Pub Date : 2021-12-01DOI: 10.15547/ast.2021.04.061
S. Chobanova, D. Penkov
Abstract. Using adapted methods for balanced experiments with poultry, the true digestibility coefficients of the essential amino acids of two high protein sunflower meals – 40+® and 47® have been established. The true digestibility coefficients by using two methods – with intact and randomized (caecectomized) birds have been compared. Six birds were tube fed and six – feed deprived for both of the fodders. The amino acids were established with amino analyzer AAA-881 after preliminary HCl hydrolysis. The mean digestibility of sunflower meal 40+® is higher in intact (88.11 versus 85.73 of sunflower meal 47®) compared to randomized birds (87.20 versus 85.46 of sunflower meal 47®). The differences by lots are statistically significant only in intact birds. The authors recommend for practical needs to use the average true digestibility coefficients between both meals, established with randomized birds (ileal digestibility).
{"title":"True digestibility of the essential amino acids of high-protein sunflower meals by balanced experiments with intact and caecectomized birds from Gallus species","authors":"S. Chobanova, D. Penkov","doi":"10.15547/ast.2021.04.061","DOIUrl":"https://doi.org/10.15547/ast.2021.04.061","url":null,"abstract":"Abstract. Using adapted methods for balanced experiments with poultry, the true digestibility coefficients of the essential amino acids of two high protein sunflower meals – 40+® and 47® have been established. The true digestibility coefficients by using two methods – with intact and randomized (caecectomized) birds have been compared. Six birds were tube fed and six – feed deprived for both of the fodders. The amino acids were established with amino analyzer AAA-881 after preliminary HCl hydrolysis. The mean digestibility of sunflower meal 40+® is higher in intact (88.11 versus 85.73 of sunflower meal 47®) compared to randomized birds (87.20 versus 85.46 of sunflower meal 47®). The differences by lots are statistically significant only in intact birds. The authors recommend for practical needs to use the average true digestibility coefficients between both meals, established with randomized birds (ileal digestibility).","PeriodicalId":55762,"journal":{"name":"Agricultural Science and Technology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46414810","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-01DOI: 10.15547/ast.2021.04.059
I. Valchev, K. Stojanchev, R. Binev
Abstract. Contamination of poultry feeds with mycotoxins is a global problem faced by poultry industry due to increased demands and availability of poor-quality cereals. The aim of the present study was to evaluate the beneficial effects of a mycotoxin binder (Mycotox NG) on relative weights of internal organs in Pekin ducks with experimental aflatoxicosis. The birds were divided into one control and six experimental groups (n=10) as follows: group І (0 mg/kg AFB1 without Mycotox NG); group ІI (0.5 g/kg Mycotox NG); group ІІI (1.0 g/kg Mycotox NG); group IV (0.2 mg/kg AFB1); group V (0.4 mg/kg AFB1); group VI (0.2 mg/kg AFB1 + 0.5 g/kg Mycotox NG) and group VII (0.4 mg/kg AFB1 + 1.0 g/kg Mycotox NG). Trial duration was 42 days. It was established that ducks fed AFB1-contaminated feed had increased relative weights of liver, kidneys, pancreas, heart, gizzard and proventriculus compared to the control group. At the same time, the relative weights of immunocompetent organs (thymus, spleen and bursa of Fabricius) were reduced. The addition of Mycotox NG to the feed contaminated with AFB1 compensated partly the changes in relative weights of visceral organs. The results from the present study demonstrated that the tested toxin binder could be effective for reduction of toxic effects of aflatoxins in domestic ducks.
