Effects of winter feed type on feed intake during the transition back to spring pasture

Abstract

Two experiments tested the effects of dif ferent winter diets on intake and digestion of pasture by rising 1-yearold red deer returned to pasture with minimal dietary management during early spring. During May 1998 forty calves were randomly allocated to five winter feeding treatments including pasture only, silage only, 40% concentrate plus silage, 60% concentrate plus silage, and 90% concentrate plus silage. Forage intakes in the five days before and after turnout on 28th September 1998 were higher in weaners fed pasture than those fed winter diets (P<0.05). Of the supplemented weaners the postturnout intake was highest from weaners fed 60% concentrate plus silage and lowest from weaners fed silage only (P<0.05). Pasture digestibility was higher in deer previously fed pasture than those fed silage and concentrate diets in winter (78% and 73% respectively, P<0.05). During May 1999 calves were randomly allocated to three winter feeding treatments including swedes only (Brassica napus var. Doon Major), silage only, and 60% concentrate plus silage. The deer were supplemented with ad libitum lucerne hay during the turnout period. During the first week, after turnout on 6th September 1999, intake was low averaging 1 kg DM/ head/d. Weaners fed swedes only during winter had significantly lower intakes that the other groups (P<0.05). During the second week the intakes increased to be greatest in the weaners fed swedes, and those fed the silage plus concentrate diet compared to the silage only diet (1.9 and 1.8 kg compared to 1.58 kg DM/head/ d respectively, P<0.05). The diet consisted of between 38 and 61% lucerne hay over the two week period. The digestibility of the diet was 62.8% in the first week and 75.2% in the second week. Live weight gain over the two week period ranged between 1.1 and 1.75 kg. The use of lucerne hay improved the overall result from the previous year. These results indica te that effects of winter diet during the transition period between winter and spring diets were small, though greater on poorer quality winter diets. Keywords: Cervus elaphus, diet change, digestibility, food intake, live weight gain, red deer