Effects of grazing chicory (Cichorium intybus) and perennial ryegrass (Lolium perenne)/white clover (Trifolium repens) pasture upon the growth and voluntary feed intake of red and hybrid deer during lactation and post-weaning growth

Abstract

Two grazing trials were carried out at Palmerston North, New Zealand using lactating red deer hinds in summer 1994 (Expt 1) and using weaner deer during the autumn, winter and spring of 1993 (Expt 2), to compare the feeding value of chicory (Cichorium intybus) and perennial ryegrass (Lolium perenne)/white clover (Trifolium repens) pasture for increasing the growth of deer calves. Red deer and hybrid (0·25 elk; 0·75 red deer) calves were used in both experiments. Experiment 2 concluded with slaughter at the end of spring, when the deer were c. 12 months old. In both experiments, animals were rotationally grazed on either pasture or chicory with DM allowances being 12 kg DM/hind per day (Expt 1), and 6, 6 and 7 kg DM/head per day during autumn, winter and spring respectively (Expt 2).Perennial ryegrass comprised 62% of pasture on offer in Expt 1 and 78–90% in Expt 2, whilst chicory comprised 90–92% of forage on offer in both experiments. Relative to pasture, chicory had a higher ratio of readily fermentable: structural carbohydrate and had higher organic matter digestibility (OMD) in summer and autumn but not in spring.Deer grazing chicory had higher voluntary feed intake (VFI), bite weight, liveweight gain (LWG), carcass dressing percentage and carcass weight and much shorter ruminating time than deer grazing pasture. Hybrid deer grew better than red deer and there were forage × genotype interactions in Expt 2, with LWG and carcass weight of hybrid deer being much greater when grazed on chicory. Carcass weight for red deer and hybrid stags was 63·2 and 73·0 kg when grazed on chicory and 56·6 and 57·0 kg when grazed on pasture. Grazing chicory advanced the date of first-cut velvet antler by 28 days and increased the weight of total harvestable (first-cut + regrowth) velvet antler. It is concluded that grazing chicory increased carcass weight, especially in hybrid stags with increased growth potential, and increased velvet antler production. This was achieved by increased VFI in all seasons and increased OMD of chicory in summer and autumn relative to deer grazing pasture. Further research is need to determine the efficiency of rumination on particle size breakdown and to measure rumen outflow rate in deer fed chicory.