{"title":"Influence on Mycotox® NG effects on relative weights of some internal organs in Pekin ducks with experimentally reproduced aflatoxicosis В1","authors":"I. Valchev, K. Stojanchev, R. Binev","doi":"10.15547/ast.2021.04.059","DOIUrl":"https://doi.org/10.15547/ast.2021.04.059","url":null,"abstract":"Abstract. Contamination of poultry feeds with mycotoxins is a global problem faced by poultry industry due to increased demands and availability of poor-quality cereals. The aim of the present study was to evaluate the beneficial effects of a mycotoxin binder (Mycotox NG) on relative weights of internal organs in Pekin ducks with experimental aflatoxicosis. The birds were divided into one control and six experimental groups (n=10) as follows: group І (0 mg/kg AFB1 without Mycotox NG); group ІI (0.5 g/kg Mycotox NG); group ІІI (1.0 g/kg Mycotox NG); group IV (0.2 mg/kg AFB1); group V (0.4 mg/kg AFB1); group VI (0.2 mg/kg AFB1 + 0.5 g/kg Mycotox NG) and group VII (0.4 mg/kg AFB1 + 1.0 g/kg Mycotox NG). Trial duration was 42 days. It was established that ducks fed AFB1-contaminated feed had increased relative weights of liver, kidneys, pancreas, heart, gizzard and proventriculus compared to the control group. At the same time, the relative weights of immunocompetent organs (thymus, spleen and bursa of Fabricius) were reduced. The addition of Mycotox NG to the feed contaminated with AFB1 compensated partly the changes in relative weights of visceral organs. The results from the present study demonstrated that the tested toxin binder could be effective for reduction of toxic effects of aflatoxins in domestic ducks.","PeriodicalId":55762,"journal":{"name":"Agricultural Science and Technology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46079061","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-01DOI: 10.15547/ast.2021.04.068
A. Ajibare, O. Olawusi-Peters, K. A. Oyinlola
Abstract. This study investigated the condition factor with microbial load of Nematopalaemon hastatus (Aurivillius, 1898) collected for two years from four coastal towns in Ilaje communities of Ondo State, Nigeria. Shrimps’ weight, length and condition factor were determined using standard methods while estimation of microbial load (Total heterotrophic bacteria, coliform, Escherichia coli, Salmonella/Shigella, and fungal counts) was done using standard microbiological methods. The correlation between microbial load and condition factor was thereafter determined using regression analysis. N. hastatus exhibited allometric growth, with low but consistent condition factor. Mean heterotrophic bacteria count was 1.107×102 CFU/g and 1.079×102 CFU/g during the dry and wet season, respectively. Mean coliform count, total Salmonella-Shigella and E. coli counts were 0.398×102 CFU/g, 0.218×102 CFU/g and 0.303×102 CFU/g, respectively, during the wet season. A significant increase in counts (mean) was observed in the dry season for the coliform (0.404×102 CFU/g), total Salmonella-Shigella (0.234×102 CFU/g) and E. coli (0.326×102 CFU/g). The mean fungal count was 0.604×102 SFU/g and 0.563×102 SFU/g during the wet and dry seasons, respectively. The microbial loads were below acceptable limits; therefore, shrimps of the study area are safe for consumption. Conclusively, the condition factor of the shrimps was non-significantly influenced by the microbes. However, there is a need to regulate and/or prevent untreated sewage and effluent discharge into natural water bodies to reduce the environmental hazards it may portend and also obtain relatively safe aquatic products for consumption.
{"title":"Microbiological load evaluation of white shrimp (Nematopalaemon hastatus Aurivillius, 1898) in the coastal waters of Ondo state, Nigeria","authors":"A. Ajibare, O. Olawusi-Peters, K. A. Oyinlola","doi":"10.15547/ast.2021.04.068","DOIUrl":"https://doi.org/10.15547/ast.2021.04.068","url":null,"abstract":"Abstract. This study investigated the condition factor with microbial load of Nematopalaemon hastatus (Aurivillius, 1898) collected for two years from four coastal towns in Ilaje communities of Ondo State, Nigeria. Shrimps’ weight, length and condition factor were determined using standard methods while estimation of microbial load (Total heterotrophic bacteria, coliform, Escherichia coli, Salmonella/Shigella, and fungal counts) was done using standard microbiological methods. The correlation between microbial load and condition factor was thereafter determined using regression analysis. N. hastatus exhibited allometric growth, with low but consistent condition factor. Mean heterotrophic bacteria count was 1.107×102 CFU/g and 1.079×102 CFU/g during the dry and wet season, respectively. Mean coliform count, total Salmonella-Shigella and E. coli counts were 0.398×102 CFU/g, 0.218×102 CFU/g and 0.303×102 CFU/g, respectively, during the wet season. A significant increase in counts (mean) was observed in the dry season for the coliform (0.404×102 CFU/g), total Salmonella-Shigella (0.234×102 CFU/g) and E. coli (0.326×102 CFU/g). The mean fungal count was 0.604×102 SFU/g and 0.563×102 SFU/g during the wet and dry seasons, respectively. The microbial loads were below acceptable limits; therefore, shrimps of the study area are safe for consumption. Conclusively, the condition factor of the shrimps was non-significantly influenced by the microbes. However, there is a need to regulate and/or prevent untreated sewage and effluent discharge into natural water bodies to reduce the environmental hazards it may portend and also obtain relatively safe aquatic products for consumption.","PeriodicalId":55762,"journal":{"name":"Agricultural Science and Technology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44785170","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-01DOI: 10.15547/ast.2021.04.055
K. Vasileva, N. Bogatzevska
Abstract. The limit values of resistance groups were established to Xanthomonas euvesicatoria and Xanthomonas vesicatoria by mean score – ms based on conducted statistical analysis of 155 selection lines of Bulgarian, introduced hybrids and pepper varieties: I- immune; R- resistant; MS- medium sensitive; S- sensitive; SS- strongly sensitive. The genetic diversity between the two bacteria suggest the use of separate resistant groups to determine the resistance. Data on the mean score of infestation on 116 pepper accessions to X. euvesicatoria and 155 (the previous 116 included) to X. vesicatoria were processed and the resistance groups were defined. Breeding pepper accessions with complex resistance requires the application of the established resistance groups to both pathogens. The limit values of the groups by ms based on the statistical analysis of the data on the resistance of pepper accessions to X. euvesicatoria and X. vesicatoria were specified.
