Utilisation of the metabolisable energy of ewe's milk by the lamb

Abstract

Efficiency of utilisation of ewe's milk by the lamb was studied.The comparative slaughter method was used to determine gain or loss in body fat, protein, and energy. Of 24 crossbred lambs used, 12 comprised an initial slaughter group; the remaining 12 were given ewe's milk for 21 days at four different levels of energy intake ranging from sub-maintenance to ad libitum.Lambs fed at the lowest plane of nutrition mobilised body fat and were in negative energy balance; all the others were in positive energy balance. The mean digestibility of ewe's milk was 98.4% and was unaffected by the plane of nutrition. The mean metabolisability of the diet was 95.6% for lambs in positive energy balance and 91.8% for those in negative energy balance. The metabolisable energy requirement for zero energy gain was 145.2 kcal/kg o . 75 24 hr, and the efficiency of utilisation of metabolisable energy for maintenance and growth was 76.9%.

Energy balance studies with weaned lambs

“…Twelve comprised an initial slaughter group (ISG) as described in a previous paper (Jagusch and Mitchell 1971). The * Lincoln College, Canterbury, N.Z.…”

Energy balance studies with weaned lambs

“…7 5 24 hr (Walker and Jagusch 1969)) or ewes' milk (112 kcal/kg o . 7 5 24 hr (Jagusch and Mitchell 1971)). Despite a lower fasting catabolism, the maintenance requirement of lambs in the present experiment (168 kcal/kg o .…”

“…The efficiency of utilisation of ME was calculated as the slope of the regression line relating energy gain (EG) to ME intake (Jagusch and Mitchell 1971;Mitchell and Jagusch 1972). …”

“…The frozen carcass and visceral components were sectioned into strips and minced and sampled as described by Jagusch and Mitchell (1971).…”

“…A number of estimates of the efficiency of utilisation of metabolisable energy (ME) by young milk-fed lambs have been published in recent years (Kielanowski andLassota 1960: Walker andJagusch 1969;Jagusch and Mitchell 1971;Norton and Walker 1971). However, little work has been conducted with young weaned ruminants, and Table 1 summarises published work pertaining to young sheep.…”