Composition of ewe's milk

Abstract

Although the composition of cow's milk has been studied by many workers, there is relatively little published information on ewe's milk and information on its content of amino acids and B vitamins is sparse and incomplete.In the present study, determinations have been made of the major constituents of ewe's milk, of its amino acid composition and its content of 8 vitamins of the B-complex. MATERIALS AND METHODSAnimals and their management. Six 2-year-old Suffolk x Clun Forest ewes were used in the experiments. They were maintained on a high plane of nutrition with a daily diet of hay and concentrates (hay 1-1 kg; barley 320 g; flaked maize 160 g; bran 80 g, linseed oil cake 40 g) with added minerals and vitamins as described by Braithwaite, Glascock & Riazuddin (1969). The ewes were machine-milked twice daily and samples of the bulked morning and evening milks were stored at -20 C C to await analysis. Individual samples were taken from 3 of the ewes on the ninth, fourteenth and nineteenth days of lactation for the vitamin analyses.For all other analyses samples of milk taken from all 6 ewes on the second, twentyfirst and forty-ninth days of lactation were used. A composite sample of cow's milk from a bulk tank from the Institute's herd of Friesian cows was included for comparative purposes.Methods of analysis. Samples were analysed for fat content by the Gerber method (British Standards Institution, 1969), for total solids by drying at 100 °C, for total N by the Kjeldahl technique, for lactose by the chloramine-T method (British Standards Institution, 1963) and for ash after heating at 500-550 °C (British Standards Institution, 1963). Solids-not-fat content was calculated by difference. Assays for riboflavin, thiamin, vitamin B 12 and folic acid were done as described by Ford et al. (1969) and those for nicotinic acid, biotin and pantothenic acid as described by Chapman et al. (1957). Vitamin B 6 was assayed as described by Gregory (1959). Most amino acids were determined, after hydrolysis by refmxing with 6 M-HC1 at 110 °C for 24 h, by the method of Spackman, Stein & Moore (1958) using a multichannel amino acid analyser (Evans Electroselenium Ltd, Halstead, Essex, England). Cystine and methionine were determined by the method of Moore (1963) using a JLC-5AH amino acid analyser (Jeolco, Tokyo, Japan). Tryptophan was determined by procedure C of Miller (1967). Amino acid analyses were carried out on whole milk and for the acid hydrolyses a large excess of 6 M-HC1 (1 ml/mg crude protein (CP)) was used to minimize destruction of amino acids due to carbohydrates and other organic constituents (Bigwood, 1960;Lindquist, 1966).

Comparison of Protein Extracts from Various Unicellular Green Sources

“…The compositions measured are similar to what has been reported earlier . When comparing to common food protein sources, like soy and bovine milk, − the microalgae and cyanobacterium amino acid compositions are more similar to soy proteins than to bovine milk (Figure ). This is illustrated by the high linear regressions between the determined amino acid compositions and the literature values of microalgae, soy, , and bovine milk , with determination coefficients of R 2 = 0.89, 0.82, and 0.66, respectively.…”

Effect of Stage of Lactation on Nutrient Composition of Tswana Sheep and Goat's Milk

“…Ash content in goat's milk generally increased by 0.02 g/100 g while that of sheep's milk increased by 0.017 g/100 g. The lowest increase was 0.01 g/100 g recorded between 110 and 152 days post-partum and the highest being 0.03 g/100 g recorded between 68 and 82 days post-partum. Ovis aries milk contained ash percentage of 0.95 at 49 days post-partum (Williams et al, 1976). This value is higher than the 0.84 recorded at 54 days post-partum in Tswana ewe's milk.…”

Iodine nutrition in ewes : effects of low to high iodine intake on iodine content of biological fluids in pregnant and lactating ewes

“…The difference between the DM concentration of colostrum that of milk has been estimated to be 30% (Williams et al, 1976;Eales & Small, 1981 Falconer (1963) and Daburon et al (1968), who used radioactive iodide. This confirms the high ability of the ovine mammary gland to concentrate iodide from plasma to milk.…”