski1*, G. Cilev2, B. Trajanoska3

1Department of Microbiology, Faculty of Veterinary Medicine, University “St. Kliment Ohridski”, 7000 Bitola, North Macedonia
2Department of Food Quality and Safety, Faculty of Veterinary Medicine, University “St. Kliment Ohridski”, 7000 Bitola, North Macedonia
3Veterinary clinic “Makseraja”, 7500 Prilep, North Macedonia

(Manuscript received 21 April 2021; accepted for publication 21 June 2021)

Abstract. The main aim of this study are the bacteria that most often cause clinical mastitis (CM) and their impact on milk reduction in Holstein-Friesian cows in the Pelagonia – North Macedonia region. 36 milk samples were taken from Holstein-Friesian breed of cows with confirmed clinical mastitis by a veterinarian. The samples were taken for the period from January 2019 to December 2020 from 20 different smallholder farms situated in the monitored region. Two sterile tubes with 10 ml of milk in each of them were taken from the affected part of the udder of the cow. A total of 86 tubes with milk from 36 mastitis cows were taken. From each sample 300 µl drips were placed in petri dishes with different selective nutrient media: Mannitol Salt Agar, MacConkey Agar, Endo Agar and Edwards nutrient medium. The petri dishes were incubated at 35±2°C for 24-48 hours in Mannitol Salt Agar, at 30-35°C for 18 to 72 hours in MacConkey Agar, at 35±2°C for 18 to 24 hours in Endo Agar and at 35-37°C for 24-48 hours in Edwards nutrient medium. Morphology of colonies and cells were examined with a microscope. A total of 119 strains were obtained and the following physiological and biochemical studies were performed to determine the new isolates: oxidase reaction, catalysis activity, indol test, hydrolysis of the hyporate, acetoin formation (acetylmethylcarbinol, Voges-Proscauer reaction) and Methyl-Roth test (MR- test). The results obtained revealed that the most common bacterial species causing clinical mastitis in Holstein-Friesian cows in 2019 and 2020 were six species of bacteria, where E. coli and Staphylococcus spp. are dominant.

Implications of captive breeding for the reintroduction of the Saker falcon (Falco cherrug) in Bulgaria

R. Petrov1,2*, Y. Andonova1, Y. Gancheva3, I. Klisurov1

1Green Balkans – Stara Zagora NGO, Stara planina str. 9, 6000 Stara Zagora, Bulgaria
2Department of General Livestock Breeding, Faculty of Veterinary Medicine, Trakia University, Student’s campus, 6000 Stara Zagora, Bulgaria
3School of Sciences, Faculty of Science and Engineering, University of Wolverhampton, Wulfruna St, WV1 1LY Wolverhampton, United Kingdom

(Manuscript received 20 June 2021; accepted for publication 5 August 2021)

Abstract. The Saker falcon (Falco cherrug) is a globally endangered species recovered in 2018 in Bulgaria. The only known active pair currently breeding in the wild in the country is made up of captive-bred and released birds, part of the first reintroduction programme for the species in Bulgaria and globally. As part of the project, sourced Saker falcons of known European origin are bred ex situ, the juveniles are parent-reared and released in the wild by means of the hacking method. The aim of this study was to evaluate the success and effectiveness of the captive breeding and rearing methods. The objective of the study was to investigate, compare and assess the results from fertilization, hatching, survival and hacking of captive bred Saker falcons registered over a 10-year period (2011-2021) at the Wildlife Rehabilitation and Breeding Centre (WRBC) Green Balkans, with a more detailed comparison of the breeding activities carried out in 2020 and 2021 (as the reintroduction programme was restarted in 2020). The results show more than threefold increase in output of laid eggs with the employment of the double clutching method in 2020 and 2021, and an overall 65% release rate of the hatched in the WRBC Saker falcons, for the investigated period.

Study on the effectiveness of chemical and biological agents to control tomato leaf miner (Tuta absoluta Meyrick, 1917)

R. Mineva1*, V. Yankova2, N. Valchev1

1Department of Plant Production, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria
2Maritsa Vegetable Crops Research Institute, 32 Brezovsko shose Str., 4003 Plovdiv, Bulgaria

(Manuscript received 1 June 2021; accepted for publication 30 July 2021)

