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The objective of the present study was to evaluate the variation of scrotal circumference of Criollo goats males selected within the Castron Plan at the beginning and end of the service period, in the South of Mendoza. 692 Criollo males were used, divided according to age by dental chronology. Scrotal circumference was measured with a flexible metal centimeter, 50 cm in total length, graduated in millimeters, in May (Southern Hemisphere autumn), at the beginning of the reproductive stage and in September (Southern Hemisphere spring), at the end of the service time. The experimental design responded to a completely randomized model, evaluating measures and standard desviations by Tukey test applying the statistical program InfoStat 2.0. The results showed values of 25, 46±1, 74 and 23, 54±2, 17 cm for males of 2 teeth, in autumn and September, respectively; 28, 15±1, 38 and 27, 03±2, 51cm for males of 4 teeth, 29, 41±1, 62 and 27, 64±2, 49 cm for males of 6 teeth and 29, 47±2, 04 and 28, 63±2, 21 cm for the full mouth male. There is a significant statistical difference (p≤0. 05) between the two evaluated periods for 2, 4 and 6 teeth males. This work concluded that the scrotal circumference of the selected Criollo goats in Plan Castron show a significant seasonal variation between the onset of the reproductive season (Southern Hemisphere autumn) and end of service (Southern Hemisphere spring), with values of that parameter at the time of service that can qualify them as satisfactory male goats [ABSTRACT FROM AUTHOR]

Ctenomys is an endemic subterranean rodent from South America, and it represents an excellent model to evaluate the effect of different factors on energy metabolism, particularly, resting metabolic rate (RMR). Its subterranean micro-environment is characterized as thermically stable, but not convective, humid, hipercapnic and hypoxic. So the capacity to dissipate heat during the hot season is further reduced. Ctenomys talarum occupies coastal grasslands dunes in the southeast of Buenos Aires province; feeds on plants located near the borrow system entrances. Therefore, they are exposed to thermal variations on the surface. This study aims to determine how RMR varies during short, medium, and long term time periods during an annual cycle in relation to abiotic (rainfall, ambient temperature, captivity) and food availability. RMR did not vary between seasons or in a year cycle. The micro-environmental stability inside burrows, the seasonal changes in the thermal conductance and behavioural strategies destined to face thermal challenges, could be signalled as responsible for RMR stability. [ABSTRACT FROM AUTHOR]

The objective of this study was to model the dynamics of annual evaporation (E) during radial growth of Pinus cooperi Blanco, which is economically and ecologically important for northern México. Dendrochronological data were used to identify a model that would, with instrumental records, relate E for the period 1964 to 2010. The correlation and regression analyses showed that E negatively affects growth during the months previous to the growth season and during the summer of the growth year (June and July). E is a significant variable that can explain water stress and that can have implications for management of P. cooperi in the face of climatic variation. [ABSTRACT FROM AUTHOR]

Se recolectaron muestras de sangre por punción de la vena coccígea de 18 y 20 vacas Charolais y Beefmaster, respectivamente, en las cuatro estaciones del año. Las vacas se mantuvieron en pastoreo rotacional en praderas de zacate Buffel (Cenchrus ciliaris L.) en el Noreste de México para evaluar el efecto de los cambios estacionales en las concentraciones séricas de glucosa, nitrógeno ureico, fósforo (P), calcio (Ca), insulina y triyodotironina (T3 ). Además, se evaluó el peso vivo (PV) y la condición corporal (CC). Los niveles séricos de glucosa y nitrógeno ureico fueron influidos (P < 0.01) de manera independiente tanto por la estación del año como por la raza. Los menores valores (P < 0.01) de glucosa y nitrógeno ureico se observaron durante el verano. El tenor mínimo de glucosa no fue menor al reportado como normal (45 mg/dL), pero en el caso del nitrógeno ureico, los contenidos más bajos durante la primavera (6.4) y el verano (5.7) fueron menores al normal (10.3 mg/dL). Los niveles más bajos (P < 0.05) de Ca y P se registraron durante la primavera, cuando la concentración de Ca (8.5 mg/dL) fue menor al valor recomendado (9.0 mg/dL). Los metabolitos séricos glucosa y nitrógeno ureico fueron diferentes (P < 0.01) entre las raza Charolais y Beefmaster, y fueron de 53 y 10.2 versus 68 y 8.7 mg/dL, respectivamente. La concentración de insulina sérica fue más baja en el verano (0.5 mg/dL ) y la T3 se modificó (P < 0.05), en forma paralela al PV, de acuerdo con la raza y la estación del año. La CC se cambió dependiendo de la estación del año, aunque 90 % de los animales mantuvieron la CC mayor de 5. El perfil metabólico sanguíneo considerado en esta investigación puede representar una herramienta útil para establecer necesidades diferenciales de suplementación para ganado en pastoreo de zacate Buffel a través del año. [ABSTRACT FROM AUTHOR]

Catch data of the yellowfin tuna (YFT) fishery were used to study the relationship between the seasonal and spatial variations of YFT with or without the presence of mesoscale structures at the entrance to the Gulf of California (19°-24° N, 104°-112° W). The YFT catches were distributed mainly over the continental shelf and around islands and seamounts. High concentration sets of YFT occurred throughout the year around the Marías islands and Cabo Corrientes, particularly in March and June. A warm (>28°C) coastal jet with a width of 1.5 Rossby radius (∼20.6 km) was observed off Cabo Corrientes during February and April, covering all the continental shelf off Cabo Corrientes. The jet moved at an average speed of 0.31 m s-1 and extended northwards to the Roca Corbetera seamount. The interaction with cooler water generated a frontal zone around which the YFT catches were concentrated. In contrast, during March the wind field was more favorable for the development of coastal upwelling off Cabo Corrientes. We observed an upwelling region with sea surface temperature of 18°C and an offshore width of about a 3.7 Rossby radius of cold water that covered some 2600 km². The YFT catches occurred in warmer water north of the upwelling zone. [ABSTRACT FROM AUTHOR]