Comportamento de pastejo de vacas das raças Canchim e Nelore.

Avaliação do tempo de pastejo de vacas das raças Canchim e Nelore paridas de agosto a outubro de 1989, amamentando bezerros canchins e 1/2 Camchi + 1/2 Nelore, respectivamente.Resumo

Associação entre características da amamentação e peso de bezerros da raça Canchim e cruzados Canchim X Nelore.

Avaliação da relação do numero de mamadas diárias (NM), duração da mamada (DM), e tempo total diário de amamentação (TT) com o peso de bezerros canchim (14) e 1/2 Canchim + 1/2 Nelore (13) e com produção de leite das vacas Canchim e Nelore

Estrés por calor en ganado lechero con énfasis en la producción de leche y los hábitos de consumo de alimento y agua. Revisión

The negative impact of heat stress (HS) in dairy cattle results in considerable economic losses at world level, as it reduces the milk production, reproductive efficiency, and productive life in the cows. In addition, the continuous genetic improvement results in highly productive cows, which are, however, less tolerant to HS because they produce greater metabolic heat. This, together with global warming, will turn HS into a hard-to-control challenge for the daily industry. In response dependent on the degree of HS, the dairy cattle carry out a series of physiological, metabolic and behavioral adjustments as thermoregulatory mechanisms for removing excess body heat and reducing the endogenous production of body heat, in order to maintain the normothermia. However, fertility and milk secretion decrease as a direct effect of hyperthermia and an indirect effect of lower dietary nutrient intake. Food and water intake are closely associated to the reduction of the productivity of dairy cattle exposed to HS. Notably, the impact of HS on productivity of dairy cattle varies among breeds, among which Bos taurus, particularly the Holstein breed, are less tolerant to HS. The identification of genes associated to thermotolerance utilized in selection programs using genetic markers to breed high milk-producing cows in warm climates is currently being studied. Therefore, the purpose of this review is to carry out a comprehensive analysis of the effects of HS on milk production, activation of thermoregulatory mechanisms and feed intake behavior in dairy cattle.El impacto negativo del estrés por calor (EC) en la ganadería lechera repercute en cuantiosas pérdidas económicas a nivel mundial, dado que reduce la producción de leche, la eficiencia reproductiva y la vida productiva de las vacas. Adicionalmente, el mejoramiento genético continuo resulta en vacas muy productivas, pero menos tolerantes al EC debido a que producen mayor calor metabólico. Esto en conjunto con el calentamiento global convertirá al EC en un reto difícil de controlar para la industria lechera. Como respuesta dependiente del grado de EC, el ganado lechero realiza una serie de ajustes fisiológicos, metabólicos y conductuales como mecanismos de termorregulación para disipar el exceso de calor corporal y reducir la producción endógena del mismo, todo dirigido a mantener la normotermia. Sin embargo, la secreción láctea y la fertilidad se reducen por efecto directo de la hipertermia e indirectamente por la reducción en el consumo de nutrientes dietéticos. Los consumos de alimento y de agua están asociados estrechamente con la reducción de la productividad en ganado lechero expuesto a EC. Cabe mencionar que el impacto del EC en la productividad del ganado lechero varía entre razas, siendo las razas Bos taurus menos tolerantes al EC, particularmente la raza Holstein. Actualmente, se investiga en la identificación de genes asociados con la termotolerancia, los cuales son empleados en programas de selección por marcadores genéticos para producir vacas altas productoras de leche en climas cálidos. Por lo tanto, el objetivo de esta revisión es hacer un análisis comprensivo de los efectos del EC sobre la producción de leche, activación de mecanismos de termorregulación y conducta de ingesta en ganado lechero

Suplementação estratégica com mistura mineral na recria de novilhas sob condições de pastejo.

Comparar o ganho de peso de 60 novilhas (Canchim, mestiças leiteiras e europeu - zebu), mantidas em pastagens de brachiaria decumbens

Impact of Caffeine on Ethanol-Induced Stimulation and Sensitization: Changes in ERK and DARPP-32 Phosphorylation in Nucleus Accumbens

Background: Caffeine is frequently consumed with ethanol to reduce the impairing effects induced by ethanol, including psychomotor slowing or incoordination. Both drugs modulate dopamine (DA)-related markers in accumbens (Acb), and Acb DA is involved in voluntary locomotion and locomotor sensitization. The present study determined whether caffeine can affect locomotion induced by acute and repeated ethanol administration in adult male CD-1 mice. Methods: Acute administration of caffeine (7.5 to 30.0 mg/kg) was evaluated for its effects on acute ethanol-induced (1.5 to 3.5 g/kg) changes in open-field horizontal locomotion, supported rearing, and rearing not supported by the wall. DA receptor-dependent phosphorylation markers were assessed: extracellular signal-regulated kinase (pERK), and dopamine-and cAMP-regulated phosphoprotein Mr32kDa phosphorylated at threonine 75 site (pDARPP-32-Thr75) in Acb core and shell. Acutely administered caffeine was also evaluated in ethanol-sensitized (1.5 g/kg) mice. Results: Acute ethanol decreased both types of rearing. Caffeine increased supported rearing but did not block ethanol -induced decreases in rearing. Both substances increased horizontal locomotion in a biphasic manner, and caffeine potentiated ethanol-induced locomotion. Although ethanol administered repeatedly induced sensitization of locomotion and unsupported rearing, acute administration of caffeine to ethanol-sensitized mice in an ethanol-free state resulted in blunted stimulant effects compared with those seen in ethanol-naïve mice. Ethanol increased pERK immunoreactivity in both subregions of the Acb, but coadministration with caffeine blunted this increase. There were no effects on pDARPP-32(Thr75) immunoreactivity. Conclusions: The present results demonstrated that, after the first administration, caffeine potentiated the stimulating actions of ethanol, but did not counteract its suppressant or ataxic effects. Moreover, our results show that caffeine has less activating effects in ethanol-sensitized animals

Análise do teor de gordura de contrafilé bovino pela RMN de 1H em alta resolução.

Avaliar o uso da técnica da RMN como técnica não destrutiva para análise do teor de gordura da carne bovina em dois tipos de cortes: na décima segunda costela (C12), corte americano, e na sexta costela