LIVESTOCK PRODUCTION AFFECTED BY ANIMAL DISEASES 19
E per kilogram of-feed was ineffective in alleviating hock disorder.
The use of soybean oil meal, however, completely prevented enlarged
hocks under conditions at the station. On the other hand, at the Minnesota
station a high incidence of this condition occurred on a cornsoybean
oil meal diet. Whole liver powder aggravated the condition,
but dried brewer's yeast (5 percent), choline chloride (0.1 percent),
and methionine (0.3 percent) helped prevent the trouble.
Bowed legs in ducks
Leg weakness, characterized by a severe bowing of the legs and ultimately
by complete crippling, has been observed in Pekin ducklings
raised on wire-mesh floors and fed practical rations at the New York
(Cornell) station. A similar leg weakness' is frequent in the Long
Island area and represents an important economic problem since ducklings
afflicted with the disorder usually do not make normal weight
gains and therefore represent a loss at market time. The station
showed that this disorder is due to a niacin deficiency and can be
prevented by supplementing the diet with 5 to 7.5 percent of dried
brewer's yeast or by adding 10 milligrams of synthetic niacin per
pound of ration.
The effect of riboflavin deficiency on the blood forming (hematopoietic)
system of animals has been noted repeatedly. In 1943 the
Wisconsin station, in studies on dogs, reported that an adequate riboflavin
intake is necessary for normal hemoglobin formation. Until
recently, however, no similar investigation has been carried out on the
chick; and since riboflavin is important in the nutrition of this species',
a study was made by the New Jersey station of the hematology of the
chick suffering from this deficiency. It was observed that such a deficiency
in White Leghorn cockerel chicks produced increased blood
separation (hematocrit), decreased mean corpuscular volume, and
decreased mean corpuscular hemoglobin concentration.
The most important change noted in the blood picture was the early
appearance of a marked increase in certain colorless cells of the bloodstream
(heterophilia leukocytosis). The increase in heterophil concentration
appeared just before the occurrence of curled-toe paralysis,
also in mild deficiencies where no paralysis was seen. The deficiency
had no effect on the hemoglobin level, the erythrocyte count, or on
leukocytes other than heterophils.
Rickets in chickens
The feeding of vitamin D and proper calcium-phosphorous levels in
poultry rations for the prevention of rickets has been practiced for
many years. However, the more rapid growth in chickens obtained
today through our newer knowledge of genetics, nutrition, and management,
requires higher levels of the vitamins, especially those intimately
involved in growth, than were necessary even a decade ago.
This fact is certainly true of vitamin D3. Recent research at the
Nebraska station indicates that more than 300 units of D8 per pound
of ration are needed by growing chicks during the first 8 weeks, undoubtedly
because of the greatly accelerated growth of our modern
U.S. Department of Agriculture. Agricultural Research Administration. Office of Experiment Stations. Report on the Agricultural Experiment Stations, 1953. Washington, D. C.. UNT Digital Library. http://digital.library.unt.edu/ark:/67531/metadc5989/. Accessed October 25, 2014.