effects of feeding wheat factory sewage on performance, nutrient digestibility and blood metabolites in finishing male calves

fifteen holstein male calves (416 ± 35 kg initial bw; mean ± sd) were employed in a replicated 3 × 3 latin square test to investigate the effect of partial replacement of barley grain by wheat factory sewage (wfs) within three 22-d periods including 16 d of adaptation and 6 d of data collection. the basal diet (wfs0) consisted of 42.5% (dm basis) barley grain, partially replaced with either 23.5% wfs (wfs10) or 47% wfs (wfs20). calves were fed ad-libitum once a day as total mixed ration with free access to water. feeding wfs decreased dry matter intake as compared with wfs0 (10.0, 9.2 and 9.2 kg/d in wfs0, wfs10, and wfs20, respectively) but there was no difference observed between wfs supplemented diets. body weight changes per period and average daily gains were not affected by dietary treatments but feed efficiency increased in calves fed wfs20 as compared with others. including wfs increased nutrient digestibility coefficients as compared with wfs0 but there was no difference observed between wfs supplemented diets. feeding wfs did not affect blood plasma metabolites expect for plasma insulin concentration which was decreased. results indicated that partially replacing barley grain with wfs in male’s calves finishing diets reduced dry matter intake, but increased nutrient digestibility and thereby feed efficiency. in general, using wheat factory sewage as by-product replaced for grain in finishing diets can be justifiable on both productivity and from on economical point of view.