Monday, September 8, 2008

7 goats excel in parasite traits

Parasite resistance and resilience are two important traits that are being evaluated in the goats that are participating in the Western Maryland Pasture-Based Meat Goat Performance Test.

Parasite resistance is the ability of the animal to avoid infection by parasites. It is measured by fecal egg counts. Every two weeks, fecal samples are collected from each individual goat. Fecal egg counts are determined (using the Modified McMaster technique) by Delaware State University (Dr. Dahlia Jackson's lab).

Goats on testParasite resilience is the ability of the animal to tolerate infection. It is measured by packed cell voume (PCV) or hematocrit, a blood test to measure anemia. Anemia is the primary symptom of barber pole worm infection. Fecal cultures from the University of Georgia confirm that the barber pole worm (Haemonchus contortus) is by far the primary parasite affecting the goats on test.

FAMACHA© scores provide a means to estimate packed cell volumes. Treatment recommendations are based on FAMACHA© scores. FAMACHA© scores are determined by the same person every two weeks (Susan Schoenian).

Parasite resistance and resilience are both economically important traits that should be of interest to all goat producers. Obviously, we value goats that do not require frequent deworming. But we should also value goats with low egg counts. Goats which have high egg counts are problematic, even if they do not require deworming, because they are contaminating the pasture with lots of worm eggs, which could cause problems for the less resilient animals.

As of August 15, there are seven goats in the test which have not required deworming or had fecal egg counts above 500 eggs per gram. This chart will be udpated as more data is collected and processed. Click on the table to view it in another browser window.

Parasite resistance and resilience dataParasite resistance and resilience are both moderately heritable traits, meaning genetic progress can be made if these traits are favored in a selection program.