PSI-20 The effect of ewe gastrointestinal nematode burden during the periparturient period on lamb growth

Abstract

Research evaluating the effects of ewe gastrointestinal nematode infection (GNI) during the periparturient period (PPR) on offspring growth is limited. We hypothesized ewes with a greater parasite burden during the PPR will negatively impact birth and weaning weight. Packed cell volume (PCV) was measured in ewes (2018, n = 11) at 3 weeks pre-partum (-3), birth, 3 (+3) and 6 (+6) wks postpartum. Lamb birth weight, weaning weight (WW), and ADG (birth - 8 weeks) were collected. Ewes in the upper 50% (n = 5–6) and lower 50% (n = 5–6) for PCV were classified as either HIGH and LOW at each time period. Data were analyzed in SAS using proc mixed (significance P ≤ 0.05). PCVs for LOW and HIGH ewes were (mean ± SEM) 27% ± 0.2% vs 30% ± 0.8% at -3, 28% ± 0.3% vs 32% ± 0.4% at birth, 24% ± 0.4% vs 29% ± 0.6% at +3, and 25% ± 0.2% vs 30% ± 1.0% at +6 respectively. Post-partum, lambs reared by LOW ewes exhibited reduced ADG (0.69 ± 0.03 kg/d vs 0.81 ± 0.03 kg/d; P = 0.02) and WW (29.34 kg ± 1.41 kg vs 33.64 kg ± 1.47 kg; P = 0.04) compared to lambs reared by HIGH ewes. Lambs reared by LOW ewes at +3 exhibited reduced ADG versus lambs reared by HIGH ewes (0.69 ± 0.034 kg/d vs. 0.81 ± 0.034 kg/d; P = 0.02). No effect of maternal PCV on birth weight or WW, at -3, birth, or +6 was observed on offspring birth weight, WW, or ADG (P ≥ 0.13). In conclusion, the effects of PPR GNI appear to be postnatal.