Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

Objective. To evaluate the botanical composition of grasslands of kikuyu (Cenchrus clandestinus) compared to tall fescue (Lolium arundinaceum cv. Cajun II), each one in association with white clover (Trifolium repens cv. Ladino), in two independent experiments conducted during two seasons, autumn 2018 and winter 2019. Methodology. Two independent experiments under small-scale milk production system (SMPS) were established in the municipality of Aculco, State of Mexico, during autumn 2018 and winter 2019. The botanical composition of grasslands under intensive continuous grazing by breeding cows was evaluated. One grassland planted with tall fescue cv. Cajun II and the other invaded by kikuyu; each grassland was associated with white clover cv. Ladino. The botanical composition of both experiments was analyzed using a complete randomized experimental design. Results. The kikuyu grassland recorded significant differences (p<0.05) with a higher proportion of forage during the winter 2018. Whereas the tall fescue cv. Cajun II grassland recorded a proportion of forage (p<0.05) higher than its proportion of dead tissue during autumn 2019. Study Implications: The study of the botanical composition of mixed grasslands destined for livestock grazing allows to identify, propose and define strategies for forage production facing agroclimatic and management conditions in order to generate a better and higher forage yield. Conclusions: The proportion of kikuyu was higher than that of tall fescue cv. Cajun II during the two seasons and years evaluated. This highlights the adaptability of kikuyu grass under agroecological conditions such as the absence of rains and high temperatures, coupled with the high stocking densities of the milk production systems in the study region.

Objective: To evaluate the dry matter accumulation, morphological composition and height in the Panicum maximum cv. Tanzania grass in order to determine the optimal cutting point under four fertilization schemes. Methodology: Tanzania grass was evaluated with fertilizations: T1) chemical (120-60-00 NPK), T2) vermicompost (10 t ha-1), T3) compost (10 t ha-1), and T4) compost + leachate. Cuts were made every 14 days where dry matter (DM), morphological composition and height were measured. A randomized complete block design was used, with an arrangement of measures repeated over time. Results: The maximum accumulation of DM in the T1, T2 and T3 treatments was at 80 days after cutting, the maximum height was with T1 at 80 days after cutting with 206.2 cm. Fertilization with biological products such as vermicompost, compost+leachate and compost presented a higher proportion and conservation of leaves over time. Study Limitations/Implications: Grasslands are not seen as a crop so in most cases they are not fertilized; when they are, it is done with chemical fertilization so there is little information about organic fertilization in tropical fodders. Conclusions: The optimal cutting point is from 50 DAC for chemical treatment, compost+leachate and vermicompost. Fertilization with vermicompost or compost+leachate can be an inexpensive and affordable option for producers to fertilize their meadows.

Objective: To evaluate the growth dynamics based on the dry matter production of Lotus corniculatus L. variety 202700 and its morphological composition. Design/Methodology/Approach: The study was carried out in the glass greenhouses of the Colegio de Postgraduados in Montecillo, Texcoco, Edo. Mexico, from December 2020 to May 2021. The effect of indole butyric acid (IBA) growth promoter in solid presentation Radix 1500 and liquid Radix T 3000 (S+ESolid and S+ELiquid) and a control (Substrate) was evaluated., a completely randomized design with three replicates was used, each with twenty pots as replicates. 1300 pots were planted, of which 20 of each treatment were taken monthly (30, 60, 90, 120 and 150 days) for subsequent data recording. Results: S+ESolid was the one that presented the highest values ​​followed by S+ELiquid and Witness (S) respectively. Study Limitations/Implications: Destructive sampling of less than 30 days or greater than 150 days was not considered. Findings/Conclusions: The plants with the application of 1500 ppm of IBA registered the greatest response in terms of variables: number of leaves, number of stems, leaves (g), stems (g), roots (g), root height (cm), root volume (cm3), greenness index, leaf area (cm2 /g) and plant height (cm), with respect to the rest of the treatments.

Objective: To evaluate seed, dry matter, and oil content yield in five accessions of castor oil plant (Ricinus communis L.) in the Altiplano Potosino Zacatecano high plateau region of Mexico, grown with a fertigation system on a mixture of sand, tezontle, and compost, with three fertilization levels.Design/Methodology/Approach: The following accessions showed an outstandingly favorable response to fertilization: ZACS2C1 (Orito Zac) which had the greater seed yield (735 g) and oil content (50.30 ± 5.23); and SLPS11C1 which had the greater weight per100 seeds (56.77 ±2.35) and dry matter (1600 g).Results: The best fertilization level for the abovementioned accessions was obtained with the low nutrient solution,Limitations/Implications of the study: while other accessions showed a variable and inverse response to the fertilization level. Results/Conclusions: To make the most of the castor oil plant, oil or fodder accessions can be selected or both accessions can be sown under an intercropping system.

Objective: To analyze fruit characteristics, genetic diversity, and in vitro spread of mesquite genotypes (Prosopis laevigata (Humb. & Bonpl.) ex Willd.) from the plains of Ojuelos-Aguascalientes, Mexico. Design/Methodology/Approach: Fruit and leaf samples were collected from 20 mesquite genotypes to analyze and extract DNA to determine their diversity using RAPDs. Simultaneously, in vitro spread tests were performed. Results: The Ojuelos de Jalisco genotype stood out for the weight of its fruits, while La Presa genotype stood out for its degrees Brix. Genotypes were grouped according to their best growth condition for their genetic analysis. In in vitro spread, AG3 with IBA allowed stem/shoot elongation and root formation; meanwhile, AgNO3 prevents leaf fall, allowing rooting and transfer to the soil. Study Implications/Limitations: This study about mesquite (P. laevigata) was limited to the plains of Ojuelos-Aguascalientes. Findings/Conclusions: Mesquite plants from the Ojuelos-Aguascalientes subregion, Mexico, were identified and georeferenced; likewise, a methodology for its in vitro spread was developed.

