Congenital Infections of Calves 673 



twenty-four hours the calf should be fed about two per cent, 

 of its body weight of milk : that is, if a calf weighs fifty 

 pounds at birth, it should be fed at first one pound of milk 

 morning and night. This ration should be continued for a 

 period of four or five days, during which time the calf will 

 lose weight but will retain its vigor and the lustre of its hair. 

 At the expiration of this period, the ration should be slowly 

 and carefully increased by four to eight ounces per feed until 

 a satisfactory ration is attained. The best source from 

 which to obtain milk is from its dam. At one time I was led 

 to believe that the milk should be taken from a healthy cow, 

 even if the rule excluded that of the dam, but more recent 

 investigations appear to contradict this view. The age-old 

 belief, that the dam's milk is better for a young animal than 

 the milk of another animal of the same or other species, ap- 

 pears to be supported by important scientific facts. I have 

 stated that the pregnant uterus generally contains potential- 

 ly pathogenic bacteria, and that the fetal alimentary tract 

 usually contains bacteria identical with those in the uterus. 

 The blood of the cow, as shown by agglutination tests, con- 

 tains protective substances (antibodies) against the bacteria 

 in her uterus. These substances do not pass the placental 

 filter or otherwise enter the fetal circulation. The bacteria 

 included in the meconium generally cause no active infection 

 in the fetus, and no antibodies are formed in its blood. 

 Hence the fetus is commonly born without any acquired re- 

 sistance to the bacteria in its alimentary tract. The milk 

 of the mother seems, however, to contain such antibodies, 

 so that a calf in feeding upon its dam's milk is taking with 

 it substances equivalent to calf scours serum. There is 

 something in the milk of the mother which tends to repress 

 the gastro-intestinal bacteria of the calf. The milk should 

 be drawn carefully under the best rules of cleanliness in a 

 sterilized pail. Special care should be taken, in cases of re- 

 tained fetal membranes or other types of genital discharge, 

 to wash and disinfect the udder prior to drawing milk for 

 the calf. 



43 



