Equine conceptus development : a mini review

Many aspects of early embryonic development in the horse are unusual or unique; this is of scientific interest and, in some cases, considerable practical significance. During early development the number of different cell types increases rapidly and the organization of these increasingly differentiated cells becomes increasingly intricate as a result of various inter-related processes that occur step-wise or simultaneously in different parts of the conceptus (i.e., the embryo proper and its associated membranes and fluid). Equine conceptus development is of practical interest for many reasons. Most significantly, following a high rate of successful fertilization (71-96%) (Ball, 1988), as many as 30-40% of developing embryos fail to survive beyond the first two weeks of gestation (Ball, 1988), the time at which gastrulation begins. Indeed, despite considerable progress in the development of treatments for common causes of sub-fertility and of assisted reproductive techniques to enhance reproductive efficiency, the need to monitor and rebreed mares that lose a pregnancy or the failure to produce a foal, remain sources of considerable economic loss to the equine breeding industry. Of course, the potential causes of early embryonic death are numerous and varied (e.g. persistent mating induced endometritis, endometrial gland insufficiency, cervical incompetence, corpus luteum (CL) failure, chromosomal, genetic and other unknown factors (LeBlanc, 2004). However, the problem is especially acute in aged mares with a history of poor fertility in which the incidence of embryonic loss between days 2 and 14 after ovulation has been reported to reach 62-73%, and in which embryonic death is due primarily to embryonic defects rather than to uterine pathology (Ball et al., 1989; Carnevale & Ginther, 1995; Ball, 2000).

museology and community development in the XXI Century

Each time more, museology professionals are confronted with terms such as community, social inequality, social inclusion and development in their quotidian. Be it in conferences, publications or museum programmes, these are increasingly recurrent terms which, in great part, translate the dynamics of a relationship between museology and community development that has been constructed since the late 60’s. Although it is not new, such relationship has gone through a major bloom in the early 90’s and arrives today as an emerging priority within the world of museology. A first glance on the subject reveals that very different approaches and forms of action share the efforts in endowing museology with a role in community development today. In addition, despite of its growing popularity, it seems to be some misunderstandings on what the work with community development requires and truly signifies, as can be pointed out in a number of assertions originated from the field of museology. Accompanying such a plural environment, discussions and disagreements about to what extend museology is able to claim a role in social change also mark its affairs with community development. People are faced, indeed, with a rather polemic and intricate scenario. To a great extend, language barriers hinder the exchange of information on current initiatives and previous experiences, as well as on the development of concepts, approaches and proposals. Lack of better interactions among the groups of museology professionals and social actors who carry out different works with community development also contributes to making the potential of museology as a resource for development more difficult to be visualised.