Abstract: A novel method for determining when cows are in estrus is disclosed comprising the step of monitoring the vaginal secretions of a cow to determine an increase in the amount of an indicator compound in said secretions. A significant increase in the amount of the indicator compound, concentrations above about 0.1 micrograms per gram of collected secretion, is indicative of estrus. The preferred indicator alcohols have ethyl ester indices of 8.1 to 8.9. In particular these alcohols are methyl-1-heptanols, such as 6-methyl-1-heptanol, or are methyl hydroxy heptenes, such as 2-methyl-7 hyroxy-.DELTA.-3-4 heptene. Alternatively, a cow may be determined to be in estrus simply to ascertaining that the concentration of methyl-1-heptanol is at least 0.1 microgram per gram of collected vaginal secretion.

Abstract: Method for precisely ascertaining the time of ovulation by monitoring the concentration of alcohols in the range of C.sub.10 -C.sub.16, particularly dodecanol. A spike in the concentration of such compound(s) is indicative of time of ovulation.

Abstract: A novel method of diagnosing periodontal disease is disclosed wherein telltale pyridine and alkyl-pyridine compounds which are detected in the oral cavity are indicative of periodontal disease. An alternate embodiment method is disclosed wherein increased concentrations of certain other compounds are detected to confirm the presence of periodontal disease.

Abstract: A novel method is provided for precisely predicting and then ascertaining the time of ovulation by monitoring the mouth air of a female, a first peak after menses in the concentration of said volatile sulfur-containing compounds in said mouth air predicting ovulation by about 5 to 7 days, and a second increase thereafter being indicative of ovulation. Alternatively, a method is provided wherein TPTZ is utilized to sense secondary characteristics associated with the production of volatile sulfur compounds for the purpose of providing a simple colorimetric home test for determining the precise time of ovulation.

Abstract: A method of monitoring the concentration of a given volatile organic compound, or of urea, or both, which compound(s) is commonly found in vaginal secretions is described as providing a reliable diagnostic indication of ovulation, and more particularly is described as providing a simple home-test method of predicting the onset of the fertile period, thereby increasing the reliability of the "rhythm method" of birth control.

Abstract: A method of monitoring the concentration of a given volatile organic compound commonly found in vaginal secretions is described as providing a reliable diagnostic indication of ovulation, and more particularly is described as providing a simple home-test method of predicting the onset of the fertile period, thereby increasing the reliability of the "rhythm metod" of birth control.