2013 Annual Report
1a.Objectives (from AD-416):
Determine early progress in selection of small ruminants for resistance to internal parasitism using a buck/ram test or on farm selection (lambs from DBSFRC will be included); Determine if selection for resistance to worms has negative effects on animal performance such as daily gain, weaning weight, or reproduction; Develop and implement a new second generation central sire performance test for sheep and goats at Langston University (lambs from DBSFRC will be included); Determine if genetic markers can be developed for resistance to worms so that a blood test could be used to identify resistant animals; Evaluate economic benefits of selection for resistance to worms; Disseminate potential benefits of selection and associated economic and management considerations for adoption by small ruminant producers; Publish information on results of the study in producer publications and on our website and breed association websites.
1b.Approach (from AD-416):
In each of three years, 15 rams/bucks from each herd/flock (including lambs from DBSFRC) will be placed on the Second Generation Small Ruminant Central Sire Performance Test (SRCPT) at Langston University. Fecal egg counts (FEC) will be collected from rams/bucks within herd/flock and they will be ranked in parasite resistance and used for subsequent breeding. Similarly, breeding females will be selected for parasite resistance based on fecal egg counts (including those from DBSFRC). Performance data will be collected on all breeding females, including days to breeding after sire introduction, litter size, birth weight, weaning weight, and body condition score. The FAMACHA score of kids/lambs and females will be determined at 8, 10, and 12 weeks of age, and FEC will be determined at 12 weeks. A similar selection protocol will occur on-farm and producer's males will enter the SRCPT.
An experiment was initiated at Langston University to characterize parasite resistance in potential replacement ram lambs and buck kids from several farms, and to characterize parasite resistance of dams (ewes and does) on farm. A new second generation central sire performance test for small ruminants was developed at Langston University, focusing on internal parasite resistance, but also determining feed intake, average daily gain, and efficiency of feed utilization. The goal is to develop early-life indicators of resistance of small ruminants to internal parasitism and assess physiological conditions affected by selection for internal parasite resistance.