Tuesday, October 4, 2016

Parasite Resilience: Top 10

Parasite resilience is the animal's ability to tolerate a parasite load. There are many ways to quantify parasite resilience. Since the barber pole worm (Haemonchus contortus) is the primary parasite affecting the goats in the test and its primary symptom is anemia, FAMACHA© scores can be used to quantify resilience. 

A packed cell volume (PCV) is the percentage of red blood cells in circulating blood. It is a measure of anemia. A FAMACHA© score is an estimate of packed cell volume (PVC) or anemia.  Growth performance can be another indicator of parasite resilience, although attaching resilience to performance is less certain, as there can be other reasons why a goat fails to grow (or grows well).

Every two weeks, FAMACHA© scores were determined. The same person (Susan) did the scoring. FAMACHA© scores were the primary criteria for determing the need to deworm an individual goat. Additional factors were considered when goats had FAMACHA© scores of 3.

Two goats tied for being the most resilient:  687 (Weber, Illinios) and 648 (Murphy, New Jersey). Each time these goats were examined, their FAMACHA© scores were 1.0. Neither goat required deworming and both goats had above average growth (ADG). Both were top 10 goats. Four of the most resilient goats in the test were top 10 goats. The other most resilient goats had other disqualifying data, such as poor growth performance or high fecal egg counts.

Ten goats had average FAMACHA© scores of 1.5. The three most resilient ones (rank of 8-10) were determined by considering growth performance and putting more emphasis on the last three FAMACHA©scores, when the parasite challenge was the highest. Two goats that had FAMACHA© scores of 3 were also eliminated.

Any goat that did not require deworming during this year's test showed considerable resilience, as clinical parasitism was high.

Top 10 Most Resilient Bucks
Rank Consigner ID Avg. FAM High FAM ADG # Tx
1 Weber* 687 1.00 1.00 0.240 0
2 Murphy* 648 1.00 1.00 0.170 0
3 Loos* 639 1.17 2.00 0.269 0
4 Murphy 650 1.17 2.00 0.137 0
5 Peters 663 1.17 2.00 0.083 0
6 Gamby 623 1.33 2.00 0.126 0
8 Barnes 605 1.50 2.00 0.113 0
9 Larr* 638 1.50 2.00 0.173 0
10 Pinneo 665 1.50 2.00 0.133 0
*Top 10 Buck