Hassan Fazaeli - Agriculture and Natural Resources Research Center of Hamedan, Hamedan, Iran
Housain Shafyee-Varzeneh - Agriculture and Natural Resources Research Center of Hamedan, Hamedan, Iran
Ali Farahpoor - Agriculture and Natural Resources Research Center of Hamedan, Hamedan, Iran
Abdolossein Moayyer - Agriculture and Natural Resources Research Center of Hamedan, Hamedan, Iran

Background This experiment was conducted to study theeffect of diet contained mushroom spent wheat straw(MSWS) remained from Agaricus bisporus mushroom aswell as the physical form of the diet on the performance ofthe feedlot calves. At the end of mushroom harvestingperiod, MSWS was collected from production room andthe casing soil was removed from the whole compost, thenit was sun dried and sampled for chemical analysis. In acompletely randomized design, 24 Holsteins male calveswith initial weight of 201.9 ± 1.0 kg were allocated tofour experimental diets containing (1) standard pellet diet;(2) pellet diet with 15 % MSWS; (3) standard mash dietand (4) mash diet contained 15 % of MSWS.Results Average daily gain was 1,261, 1,146, 1,093 and830 g; dry matter intake was 7.91, 6.51, 8.07 and 8.15 kg/animal/day and feed conversion ratio was 6.32, 5.69, 7.39and 8.76 for the diets respectively that were significantlydifferent (P.05) among the treatments. Results ofslaughtering observations showed that no differences couldbe detected in carcass and internal organs of the calves thatreceived different diets.Conclusions The spent compost straw could be includedup to 15 % in finishing calve diet in the pellet form.

Mushroom compost straw Agaricus bisporus Fattening calves