Sheep Ingestive Behavior and Tannin Selection in Pampa Grassland and Feedlot

Authors

Marina Terra Braga

Document Type

Book

Journal/Book Title/Conference

Universidade Federal do Rio Grande do Sul, Porto Alegre (RS) Brasil

Publication Date

2023

Abstract

The Pampa grassland biome has high plant biodiversity, some with significant secondary compound concentrations such as tannins. Tannin inclusion in ruminant diets may improve meat quality and productivity. However, voluntary intake of this phenolic compound can be a challenge. This dissertation includes three studies within this context. The first study documented whether sheep consume tannin-rich Desmodium incanum (DI), the most common Pampa herbaceous legume species. The second study evaluated how forage tannin and protein concentration influenced sheep feedlot feed selection and the diet affects performance parameters. The third study evaluated sheep feeding behavior in a Pampa native pasture, and how season, sward characteristics and parasite infection influenced it. Tagging individual DI plants allowed identification of those sheep consumed. After 3 days of grazing, >70% were grazed. In the second study, feed intake decreased when tannin was added alongside a high-protein feed. However, when tanninfree feed was not a choice, the 4% tannin extract inclusion did not affect feed intake, aside from decreasing blood urea nitrogen and increasing fecal nitrogen excretion. Average daily gain was not affected by the inclusion of tannins. Fall grazing time was greater, while spring and summer showed no difference. Ruminating time decreased with season progression: spring > summer> fall. There was a moderate positive correlation between dead material percentage in the pasture and grazing time (P < 0.000, r = 0.462), and a moderate negative correlation between dead material and ruminating time (P < 0.000, r = -0.488). When managed correctly, Pampa offers optimal conditions for sustainable sheep farming, producing high-quality meat resulting from forage tannin ingestion. Further studies are encouraged to address DI tannin intake influence on sheep performance.

Recommended Citation

Braga, Marina Terra, "Sheep Ingestive Behavior and Tannin Selection in Pampa Grassland and Feedlot" (2023). Green Canyon Environmental Research Area, Logan Utah. Paper 283.
http://digitalcommons.usu.edu/grcanyon/283