Revista Agro Productividad
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Prediction of weaning weight of grazing beef by machine learning
Get PDFObjective: Train and validate models with variables available at the time of calving to predict the weaning weight (WW) of grazing beef cattle.
Design/methodology/approach: Machine learning (ML) and ordinary least squares (OLS) algorithms were used to model WW of grazing beef calves. There were three scenarios of variable’s availability for modeling, the model of best fit was identified using the determination coefficient (r2), the mean square error and bias.
Results: ML models were better than OLS in all scenarios. The r2 was 0.70, 0.67 and 0.78 for the ML with the following modeling variables available: B) dam age and parturition, sex and birth weight, age at weaning and month of birth; I) additionally, dam’s weight at calving, type of calving, calf and dam racial purity; A) additionally, type of service, cow and sire tags.
Limitations on study/implications: The ML and OLS models were representative of this specific database. Further modeling with regional or national databases are needed. Under scenario B, the ML was better in modeling the WW with basic data.
Findings/conclusions: The ML was superior to the OLS without over fitting, since WW predictions were adequate for data not included in model training.Objective: To develop and validate models using the variables available at calving to predict the weaning weight (WW) of grazing beef calves.
Design/Methodology/Approach: The WW was modelled using machine learning (ML) algorithms and ordinary least squares (OLS). The model included three variable availability scenarios and the best fit was identified using the coefficient of determination (r2), the mean squared error, and the bias.
Results: ML algorithms achieved a better fit than OLS in all scenarios. ML had a 0.70, 0.67, and 0.78 r2 when the following modelling variables were available: B) dam age at calving and parity, calf sex and weight, weaning age, and calving date; I) in addition to the previous variables, dams’ weight at calving, type of calving, calf and cow racial purity; and A) in addition to the all the previous variables, type of service, cow and sire tags and sire breed.
Study Limitations/Implications: The ML and OLS models were representative of a specific database. Modelling based on regional or national data should be studied. Using the lowest number of variables in this study, ML in scenario B provided an acceptable fitting for the prediction modelling of the WW of grazing beef calves.
Findings/Conclusions: ML performed better than OLS, without causing an overfitting, based on the suitability of the WW predictions regarding a database that was not used to train the model
Bat community structure in the Tabasco Plain wetlands
Get PDFObjetive: Describe the diversity of bat communities in two types of wetlands within the coastal plain of Tabasco's state to.
Metodology: Samplings were carried out during three consecutive years in two different seasons of the year, dry and rainy; two types of vegetation, mangrove forest and popal-tular were considered. Mist-nets were used during three effective sampling days per station, spanning six-hour periods within 30-minute monitoring intervals.
Results: A total of 510 individuals representing 22 bat species of six families were registered; the phyllostomid bats presented the highest richness and abundance. The bat species Artibeus jamaicensis, Noctilio leporinus, and Glossophaga soricine were the most representative. We found enhanced richness in the mangrove forest with 18 bat species, while popal-tular vegetation 12 species were found; the diversity of order 1 indicated that the mangrove forest richness is 0.78, which is highest than the popal-tular vegetation. Seven food guilds were identified, the frugivores were the most dominant; additionally, three bat species are under protection based on NOM-059-SEMARNAT-2010, representing 12% of the state's protected species.
Implications: Evaluating the bats community in wetlands is important to know the richness and abundance of this group, to generate base information
Conclusions: Mangrove forests were the type of vegetation with the largest richness and abundance of bats, which might be considered crucial for the conservation of this group of mammals, providing shelter and food. In general, wetlands are important habitats for this group.Objective: To describe the diversity of bat communities in two types of wetlands in the coastal region of the Tabasco Plain.
Methodology: Sampling was carried out at two different times of the year (dry and wet seasons) for three consecutive years, considering two types of vegetation (mangrove and popal-tular). The samples were collected during 3 effective days (6 h periods with 30 min monitoring intervals) per station, using mist nets.
Results: A total of 510 individuals belonging to 22 species of six families were recorded; the phyllostomid bats were the most diverse and abundant. The Artibeus jamaicensis, Noctilio leporinus, and Glossophaga soricina species were the most representative. The vegetation with the greatest diversity was the mangrove with 18 species, while 12 species were found in the popal-tular areas. The diversity of order 1 indicates that the mangrove has 0.78 more diversity than the popal-tular. Seven food guilds were present, including the dominant frugivorous animals. Only three species fall within a protection category, according to NOM-059-SEMARNAT-2010; they comprise 12% of the protected species in the state of Tabasco, Mexico.
