The Net Mineral Requirement for Maintenance and Growth of Dorper x Hu Ewe Lambs
The Net Mineral Requirement for Maintenance and Growth of Dorper x Hu Ewe Lambs
Hao Zhang,1,2,3,* Hai Tao Nie,3 Tie Wei Ma,3 Zi Yu Wang3 and Feng Wang3
ABSTRACT
A comparative slaughter trial was conducted to estimate the mineral concentrations and distributions in the main body tissues and the net requirements for maintenance and growth of F1Dorper × Hu ewe lambs. Thirty-five ewe lambs averaging 33.52±0.56 kg body weight (BW) were used. Seven ewe lambs were randomly chosen and slaughtered at 34.93 ± 0.37 kg BW as the baseline group for measuring initial body composition. Another seven lambs were also randomly chosen and offered a pelleted mixed diet (approximately concentrate : roughage = 60 : 40, DM basis) for ad libitum intake and slaughtered at 41.73 ± 0.53 kg BW. The remaining lambs (n = 21) were allocated randomly on d 0 to 3 treatment intake levels (treatments were ad libitum or restricted to 70 or 40% of the ad libitum intake) within 7 slaughter groups. A slaughter group contained 1 lamb from each treatment, and lambs were slaughtered when the ad libitum treatment lamb reached approximately 50 kg BW. Non-carcass components (head + feet, hide, internal organs + blood) and empty bodies of the lambs were weighed, ground, mixed, and subsampled for chemical analyses. The Ca, P, Na, and Mg were mainly distributed in bone, except for K, which was mainly distributed in the muscle tissues. The net macromineral requirements for maintenance were 20.20 mg Ca, 13.50 mg P, 3.80 mg Na, 7.91 mg K, and 1.10 mg Mg/kg empty body weight (EBW) for ewes. The net requirements for growth ranged from 11.79 to 12.06 g Ca, 6.04 to 6.16 g P, 1.66 to 1.74 g K, 0.40 to 0.42 g Mg, and 0.98 to 0.95 g Na /kg of EBW gain (EBWG) for ewes from 35 to 50 kg BW. These results for the mineral requirements may help to formulate more balanced diets for F1 Dorper × Hu ewe lambs in the growth phase of 35 to 50 kg BW.
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June 2018
Vol. 50, Iss. 3, Pages 799-1198