{"title":"Statistical analysis of resistance variability of pepper accessions to Xanthomonas euvesicatoria and Xanthomonas vesicatoria","authors":"K. Vasileva, N. Bogatzevska","doi":"10.15547/ast.2021.04.055","DOIUrl":"https://doi.org/10.15547/ast.2021.04.055","url":null,"abstract":"Abstract. The limit values of resistance groups were established to Xanthomonas euvesicatoria and Xanthomonas vesicatoria by mean score – ms based on conducted statistical analysis of 155 selection lines of Bulgarian, introduced hybrids and pepper varieties: I- immune; R- resistant; MS- medium sensitive; S- sensitive; SS- strongly sensitive. The genetic diversity between the two bacteria suggest the use of separate resistant groups to determine the resistance. Data on the mean score of infestation on 116 pepper accessions to X. euvesicatoria and 155 (the previous 116 included) to X. vesicatoria were processed and the resistance groups were defined. Breeding pepper accessions with complex resistance requires the application of the established resistance groups to both pathogens. The limit values of the groups by ms based on the statistical analysis of the data on the resistance of pepper accessions to X. euvesicatoria and X. vesicatoria were specified.","PeriodicalId":55762,"journal":{"name":"Agricultural Science and Technology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45376211","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-01DOI: 10.15547/ast.2021.04.060
H. Lukanov, I. Pavlova, A. Genchev
Abstract. The study was conducted with 224 domestic quails from the specialized meat-type WG line. The duration of fattening period and sex on productive traits, slaughter traits and meat quality of quails was evaluated. The study has shown that the longer duration of the fattening period in quails from the meat-type line WG was associated with lower production efficiency, with more reduction after the 35th day of life. The production efficiency in male quails was lower compared to that in females. The dispersion analysis demonstrated that the determination of 72.2% and 69.6% of dressed carcass weight and deboned meat weight, respectively, depended on fattening period duration (p<0.001). When fattening increased from 28 to 42 days, the amount of feed necessary for one bird increased by 73% and 87%, corresponding to increased costs by 64.5% and 77%. For production of 1 kg dressed quail carcasses, the necessary feed increased by 42.3-45.8% on a weight basis and by 35-37.7% on a cost basis. For production of 1 kg deboned quail meat, corresponding increases are by 42.1-49.5% and 34.8-41.2%, respectively. The period between 28 and 35 days of age was the most appropriate for planning slaughter of WG quails. During that period, the economic efficiency, although already declining, was still within acceptable limits and the increase in quantitative traits in both sexes – still relevant, making the produce more attractive for consumers. With age, the changes in colour characteristics of M. pectoralis superficialis result in darkening of meat (p<0.001). Thus, it assumes nuances specific rather for game meat. This effect is desirable, as it improves the commercial presentation of domestic quail meat in line with consumers’ attitudes.
