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Y. Tsukahara, T. A. Gipson, S. P. Hart, L. J. Dawson, Z. Wang, R. Puchala, T. Sahlu, A. L. Goetsch, 1705 The response to artificial infection with Haemonchus contortus and growth performance of sheep and goat progeny of selected parents in a central performance test, Journal of Animal Science, Volume 94, Issue suppl_5, October 2016, Page 831, https://doi.org/10.2527/jam2016-1705
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Abstract
Fifteen Katahdin (KS-A; 4.0 mo old, 38 kg), 5 Katahdin (KS-B; 3.0 mo, 20 kg), 16 Dorper (DS; 3.4 mo, 25 kg), and 17 St. Croix sheep (CS; 4.2 mo, 18 kg) and 20 Kiko (KG; 3.9 mo, 19 kg), 16 Boer (BG; 4.4 mo, 16 kg), and 18 Spanish goat (SG; 4.3 mo, 18 kg) males from 5 commercial farms in KS, MO, and AR and Langston University (LU) were used to investigate growth performance and response to artificial infection with Haemonchus contortus in year 3 of a central test at LU. Animals tested were progeny of dams (based on on-farm data) and sires classified as Resistant and Moderate in year 2. The test entailed an adjustment period of 2 wk followed by 8 wk of data collection. Animal groups were housed separately in adjacent pens with automated feeders allowing free-choice access to a 15% CP diet. During adaptation, anthelmintic treatment resulted in low fecal egg count (FEC; < 600 eggs/g), after which 10,000 larvae were administered orally. Packed cell volume (PCV) was measured weekly and FEC was determined 5 times in wk 5-9. The cubic clustering criterion of SAS® categorized resistance classes. The GLM procedure included animal group and resistance classification, initial BW, PCV, and FEC were covariates, and the logarithmic transformation ln(x+100) was used for mean FEC. Animal group affected (P < 0.01) ADG (308, 264, 321, 254, 139, 243, and 147 g; SEM = 14.6), DMI (2.34, 1.65, 1.65, 1.32, 0.79, 1.28, and 0.94 kg/d; SEM = 0.069), and PCV (25.4, 24.3, 28.6, 29.3, 25.8, 22.9, and 25.7% for KS-A, KS-B, DS, CS, KG, BG, and SG, respectively; SEM = 0.65). The resistant males had highest (P = 0.04) ADG (256, 237, and 225 g for Resistant, Moderate, and Susceptible, respectively; SEM = 8.8). There was an animal group × resistance classification interaction (P = 0.04) on FEC (270, 2346, and 4633 with KS-A, 1088, 5272, and 8263 with KS-B, 442, 1140, and 2370 with DS, 209, 870, and 2368 with CS, 248, 994, and 2431 with KG, 1182, 2164, and 4523 with BG, and 215, 1203, and 3132 eggs/g (untransformed) with SG for Resistant, Moderate, and Susceptible classes, respectively; SEM = 295.0). The correlation coefficient between sire and progeny FEC was 0.27 (P = 0.004) and that of PCV was 0.44 (P < 0.001). In conclusion, selection for resistance did not adversely affect performance of males, and there were moderate relationships between indices of parasite infection of sires and progeny.
