Severe undernutrition in growing and adult animals

The plane of nutrition has a profound effect on the development of the skeleton, but skeletal growth has been shown to continue slowly even when the supply of food is very small (Aron, 1911;Morgulis, 1923;Jackson, 1932).The rate of growth affects the shape and form of the whole carcass and this is particularly important in preparing farm animals for the market (Waters, 1908(Waters, , 1909;;Moulton, Trowbridge & Haigh, 1921, 1922;Hammond, 1932).The literature was reviewed by Smith (1931).The general principles as they apply to the pig were defined by a masterly investigation of McMeekan (rg4oa-c; 1941).The inspiration for it came from the personal influence and published work of D r John Hammond, to which full references were given.McMeekan (194ob) made an 'age' comparison at 16 weeks and established that a low plane of nutrition had produced skulls and lower jaws about half the weight of, and a different shape from, those of animals reared on a high plane.Growth in length was penalized less than growth in width, but the thickness of the cranium was affected more than either and was only 3 mm in the animals on a low plane as against 18 mm in the others.McMeekan ( 1 9 4 0 ~) made a 'weight' comparison at zoo Ib, which the animals on the high plane of nutrition reached in 180 days and those on the low plane in 300 days.He found that at this weight the skulls and lower jaws of the animals on the low plane were heavier and longer, but relatively narrower, than those of the animals on the high plane.Other measurements of the skull were made, particularly of its weight, but the teeth were not investigated.The present investigation concerns animals much more severely undernourished than those of McMeekan, and observations have been included on the teeth, which have not hitherto been systematically investigated in undernourished animals or in man.Hellman (1923) (see also Boas, 1933) reported that, although the poorer children in a population were less well developed physically than the rich, their dentition was not delayed, and in fact accelerated.Trowell, Davies & Dean (1954) made a note that even the severe protein deficiencies and stunting of growth met with in kwashiorkor did not seem to hold up dental development.They pointed out how incongruous it was to see the mouths of these tiny children crowded with teeth.The observation is in