Growth and venison production from red deer (Cervus elaphus) grazing red clover (Trifolium pratense) or perennial ryegrass (Lolium perenne)/white clover (Trifolium repens) pasture

Abstract

A study of growth and venison production from weaner red deer grazing pure tetraploid red clover (RC) or conventional perennial ryegrass/white clover (PRG) pasture was conducted in 1990, with the objective of attaining a minimum slaughter liveweight of 92 kg (50 kg carcass) by 12 months of age in the stags. Ten weaner red deer stags and ten weaner red deer hinds were randomly selected and rotationally grazed on either RC or PRG forage. In autumn and spring, forage allowances were 7 kgDM/hd/day and 8 kgDM/hd/day respectively. In winter, the animals from both groups were grazed together on PRG pasture, at a residual dry matter (DM) of 1100 kgDM/ha. Total nitrogen (N) concentration was higher in RC on offer than in PRG on offer (autumn 3·4 v. 3·1 %DM; spring 3·8 v. 3·1 %DM), whilst organic matter digestibility (OMD; autumn 80·5 v. 76·5%; spring 82·1 v. 80·3%) was also higher for RC on offer. Diet selected showed similar differences in total N concentration, but there were negligible differences between forages in OMD.Liveweight gains of RC and PRG stags were respectively 263 v. 192 g/day, 101 v. 106 g/day and 354 v. 341 g/day during autumn, winter and spring, with the corresponding values for hinds being 198. 173 g/day, 52 v. 53 g/day and 242 v. 218 g/day. At one year of age, stags grazing RC were 7 kg heavier and hinds 3 kg heavier than animals grazing PRG pasture. Animals grazing RC forage had higher voluntary feed intake (VFI) in both autumn (P < 0·10) and spring (P < 0·001), than animals grazing PRG pasture.All stags grazing RC forage reached the minimum slaughter liveweight by one year of age, compared to 75% of those grazing PRG pasture. At slaughter, stags that had grazed RC produced heavier carcass weights (59·9 v. 54·5 kg, P < 0·01), had higher carcass dressing percentage (55·3 v. 53·2 %; P < 0·01), and tended to have slightly greater carcass subcutaneous fat depth than stags grazing PRG pasture, but this effect disappeared when the data were corrected to equal carcass weight. All stags grazing RC produced velvet antler, relative to 75% of those grazing PRG; in stags producing harvestable velvet antler, there was no difference in antler weight between those grazing RC and PRG. It is concluded that RC offers potential as a special-purpose forage for the growth of weaner red deer.