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

The presence of Staphylococcus aureus in the skin of bovine udder has been proposed as a source of upward contamination to the mammary gland, which causes the development of mastitis and the presence of this bacterium in milk. The entry of S. aureus into the food chain becomes a public health problem due to the dissemination of antibiotic-resistant strains from animals to food and therefore to humans. Therefore, this study aimed to determine resistance to antibiotics and associated genes in strains of S. aureus isolated from the skin of bovine udder. Antibiotic resistance was determined by minimum inhibitory concentration and the presence of antibiotic resistance genes by endpoint PCR. The strains of S. aureus showed a high frequency of resistance to beta-lactams, macrolides, lincosamides, and tetracyclines. The strains were resistant to cefoxitin but the mecA gene was not found; of the ermA-C genes, ermB was the most frequently found gene (16.39 %); the msrA gene was found in most strains with constitutive resistance to macrolides and lincosamides (88.46 %); the tetM gene was found in 64.28 % of the tetracycline-resistant strains. In conclusion, the strains of S. aureus isolated from bovine udder skin presented different degrees of resistance to different groups of antibiotics, which can be explained by the presence of associated genes.

The consumption of milk-based products is of great economic and social importance in Mexico. Artisanal cheeses are the economic basis of many small producers in the country; nevertheless, one of the major threats to this sector is the manifestation of foodborne diseases (FBDs) due to poor quality and safety during the production process. Three cow’s milk cheese production units were sampled in the municipality of Aculco, State of Mexico, Mexico, with the aim of detecting the presence of Staphylococcus aureus, Salmonella spp, and total coliforms on plate in artisanal cheeses. The methodology of NOM-210-SSA1-2014 and the methodology of NOM-113-SSA1-1994 were used, obtaining results for the three production units above the limits allowed by the regulations for S. aureus and total coliforms, but demonstrating the absence of Salmonella spp. An evaluation was made by means of questionnaires and observation of the production, sanitization, and storage processes of the products, as well as descriptive statistics of the results, to establish the main causes of the high counts in the microbiological analyses, determining that the main cause is the lack of implementation of good manufacturing practices, such as hand washing, specific clothing for the work area, and sanitization of the different areas of the cheese factories and the tools used during the manufacturing process.

The present research aimed to determine the mineral concentrations in forage, water, and blood serum, and the clinical signs of grazing cows. Twenty-five (25) Angus and Hereford cows of different physiological states were analyzed, from which blood samples were taken by venipuncture. Forage samples were collected using the hand-plucking technique and water was collected from available sources. The determination of minerals was performed by atomic absorption spectrophotometry and visible ultraviolet spectrophotometry. The blood serum of the cows showed deficient concentrations of copper (100 %), zinc (88 %), sodium (52 %), potassium (36 %), and phosphorus (16 %). Iron and manganese were in concentrations above the normal range. A copper deficiency classification index (CUDI) was generated: severe 0.41-0.48 mg L-1, moderate > 0.48-0.54 mg L-1, and mild > 0.54 -0.79 mg L-1. Sixty-eight, 20, and 12 % of the cows corresponded to the given classification, respectively. The following signs were identified: abortions, lameness, dull, shaggy, and discolored hair, tearing, steely hair, goiter, and pica. For forage, deficient levels of copper (1.27 mg kg-1) and zinc (24.5 mg kg-1) were found. In water, copper and zinc were not detectable, and there was excess iron 0.345 (mg L-1). In conclusion, the primary deficiency is copper, caused by deficiencies in forage, water, and possible imbalances caused by other minerals.

Honey is a strategic resource of great importance worldwide, both from a nutritional and cultural point of view, and Mexico ranks as one of the largest global producers and exporters, with more than 58,000 t produced in 2023. Despite its leadership in production, the Mexican beekeeping sector faces serious logistical challenges, especially in internal distribution, where inefficiency in transport routes generates considerable economic losses, particularly affecting small producers. These logistical issues limit the sector’s ability to meet the growing domestic demand for quality honey, affecting both the competitiveness and profitability of the sector. In this context, this study proposes an optimization model based on linear programming, the objective of which is to identify the most efficient distribution routes between producing and consuming states within Mexico. The model considers key variables, such as regional supply and demand capacities and transportation costs, in order to maximize the use of available resources. The implementation of this approach has the potential to improve the competitiveness of the beekeeping sector, increasing profit margins for producers and facilitating access to local and national markets, which would contribute to meeting the growing demand for natural and quality honey.  

