A study of the composition of Clun Forest ewe's milk:III. Ewe's milk fat: a preliminary study

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Six ewes were milked over a lactation period of 12 weeks beginning 2 weeks after parturition. Milk fat, total crude protein, and protein fractions were determined in each weekly milk sample.Milk fat and total crude protein in whole milk increased significantly over the lactation, attaining mean values of 5-8 and 5-9% respectively. The concentration of the caseins, total albumins and y?-lactoglobulin in the whole milk also increased significantly over the lactation, with mean concentrations of 4-67, 0-80 and 0-54% respectively. The mean concentrations of these fractions, expressed as a percentage of the total crude protein, were, caseins 78-7, total albumins 13-5 and /Mactoglobulin 9-1.The following fractions, whose mean percentage concentrations in whole milk are given in parentheses, showed no significant trends over the lactation: a-lactalbumin + serum albumin (0-26), proteose-peptones (0-05), globulins (0-06) and non-protein nitrogen (0-35). Expressed as percentages of total crude protein, these concentrations are 4-4, 0-8, 1-1 and 5-6 respectively.The milk constituents synthesized in the mammary gland, i.e. fat, caseins and y?-lactoglobulin showed significant correlations in concentration in whole milk as well as significant increases in concentration over the lactation. INTRODUCTIONBrouchard & Brisson (1969) was published reporting changes over a lactation in the protein fractions

Section: Introductionmentioning

confidence: 99%

A study of the composition of Clun Forest ewe's milk. IV. The proteins of ewe's milk and their variation with stage of lactation

Poulton

Ashton

1970

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“…TMTTJ nTvrTr"rTrwr ^n e ^r s * a m l °^ tn^s investigation was to compare the milk yield ol a group of ewes obtained by a Previous papers in this series (Ashton, Owen & lamb-suckling technique with that obtained by Ingleton, 1964;Ashton & Yousef, 1966; Yousef & machine milking following oxytocin injection. The Ashton, 1967;Poulton & Ashton, 1970) have dealt second aim was to study the effect of a cereal-rich mainly with the compositional aspects of ewe's diet, as opposed to the more normal diet of hay milk without reference to yield of milk or milk and commercial concentrates, on the yield of milk constituents. Information on the milk yield of ewes and its constituents.…”

mentioning

confidence: 99%

Studies on ewe's milk:V. The effect of high cereal diets on ewes and on the yield of milk and milk constituents

Poulton¹,

Ashton²

1972

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Milk yields determined by a lamb-suckling and an oxytocin technique were compared using a control group of four ewes. Both methods showed a similar linear decrease in yield with advancing lactation, but the oxytocin method gave 23% more milk presumably because residual milk was included.When the diet of lactating ewes was changed so that the amounts of hay and commercial concentrates were reduced in favour of flaked maize, such severe acidosis developed when 39-5% of this food was introduced abruptly or 53% more gradually over one week, that the trials were discontinued.Rolled barley, which probably ferments more slowly, was therefore used instead of flaked maize. Levels up to 62-9 %, gradually introduced over a period of 3 weeks, also produced acidosis whose severity varied greatly in individual ewes.Milk yield was also determined by the oxytocin technique for ewes receiving normal diets followed by those rich in rolled barley, and the milk was analysed for fat, protein and lactose. The composition of the milk was extremely variable during rolled barley feeding, but there was an indication of an increase in the percentage of crude protein and also fat, after a marked fall in the latter in the milk of two ewes with the change to the low-fibre diet.Diet had little effect on yields of milk and its components but, on the rolled barley diets, the rate of decrease of these yields was arrested (or even reversed in the case of fat), with a high degree of significance (milk yield P < 0-05, fat yield P < 0-01, protein yield JP < 0*01). These observations are discussed, in the light of knowledge on the effect of diet on molar proportions of volatile fatty acids in the rumen.

“…Such information may have potential application for both animal breeders and those who use animals for certain nutritional or related studies. An illustration of this is the recent report by Yousef & Ashton (1967) in which they indicated that differences existed among individual ewes for percentage fatty acid composition of milk fat and they also suggested that breed differences might exist. The mice used in this study provided evidence that genetic differences existed between inbred lines for certain carcass traits including relative amounts of fatty acids.…”

Section: Discussionmentioning

confidence: 99%

Genetic differences for fatty acids and other body components in mice

Boylan

Roberts

1968

SUMMARYDifferences in fatty acid composition and other body components were studied in two inbred lines of mice and crosses between them (reciprocals). The two inbred lines differed significantly (P < 0·05) in percentage moisture and percentage fat in the carcass, but there was no difference between the two kinds of crossbreds. Percentage protein of the carcass did not differ among the lines. Seven fatty acids were identified and considerable variation in the amount of each was found in the mice. About 65 % of the fatty acids identified was composed of palmitic and oleic. The two inbred lines differed significantly (P < 0·05) from each other for four of the seven fatty acids. The crossbred mice also differed for four of the seven fatty acids, but not necessarily the same acids as for the parental lines. Heterosis (crossbreds exceeding the mean of the parents) was observed for several traits. Crossbreds had a larger percentage protein and less fat in their carcasses than the inbreds. Crossbreds exceeded the inbreds for percentage lauric and percentage myristic acids, but had less palmitoleic acid than the inbreds. In general crossbreds had a higher percentage of saturated fatty acids than the inbreds.