Energy Requirements and Growth of Captive Lesser Scaup

Energy requirements of captive Lesser Scaup ducks (Aythya affinis) were determined from hatching to 12 weeks using a feeding trial and comparative slaughter method. Food intake was measured directly; metabolizable energy intake by a chromic oxide indicator and calorimetry; net energy for gain by comparative slaughter; and total heat production by difference. Live weight growth was measured and dry matter growth estimated from a regression of percentage dry matter on age. Food intake (dry) increased from 6.7 gm./duck/day during the 1st week to a peak of 52.5 gm. in the 5th week. Metabolizable energy intake averaged 5,575 Kcal. during the first 7 weeks, the assumed preflight period. Percentage carcass dry matter increased from 30 percent at 1 week to 45 percent at 12 weeks. A similar trend occurred in wild scaup though percentages were lower due to the lower fat content. Data are given for the proximate composition of carcasses for the first 12 weeks.