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

This study evaluated the serum cortisol level and its relationship with the work type, age and sex of mules in tropical conditions. Each blood serum obtained from 97 mules was analyzed by a commercial ELISA kit specific to cortisol. The mean cortisol level was 96.3 ng/mL with no significant differences regarding the variables evaluated making it suitable for used as reference value. Also, this is lower than reported in previous studies in show and recreation horses from the same region (133.0 ng/mL). In summary, it is important to utilize species-specific values and conduct studies to determine the mules' ability to adapt and resist.

La tricomoniasis es una enfermedad causada por el protozoo Trichomonas foetus (T. foetus), que causa problemas reproductivos en el ganado y parasita intestinalmente a los gatos, provocando procesos diarreicos intermitentes cuando son jóvenes y asintomáticos en los adultos. T. foetus vive en el tracto reproductivo de las vacas y se relaciona con infertilidad, infección uterina e incluso abortos. La coexistencia con gatos en zonas ganaderas puede transmitir T. foetus al ganado vacuno. Por lo anterior, el objetivo de este estudio fue determinar las frecuencias de tricomoniasis felina y bovina y su asociación en unidades de producción pecuaria de la zona centro de Veracruz, México. Se recogieron cincuenta y cinco (55) muestras, las cuales se inocularon en medios de cultivo comerciales específicos. Se calcularon la frecuencia de animales positivos a la tricomoniasis y el índice de probabilidad para estimar los factores de riesgo de infección. El 30.91 % de los casos fueron positivos para T. foetus, mientras que la frecuencia intraespecífica fue del 36 % (IC 95%: 18.70-57.3) en vacas, 14.3 % (IC 95%: 2.52-43.85) en toros y 37.5 % (IC 95%: 16.28-64.13) en gatos. No se encontró riesgo (P>0.05) de infección por T. foetus en bovinos debido a la cohabitación con gatos. En el presente estudio, sólo se identificó la presencia de T. foetus en diferentes unidades de producción ganadera en las que coexisten bovinos y felinos.

Aethina tumida is a pest that causes structural and production damage in the beekeeping industry. The control method includes using synthetic pesticides that can affect bees, contaminate honey and other hive products, and generate resistance to pests. The present study assessed the coleoptericidal effect of a crude extract of ChiBLUV 02 recombinant chitinase of Bacillus licheniformis UV01 expressed in Escherichia coli BL21 (De3) strains on the species Aethina tumida. Different units of enzymatic activity (0.42, 1.26, 2.10. 4.20, 8.40, 12.60, 16.80, and 21.00 U/ml) mixed with the maintenance food for larvae and beetles were evaluated. The food was provided in portions of 1 g/d for 3 days, and the coleoptericidal effect was evaluated at 24, 48, and 72 h. The LC50 and LC90 were calculated using a Probit analysis. Applying 21.00 U/ml of recombinant chitinase promoted mortality of 45 % of larvae after 72 h of administration; nevertheless, none of the concentrations evaluated affected adult beetles. The Probit analysis indicated that 27.03 and 168.92 U/mL are needed to promote mortality of 50 % (LC50) and 90 % (LC90) of Aethina tumida. The enzymatic activity of the crude extracts was low to achieve higher mortality of the larvae and adults of Aethina tumida; therefore, the chitinolytic activity in the ChiBLUV 02 strains should be improved to increase their coleoptericidal effect.

