VOLUNTARY FEED-INTAKE, GROWTH-CHARACTERISTICS AND SERUM CONCENTRATIONS OF THYROID-HORMONES IN MALE AND FEMALE AXIS FAWNS (AXIS-AXIS)

A study was conducted to characterize the voluntary feed intake and gr owth patterns of male and female axis fawns (Axis axis) relative to en vironmental influences and thyroid hormone concentrations. Axis fawns (n=4 male and 5 female) were removed from their dams after birth and r eared artificially. Fawns were weighed at birth and at 4 months of age (weaning). At weaning, fawns were fed ad-libitum a complete deer feed and maintained on the ration for 280 days. Body weights and blood sam ples were taken weekly; and feed and water intakes, photoperiod and am bient temperature recorded daily. Serum concentrations of T-3 and T-4 were determined by RIA. Fawn birth weight, 120-day pre-weaning ADG and weaning weight did not differ (P>0.10) between male and female fawns. Post-weaning, fawns increased (P<0.001) in BW throughout the 280-day feeding period. Average daily gains of axis fawns increased (P<0.01) f rom 106.0 and 105.0 g/day to 148.2 and 119.3 g/day for male and female fawns, respectively, during the first 84 days post-weaning. Average d aily feed intake increased over time (P<0.001), but was similar (P>0.1 0) for male and female fawns. Male fawns had a greater (P<0.05) feed e fficiency than female fawns relative to the entire 280-day feeding per iod. Serum concentrations of T-3 and T-4 were positively correlated (P <0.001) and increased to their highest concentrations between January and February. Ambient temperature and hours of daylight were negativel y correlated (P<0.01) with concentrations of both T-3 and T-4 Fawn fee d intake was positively correlated (P<0.05) with concentrations of T-3 and T-4, while feed intake was negatively correlated (P<0.05) with me an ambient temperature and photoperiod. While seasonal effects on thyr oid hormones and feed intake were noted, the absence of reduced feed i ntake or slowed growth during winter months may indicate that axis faw ns are affected by seasonal influences differently than more temperate deer species. (C) 1998 Elsevier Science B.V. All rights reserved.