Disease surveillance can be a very useful tool in disease control programs. Disease surveillance lets you know how your disease control program is working at various points in time. There are two general methods to survey the level of disease in a herd. One of them is by examining animals and the other is by examining data from animals. If the level of clinical parasitism in a herd of goats is a concern then do a FAMACHA test on the goats. The FAMACHA is described in the parasite control module but in brief you look at the conjunctiva (inner lid) of the goat’s eye and if it is bright red it gets a score of 1 and if it is white it gets a score of 5. Goats with scores of 3, 4, and 5 are anemic as a result of clinical parasitism. If your goats score 1 or 2 your parasite control program is working very well.

Alternatively, fecal samples and blood samples could be collected and a laboratory could determine the Packed Cell Volumes (PCV) and the Fecal Egg Counts (FEC). If PCV’s are all over 30% and FEC are less then 100 EPG then the parasite control program is working very well. Some diseases may present few external signs. Johne’s disease is a chronic mycobacterial enteritis that causes malabsorption and maldigestion in ruminants. It takes years to develop. Instead of waiting for disease signs, it would be appropriate to test by serology or by fecal bacterial culture. It is important to understand that when you see clinical disease in one goat of a herd you are usually just looking at the “tip of the iceberg.” With most diseases, such as Johne’s disease for example, 10-20 subclinical cases can be found for every one clinical case seen.

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