Today, there are some 200 different breeds. Goats have been used by the U.S. Fish and Wildlife Service, the Bureau of Reclamation, the Bureau of Land Management, and the U.S. Forest Service. State, county and city contractors (such as the city of Seattle) have also used goats for weed and invasive species control.
Recent data has redefined the way that urologists look at PSA, and what is considered a normal PSA. Age-adjusted PSA values take into account that a 40-year-old should not have the same PSA as an 80-year-old. Accepted age-adjusted PSA rates are below 2.4 ng/ml for men under the age of 50 and 6.5 ng/ml for patients in their 70s. Other limits have been defined for varying age ranges, but there is not universal agreement about the accuracy of the age-adjusted levels.
In order to increase the efficacy of serum PSA interpretation, a number of performance variables are used clinically. These include age-adjusted PSA, density, velocity, and the free-to-complexed PSA ratio. Age Adjusted PSA: Since PSA normally rises with age, age-adjusted thresholds have been described. Benign growth of the prostate that normally occurs with age is the most common cause of PSA elevation. Roughly 70% of patients with an elevated PSA level between 4 and 10 will have a negative prostate biopsy. Conversely, there is no level of PSA at which you can guarantee a patient that they do not have cancer. Moreover, the absolute PSA level does not predict whether or not prostate cancer is harmful.