Brucellosis is a serious zoonotic endemic disease in more than 170 regions worldwide. It is primarily a reproductive disease affecting human and animal health, and its effects can damage producers, and regional and national economies. In Mexico, cattle are a vital protein source and a substantial portion of the livestock sector. As an alternative animal protein source, water buffalo Bubalus bubalis was introduced to Mexico in the early 1990s and is now grown in almost all its states. However, more than 30 yr after its introduction, minimal data is available on brucellosis epidemiology in this species. Brucella spp. serological frequency in water buffalo from the states of Campeche, Tabasco, and Oaxaca, Mexico, was estimated using a cross-sectional study with non-probabilistic sampling. A total of 825 animals from eighteen herds were sampled. Screening was done using the Rose Bengal card test and confirmation with a Rivanol test. Frequencies were calculated by state and municipality. Overall frequency was 4 % with the card test and 3 % with Rivanol. All three states had seropositive cases, and 66.6 % of the sampled production units had seropositive buffalo. This constitutes the first report for the states of Campeche and Oaxaca. Although Brucella spp. seroprevalence can change over time and responds to multiple variables, the identification of seropositive animals in an eradication zone (Campeche) is serious given the current active nationwide campaign against brucellosis.

This research aimed to determine the occurrence of lice in Buffalo Production Units (BPU) in Veracruz, Mexico. Fifty-seven (57) buffaloes of different sexes and ages were inspected in two BPUs located in the municipalities of Cotaxtla and Medellín de Bravo (BPU1 and BPU2). The lice were collected from different regions of the body and preserved in vials with 70 % ethanol for transfer to the laboratory. Taxonomic identification was performed with stereoscopic and scanning electron microscopy. The frequency, abundance, and intensity of lice in each BPU, anatomical region, and developmental stage evaluated were calculated. The overall frequency of lice infestation was 78.9 (CI95%: 65.7 - 88.2). The frequency for BPU1 and BPU2 was 60 % and 100 %, respectively. Six hundred ten lice were collected from the two BPU and only the louse species Haematopinus tuberculatus was found. The abundance was 610 lice/57 buffaloes in total (10.7) and the intensity was 610 lice/45 infested buffaloes (13.6). The costal region was the place with the highest presence of lice. The nit/egg stage was the most abundant, followed by adult lice and nymphs (78.4 %, 16.1 %, and 5.1 %, respectively). The high frequency of lice in buffaloes at BPU in Veracruz can compromise animal health and meat and milk production in buffalo production systems.

The objective was to evaluate the effect of the seasonal water balance (SWB) on the yield and biochemical composition of Leucaena leucocephala. Three 5 x 5 m plots were established in a warm sub-humid climate (Aw1). Nine sampling cuts were made every 42 d in seven seasons of the year, classified by their SWB (mm d-1) as follows: “North winds” -0.18 (N, Dec-Jan); Dry -2.39 (S, Feb-Apr); Onset rains 1.77 (On-R, Apr-May); Full rains 4.89 (FR, Jun-Jul); Extreme rains 8.32 (Ex-R, Jul-Aug); Late rains 3.74 (LR, Aug-Sep), and Residual rains -1.46 (Re-R, Sep-Dec). Dry matter yield and biochemical composition , based on which the rumen-soluble carbohydrate and protein fractions were estimated. A randomized, complete block statistical design with seven treatments was utilized. Means were compared by Tukey test (P≤0.05). The DM yield (kg ha-1) decreased to 152d in Nw and D with SWB-, and increased to 1,497b in FR and LR with SWB+. True soluble protein (TSP, %CP) increases to 73.1a in Nw and D with SWB- and decreases to 69.8b in FR and LR with  SWB+.  Non-fiber carbohydrates (NFC, %Total carbohydrates) decrease to 44.4b in Nw and D and increase to 54.7a in FR and LR. The authors concluded that the NFC decreases and the TSP increases in Nw and D with SWB- magnifying the energy/protein imbalance in the rumen for microbial protein synthesis.

The objective of this study was to evaluate the effect of aqueous extract of chaparral (Larrea tridentata) on the productive performance, hematological profile, white cell count, organ weights, and antibody titers against Newcastle disease in broiler chicks. 600 1-d-old Cobb breed chicks were assigned to the following treatments: 0, 5, 10, 10, 15, 20, and 25 mg of an aqueous chaparral extract per kg of feed. Feed consumption, weight gain, and feed conversion rate were recorded and analyzed. In addition, leukocyte cell counts, Newcastle antibody titers were evaluated and the weight of the thymus, spleen, and Fabricius’ bag was recorded. Weight gains were improved (P<0.05) with the chaparral extracts compared to the control group, while the best feed conversion rate (P<0.05) was obtained with 15 mg of the extract. Leukocyte counts and organ weights were not affected by the extract. The highest titers against Newcastle disease (P<0.05) were found with 15 mg of chaparral extract. This study concludes that an aqueous extract of chaparral at a dose of 15 mg per kg of feed is an alternative to improve the immune response and, therefore, the weight gain in broiler chicks.

