The Effects Of Heat Stress On Human Development Essay

1661 Words Dec 3rd, 2016 7 Pages
Summary Heat stress has shown to be detrimental to male reproduction, affecting the testicles and spermatogenesis. In 2010, a study was conducted in Iran using male lambs which were exposed to chronic heat stress. The objective of the study was to investigate the effect of moderate and high temperatures on testicular structures and on testosterone and cortisol concentrations in the developing ram lambs. Twenty fall born ram lambs were randomly assigned to a group: either to an outdoor heat stress (HS) group where temperatures ranged 31-50C (n=10) or an indoor thermo-neutral temperature (TN) group where temperatures ranged from 26-32C (n=10). The span of the study was from May to October which is typically the non-breeding season in seasonal sheep. Each month blood was drawn to assess serum testosterone and cortisol levels. At the end of the study the ram lambs were all slaughtered and their testicles were weighed and subject to a histopathology exam.
There was a significant difference in temperatures between the HS group and the TN group. There was no significant difference in testosterone concentration between the two groups, only numerical differences; testosterone levels did increase as the months passed and coming closer to the breeding season. Cortisol levels were also not different throughout the study except for August and October. Testicle size was different between the groups with the HS group having severe testicular degeneration at the germ line with no…

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