Caloric stress alters fat characteristics and Hsp70 expression in milk somatic cells of lactating beef cows

Selection for higher production rate in cattle inhabiting challenging habitats may be considered disadvantageous because of possible deleterious effects on immunity and reproduction and, consequently, on calf crop percentage. In Israel, free-grazing high productive beef cows experience reduction in nutritional quality of forage during up to 8 months of the year. As milk production by dams dictates calf performance, dam’s nutritional needs and rebreeding rates, the aim of the present study was to test how lactating beef cows deal with combined caloric and protein stress both at the productive and self protective levels. For this purpose, we studied the effect of long-term caloric stress on milk characteristics and gene expression of stress and milk components producing proteins. Lactating dams responded to caloric stress by decreased body weight, milk, and milk protein production. To compensate for total energy loses in milk, they produced milk of higher fat concentration and shifted the proportions of its fatty acids towards long and unsaturated ones. This was reflected by increased mRNA transcription of the fatty acid binding protein. Prolonged low-energy diet promoted cell-specific heat shock protein (Hsp) response; whereas significant increase of Hsp90 but unchanged levels of Hsp70 proteins were observed in white blood cells, the expression of Hsp70 in milk somatic cells was markedly attenuated, in parallel with a marked increase of αs1-casein expression. At the mammary gland level, these results may indicate a decrease in turnover of proteins and a shift to an exclusive expression of milk components producing factors. Similar responses to caloric stress were revealed also in ketotic dairy cows. Ketosis promoted a shift towards long and unsaturated fatty acids and an increased expression of αs1-casein in milk somatic cells. These findings may reflect an evolutionary-preserved mechanism in lactating cows for coping with caloric restriction. Overall, our results provide an index to test suitability of beef cattle breeds to inadequate caloric demands

Desarrollando un marco para el liderazgo ético

Interest in ethical leadership from academics and practitioners has grown enormously in recent years. This article addresses this literature through a framework that identifies three interlocking questions. First, who are ethical leaders and what are their characteristics? Second, how do ethical leaders do what they do? Third, why do leaders do as they do and what are the outcomes of ethical leadership? Different dimensions to ethical leadership are examined and presented as three interlocking circles; Virtues, Purposes and Practices. This framework presents an integrated approach to ethical leadership and argues that future research take this holistic framework and apply it to different sectors or contexts

Leaders' personal wisdom and leader-member exchange quality: The role of individualized consideration

Business scholars have recently proposed that the virtue of personal wisdom may predict leadership behaviors and the quality of leader-follower relationships. This study investigated relationships among leaders' personal wisdom-defined as the integration of advanced cognitive, reflective, and affective personality characteristics (Ardelt, Hum Dev 47:257-285, 2004)-transformational leadership behaviors, and leader-member exchange (LMX) quality. It was hypothesized that leaders' personal wisdom positively predicts LMX quality and that intellectual stimulation and individualized consideration, two dimensions of transformational leadership, mediate this relationship. Data came from 75 religious leaders and 1-3 employees of each leader (N = 158). Results showed that leaders' personal wisdom had a positive indirect effect on follower ratings of LMX quality through individualized consideration, even after controlling for Big Five personality traits, emotional intelligence, and narcissism. In contrast, intellectual stimulation and the other two dimensions of transformational leadership (idealized influence and inspirational motivation) did not mediate the positive relationship between leaders' personal wisdom and LMX quality. Implications for future research on personal wisdom and leadership are discussed, and some tentative suggestions for leadership development are outlined