The objective was to evaluate the effect of nitrogen fertilization and irrigation (FI) by season of the year on the dry matter yield (DMY) and biochemical composition of tropical grasses. Five grass varieties were used. Each with three replications with FI and three replications without FI. The pastures were cut every 35 d. The dose of nitrogen fertilization was 138 kg/ha/yr, equivalent to 300 kg of urea. The plots with FI were irrigated from December to May. The seasons were: rainy (R, Jun-Nov), “north winds” (N, Dec-Feb), and dry (D, Mar-May). DMY was determined, and the available carbohydrate and protein fractions were estimated. The statistical design was completely randomized in a split-split-plot arrangement. Means were compared by Tukey (P≤0.05). Without FI, in R, DMY is 53 % of the amount produced with FI, and in N and D, it is only 26 and 15 %, respectively. Non-protein nitrogen and rumen-soluble true protein are the protein fractions that are most increased with FI. Total carbohydrates (TC), non-fibrous carbohydrates (NFC), and digestible neutral detergent fiber (NDF) are higher in R and D, and the pastures without FI showed the highest increases in TC in D, NFC in R and D, and digestible NDF in D. Indigestible fractions increase during the “north wind” season, and regarding pastures with FI, they also increase during the dry season. The effect of FI on carbohydrate fractions is climate-dependent.

The objective was to characterize the forage balance during the dry and rainy seasons in 17 municipalities in the tropical zone of central Veracruz, Mexico, in order to typify and identify recommendation domains. For this purpose, the 2019 national livestock register data were used through the Individual Livestock Identification System (SINIIGA in Spanish), which records each production unit (PU). The seasonal forage balance was calculated for each LPU to estimate the dry matter (DM) requirements per animal unit; having thus determined the average DM deficit, it was grouped into the 17 municipalities. General linear models and descriptive values were used for a total number of 17,892 PU. These production units had an average area of 19.40 ha, 23.67 animal units (AU) per herd, and a stocking rate of 1.22 AU ha-1. This rate was considered high for the technological conditions of the area, where the forage balance is usually negative in the dry season. The authors concluded that the forage balance in the rainy season is positive and, therefore, recommend considering the use of technologies for forage conservation during the dry season. Furthermore, there is a need to typify the different conditions of the PU more precisely in order to provide more site-specific recommendations.

The genus Amblyomma includes ticks that parasitize a wide variety of terrestrial vertebrates in humid tropical and subtropical regions. Globally, 136 species have been identified, some of which are important in public and veterinary health as they act as vectors of zoonotic diseases. Currently, there are records of 25 species that parasitize a diversity of hosts, including amphibians, reptiles, birds, and mammals. In Mexico, 17 species of ticks of the genus Amblyomma were initially identified, but this number has increased significantly over time. The presence of Amblyomma inornatum, a neotropical species that shows a preference for infesting ruminants, has been documented in the state of Michoacán. Despite its presence in the region, its status remains not determined (ND) due to a lack of information on its distribution and hosts. This species is relevant in the vector field since it can transmit pathogens such as Ehrlichia, Rickettsia, and Borrelia, which can affect humans. The results of a sampling carried out in a bovine production unit (BPU) in Michoacán during November 2022 are reported here. The presence of A. inornatum was verified by scanning electron morphology. This finding establishes the presence of A. inornatum in the region and forms the basis for future research on host preferences, including cattle, and the role of this tick as a vector of important diseases in One Health.