Implications: In order to determine their diversity and abundance —and ultimately to develop base information—, communities in the wetlands must be evaluated.
Conclusions: The mangroves host the greatest diversity and abundance of bats to which they provide shelter and food. Therefore, they are considered crucial for their conservation and, overall, they are important habitats for this grou
Effect of different stocking densities in juveniles of American crocodile (Crocodylus acutus, Crocodilia, Crocodylidae) in captivity
Get PDFObjective: The present study focused on the effect of different stocking densities:12 (D12), 18 (D18) and 24 (D24) individuals/m2 on growth (weight and length) and survival in juvenile river crocodiles (Crocodylus acutus).
Design/methodology/approach: The crocodiles were cultured in each treatment by triplicate for 43-days in nine plastic tanks and fed a diet based on a mix of beef liver, fish and commercial dog food.
Results: At the end of the experiment, there were not significant differences among treatments in the growth variables, recording a low increment in weight and total length (38.99 ± 8.96 g and 4.19 ± 1.36 cm; mean ± SD) in all densities as well as overall survival of 62.02 ± 7.67% (mean ± SD). The stocking density of 24 individuals/m2 was significantly higher in biomass production by m2 for the stocking densities of 18 and 12 individuals (p<0.05).
Limitations on study/implications: The development of culture techniques is a tool to assess the potential of this ecologically important species for its conservation and eventual commercialization.
Findings/conclusions: Based on the results, it can be recommended a stocking density of 24 individuals/m2 (D24) to optimize the use of space and infrastructure profitability.Objective: To evaluate the effect of different stocking densities:12 (D12), 18 (D18) and 24 (D24) individuals m-2 (ind m-2) on growth (weight and length) and survival in juvenile river crocodiles (Crocodylus acutus).
Design/methodology/approach: The crocodiles were cultured in each treatment by triplicate for 43-d in nine plastic tanks and fed a diet based on a mix of beef liver, fish and commercial dog food.
Results: At the end of the experiment, there were not significant differences among treatments in the growth variables, recording a low increment in weight and total length (38.99 ± 8.96 g and 4.19 ± 1.36 cm; mean ± SD) in all densities as well as overall survival of 62.02 ± 7.67% (mean ± SD). The stocking density of 24 ind m-2 was significantly higher in biomass production by m2 for the stocking densities of 18 and 12 individuals (p < 0.05).
Limitations on study/implications: The development of culture techniques is a tool to assess the potential of this ecologically important species for its conservation and eventual commercialization.
Findings/conclusions: It can be recommended a stocking density of 24 ind m-2 (D24) to optimize the use of space and infrastructure profitabilit
Coffee (Coffea arabica L.) harvesting time and its influence on the seed quality of the Costa Rica 95 and Garnica varieties
Get PDFABSTRACT
Objective: The objective of this research was to determine the importance of the harvest time, on the physical quality and viability of the seed by means of the tetrazolium test.
Design/methodology/approach: The research was conducted under a completely randomized experimental design, the viability in embryos was taken based on a 5-color staining pattern. An analysis of variance and the comparison of means by Tukey (P? 0.05) were performed with the SAS 9.2 program.
Results: The varieties under study showed significant differences in all the variables studied related to physical quality of seeds, such as volumetric weight and weight of 1000 seeds. The best seed viability was obtained in the harvest season of January.
Limitations of the study/implications:The results obtained are limited to the varieties, environmental conditions and the time in which the varieties were evaluated.
Conclusions: The harvest time has an effect on better seed physical characteristics and better viability evaluated with tetrazolium in the seeds of coffee varieties.Objective: To determine the impact of the harvesting time of two coffee varieties on the physical quality and viability of seeds, using the tetrazolium testing.
Design/Methodology/Approach: The research was carried out using a completely randomized design; the evaluation of the embryo viability was based on a five-color pattern staining design. The Garnica and Costa Rica 95 varieties and two harvesting times were used (December and January). An analysis of variance and a Tukey’s means comparison test (p ≤ 0.05) were carried out, using the SAS 902 software.
Results: The study varieties showed significative differences in all the variables related to the physical quality of the seeds, including volumetric weight and weight of 1,000 beans. The best seed viability was obtained during the harvest carried out in January.
