The aim of this study was to evaluate the intensity of the annual sexual behavior (SB) of Boer bucks under tropical conditions in southern Mexico. For one year, 16 extensively grazing males were evaluated for SB individually with estrogenized goats. From the beginning of the experiment and every 30 days, body weight (BW), body condition (BC), testicular circumference (TC), odor intensity (OI), and SB (nudging, ano-genital sniffing, flehmen, mounting attempts, mounts with intromission, and self-urination) were recorded. The bucks showed more intense SB during the months of November to May than during the months of June to October (p < 0.05). Greater frequencies were found for nudging, ano-genital sniffing, mounting attempts, and self-urination in the months of November to May (p < 0.001). BW was lower during the months of January to August than in the months of September to December (p < 0.05). On the other hand, TC increased from October to December (p < 0.05). Similarly, the OI in males varied over time (time effect; p < 0.001). In fact, an increased odor was found from October to December. The conclusions are that breed male goats from the tropics of Guerrero have a more intense SB during the months of November to May, but TC, OI, BW, and BC correspond to the time of the year when forage availability is the greatest.

Objective: To determine the concentration of arsenic (As), cadmium (Cd), copper (Cu), chromium (Cr), lead (Pb), and zinc (Zn) in milk and cheese by comparing the use of nitric acid (HNO₃) and a mixture of nitric acid and hydrogen peroxide (HNO₃ + H₂O₂) in acid digestion. Design/methodology/approach: The milk for the study was collected from storage tanks in various localities of Huejotzingo, and the different types of cheese came from Santa Ana Xalmimilulco, Huejotzingo, Puebla, Mexico. Digestion was carried out in a CEM MarsX microwave. Elemental concentrations were determined by Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). Results: The combination of HNO₃ + H₂O₂ in milk digestion resulted in higher concentrations of Cd, Pb, and Zn. Conversely, the concentration of As was higher when using only HNO₃ for digestion. No significant differences were found for Cr and Cu between the two digestion methods. In the case of Oaxaca cheese, digestion with HNO₃ resulted in higher concentrations of As. Acid digestions did not affect the concentrations of the remaining elements. The same behavior was observed for Ranchero cheese, since the digestion combining HNO₃ + H₂O₂ resulted in lower As concentrations, as compared to the digestion with only HNO₃. Pb and Zn were not significantly affected by the treatments, while the concentrations of Cd, Cr, and Cu could not be determined when samples were treated with the HNO₃ + H₂O₂ combination. Limitations: In this work we were able to determine the concentration of a number of metals present in milk and cheese using nitric acid and hydrogen peroxide in acid digestion. However, we recommend more tests are carried out to establish which acid or combination of acids allows for a broader detection of metals. Findings/Conclusions: According to the results obtained in this work, we can conclude that there is specificity for metal detection, with HNO₃ being the most efficient.

Objetivo. El presente estudio tuvo como objetivo evaluar el control de la papilomatosis bovina (PB) con vacuna autógena en condiciones del trópico de Guerrero. Materiales y métodos. En el experimento se usaron 18 hembras bovinas que fueron divididas en tres tratamientos de acuerdo al rancho (6 hembras/grupo). Tratamiento 1 (T1-inmunovacuna), tratamiento 2 (T2-histovacuna) y tratamiento 3 (T3-plasmaterapia). Resultados. Al inicio del estudio se encontró una alta incidencia de papilomas en las hembras bovinas [(T1 (190 papilomas), T2 (95 papilomas) y T3 (100 papilomas)]. Con la administración de la vacuna autógena disminuyó significativamente (T1 y T3) el número de papilomas a través de las aplicaciones de la 1 (147 y 66 papilomas) a la 5 (10 y 9 papilomas); (p<0.05). También existió una diferencia significativa entre tratamientos de acuerdo al periodo de aplicación de la vacuna (3 a la 5) disminuyendo el número de papilomas (efecto periodo; p<0.05). Por su parte, se observó una interacción tratamiento x periodo disminuyendo el número de papilomas en la cuarta y quinta administración (T1 y T3; p<0.05). Conclusiones. La administración repetida de la vacuna autógena en las hembras bovinas disminuyó el número de papilomas entre la cuarta y quinta aplicación en los tratamientos 1 y 3.

Using an Ekomilk Bond Total Ultrasonic Milk Analyzer, the physicochemical characteristics of milk from 10 herds and 237 samples were analyzed during the rainy season (July and August; 109 samples) and dry season (January and February; 128 samples), providing the following measures: fat (%), non-fat solids (NFSs; %), density (g/mL), freezing point (°C), acidity (%), temperature (°C), lactose (%), conductivity (mS/cm), pH and water (%). In this study, there was a higher percentage of fat (2.975 vs. 5.001%) and a higher density (1033.692 vs. 1035.45 g/mL) in milk during the dry season compared to during the rainy season (p < 0.05). The rest of the milk characteristics were not significantly different relative to the study season (p > 0.05). The variables of fat and temperature of milk presented higher values in the dry season than in the rainy season, whereas the variables of density, freezing point and conductivity presented higher values in the rainy season than in the dry season (p < 0.001). Regarding the variables of NFSs, protein, acidity, lactose, pH and water percentage, the results were similar in the two study seasons (p > 0.05). Finally, density maintained significant positive correlations with the variables of protein, freezing point and lactose (p < 0.05). However, fat showed significant negative correlations with density, freezing point, acidity and conductivity (p < 0.05). In conclusion, the physicochemical characteristics of raw milk from dual-purpose cows per herd are better during the rainy season.

Two groups of ewes (10 lactating and 10 non-lactating) were used to evaluate the effect of heat stress during summer under tropical conditions. In this study, a temperature and humidity index (THI) was found that ranged between 65 and 79 (morning and afternoon). Likewise, a heat tolerance coefficient (HTC) of 6 units was observed. The highest breathing frequency (BF; 115.46 ± 35.25 breaths per minute (bpm)) and rectal temperature (RT; 38.95 ± 0.51 °C) were found during the afternoon in the group of lactating ewes. The means were compared by group, time of the day, and interaction, and only significant differences were found between groups for RT and udder temperature (p < 0.001). In the case of time of day, all parameters were higher during the afternoon, regardless of the group of ewes (p < 0.001). Likewise, an interaction was found in the parameters RT, right paralumbar fossa (RPF), rump, leg, and udder (p < 0.001). In conclusion, Blackbelly ewes lactating during the summer in the tropics have higher skin temperatures, and also raise BF and RT to tolerate HS in tropical climates.

En el estado de Guerrero, la región Costa Grande, se localiza en el trópico subhúmedo mexicano; lugar donde la ganadería ovina es importante para el sector agropecuario de esta región del país. Sin embargo, algunos factores de riesgo que favorecen la infestación por parasitosis gastrointestinales en ovinos son los ambientales, de manejo y medicina preventiva (González-Garduño et al., 2011). Los principales parásitos en ovinos en regiones tropicales son los nematodos como: Haemonchus contortus, Cooperia curticei, Trichostongylus colubriformis, Strongyloides papillosus, Bunostomum trigonocephallum, Oesophagostomum columbianum, y Trichuris ovis (Ponce-Covarrubias et al., 2022). Estos factores afectan fuertemente la salud y bienestar animal, pues son causantes de pérdidas económicas para el ovinocultor local. En efecto, las ovejas independientemente de su estado fisiológico son afectadas en su productividad y salud, ya que se observa una disminución del peso, condición corporal y problemas de anemia (Can-Celis et al., 2020).