Abolfazl Zali - Department of Animal Science, Campus of Agriculture and Natural Resources, University of Tehran, Karaj, Alborz, Iran
Farhad Parnian-Khajehdizaj - Department of Animal Sciences, Faculty of Agriculture, University of Tabriz, Tabriz, Iran
Farhang Fatehi - Department of Animal Science, Campus of Agriculture and Natural Resources, University of Tehran, Karaj, Alborz, Iran
Seyed Ahmad Hosseini - Department of Animal Science, Campus of Agriculture and Natural Resources, University of Tehran, Karaj, Alborz, Iran

In the present study, the potential nutritive values and in vivo responses of the dried dairy waste (DDW) as a protein substitution for canola meal in the diet of male calves were evaluated. Thirty male Holstein calves were randomly assigned to three treatments in a randomized complete design with ۱۰۴ days of the experiment. Treatments were control (without DDW), a low level of DDW (۱.۶۵% of diet CM was substituted by DDW), and a high level of DDW (۳.۳۰% of diet CM was substituted by DDW). Dry matter (DM) intakes averaged ۹.۹۱ and ۹.۵۵ kg per day for control and DDW supplemented diets. Calves showed similar total-tract digestibility values for dry matter (DM), organic matter (OM), neutral detergent fiber (NDF), and ether extract (EE) for all treatments. However, there was no decrease in average daily gain and feed conversion ratio when calves received diets containing DDW in different levels compared with control. Totally, the results of the current study showed that DDW could be considered as a potential source of protein in the diet of Holstein calves.

Average daily gain, Canola meal, Industrial-dairy waste, Male Holstein calves, Nutrient digestibility