Date of Award

2013

Document Type

Thesis

First Advisor

Worku, Mulumebet

Abstract

The objective of this study was to evaluate the innate immune response in goats co-grazed with St. Croix sheep. Boer goats (20) and St. Croix sheep (10) were co-grazed on the same pasture. A second group of Boer goats (10) were grazed on a separate pasture. On days 0 and 56 of the study body weights, FAMACHA© scores, blood (for packed cell volume and white blood cell differentials) and fecal samples (for fecal egg counts) were collected and the data analyzed using SAS PROC GLM. To evaluate the goat’s infection status blood from sheep and goats with low infection (7) and goats with moderate infection (7) to measure cytokine and immunoglobulin concentrations in serum and to identify and measure the expression of genes (TLR-2, TLR-4 and NRAMP1) through PCR followed by single strand conformational polymorphism analysis. The extra-label use of Cydectin (Moxidectin) was assessed on goats resulting in a 90% efficacy in the reduction of H.contortus and 81% in coccidia. There were no differences in FAMACHA© scores or PCV’s between the sheep and goats (p>0.05). Sheep had lower FEC’s than the goats they were co-grazed with (p<0.05). Goats non co-grazed had higher levels of neutrophils (p<0.05). Sheep had higher levels of eosinophils than the goats (p<0.05). Proinflammatory cytokines and immunoglobulins were secreted in both the sheep and goats. All genes studied were detected in genomic DNA and expressed in blood. Single strand confirmation polymorphism analysis showed a different pattern of migration for the sheep TLR-2 compared to goat. The differences in eosinophil counts, GM-CSF production levels and the TLR-2 gene between the GIN resistant sheep and susceptible goats may offer markers for selection to improve host genetic resistance against GIN in goats.

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