A total of 804 bulls were randomly housed in 12 pens (67 bulls/pen) with different types of shade (conventional with sheet metal [CS], double shade with sheet metal [DS], dome without fans [DNF], and dome with fans [DWF]) to determine the best shade system in intensive fattening of Bos indicus cattle based on thermoregulation and productive responses under subtropical conditions. Ten bulls/pen were randomly selected for the assessment of thermoregulation. The environmental conditions were of “moderate heat stress”. The pens with CS and DWF promoted lower morning respiratory rate in the bulls, but in the afternoon, only the DWF pens maintained this effect. Regardless of the time, the DWF pens reduced the surface temperatures of the bulls’ head, neck, back, rump, and eye compared to the other types of shades. In contrast, the DNF bulls had the highest total protein concentration than the others; the type of shade did not affect the hematological profile and the serum concentrations of glucose, cholesterol, triglycerides, urea, sodium, and chlorine. Thyroid hormone concentrations were higher in bulls with CS and DS than in bulls with DNF and DWF. Compared to CS and DS, DNF and DWF shades increased feed intake and feed efficiency, but reduced meat marbling, without affecting weight gain, carcass yield, and meat hardness or color. In conclusion, Bos indicus bulls under moderate heat stress showed a better physiological thermoregulation capacity and feed efficiency in pens equipped with dome shade and fans.

The objective of the study was to develop a combined approach of deterministic modeling and Monte Carlo simulation to establish the optimal technical-economic level for fattening commercial genetic lines of turkeys in the municipality of Temascaltepec, Mexico. Data from 42 turkeys of the double-breasted diamond genetic variety, with an average age of three weeks and an initial body weight of 1.077 ± 0.132 kg, were analyzed. In order to model the relationship between feed consumption and final weight of the turkeys, a quadratic production function was fitted using nonlinear regression along with a Monte Carlo simulation analysis to evaluate the risk associated with fluctuations in feed costs and the selling price of turkeys. The deterministic analysis identified that economic profitability is maximized when turkeys consume 26.81 kg of feed and reach a live weight of 11.30 kg. The Monte Carlo simulation confirmed the validity of these results under scenarios of uncertainty in sales prices and feed costs, estimating an average net profit of $379.29 per bird in the economic optimum, compared to $325.39 in the technical optimum, representing a 16.56 % increase in profitability per turkey. These findings confirm that integrating deterministic modeling with stochastic simulation constitutes an effective methodological tool for production decision-making under conditions of variability and uncertainty. It is recommended that this approach be validated in other agricultural contexts to strengthen its practical applicability.

La producción de alimentos tradicionales se encuentra fuertemente ligada a las regiones de origen donde son producidos; estos productos forman parte de la cultura y son elementos clave en la gastronomía de las regiones, ya que presentan características sensoriales y nutricionales únicas, derivadas de los procesos de elaboración. Este estudio tuvo como objetivo identificar los atributos de valorización que una muestra otorga de consumidores al queso Seco Encerado, mediante la técnica de experimentos de elección discreta, así mismo, determinar la disposición a pagar (DAP) extra por cada kilogramo de queso. Como resultados importantes, se identificaron los atributos significativos: precio, origen y proceso, así como, las interacciones:  precio - origen y proceso - etiqueta. Se identificaron los atributos que el consumidor considera importantes en el proceso de elección de compra del producto y por los cuales está dispuesto a pagar un sobre precio; se generaron dos grupos de consumidores (amantes nativos de los quesos madurados y consumidores de quesos), los cuales presentan interés por diferentes atributos de valoración, diferentes características sociodemográficas y relaciones intrínsecas del producto con el territorio. En esta investigación se exploró la valoración y la DAP por el queso Seco Encerado, identificando una tendencia positiva por parte de los consumidores hacia este producto.

