When money is borrowed, interest is typically calculated as a percentage of the principal, the amount owed to the lender. The percentage of the principal that is paid over a certain period of time (typically a year) is called the interest rate. Interest rates are market prices which are determined by supply and demand.
Swollen nipples in dogs is a common symptom seen in mastitis. Mastitis occurs when there is an infection of the mammary glands. Mastitis is common in female dogs who are in the process of nursing. In mastitis, the dog's mammary glands become swollen and painful. The milk is toxic in affected nipples.
Sheaths also swell as a result of being dirty.. Horses with large beans (accumulations of secretions at the end of the penis) and large accumulations of sheath smegma (normal pasty secretion) often swell. Horses that urinate into their sheaths tend to have dirtier sheaths and more problems with swelling.