Effects of supplemental feeding on intake by kid, yearling, and adult Angora goats on rangeland.

Abstract

Sixty female Angoras, including 20 each of kids (9 mo), pregnant yearlings (21 mo), and pregnant adults (2.5 to 4 yr), were used to determine the effects of supplemental feed and level of supplemental digestible DM (DDM) on voluntary intake on rangeland. Treatments included negative control (NC: no supplemental feed) and supplements to provide equal CP (3 g/kg of BW.75) and either 4.8, 9.8, or 19.8 g/kg of BW.75 of DDM per day. Forage intake (FI), gastrointestinal tract fill (FILL), mean particulate turnover, mean particulate whole-tract residence time, fecal output, and forage DM digestibility (FDMD) were measured in all goats using a pulse-dose marker technique when the yearling and adult goats were in late pregnancy. Forage intake increased (quadratic regression, P = .01) at the low level of feeding, but both FI and FDMD decreased in a quadratic pattern in the pregnant goats as DDM feeding level increased. Total DDM intake reached a maximum at the medium supplementation level. Stimulative, additive, and substitutive effects on forage intake were observed as feeding level increased. Yearling goats had lower FILL and intake than kids and adults (metabolic BW basis), which may explain problems associated with reproduction in young goats.