Good management of extensive cattle grazing can be used as a tool to prevent pasture degradation. Grazing systems make it possible to regulate the pressure exerted on the pasture and optimize production. Two grazing systems under similar ecological conditions were evaluated: rotational (RS) and continuous (CS). Both systems have been implemented for more than 20 years in two plots of land of Rancho San Rafael, Canatlán, Durango, Mexico. To determine their impact, the pasture responses in soil, vegetation, and cattle were analyzed. Data were analyzed under a completely randomized design with RStudio and Tukey (P<0.05) for forage production/height, plant cover, and soil minerals. Live weight gain was calculated and compared, stratified by weight ranges, in young stocker heifers (13-15 mo old) for both grazing systems. Significant differences (P<0.05) were found for the rotational system, where there was a greater amount of available dry matter (DM), as well as increases in nitrate, sodium, calcium, potassium, and electrical conductivity of the soil. Both forage height and weight gain showed no differences (P>0.05); nevertheless, a significant advantage (P<0.05) was only found in weight gain for heifers ranging from 121 to 160 kg. The rotational system showed an advantage for forage production due to the periodic rest of the pasture, which allowed greater availability of biomass. Significant improvements (P<0.05) were identified for nitrate, sodium, and potassium levels in the soil, which are relevant indicators for pasture productivity.

The purpose was to evaluate the production and content of dry matter (DM), bromatological composition, digestibility and degradation kinetics of DM and neutral detergent fiber (NDF), and the estimated milk production in the silage from brown midrib corn hybrids (BMHs) and conventional corn hybrids (CVHs). CVHs produced 21 % more DM than BMHs (27.4 vs 22.5 t ha-1, respectively), and there was an increase when harvesting at stage R5 (25.7 t ha-1) compared to stage R4 (24.3 t ha-1). The harvest stage did not affect the digestibility of DM or NDFD  but  the year  and  type of  hybrid affected  the fraction  of indigestible  NDF (iNDF, % DM),  which was higher in 2020 (25.6 %) than in 2019 (13.8 %) and in CVHs (22.6 %) than in BMHs (16.8 %). Consequently, milk production per ton of DM (MIT) was higher in 2019 and in BMHs compared to 2020 and CVHs. In contrast, the year did not affect milk production per hectare (MIHA) as the higher DM production in 2020 compensated for the drop in MIT, but the lower DM production in BMHs reduced the value of MIHA compared to CVHs (29.1 vs 32.5 t ha-1, respectively). The MIHA estimate increased when harvesting at stage R5 (31.8 t ha-1) compared to R4 (29.7 t ha-1). Although the BMHs had better digestibility and more milk production potential per ton of DM, the higher DM yield in CVHs compensated for the difference, and more milk was obtained per hectare.

This research aimed to evaluate the root biomass of perennial ryegrass (R) (Lolium perenne) with different nitrogenous sources and associations with white clover (Wc) (Trifolium repens) and red clover (Rc) (Trifolium pratense), as well as the nodulation capacity of white or red clover. Two experiments were conducted: (Exp1) monoculture of perennial ryegrass, fertilized with nitrogen (urea, slow-release urea, ammonium nitrate, foliar nitrogen, ammonium nitrate + foliar nitrogen, and a control or without application), and (Exp 2) mixtures of ryegrass with white or red clover, in low and high density, and a control. They were replicated in 2 localities: Tumbaco (Tm) and Machachi (Mc), in Pichincha, Ecuador. The statistical design was a randomized block design (n=3), and a soil analysis was performed at the beginning. Root biomass (Rb) was evaluated on a dry basis in the 2 experiments; for its part, in Exp 2, the number (Nn) and weight of nodules (Nw) were also evaluated. The results indicate that species modify their root growth as an adaptation to environmental conditions. In Exp 1 in Tm, where there was a higher temperature, there was a higher Rb. In Exp 2, the mixtures of R and Rc accumulated greater root biomass. For Nn and Nw, Wc had the highest values. Based on these results, it can be concluded that the environment plays a preponderant role in root biomass and that species adapt by modifying this trait and the number and dry weight of nodules.