a Social, Genetic, Developmental & Psychiatry Centre, Institute of Psychiatry, King's College London, London SE5 8AF, United Kingdom b School of Education, University of Delaware, Newark, DE 19716 USA c Psychology Department, Logan Hall 160, University of New Mexico, MSC03 2220 Albuquerque, NM 87131 USA d Department of Pathology, School of Medicine, University of New Mexico, MSCO8 4640, Albuque...

Several recent studies have shown that the fecundity of a man decreases progressively with sperm concentrations below 40 million spermatozoa per mL. Therefore, it is unfortunate that the new World Health Organization guidelines for semen analysis recommend lowering the lower cutoff value for normal sperm concentration from 20 to 15 million spermatozoa per mL. As a result large groups of subfert...

the purpose of this study was to evaluate the probable effects of the vitamin e addition in different levels to the extender of chicken semen on spermatozoa quality during storage of semen at 4°c for 0, 3, 6, 10 and 24 hours. eight young ross broiler breeder strain 308 roosters were used in this experiment. the collected semen from all roosters was mixed together and diluted with modified a rin...

Multiple studies from around the world have suggested that semen quality is declining globally. However, all studies suffer from variable semen sampling criteria, selection bias with respect to the types of men volunteering to participate, and a bias with respect to a tendency to examine only samples from high-income countries. This heterogeneity in approaches, especially given the undersamplin...

BACKGROUND Studies have suggested that the quality of human semen has been declining over recent decades, presumably because of lifestyle or environmental factors. METHODS Polychlorinated biphenyls and organochlorine pesticides were analysed in the plasma of 25 men with poor semen quality, 20 men with normal semen quality and idiopathic subfertility and 27 men with normal semen quality and fe...

We propose a scaled linear mixed model to assess the effects of exposure and other covariates on multiple continuous outcomes. The most general form of the model allows a different exposure effect for each outcome. An important special case is a model that represents the exposure effects using a common global measure that can be characterized in terms of effect sizes. Correlations among differe...

Modern societal pressures and expectations over the past several decades have resulted in the tendency for couples to delay conception. While women experience a notable decrease in oocyte production in their late thirties, the effect of age on spermatogenesis is less well described. While there are no known limits to the age at which men can father children, the effects of advanced paternal age...

Semen cryopreservation and artificial insemination (AI) are potentially valuable methods for supporting the breeding management of endangered species like the Asian elephant. Cryopreservation of Asian elephant semen has however proven problematic with respect to maintenance of both adequate semen quality and fertility post-thaw. In this study, nine ejaculates from three adult bulls were used to...

Artificial insemination (AI) is the preferred method for reproduction in the majority of the intensive pig production systems Worldwide. To this end, fresh extended ready-to-use semen doses are either purchased from AI-centres or produced by boars kept on-farm. For profitable semen production, it is necessary to obtain a maximum amount of high quality semen from each boar. This paper reviews cu...

the purpose of this study was to evaluate the probable effects of leptin addition in different levels to the semen extender on sperm quality (motility and motility parameters, viability, sperm membrane integrity, and dna damage). semen specimens were evaluated immediately after leptin addition, equilibration time and after thawing the frozen semen. five healthy buffalo bulls (5 ejaculates from ...