Abstract
This study evaluated the intake of 8 major browse species by Spanish goats (Capra hircus). Diet preference and a selection order was established for the 8 browse species by calculating instantaneous intake rates (IIR, mg/sec) following 2 types of feeding trials. A 30-sec single species feeding trial allowed for the observation of IIR by goats on only one species. The multiple species trial allowed for goats to select their browse preference during a 5-min time period. According to IIR, goat diet preference for both trials was: lime pricklyash > brasil > hogplum > spiny hackberry > catclaw acacia > Texas persimmon > huisache > kidneywood. Physical and chemical attributes of the browse species were measured and either elicited or deterred a grazing response. For both trials (single and multiple) significant correlations (P < 0.05) between physical traits and IIR included leaf weight (0.65, 0.61) and canopy volume (0.44, 0.51). Additionally, three wavelengths were identified by near infrared spectroscopy (NIRS) as contributors or deterrents to intake. These included: 1612 nm, 2148 nm and 2452 nm. Wavelength 1612 nm is associated with olefins, a form of alkenes, and wavelengths 2148 nm and 2452 nm are associated with aromatic compounds. One common olefin is ethylene, which is involved in plant growth responses and abscission of leaves. As the ethylene content of each browse species increased, leaf drop occurred and utilization may have decreased.
Zimmerman, Eric Edward (2002). Effects of physical and chemical traits affecting intake of woody plants by goats. Master's thesis, Texas A&M University. Available electronically from
https : / /hdl .handle .net /1969 .1 /ETD -TAMU -2002 -THESIS -Z56.