Objective: Evaluate the effect of four diets on the productive performance of rabbits, carcass yields, meat color and pH. Design/methodology/approach: Thirty-two California breed rabbits were randomly assigned to each of the following diets: “commercial feed” alone; “commercial feed + biological-activator”; “alfalfa forage + biological activator” and “integral feed + biological-activator”. In the animals were evaluated: daily weight gain (DWG), feed conversion (FC), daily feed intake (DFI), body weight (BW), empty body weight (EBW) and carcass yields. In the meat were determined: pH, luminosity, red color and yellow color. Means were compared using the Duncan test (α = 0.05). Results: The commercial feed diets showed (P < 0.05) higher DWG, DFI, BW and EBW than he other diets. The “commercial feed + biological-activator” diet produced (P < 0.05) in general, higher carcass weights and yields than the alfalfa-based diet, which produced (P < 0.05) a higher pH and yellow color in the meat than the “commercial feed alone” diet. Study Limitations/Implications: The feeding of the rabbits by adding the biological-activator improves the performance, the color of the meat and the pH. Findings/conclusions: to add the biological-activator into the commercial feed improves the yield of empty body weight; to add it into the alfalfa forage and compare it with the commercial feed (alone or with activator) improves both the color of meat (making it more yellow) and the pH (making it higher).

Objective: study the effects of different sources of artificial light on the growth of alfalfa plants (Medicago sativa L.). Design/Methodology/Approximation: The experiment was established on four shelves with a height of 2.50 m with three divisions each, each division 80 x 60 cm long and wide, respectively. In three of the upper divisions the sun's rays were allowed to penetrate, in the remaining nine divisions three different sources of artificial light (LED, incandescent and fluorescent) were placed, three divisions for each light source, at a density of four lamps per division. The energy expenditure per lamp, the intensity of photons and the production of dry matter were quantified. Results: The data indicated that the incandescent lamp had an energy expenditure 8 times higher than the LED lamp and 3.5 times higher than the fluorescent, however, the intensity of light emitted is 3 and 2 times higher in the LED lamp vs. incandescent and fluorescent. respectively, the highest production of dry matter was found with sunlight, obtaining values of 391 g m-2 and the lowest production with the incandescent lamp with 17 g m-2. Study limitations/Implications: It is necessary to continue carrying out research work on forage production with artificial light, to increase biomass yields. Findings/Conclusions: With the data obtained, it is concluded that LED light can be a viable alternative in the future to produce food for animal consumption.

ABSTRACT The objective of this study was to characterize the goat production units of the central mountainous area of the state of Veracruz. A multiple case study was carried out considering socioeconomic aspects, type of forage, goat feeding, reproduction, improvement, and health. The results showed that goat farming and cheese production represent between 50 and 100% of the producers' income. The cultivated forages and the type of goat feed of the production units in the mountainous area are King grass CT-115, Maralfalfa, African Star, Alfalfa and Corn. Animal reproduction is carried out by controlled mating and births occur at the beginning and end of each year. The goat herds do not exceed 150 heads with a predominance of Saanen and Alpine breeds. The average daily production of milk ranges between 16-90 L and with a production of 2-3 L milk for animal/day. The activity is family-type and involves cultivation, animal management, milk production and the manufacturing of artisanal cheeses. Studies are required to confirm individual milk production.

Objective. To characterize the habitat of the Montezuma quail (Cyrtonyx montezumae) in Rancho Chapultepec, Durango, Mexico.Design/Methodology/Approach. From February to October 2020, fieldwork was carried out to search for Montezuma quail sites using transects and sounds. Subsequently each site-of-use was characterized; for each of them three random sites were located. Intercept lines (or Canfield), embedded frames, and nearest neighbour techniques were used. Recorded data were analysed using Principal component analysis (PCA); Frequency ofobservation (FO); Kruskal-Wallis; and Poisson regression (PR).Results. The PCA showed values for sites of use= 48, non-use= 43, and both= 36 of the present variability in vegetation-habitat variables. FO showed values per site of use = 6.25%; non-use = 2.08% and both = 1.56%; and per species in sites of use = 3.57, non- use = 3.85 and both = 3.33%. Kruskal-Wallis exhibited significant differences in richness and abundance and similarity in diversity. Poisson regression (PR) showed the effect of some vegetation-habitat variables on the Montezuma quail.Limitations /Implications of the study. The monitoring period evaluated only comprised a short space of time. It is suggested to extend the sampling time, allowing to visualize the population fluctuation regarding this variable.Findings/Conclusions: It was possible to determine that there is an association between the variables of the vegetation-habitat with the presence of C. montezumae. Vegetation type is the variable that determines the incidence of this species.

ABSTRACT Objective: To present a review about the knowledge of the fish of the family poecilidade in Mexico. Design/methodology/approach: The present review was carried out through the search and bibliographic compilation of literature, as well as in the consultation of articles in different databases, for its subsequent analysis. Results: Mexico has a great diversity of poeciliids with 105 species registered, 64 are endemic, most are in some category of protection, distributed throughout the national territory, mainly in the Usumacinta River basin. In this area, their reproductive biology and feeding have been studied, which vary according to the species. Their culture in Mexico, focuses on the commercialization of ornamental species both native and exotic.              Limitations on study/implications: The poecilid fishes are a well study group; however, the information about the mexican species is scattered and in different areas are limited. Findings/conclusions: Mexico is the country with the greatest diversity of poecilid fish worldwide, most of which are in some category of protection, and are a group well distributed throughout the national territory, with potential as environmental indicators and toxicological studies.