R. Bras. Zootec.01/Mar/2017;46(3):231-9.
Trace mineral requirements for growth of Moxotó goats grazing in the semiarid region of Brazil
A comparative slaughter trial was conducted to estimate the body composition and net requirements of Cu, Zn, Mn, Fe, and Co for growth of castrated Moxotó goat kids, with15.69±0.78 kg initial body weight (BW), grazing in the semiarid region of Brazil. The baseline group consisted of four randomly selected kids (15.37±0.30 kg BW). Thirty-two kids were randomly allocated into eight groups (considered as block), distributed among four levels of concentrate supplementation (0, 0.5, 1.0, and 1.5% BW). Animals in a group were slaughtered when the 1.5% BW treatment kids in the group reached approximately 25 kg BW. The trace element content (mg/kg of empty body weight) ranged from 23.68 to 27.81 mg Zn, 35.70 to 47.29 mg Fe, 0.86 to 1.09 mg Mn, 1.45 to 1.75 mg Cu, and 0.83 to 0.87 mg Co for Moxotó kids at 15 and 25 kg BW, respectively. The net requirements (mg/kg of empty body weight gain) ranged from 30.43 to 35.74 mg Zn, 53.48 to 70.84 mg Fe, 1.22 to 1.54 mg Mn, 1.93 to 2.32 mg Cu, and 0.91 to 0.95 mg Co for animals with BW ranging from 15 to 25 kg, respectively. Indigenous goats grazing in the semiarid region of Brazil have different requirements from those values recommended by international committees for dairy and meat goats.