Study Limitations/Implications: The results obtained are limited to the varieties in question, as well as the environmental conditions and period during which the said varieties were evaluated.
Conclusions: The harvesting time of the two varieties of coffee has an influence on the physical characteristics of the seeds and on the viability, evaluation carried out using tetrazolium
Implementation of stubble in agricultural production: A review
Get PDFObjective: Elucidate the benefits that agricultural residues or stubble have in agricultural activities, this through a bibliographic and objective review that helps to make the actors of agricultural sector aware of the benefits and their correct implementation in production systems.
Design/methodology/approach: Detailed review of scientific articles from the main academic databases and repositories. Taking into account aspects such as the use of stubble as plant cover; effects and changes in physical and chemical structure of soil; crop yield and use for livestock feeding.
Results: The use of stubble has beneficial effects on agricultural activities. In agriculture it is proven that they have positive effects for the proliferation of beneficial organisms and assimilation of nutrients, which are easily absorbed by plants, consequently, crop yield is maximized in quantity and quality. In livestock sector, the stubble implement provides nutrients such as proteins, ashes and vitamins, which together with conventional diets, reduce production costs and improve meat and milk production.
Limitations on study/implications: The repertoire of scientific articles of stubble is very broad, making it difficult to assimilate the information. In Mexico, particularly, more research is needed to inform farmers of the possible uses of stubble.
Findings/conclusions: The use of stubble in agricultural activities generates benefits at ecological and economic levels, which ensure the sustainability and resilience of agroecosystems. Nutritional content of stubble is a function of the species and/or varieties of agricultural species. The lack of knowledge in the management of stubble leads to these being incinerated, releasing particles and toxic and polluting substances for the environment, further favoring the conditions for greenhouse effect.
Keywords: stubble, vegetation cover, yield, sustainability, resilience.Objective: To elucidate the benefits that agricultural residues or stubble have in agricultural activities, through a bibliographic and objective review that could help to make the actors of agricultural sector aware of the benefits and their correct implementation in production systems.
Design/methodology/approach: A detailed review of scientific articles from the main academic databases and repositories was performed. We took into account aspects such as the use of stubble as plant cover; effects and changes in physical and chemical structure of soil; crop yield and use for livestock feeding.
Results: The use of stubble has beneficial effects on agricultural activities. In agriculture, they have positive effects for the proliferation of beneficial organisms and assimilation of nutrients, which are easily absorbed by plants. Consequently, crop yield is maximized both in quantity and quality terms. In livestock sector, the stubble implement provides nutrients such as proteins, ashes and vitamins, which together with conventional diets, reduce production costs and improve meat and milk production.
Limitations on study/implications: The repertoire of scientific articles related to stubble is very broad, making it difficult to assimilate the information. In Mexico, particularly, more research is needed to inform farmers of the possible uses of stubble.
Findings/conclusions: The use of stubble in agricultural activities generates benefits at ecological and economic levels, which ensure the sustainability and resilience of agroecosystems. Nutritional content of stubble is a function of the species and/or varieties of agricultural species. The lack of knowledge in the management of stubble leads to these being incinerated, releasing particles and toxic and polluting substances for the environment, further favoring the conditions for greenhouse effect
Sensory perspectives of the consumption of chips-type snacks made from black bean (Phaseolus vulgaris L) and peanut (Arachis hypogaea Linn) flours by university students in the Toluca Valley
Get PDFObjective: The objective of this study is to evaluate the sensory perspectives of chips-type snacks made from black bean dry (Phaseolus vulgaris L) and peanut (Arachis hypogaea Linn) flours in a university population.
Design/methodology/approach: Two formulations were realized from peanut and black bean previously toasted and milled: 1) (PF) 50% peanut flour, 12.5% rice flour and 12.5 % cornstarch; 2) (BbF) 50% black bean flour, 12.5% wheat flour and 12.5% cornstarch. Each mixture of flours was extruded and fried until obtained chips-type snacks. A statistical-descriptive study was carried out from the observation of the eating habits of university students in the State of Mexico. On other hand, an affective test was tested to evaluate the acceptance of chips-type snacks made with PF and BbF in the categories of odor, taste, hardness, and easy to break.
Findings/conclusion:
According to the questionnaire, the female gender has higher snack consumption than the male population. On another hand, potato chips are in third place as the most consumed snacks for women they preferred to consume them in their houses. Peanut and chickpea flour are the most preferred by the female population. There was no significant difference (p˃0.05) between the snacks prepared with PF and BbF, but 60% of the consumer accepted both snacks. It is concluded that the chips-type snacks made with different formulations could be a healthy alternative for the students, also it kind of products have good acceptability. Finally knowing the sensory perspectives could provide important information for developing healthier and easier-to-eat snacks.