Abstract. In growing four tomato varieties in greenhouses, the effect of a conventional and integrated scheme for control of tomato leaf miner (Tuta absoluta Meyrick, 1917) was studied. Six consecutive treatments were performed at ten-day intervals. The conventional scheme includes the following products: Confidor Energy OD 0.08%, Ampligo 150 ZC 400 ml/ha, Coragen 20 SC 200 ml/ha, Exalt 25 SC 2400 ml/ha, Voliam Targo 063 SC 800 ml/ha and Voliam Targo 063 SC 800 ml/ha. In the integrated scheme the following products for plant protection are used – Confidor Energy OD 0.08%, Sineis 480 SC 250 ml/ha, Sineis 480 SC 250 ml/ha, Voliam Targo 063 SC 800 ml/ha, Neem Azal T/S 0.3% and Neem Azal T/S 0.3%. The effectiveness of the plant protection products against the tomato leaf miner, the degree of pest attack of the different varieties and the tomato productivity were studied in this experiment. It was established that in the conventional and in the integrated treatment scheme, the highest efficiency was shown by the product Voliam Targo 063 SC, applied in a dose of 800 ml/ha on the seventh day after spraying. The percentage of damaged plants was the lowest in the variety Clarosa F1 (4.00%), with the application of the conventional plant protection scheme. The results were similar in the integrated scheme – 6.00%, while in the control the degree of infestation reached 18.00%. The percentage of damaged fruits in both treatment schemes was 6.00%, significantly lower than in the control (24.00%). The highest tomato productivity was observed with the application of the conventional plant protection scheme in Manusa F1 variety.

Design parameters of furrow forming and compacting roller of the combined seeder STS-80

G. Hristova1*, M. Dallev2, G. Tihanov1

1Department of Agricultural Engineering, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria
2Department of Agricultural machinery, Faculty of horticulture with viticulture, Agricultural University of Plovdiv, 12 Mendeleev Blvd., 4000 Plovdiv, Bulgaria

(Manuscript received 22 June 2021; accepted for publication 10 August 2021)

Abstract. A turf seed drill (STS-80) has been designed, in which the seeds from the sowing machines are sent to the soil through seed pipes. The size of the seeds is relatively small, therefore it is a requirement for them to be sown at a depth between 0.5 cm and 1.5 cm. The drill allows the following operations to be performed simultaneously: soil furrowing, seed sowing, and soil compaction with a compaction roller. The structure of the individual bodies that make up the aggregate is essential for the smooth running of the work process. Two rollers have been developed, which allow the providing of the necessary agro-technical requirements for sowing grass seeds. The role of the roller mounted in the front part of the drill is to make furrows in the soil at a depth of 1.5 cm, where the grass seeds fall. The roller, located in the rear of the unit, dulls the surface of the soil after the seeds enter it. This creates additional dynamic force, which increases the degree of soil compaction and the intensity of destruction of soil aggregates at a certain mass of the roller.

Pulsation parameters of new and used milking liners with round cross section

G. Dineva*, K. Peychev, D. Georgiev

Department of Agricultural Engineering, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria

(Manuscript received 4 June 2021; accepted for publication 26 July 2021)

Abstract. Milking machines equipped with new and used milking liners with a round cross section were studied. The used milking membranes were operated for 3 months on a farm for rearing 60 cows (Holstein cattle) with double milking per day. The experiment involved recording the standard pulsation phases “a”, “b”, “c” and “d” (in absolute units) in the frequency range from 1 Hz to 2.5 Hz, in a vacuum mode of 40 kPa and 50 kPa and at a pulsation ratio of 50/50%. It was found that the transients (phase “a” and phase “c”) are faster and the established phases (phase “b” and phase “d”) are longer in milking units equipped with used milking liners. The conclusions are related to the service life of the milking liners.

Comparative study of a milking unit pulsation system in laboratory and field conditions

G. Dineva*

Department of Agricultural Engineering, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria

(Manuscript received 20 May 2021; accepted for publication 12 July 2021)

Abstract. A comparative study of the pulsation phases in classic milking units was performed. The testing of the same is done in laboratory and field conditions (during milking). The pulsation settings at which the test was performed were pulsation rate 60 min-1 and 90 min-1, ratio 50/50% and vacuum mode 50 kPa. The experiments were performed in the laboratory of “Machine milking” (Department of Agricultural Engineering, Faculty of Agriculture, Trakia University) on a milking installation with a pipe line and on a farm for 60 lactating cows at the same milking installation. It was found that the transients (phases “a” and “c”) are significantly reduced during milking. Respectively, the actual phases (phases “b” and “d”) are significantly increased during the milking process. The conclusions are related to the settings and timely diagnostics of the milking machine.

Selectivity and stability of herbicides, herbicide tank mixtures and herbicide combinations on seed yield of Clearfield oilseed canola (Brassica napus L.)

