Nutritional, behavioral and performance parameters of F1 Holstein x Zebu cows at different lactation stages / [Parâmetros nutricionais, comportamento ingestivo e desempenho de vacas F1 Holandês x Zebu em diferentes estádios da lactação]

The objective of this study was to evaluate the different lactation stages of F1 Holstein x Zebu cows on intake and digestibility of nutrients, nitrogen use efficiency, feeding behavior and performance. Thirty-six F1 Holstein × Zebu cows with initial body weight (BW) of 482±43kg were used. The early, mid and late lactation stages were characterized after 50±13, 111.5±11.75 and 183.0±17.5 days in milk, respectively. A completely randomized design with three lactation stages and 12 cows in each treatment group was used. Dry matter intake (P=0.01) was higher in late lactation. Milk yield (P<0.01) was 24.17% higher in early lactation than in other stages. Body weight was lowest in mid-lactation cows (465.63kg; P<0.01). The feed efficiency was 23.36% higher in early lactation than in other stages (0.82kg of milk/kg of DM). F1 Holstein x Zebu cows have increased dry matter intake in late lactation. Milk yield and feed efficiency in early lactation were benefited by changes in feeding behavior, such as increased rumination time.(AU)

O objetivo deste estudo foi avaliar os diferentes estágios de lactação de vacas F1 Holandês x Zebu quanto ao consumo e à digestibilidade de nutrientes, à eficiência no uso de nitrogênio, ao comportamento ingestivo e ao desempenho. Trinta e seis vacas F1 Holandês × Zebu, com peso corporal inicial (PC) de 482±43kg, foram utilizadas. Os estágios inicial, médio e final da lactação foram caracterizados após 50±13, 111,5±11,75 e 183,0±17,5 dias de lactação, respectivamente. O arranjo experimental adotado foi o delineamento inteiramente ao acaso, com três fases de lactação e 12 vacas em cada grupo de tratamento. O consumo de matéria seca (P=0,01) foi maior no período final da lactação. Na fase inicial da lactação, a produção de leite (P<0,01) foi maior em 24,17% em comparação às demais fases. Na fase intermediária da lactação, as vacas apresentaram menor peso corporal (465,63kg; P<0,01) em relação às demais fases. A eficiência alimentar foi maior em 23,36% na fase inicial da lactação (0,82kg de leite/kg de MS). Vacas F1 Holandês x Zebu aumentam o consumo de matéria seca no período final da lactação. A produção de leite e a eficiência alimentar no início da lactação foram favorecidas por mudanças no comportamento ingestivo, como o aumento do tempo de ruminação.(AU)

Decreased biological activity is related to abnormal multimeric structure of von Willebrand factor in pulmonary hypertension

We evaluated the correlation between decreased biological activity and abnormalities in the multimeric structure of plasma von Willebrand factor (vWF) in 27 pulmonary hypertensive patients (median age, 21 years). The biological activity of vWF was measured by the ristocetin cofactor assay and its multimeric structure was assessed by Western immunoblotting after SDS-agarose gel electrophoresis. In spite of high antigenic activity of vWF in plasma (139 ñ 65 vs 91 ñ 27 per cent in controls, P=0.003), the biological activity expressed as a percent of the control value was decreased in pulmonary hypertensive patients (60-88 per cent activity, 95 per cent CI for the mean). High molecular weight multimers (biologically active forms) were absent in patients and there was a significant increase in the concentration of low molecular weight polymers in comparison with normals (56 ñ 12 and 35 ñ 12 per cent of total multimer density, respectively, P<0.001). Multimeric abnormalities were positively correlated with plasma vWF levels (r=0.51, P=0.0007) and negatively correlated with vWF biological activity (r=-0.54, P=0.004). Thus, decreased biological function is related to abnormalities in the multimeric structure of vWF, possibility reflecting extensive endothelial dysfunction in pulmonary hypertension.

Mantenimiento de equipos en los sistemas de agua potable y alcantarillado

Manual que pretende servir como guía para el desarrollo de sistemas de mantenimiento en las empresas de agua potable y saneamiento. Dirigido a los gerentes de mantenimiento de tales con empresas, bajo los siguientes enfoques: conceptual, que presenta el mantenimiento como una parte que se interrelaciona con las otras partes de la empresa; la otra muestra los fundamentos a tomarse en cuenta para implantar un sistema de mantenimiento preventivo