{"title":"Effect of different fattening period duration on meat productivity of domestic quails","authors":"H. Lukanov, I. Pavlova, A. Genchev","doi":"10.15547/ast.2021.04.060","DOIUrl":"https://doi.org/10.15547/ast.2021.04.060","url":null,"abstract":"Abstract. The study was conducted with 224 domestic quails from the specialized meat-type WG line. The duration of fattening period and sex on productive traits, slaughter traits and meat quality of quails was evaluated. The study has shown that the longer duration of the fattening period in quails from the meat-type line WG was associated with lower production efficiency, with more reduction after the 35th day of life. The production efficiency in male quails was lower compared to that in females. The dispersion analysis demonstrated that the determination of 72.2% and 69.6% of dressed carcass weight and deboned meat weight, respectively, depended on fattening period duration (p<0.001). When fattening increased from 28 to 42 days, the amount of feed necessary for one bird increased by 73% and 87%, corresponding to increased costs by 64.5% and 77%. For production of 1 kg dressed quail carcasses, the necessary feed increased by 42.3-45.8% on a weight basis and by 35-37.7% on a cost basis. For production of 1 kg deboned quail meat, corresponding increases are by 42.1-49.5% and 34.8-41.2%, respectively. The period between 28 and 35 days of age was the most appropriate for planning slaughter of WG quails. During that period, the economic efficiency, although already declining, was still within acceptable limits and the increase in quantitative traits in both sexes – still relevant, making the produce more attractive for consumers. With age, the changes in colour characteristics of M. pectoralis superficialis result in darkening of meat (p<0.001). Thus, it assumes nuances specific rather for game meat. This effect is desirable, as it improves the commercial presentation of domestic quail meat in line with consumers’ attitudes.","PeriodicalId":55762,"journal":{"name":"Agricultural Science and Technology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43081931","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-09-01DOI: 10.15547/ast.2021.03.037
A. Zhivondov, S. Savchovska, S. Pandova, D. Petkova, P. Doykina, I. Manolov
Abstract. The article presents a three-year traceability (2018, 2019, 2020) of biometric results of the fruits of eight peach and nectarine varieties. The study covers the fifth, sixth and seventh vegetation period from the period of full fruiting. Varieties included in this investigation were “Filina” (peach, clingstone), “Gergana” (nectarine, clingstone), “July Lady” (peach, semi-clingstone), “Ufo 4” (flat peach, semi-clingstone), “Laskava” (peach, freestone), “Morsiani 90” (nectarine, freestone), “Flat Queen” (flat peach, freestone), and “Evmolpiya” (peach, freestone). The experimental collection plantation was created in the spring of 2014 on the territory of the Fruit Growing Research Institute, Plovdiv, (lat. 42.10384828045957 and long. 24.72164848814686). The data analysis shows that the varieties “Laskava” and “Evmolpiya” produce fruits with the highest weight – 319.60 g and 303.60 g, respectively. Medium weight is registered in the “Morsiani 90” variety (226.07 g) and the “July Lady” variety (193.87 g). “UFO 4” is characterized with the smallest fruits – an average of 143.83 g and the highest flesh yield. Considering the fact that the “Filina” variety is very early ripening, its fruits can be treated as large for the season – 170.21 g. The stones of the “July Lady”, “Morsiani 90” and “Evmolpiya” varieties have the largest average mass
{"title":"Biometric data of peach and nectarine fruit and stones","authors":"A. Zhivondov, S. Savchovska, S. Pandova, D. Petkova, P. Doykina, I. Manolov","doi":"10.15547/ast.2021.03.037","DOIUrl":"https://doi.org/10.15547/ast.2021.03.037","url":null,"abstract":"Abstract. The article presents a three-year traceability (2018, 2019, 2020) of biometric results of the fruits of eight peach and nectarine varieties. The study covers the fifth, sixth and seventh vegetation period from the period of full fruiting. Varieties included in this investigation were “Filina” (peach, clingstone), “Gergana” (nectarine, clingstone), “July Lady” (peach, semi-clingstone), “Ufo 4” (flat peach, semi-clingstone), “Laskava” (peach, freestone), “Morsiani 90” (nectarine, freestone), “Flat Queen” (flat peach, freestone), and “Evmolpiya” (peach, freestone). The experimental collection plantation was created in the spring of 2014 on the territory of the Fruit Growing Research Institute, Plovdiv, (lat. 42.10384828045957 and long. 24.72164848814686). The data analysis shows that the varieties “Laskava” and “Evmolpiya” produce fruits with the highest weight – 319.60 g and 303.60 g, respectively. Medium weight is registered in the “Morsiani 90” variety (226.07 g) and the “July Lady” variety (193.87 g). “UFO 4” is characterized with the smallest fruits – an average of 143.83 g and the highest flesh yield. Considering the fact that the “Filina” variety is very early ripening, its fruits can be treated as large for the season – 170.21 g. The stones of the “July Lady”, “Morsiani 90” and “Evmolpiya” varieties have the largest average mass","PeriodicalId":55762,"journal":{"name":"Agricultural Science and Technology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43515723","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-09-01DOI: 10.15547/ast.2021.03.036
