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
…show more content…
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 impact on somatic (sertoli and leydig) cells. It was concluded that chronic heat stress during the non-breeding season impacted developing ram lambs negatively, with impairment of the testicular germ line without any effects in testosterone and cortisol concentrations. Mean testicular weights were significantly different with the indoor having an average of 151g and the outdoor group having an average of 90g. At the microscopic level, the testicles from the HS group showed no clear spermatocytes, spermatogonia, or …show more content…
However the differences in breeds involving hair sheep versus wool type sheep and heat stress affecting testicular function has not been intensively studied. The objective of the study is to find differences in developing ram lambs by evaluating testicular structure and endocrine profiles in meat type breeds of sheep, Dorper (hair type) versus Suffolk (wool type) when experiencing chronic heat stress in the non-breeding season (April-Oct) . Dorper ram lambs (hair type sheep) are much better adapted to withstand the negative effects of heat stress on testicular size and structure and spermatogenesis, compared to Suffolk ram lambs (wool type
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 impact on somatic (sertoli and leydig) cells. It was concluded that chronic heat stress during the non-breeding season impacted developing ram lambs negatively, with impairment of the testicular germ line without any effects in testosterone and cortisol concentrations. Mean testicular weights were significantly different with the indoor having an average of 151g and the outdoor group having an average of 90g. At the microscopic level, the testicles from the HS group showed no clear spermatocytes, spermatogonia, or …show more content…
However the differences in breeds involving hair sheep versus wool type sheep and heat stress affecting testicular function has not been intensively studied. The objective of the study is to find differences in developing ram lambs by evaluating testicular structure and endocrine profiles in meat type breeds of sheep, Dorper (hair type) versus Suffolk (wool type) when experiencing chronic heat stress in the non-breeding season (April-Oct) . Dorper ram lambs (hair type sheep) are much better adapted to withstand the negative effects of heat stress on testicular size and structure and spermatogenesis, compared to Suffolk ram lambs (wool type