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When pigs of 50 pounds initial weight were fed on coarse, medium,or finely ground oats, adequately supplemented by proteins and minerals,significantly faster gains were obtained as the modulus became finer. Pigs fed coarse, medium, and fine modulus reached 121, 132, and 155 pounds liveweight, respectively in 60 days of feeding.Feed consumption over the 60-day growth period increased as the modulus became finer but this was due almost entirely to the increased size of pig because of faster growth rates. Pigs of equal size are approximately equal amounts of feed daily.Fibrous portions made up largely of hulls were decidedly unpalatable to the younger pigs, and unless they were finely ground, they were sorted out and refused.Grinding oats to various degrees of fineness did not affect the extent to which the older pigs digested the dry matter. When the young pigs were unable to separate the hulls, because of fine grinding, no age differences were noted in dry matter digestibility.

Data are presented to show that the biological value of protein fed at a level of 10% decreases as pigs increase in body weight. It is suggested that studies on biological value of protein for growing pigs be designed to permit analyses by covariance as a means of measuring the collective errors introduced by variables associated with advancing weight and age. Comparisons of data from various studies may then be made without confounding with these factors.

Relationships between 18 serum lipid and protein constituents and selected carcass measurements were studied in two experiments involving a total of 144 Yorkshire pigs. The magnitude of the correlation coefficients and the variation occurring between experiments indicate that none of the serum constituents measured is of significant value as an indicator of carcass quality in an individual animal.

Solvent-extracted rapeseed meal of B. campestrisL. origin, free of active myrosinase and retaining most of its original complement of thioglucosides, was fed to pigs in growing and finishing rations at levels up to 10% of the diet. Cross-treatments of zero and 0.022% iodinated casein were used over the 23- to 45- kg. weight range. Twenty-four gilts and 24 barrows of Yorkshire breeding were involved, and growth rates, digestibility, feed utilization and carcass merit were assessed.The use of either 5 or 10% rapeseed meal significantly depressed rate of gain and feed intake in the growing period (23 to 45 kg.). Iodinated casein had no effect on the response to rapeseed meal. A level of 5% rapeseed meal in the finisher ration had no effect on swine performance.Failure of iodinated casein to counteract the adverse effects of rapeseed meal and the lack of effects of rapeseed meal on efficiency of feed utilization or digestibility of energy and protein indicate that this type of meal differs appreciably from meals previously tested with swine, in terms of physiological effects on the animal. Rate of gain closely reflected feed intake levels; hence, palatability may have been involved.The addition of a myrosinase source (ground rapeseed screenings) resulted in three times as much depression in rate of gain in pigs fed grower rations containing rapeseed meal as occurred in the absence of rapeseed screenings. Reduced gains also occurred with rations containing 5% rapeseed meal fed with myrosinase in the finishing period, and there was evidence of depression in digestibility coefficients for energy and protein due to ingestion of the enzyme source. These results confirm previous findings in vitroand with mice, in which myrosinase was implicated in the toxicity complex of rapeseed meal.

The effects of aureomycin, terramycin, penicillin, and streptomycin on the synthesis of vitamin B12in the gastrointestinal tract of the chick fed a vitamin B12-free diet have been studied by means of radiocobalt. Cobalt had no effect by itself but in the presence of an antibiotic resulted in a definite increase in weight. Chicks receiving antibiotics excreted more cobalt and less vitamin B12than those without supplementation. Synthesis of vitamin B12in the gastrointestinal tract occurs as early as the proventriculus. Both the rate and the site of synthesis are influenced by the antibiotic fed. A higher concentration of cobalt is found in the tissues of chicks not receiving antibiotics. Antibiotics appear to have no marked effect on vitamin B12concentration in the tissues except in the blood and gall bladder. The relatively large amount of vitamin B12in the blood of chicks not supplemented with antibiotics suggests the poor utilization of this vitamin or the synthesis of a physiologically ineffective form.