Limitations on study/implications: More studies about the characterization of the chips-type snacks are required, also a mix of both legumes could be realized
Characterization of black mangrove (Avicennia germinans) and red mangrove (Rhizophora mangle) ecosystems in Paraíso, Tabasco, Mexico
Get PDFObjective: The characterization of black and red mangrove ecosystems in the coastal zone of Paraiso, Tabasco, Mexico.
Design/methodology/approach: Four plots were randomly set in each mangrove ecosystem. Inside each plot, trees were counted, and measured for basal area, DBH, vegetation cover and height. We estimated seven diametric classes to calculate the relative species richness and emergence/disappearance dynamics in both ecosystems. Soil samples were survey at two depths and during different seasons (dry and rainfall), the samples were tested for organic matter (OM), soil organic carbon (SOC), nitrogen content (N), phosphorus (Olsen P), pH, exchangeable bases and humic and fulvic acids; with the objective to characterize nutrient flux dynamics between seasons and compare the two mangrove ecosystems.
Results: Red mangrove ecosystems contains higher OM during rainy season. Black mangrove ecosystems showed low contents of OM and exchangeable bases during dry season. More species richness was achieved by red mangroves, and black mangroves presented higher and thicker trees.
Limitations on study/implications: Regional characterization of mangrove ecosystems provide information about nutrient flux, which is necessary to the adequate proposal of protection and conservation programs of these wetlands.
Findings/conclusions: Dominant mangrove specie affect nutrient flux in soils associated to these ecosystems, suggesting they have specific functions in the ecosystem dynamics.O
Objective: To characterize black and red mangrove ecosystems in the coastal zone of Paraíso, Tabasco, Mexico.
Design/Methodology/Approach: Four plots were randomly established in each mangrove ecosystem. Inside each plot, trees were counted per transect, and measured for basal area, diameter at breast height, plant cover and height. Seven diametric classes were estimated to calculate the relative species richness and the dynamics of emergence/disappearance in the ecosystem. Soil samples were surveyed at two depths and during different seasons (dry and rainy). The samples were tested for organic matter (OM), nitrogen content (N), phosphorus (Olsen P), pH, exchangeable bases and humic and fulvic acids; with the objective to characterize nutrient flux dynamics between seasons and compare the two mangrove ecosystems.
Results: Red mangrove ecosystems contain higher OM during rainy season. Black mangrove ecosystems showed low contents of OM and exchangeable bases during dry season. The species with more individuals m-2 is red mangrove, and black mangrove presents individuals with greater basal area and diameters.
Study Limitations/Implications: Regional characterization of mangrove ecosystems provides information about nutrient flux, which is necessary for the adequate proposal of protection and conservation programs of these wetlands.
Findings/Conclusions: The dominant mangrove species affects nutrient flux in soils associated to the ecosystem, suggesting they have specific functions in the ecosystem dynamics
Detection of huanglongbing of citruses (Citrus sp.) through Sentinel-2satellite images in Huimanguillo, Tabasco, Mexico
Get PDFObjective: develop a fast, practical and economical methodology for the determination of plants with HLB symptoms, by exploring the potential use of Sentinel-2 satellite images.
Design/methodology/approach: Sentinel-2 images were used to perform a supervised classification to discriminate healthy Persian lime trees and trees with HLB molecularly verified by qPCR, as well as other land uses in the citrus growing area of Huimanguillo, Tabasco.
Results: The results showed that in the green (560nm), red (665 nm) and near infrared (705 nm) band regions the spectral response of trees with HLB is higher than that of healthy trees. An area of 26.96 and 12 981 hectares of Persian lime affected and free of HLB was found, respectively, with an accuracy of 0.84 % and a Kappa coefficient of 0.83. Field verification corroborated three plantations in which plants with HLB were previously detected and are currently in production.
Limitations on study/implications: The study was carried out in the period of less cloud cover, as this is a limiting factor for the analysis of the image since it can lead to inadequate tracking of the affected area.
Findings/conclusions: The results showed that using Sentinel-2 satellite images, it is possible to differentiate Persian lemon plants affected by HLB from healthy plants.Objective: Develop a fast, practical, and inexpensive methodology for determining plants with HLB symptoms by exploring the potential use of Sentinel-2 satellite images.
