[Absorption of colostral immunoglobulins].

The small intestine is regarded as the site of absorption by the majority of investigators. The high pH level of the abomasum in newborn calves prevents proteolytic digestion of immune globulins. The results of studies are not unanimous in their answers to the question whether absorption is or is not selective. The effectiveness of absorption of colostrum by the intestinal epithelium of a newborn calf shows a linear decrease from birth to the so-called closure. With a few exceptions, all calves are believed to absorb Ig up to twelve hours after birth. Two litres of colostrum should be administered to newborn calves within twelve hours after delivery. It is a fairly common view that the dam has a favourable effect on absorption. Too many calves which are left with the dam are found not to suckle as a result of a variety of causes. The site of delivery also is a factor in these cases. The answer to the questions whether the weight of the calf, the season and the temperature have an effect on the absorption of colostrum is rather obscure in in view of the marked variations in investigations. The literature is not unanimous in answering the question whether effects of the breed play an important role in the absorption of Ig. If absorption of Ig should be affected by corticosteroids or hormones, this effect will be merely marginal. For several reasons, administering corticosteroids to pregnant cows or newborn calves is not advisable.