Nitrogen balance studies with the milk-fed lamb

Abstract

I. Thirty-three cross-bred lambs were given reconstituted dried whole cow's milk from I week of age at different levels of intake and at different frequencies of feeding. 2.Feeding frequency had no effect on live-weight gain, N retention or total body composition.3. Lambs given two feeds daily had significantly heavier abomasums than pair-fed lambs given six feeds daily. 4.The weights of fat, protein (N x 6 2 5 ) and water in the body were closely related to empty body weight; body composition (% of empty body) was not significantly affected by the level of milk intake or by the rate of growth.5 . Live-weight gain was closely related to energy intake (r = +o.gg) and to N retention (r = +o*g7). A live-weight gain of IOO g was associated with an intake of 51 I kcal and a N retention of 2.28 g N.Lambs and calves when reared with their dams are known to suckle at more frequent intervals than is usually practicable when they are hand-reared (Munro, 1955 ;. There is at present no evidence that feeding frequency has any marked effect on the growth rate or utilization of energy and nitrogen by the preruminant lamb or calf (Voelker & Jacobson, 1953), though studies with other animals suggest that both protein and fat metabolism may be affected (Cohn, 1962;Mochrie, 1964).The present paper describes three experiments, with milk-fed lambs, in which the effect of frequency of feeding over a wide range of energy and N intakes was studied. In the first experiment, lambs were bottle-fed two, three or six times daily, the intakes of energy being similar but controlled throughout. In the second experiment, lambs which were allowed to feed ad lib. twice daily were compared with pair-fed lambs given the same amount of milk in six feeds. In the third experiment, lambs were allowed to self-feed to appetite. The effect of feeding frequency on live-weight gain, N balance and total body composition was measured. EXPERIMENTALExperimental design Expt I . Comparison of two, three and six feeds daily. Fifteen male lambs were allotted at random to the dietary treatments. The experimental period of 4 weeks was divided into two equal periods (periods I and 2). The diet was given for a preliminary period of I week followed by a collection period of I week. The intake of feed was determined by the live weight of the lamb at the beginning of each preliminary period, and was * Paper no. 4 : Br.

Response of rat adrenal cholesteryl esters to cold stress

“…They were then homogenized (Polytron, model PT 10, Brinkman Instruments Ltd., Rexdale, Ontario) for 30 sec in 10 ml of 2:1 chloroformmethanol and extraction of the lipid continued for 60 min at room temperature under nitrogen. After removal of the residue by filtration the extract was washed with water and the lipids isolated as previously described (19). Total lipids were fractionated by thin layer chromatography (TLC) on Adsorbosil 1 (Applied Science Labs.…”

“…Cholesteryl esters, visualized by spraying the plate with Rhodamine 6G and viewing under ultra violet light, were extracted from the gel with freshly redistilled diethyl ether. Methyl pentadecanoate was added as an internal standard, the cholesteryl esters were transesterified with boron fluoridemethanol and the resulting methyl esters purified by TLC (19). The fatty acid composition of the adrenal cholesteryl esters was determined by gas liquid chromatography using the equipment and procedures previously described (19).…”

“…Methyl pentadecanoate was added as an internal standard, the cholesteryl esters were transesterified with boron fluoridemethanol and the resulting methyl esters purified by TLC (19). The fatty acid composition of the adrenal cholesteryl esters was determined by gas liquid chromatography using the equipment and procedures previously described (19). The esters from animals fed corn or coconut oil were fractionated on a 150 x 0.2 cm column containing 15% EGSS-X on 80-100 mesh Chromosorb W (Applied Science Labs., Inc.) and operated isothermally at 180-185 C. In order to separate 18:3(n-3) from 20:1 (n-9) and bSelectivity Index = decrease in concentration of ester expressed as per cent of decrease in total ester divided by mole per cent of ester in control (17).…”

Renal Control of Plasma Urea Level in Sheep: The Diuretic Effect of Urea, Potassium and Sodium Chloride

“…(Faichney & Colebrook, 1979). The wethers were fitted with harnesses and faecal collecting apparatuses of the type described by Walker & Faichney (1964).…”

Efficacy of linoleic acid administered rectally as monoglyceride

“…A three-day administration of EFA was chosen to test whether short-term rectal administration of linoleic acidrich MG is feasible and effective, and because changes in the fatty acid composition of liver lipids of EFAdeficient rats were already apparent within 24 hr after linoleic acid administration (23). Full recovery including restoration of 20:4oJ6 to normal values would have taken much longer (24). The amount of linoleic acid administered represents about 0.32% of the calories, and the 7-wk-old EFA-deficient rats consumed about 11 g of fat-free diet per day.…”