This study was conducted on Rahmani rams to investigate the influence of sugarcane bagasse silage treated with urea, live yeast or pronifer on physiological response to sun exposure. Sixteen Rahmani rams with an average body weight of 29 kg were used in four feeding groups, untreated bagasse, 3% urea treated bagasse , urea and yeast (10 g per animal daily) treated bagasse and urea and pronifer (2 g per animal daily) treated bagasse. Pronifer is feed additive made by specific lactic acid fermentation of heat-treated soybean meal and malt. Animals were subjected to solar radiation during 3 succession days for 2 hrs. from 13:00 to 15.00. Average air temperature and relative humidity during exposure were 40 ◦C and 70%, respectively. Respiration rate (RR), pulse rate (PR) and rectal (RT), skin (ST) and wool temperatures (WT) were measured before and after exposure. Blood samples were collected before and after exposure for the determinations of serum total protein, albumin, glucose, urea-N, cholesterol, total bilirubin, AST and ALT. No significant effect of urea, live yeast or pronifer on RT, ST, RR, PR and WT after sun exposure, but the highest value was found in RR for urea group. Also, treatments had no significant effects on serum total protein, albumin and globulin after sun exposure. Glucose is one of the most blood parameters can be affected by exposure to solar radiation, but cholesterol and urea-N were not affected. Animals fed urea had the highest response for serum glucose, ALT and AST during exposure to direct sunlight. In conclusion, using sugarcane bagasse silage with live yeast or pronifer may be useful under sun exposure but urea treatment may be not recommended under sun exposure.