Abstract :
Thirty-six 1.0-year-old Liao Ning Cashmere goat wethers (BW= 22.01±0.59 kg) were used
to determine the effects of dietary zinc (Zn) level on the performance, nutrient digestibility
and plasma Zn status during the cashmere fiber growing period. The goats were randomly
divided into four groups that were fed a basal diet containing 22.3mg Zn/kg dry matter
(DM) with 0, 15, 30 or 45mg Zn/kg DM as reagent grade ZnSO4·7H2O. The experiment
lasted 60 days including a 7-day metabolism trial. Both average daily gain (ADG) and feed
efficiency were improved (P < 0.05) by Zn supplementation and were higher (P < 0.05) for
the treatment groups supplemented with 30 and 45mg Zn/kg DM compared with 15mg
Zn/kg DM. Zn supplementation had no influence on the length and diameter of cashmere
fiber (P > 0.05). Digestibility of DM, crude protein (CP), neutral detergent fiber (NDF) and
acid detergent fiber (ADF) did not differ among treatments (P > 0.05). Plasma Zn concentrations
were increased (P < 0.01) by Zn supplementation and were higher (P < 0.05) for the
treatment groups supplemented with 30 and 45mg Zn/kg DMcompared with 15mg Zn/kg
DM. Zn apparent absorption rate and apparent retention rate were decreased (P < 0.05) by
Zn supplementation, but did not differ among Zn supplemented treatments (P > 0.05). In
conclusion, a control diet containing 22.3mg Zn/kg DM was inadequate for achieving optimal
growth performance in Cashmere goats, and the recommended level of dietary Zn for
such goats is 52.3 mg/kg DM during the cashmere fiber growing period.
