Influence of age and body condition on consumption of redberry juniper (Juniperus pinchotti) and disposition of 4 Monoterpenes in goats. Frost, Rachel ^*,1, Launchbaugh, Karen¹, Taylor, Charles², ¹ Department of Rangeland Ecology & Management, Moscow, ID² Texas A&M University Research Station, Sonora, TX

ABSTRACT- Redberry juniper (Juniperus pinchotti), is an invasive, evergreen shrub that is rapidly expanding throughout western and central Texas. Goats will consume some juniper on rangelands, however, intake is limited by monoterpenes. The objective of our research was to determine how the age and body condition of an animal influences its consumption of juniper and examine the disposition of monoterpenes in goats. Forty goats(n=20 young and n=20 mature) were assigned to either a high (HBC)or low (LBC) body condition treatment and fed basal rations to reach body condition scores of 4 or 2 (on a 1-5 scale). Experiment 1 examined the intake of redberry juniper leaves. Animals in LBC consumed more juniper than animals in HBC (P<0.05). There was a trend for young animals to consume more than mature animals within the body conditions. Experiment 2 was a pharmacokinetic analysis of the disposition of 4 monoterpenes found in redberry juniper. All animals were dosed intraruminally and blood samples were collected at .25, .50, .75, 1, 1.5, 2, 3, 4, 6, 8, 12, and 18 hrs, post dosing and analyzed for monoterpene content. For experiment 3, all goats were offered a synthetic ration that mimicked redberry juniper in quality and intake was accessed with increasing monoterpene levels in the synthetic diet. Results of the pharmacokinetic analysis and experiment 3 will be discussed. A better understanding of how these attributes affect diet selection will be applicable to the vegetation management industry and aid livestock producers in improving grazing management.

KEY WORDS: age, Redberry juniper, body condition, monoterpenes