PSXII-28 Impacts of ground red clover on nutrient intake and digestibility in lambs fed with novel endophyte-infected fescue.

Abstract Red clover (RC) contains biochanin A (BA), a flavonoid compound that exhibits estrogenic activity. Recently, biochanin A has been shown to improve feed efficiency in rams, but the cause of improvement requires further evaluation. Thus, this study aimed to investigate the effects of different levels of red clover (3351 µg/g BA) on nutrient intake and digestibility in lambs offered non-toxic, novel endophyte infected tall fescue hay (NE+). Forty Dorper lambs were allocated to individual pens in a completely randomized block design with two periods (20 lambs/period). Each lamb received one of the following diets: NE+ only RC (RC0), or NE+ fed with ground (5-mm) red clover at 5 (RC5), 10 (RC10), or 15 (RC15) % of the diet. Total feces and urine were collected for 5 days after an initial 14-day adaptation, and blood samples were collected prior to feeding and 2 and 6 hours after feeding on day 20 of each of the 2 periods. Data were analyzed using “gt”, “lme4”, “lmerTest”, “emmeans,” and “multcomp” packages in RStudio (RStudio Team, 2024). Dry matter and OM digestibility were greater (P < 0.05) in lambs offered RC0 and RC5 compared with those offered RC10, but RC15 was not different (P > 0.05) from the other treatments. Lambs offered RC0, and RC5 diets had greater (P < 0.05) ADF digestibility than those offered RC15, but RC10 was not different (P > 0.05) from other treatments. The apparent N absorption was greater from RC0 and RC5 compared with RC10 and RC15. Dry matter and organic matter intake, neutral detergent fiber digestion, and blood urea nitrogen were not different (P ≥ 0.07) among treatments. Inclusion of ground red clover did not improve DM, OM, or fiber intake, DM, OM, or ADF digestibility, or nitrogen apparent absorption in lambs offered NE+ tall fescue hay.