G. Delchev*

Department of Plant Production, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria

(Manuscript received 31 May 2021; accepted for publication 26 July 2021)

Abstract. During the period 2018-2020 a field experiment was carried out with the winter Clearfield oilseed canola hybrid Phoenix CL (Brassica napus L). Factor A included the years of investigation. Factor B included untreated control, 2 combined herbicides: Cleranda SC and Cleravo SC; 6 herbicide tank mixtures: Electron 500 SC + Maza 4 SL, Springbok + Maza 4 SL, Tanaris + Maza 4 SL, Butisan max + Maza 4 SL, Cliofar 600 SL + Maza 4 SL and Galera super + Maza 4 SL; 6 herbicide combinations: Caliph 480 ЕC + Maza 4 SL, Caliph mega + Maza 4 SL, Bismark CS + Maza 4 SL, Nero ЕC + Maza 4 SL, Brasan 540 EC + Maza 4 SL and Colsor trio ЕC + Maza 4 SL. Herbicides Cleranda, Cleravo and Maza were used in addition with adjuvant Dash HC. Foliar-applied herbicides were treated during 2-4 leaf canola stage. Soil-applied combined herbicides were treated during after sowing before emergence period of the canola. It was found that: (i) the highest seed yields are obtained by use of combined herbicide Cleranda, followed by herbicide tank mixture Electron + Maza and combined herbicide Cleravo; (ii) the high canola yields are also obtained by herbicide tank mixtures Butizan max + Maza, Springbok + Maza, Tanaris + Maza, as well as by herbicide combinations Caliph mega + Maza, Brasan + Maza, Bismarck + Maza; (iii) technologically the most valuable are combined herbicide Cleranda, followed by herbicide tank mixture Electron + Maza and combined herbicide Cleravo; (iv) in terms of technology for growing winter Clearfield oilseed canola, herbicide tank mixtures Springbok + Maza, Butisan max + Maza and Tanaris + Maza, as well as herbicide combinations Caliph mega + Maza, Bismar + Maza and, Nero + Maza get high rating; herbicide tank mixtures Cliofar + Maza and Galera super + Maza and herbicide combinations Caliph + Maza and Colsor trio + Maza get low rating.

Operational characteristics of a machine-tractor unit for direct sowing of barley using the JD LINK telematics system

G. Tihanov*, G. Hristova

Department of Agricultural Engineering, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria

(Manuscript received 11 June 2021; accepted for publication 26 August 2021)

Abstract. A study has been conducted for some operational indicators of a machine-tractor unit (MTU) for direct sowing of barley. The data for this study has been collected and retrieved by using the JD Link telematics system from two different fields sown with barley: field A with irregular shape and area of 13.75 ha and field B with rectangular shape and area of 16.26 ha. It was found that for both fields the values for the most monitored parameters were very close as follows: for the engine speed of the sowing unit during working stroke – 1553.65 min-1 (A) and 1586.11 min-1 (B) (the difference is <2.08%); for the idle mode of the sowing unit – 900.08 min-1 (A) and 905.63 min-1 (B) (the difference is <0.62%); for the actual working speed – 9.97 km/h (А) and 10.16 km/h (В) (the difference is <1.9%), registered when the MTU is performing the technological operation “sowing”; those parameters of MTU are nor influenced by the field size and shape. Larger differences in values between the two fields were established in terms of the relative share of engine used – 19.98% (A) and 21.55% (B) (the difference is <7.3%) and for the consumed diesel fuel (in field А it was 7.2% liters higher than in field В, respectively, 11.7% higher referring to the average diesel fuel consumption – liters per hour). The actual hourly productivity in field A was 20% lower than in field B – 3.05 vs 3.81, which is due to the fact that in the field with irregular shape – A the sowing unit made more turns at the end of the levels than in the field with rectangular shape – B.

Food consumption and winter mortality in bee colonies wintering in hives made from different materials with lattice and solid bottom

I. Zhelyazkova*, S. Lazarov

Department of Animal husbandry – Non-ruminants and other animals, Faculty of Agriculture, Trakia University, Student’s campus, 6000 Stara Zagora, Bulgaria

(Manuscript received 10 June 2021; accepted for publication 2 August 2021)

Abstract. The objective of the present study is to examine the changes in some indicators characterizing the winter hardiness of bee colonies settled in hives made of different material (polystyrene, wood, ceramics) and with different type of bottom (lattice or solid). Some parameters which characterize the wintering of bee colonies (amount of dead bees and quantity of food consumption in winter) have been investigated. The bee colonies were housed in 10-frame Dadant Blatt hives with a lattice and solid bottom situated at the Training Apiary of the Faculty of Agriculture, Trakia University, Stara Zagora, Bulgaria. Two inspections of the bee colonies were carried out (during wintering in November 2020 and at the beginning of the active season in March 2021). Amount of bees in the bee hive (strength) and amount of capped honey in the honeycombs were reported. In bee colonies wintering in hives with a lattice bottom, the consumption of food per 1 kg of bees was 1.639 kg (50%) higher than in hives with a solid bottom. Winter mortality of bees in hives with a lattice bottom was higher compared to this indicator in the hives with a solid bottom, 16.19±10.72% and 12.59±3.57%, respectively, which can be considered excellent wintering below 15% and good wintering in the range of 15.0-19.99%.