Although the ability to absorb colostrum is lost within a couple of days of birth, colostrum appears to still be capable of exerting a local effect on body surfaces such as the intestinal tract when it is eaten, or the skin and mouth when it is applied topically. 1  Most commercial colostrum preparations come from cows.
The air sacs of birds extend into the humerus (the bone between the shoulder and elbow), the femur (the thigh bone), the vertebrae and even the skull. Birds do not have a diaphragm; instead, air is moved in and out of the respiratory system through pressure changes in the air sacs.Muscles in the chest cause the sternum to be pushed outward. This creates a negative pressure in the air sacs, causing air to enter the respiratory system.espiration in birds is much different than in mammals. Birds have a larynx, but it is not used to make sounds. Instead, an organ termed the syrinx serves as the voice box.. Birds have lungs, but they also have air sacs. Depending upon the species, the bird has seven or nine air sacs.
Another important feature of the avian respiratory system is also part of the avian skeletal system. Some of a bird's bones are hollow. The air sacs in a bird's lungs connect to the air spaces in these bones, and the bones then act as part of the avian respiratory system. They are called pneumatic bones and include the skull, humerus, clavicle, keel, pelvic girdle, and lumbar and sacral vertebrae.