EFFECTS OF ALKALI TREATMENT AND GAMMA IRRADIATION ON THE CHEMICAL COMPOSITION ANDIN VITRORUMEN DIGESTIBILITY OF CERTAIN SPECIES OF WOOD

Changes in the chemical composition and in vitro rumen digestibility of alder, fir, poplar and sludge were studied after treatment with NaOH and gamma irradiation. Treatment with alkali increased the percentage of cellulose and acid detergent fiber (ADF) in all species of wood studied, whereas the average acid detergent lignin (ADL) content was not affected. Alkali treatment increased the in vitro dry matter disappearance (DMD) of alder and poplar, and increased the in vitro cellulose digestion of alder, poplar and sludge. Samples of the four species of wood that were exposed to 1 × 108or 2 × 108rads of gamma irradiation were lower in cellulose, ADF and ADL content than the untreated samples, or those exposed to 1 × 106or 1 × 107rads. In vitro DMD, cellulose digestion and volatile fatty acid production were higher in samples of all four species exposed to 1 × 108or 2 × 108rads, than in untreated samples, or in those exposed to 1 × 106or 1 × 107rads.

CHARACTERISTICS OF YOUTHFUL BEEF CARCASSES IN RELATION TO WEIGHT, AGE AND SEX: III. MEAT QUALITY ATTRIBUTES

A total of 574 youthful beef carcasses from three sources comprising 168 steers, 147 heifers and 259 bulls were processed to study the influence of carcass weight, age and sex on beef quality. Source differences in pre-slaughter treatment were associated with differences in ultimate pH and in color of the longissimus dorsi muscle. Dark color and high pH values (pH > 6.0) were characteristic of the 1. dorsi muscle from bulls subjected to the greatest pre-slaughter stress. Stress effects markedly influenced palatability factors, with dark-colored bull beef from this one source scoring significantly higher for tenderness, juiciness and flavor than beef from steers subjected to the same pre-slaughter treatment. For these bulls the correlation between tenderness and meat color score was −0.50. Comparisons within source groups indicated that in meat color and shear values at 72 hr post mortem, heifers were superior to bulls and inferior to steers. After excluding the stressed (high ultimate pH) bulls from one source there were no significant sex-source differences in shear value at 13 days. However, taste panel evaluations indicated unstressed bull beef to be less tender than beef from heifers. Heifers had significantly more marbling than comparable bulls or steers, but differences in percent ether extract were significant only for the heifer-bull comparison. Correlations between live-weight and the various quality measurements were generally insignificant. A negative relationship was indicated between tenderness and age for bull carcasses (correlations about −0.3 in terms of merit) and the amount of chemically determined intramuscular fat of bulls was positively correlated (0.3 to 0.4) with age.

A discussion on units and standards

The sequence of papers following, contributed by members of the staff of the National Physical Laboratory, gives an account of most of the units and standards which are studied at the Laboratory. Each paper explains briefly the principal technical points involved, together with a short history. Of necessity a standard is to some extent a convention, and it may therefore be well to introduce the subject by a short review of the legal and conventional authorities on which they depend. For the metric system the main international authority is the Conference Generale des oids et Mesures, at which duly accredited delegates of each of the thirty-two nations subscribing to the 1875 Treaty, the Convention du Metre, are present, and which, in normal circumstances, meets every six years. The Comite International des Poids et Mesures is the Executive body appointed by the Conference Generale to manage the affairs of the Bureau International des Poids et Mesures between meetings of the Conference Generale. It consists of eighteen members, elected by the Conference, each of whom must belong to a different State, but who, as members of the Committee, are no longer representatives only of their individual countries, but of all subscribing countries. The International Committee meets every two years, makes recommendations to the General Conference, or acts on authority delegated to it by the Conference.