The effect of environmental and biological factors on STT I and normal total tear protein concentration in Japanese black calves.

To identify reference values for the Schirmer tear test I (STT I) in Japanese black cattle, investigate the effects of variables (sex, age, time of day, and environment in the barn including environmental temperature, humidity, illuminance, and ammonia concentration) on tear production, and determine total tear protein concentration. One-hundred-and-thirty-seven Japanese black cattle (67 females and 70 males, age 3-90 days) were evaluated. The mean STT I values was 18.