Effect of organic zinc sources on performance, zinc status and carcass, meat and claw quality in fattening bulls

A total of 4×15 growing Red Holstein crossbreeding bulls were used to assess the effect of two organic zinc sources, i.e. Zn proteinate and Zn polysaccharide, compared with Zn oxide and a control treatment without Zn supplementation on feed intake, growth rate, zinc status as well as carcass, M. longissimus thoracis and claw quality. The chosen zinc level of 45 mg/kg DM corresponded to recommended requirements (RAP, 1999). The feeding trial lasted for 284 days and comprised the weight range (average) 146–520 kg live weight. The ration consisted of maize and grass silage supplemented with concentrate and a mineral–vitamin mix. The chemical form of added Zn sources had no significant effect on the average dry matter intake, growth rate or feed conversion ratio. Dietary treatment influenced neither zinc status nor carcass and meat quality in a statistical way. In comparison to inorganic Zn, feeding organic Zn compounds to bulls resulted in some improvement in claw quality