Design/Methodology/Approach: Sentinel-2 images were used to perform a supervised classification to discriminate healthy Persian lime trees and trees with HLB molecularly verified by qPCR, and other land uses in the citrus growing area of Huimanguillo, Tabasco.
Results: The results showed that in the green (560nm), red (665 nm), and near-infrared (705 nm) band regions, the spectral response of trees with HLB is higher than that of healthy trees. Likewise, there is an area of 26.96 and 12 981 hectares of Persian lime affected and free of HLB, respectively, with an accuracy of 0.84 % and a Kappa coefficient of 0.83. Field verification corroborated three plantations where plants with HLB were previously detected and are currently in production.
Study Limitations/Implications: The study was carried out in the season of less cloud cover, as this is a limiting factor for the image analysis since it can lead to inadequate tracking of the affected area.
Findings/Conclusions: The results showed that it is possible to differentiate Persian lime plants affected by HLB from healthy plants using Sentinel-2 satellite image
Validation of a model to estimate climate effects on wheat (Triticum aestivum L.) production in a hydrological basin
Get PDFObjective. To validate a simulation model which enables the estimation of wheat (Triticum aestivum L.) production, based on climatic variables in the lower Mayo River basin in Sonora, Mexico.
Design/methodology/ approach. The Soil and Water Assessment Tool (SWAT) Crop Yield simulation model was used to estimate productive wheat yields. The model was fed with climatic data for the 1979-2014 period, provided by the National Centers for Environmental Prediction. Subsequently, the results were validated using the Nash-Sutcliffe, PBIAS, and R2 statistics. The predictive capacity of the model was validated in four of the six Hydrological Response Units with agricultural land in the study area: 26, 27, 28, and 31.
Study limitations/implications. The model does not include adaptation measures and future production scenarios based on climate data estimation must be developed.
Findings/conclusions. The influence of climate change on wheat production has been confirmed; the predictive model used is an important tool that can be adjusted and adapted to other regions and production systems.
Morphology and forage quality in buffel, rhodes, and blue grama grasses in Valle del Mezquital: Grasses of semiarid
No full textThe objective of the study was to evaluate the production and quality of forage in buffel (Pennisetum ciliare), rhodes (Chloris gayana) and blue grama (Bouteloua gracilis) with three defoliation dates at 50, 80 and 110 days after regrowth (dar) in Valle del Mezquital. Crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), total digestible nutrients (TDN), relative forage value (RFV) and metabolic energy (ME) were determined. A completely randomized design with three repetitions was used and Tukey for separation of means (α 0.05) and GLM SAS to analyzer data. The highest forage production occurs in rhodes grass at 110 dar (12936 kg DM ha-1). The highest CP (10.6%) was found in buffel at 50 ddr, in rhodes grass both values (80 and 110) dar the were lower than 7%. The largest RFV were for exotic grasses; however, blue grama registered higher TDN. The lowest ME is operated in rhodes at 80 dar (1.76) and higher for buffel at 50 dar (1.91). The three varieties could defoliate when the plants show intermediate values in yield and nutritional value, that is, after 80 days of regrowth; individually it is recommended to defoliate buffel and rhodes at 50 dar.This study aims to evaluate the production and quality of buffel (Pennisetum ciliare), rhodes (Chloris gayana), and blue grama (Bouteloua gracilis) forage with three defoliation dates —at 50, 80, and 110 days after regrowth (dar)— in Valle del Mezquital. Crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), total digestible nutrients (TDN), relative feed value (RFV), and metabolizable energy (ME) were determined. A completely randomized design with three repetitions, a Tukey test for mean separation (α 0.05), and SAS Proc GLM for data analysis were used. The highest forage production occurs in the rhodes forage at 110 dar (12,936 kg DM ha-1). The highest CP (10.6%) was found in the buffel forage at 50 dar; in the rhodes forage, both values (80 and 110) were lower than 7%. The highest RFV was obtained by exotic grasses; however, higher TDN was recorded for the blue grama grass. Rhodes grass obtained the lowest ME at 80 dar (1.76), while the highest ME was obtained by buffel at 50 dar (1.91). The three varieties can be defoliated when the plants show intermediate yield and nutritional value, i.e., 80 days after the regrowth begins; nevertheless, buffel and rhodes should be defoliated at 50 dar