V. Dimitrova, R. Dragov
Abstract. Cotton breeding in Bulgaria is mainly aimed at improving the earliness, productivity and fiber quality of modern varieties. The creation of new genetic diversity is one of the basic prerequisites for the success of breeding programs. The aim of the study was to evaluate cotton lines obtained by intraspecific and remote hybridization combined with backcross technology, with a view to their most effective usage in selection. Twenty-three lines were included in competitive variety trials conducted during the 2014-2017 period. The averaged results showed that lines 550, 639, 641, obtained by remote hybridization, appeared to be very promising. These three lines were distinguished by the best combination of productivity, fiber length and fiber lint percentage, and by these three indicators they exceeded the standard variety Chirpan-539. A new cotton variety Aida (No. 457) was approved, which in seed cotton yield and fiber yield, and technological fiber properties surpassed the standard varieties Chirpan-539 for earliness and productivity and Avangard-264 for fiber quality. The candidate variety 535 continued the state variety testing. Two new candidate cotton varieties No. 550 and No. 553 were released. In the state variety testing the three candidate varieties confirmed their qualities. The obtained lines, distinguished by one trait or by a complex of qualities, enriched the gene pool of Bulgarian cotton.
{"title":"Breeding assessment of new promising cotton lines","authors":"V. Dimitrova, R. Dragov","doi":"10.15547/ast.2021.03.036","DOIUrl":"https://doi.org/10.15547/ast.2021.03.036","url":null,"abstract":"Abstract. Cotton breeding in Bulgaria is mainly aimed at improving the earliness, productivity and fiber quality of modern varieties. The creation of new genetic diversity is one of the basic prerequisites for the success of breeding programs. The aim of the study was to evaluate cotton lines obtained by intraspecific and remote hybridization combined with backcross technology, with a view to their most effective usage in selection. Twenty-three lines were included in competitive variety trials conducted during the 2014-2017 period. The averaged results showed that lines 550, 639, 641, obtained by remote hybridization, appeared to be very promising. These three lines were distinguished by the best combination of productivity, fiber length and fiber lint percentage, and by these three indicators they exceeded the standard variety Chirpan-539. A new cotton variety Aida (No. 457) was approved, which in seed cotton yield and fiber yield, and technological fiber properties surpassed the standard varieties Chirpan-539 for earliness and productivity and Avangard-264 for fiber quality. The candidate variety 535 continued the state variety testing. Two new candidate cotton varieties No. 550 and No. 553 were released. In the state variety testing the three candidate varieties confirmed their qualities. The obtained lines, distinguished by one trait or by a complex of qualities, enriched the gene pool of Bulgarian cotton.","PeriodicalId":55762,"journal":{"name":"Agricultural Science and Technology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42285252","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-09-01DOI: 10.15547//ast.2021.03.047
G. Dineva, K. Peychev, D. Georgiev
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.
{"title":"Pulsation parameters of new and used milking liners with round cross section","authors":"G. Dineva, K. Peychev, D. Georgiev","doi":"10.15547//ast.2021.03.047","DOIUrl":"https://doi.org/10.15547//ast.2021.03.047","url":null,"abstract":"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.","PeriodicalId":55762,"journal":{"name":"Agricultural Science and Technology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48230022","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-09-01DOI: 10.15547/ast.2021.03.048
Galya Hristova, M. Dallev, G. Tihanov
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.
{"title":"Design parameters of furrow forming and compacting roller of the combined seeder STS-80","authors":"Galya Hristova, M. Dallev, G. Tihanov","doi":"10.15547/ast.2021.03.048","DOIUrl":"https://doi.org/10.15547/ast.2021.03.048","url":null,"abstract":"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.","PeriodicalId":55762,"journal":{"name":"Agricultural Science and Technology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44671020","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-09-01DOI: 10.15547/ast.2021.03.044
G. Tihanov, Galya Hristova
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.
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