A comparison of oak browse ( Quercus spp.) and silages of rye and maize with respect to voluntary intake, digestibility, nitrogen balance and rumination time in penned Korean sika deer

Abstract

Two experiments were conducted to compare the voluntary feed intake, apparent digestibility, nitrogen (N) balance and rumination time of oak browse and different silages as roughage sources of sika deer to look into the possibility of feeding silages instead of oak browse which is in short supply and expensive in Korea. In Experiment 1, three sika deer with average body weight of 44.3 kg were fed three different roughages (oak browse, untreated rye silage, and formic acid treated silage) in a 3 × 3 Latin square design. Experiment 2 was conducted using four sika deer averaging 44.0 kg in body weight. They were fed four different experimental roughages (oak browse versus three different silages produced from maize of milk stage, dough stage, and yellow stage of maturity) in a 4 × 4 Latin square design. All the experimental animal were fed 0.5 kg of concentrate per day in addition to the experimental roughages. Intakes of dry matter, organic matter, crude protein and neutral detergent fiber were higher for oak browse than those for rye and maize silages in Experiments 1 and 2, respectively. Apparent digestibility of all nutrients was significantly ( P < 0.001) higher for the rye and maize silages than for the oak browse. Due to the differences in nutrient digestibility, total amounts of nutrient digested were significantly ( P < 0.001) higher for the rye and maize silages than oak browse. Fecal N excretion was significantly higher ( P < 0.001) for the oak browse than for the rye and maize silages, with no difference between the silages. However, urinary N excretion was higher with rye and maize silages compared with that for the oak browse. Sika deer fed rye and maize silages had significantly higher ( P < 0.001) N retention than animals on oak browse. Times spent ruminating were not significantly different among diets in both experiments. The results indicate that oak browse may be replaced with either rye or maize silage roughage sources for sika deer.