Soybean-Supplemented Nursing Ewes Showed Better Performance and Immune Response than Corn-Supplemented Ewes while Grazing in Woodlands

Abstract

Gastrointestinal (GI) parasitism is one of the major health threats to pasture-raised sheep in the southeast USA. Poor forage quality contaminated with GI parasites need supplemental feeding during high nutrient demand stages like lactation, however the optimal supplement for improving performance and immunity in woodlands is yet to be answered. This study hypothesizes that nursing ewes' performance and immune function would be better with soybean vs. corn supplements. The study aimed to evaluate corn and soybean supplements’ effect on nursing ewes’ performance and immunity against GI parasites. Eighteen Katahdin-St. Croix cross-nursing ewes were divided into two groups, each grazing on separate sets of woodland plots (3 plots/group) and rotated in the respective plots with ad libitum hay from May to August 2022. One group received whole corn, and the other with whole soybean (0.5% of live weight). Animal performance data (live weight, FAMACHA score, and body condition score (BCS)) were collected on Day 1, fortnightly, and at the study’s end. Fecal and blood samples were collected on Days 1, 45, and 80. Fecal samples were analyzed for the type and quantity of GI parasites, and blood samples for RBC, PCV, WBC, and immunoglobulins (IgA, IgG, and IgE). All data were analyzed in SAS 9.4. The soybean group showed better live weight (22%, p<0.05), FAMACHA score (13%, p<0.01), BCS (8%, p<0.001) and IgG level (p<0.0001) compared to the corn group. In conclusion, soybean is a superior supplement than corn for enhancing nursing ewes' performance and resiliency against GI parasites in woodlands.