THE EFFECTS OF FEEDING GRASS-SILAGE AND MOLASSED SUGAR-BEET PULP EITHER SEPARATELY OR AS AN ENSILED MIXTURE TO TWIN-BEARING EWES

First-harvest, precision-chopped Lolium perenne grass with a dry matte r (DM) content of 132.0 g/kg and water-soluble carbohydrate (WSC) and crude protein (CP) contents of 24 g/kg and 106 g/kg DM, respectively, was ensiled in farm scale silos following the addition of formic acid (FA) (2.5 1/t) or molassed sugarbeet pulp (MSBP) (50 kg/t). Mature twi n-bearing ewes in = 56) were allocated to one of seven treatments and offered either FA-treated silage or MSBP silage nd libitum. The trial commenced on day 91 of pregnancy, when the ewes were offered FA-treate d silage (T1), FA-treated silage+soyabean meal (T2), MSBP silage (T3), MSBP silage+soyabean meal (T4), FA-treated silage+MSBP (T5), FA-treat ed silage+MSBP+soyabean meal (T6) or FA-treated silage+a barley-based supplement (150 g CP per kg DM) (T7, control). Soyabean meal supplemen tation was only offered in the last 3 weeks of pregnancy, with the obj ective of achieving a total CP intake of 220 g/ewe per day. Compared w ith the FA-treated silage, the MSBP silage had a higher nitrogen conte nt (P < 0.01) and a lower neutral detergent fibre (NDF) content, but t he two silages did not differ in DM, acid detergent fibre (ADF) or gro ss energy contents. Silage DM intakes (SDMI) were higher on the MSBP s ilage-based diets (T3, T4) than for any other treatment (P < 0.05). Th e addition of soyabean meal significantly increased SDMI in T2 in the last week of pregnancy (P < 0.05), but there was no response in SDMI t o soyabean meal supplementation in any of the other treatments. Ewe li veweight changes (kg) of -0.4, 4.1, 7.8, 10.2, 7.1, 9.6 and 10.8 (S.E. +/-1.2), body condition score changes of -0.96, -0.59, -0.42, -0.33, - 0.37, +0.01 and -0.27 (S.E.+/-0.1) and total lamb birth weights (kg)of 8.0, 8.7, 9.2, 9.9, 8.6, 8.0 and 10.4 (S.E.+/-0.5) were recorded for ewes in T1 to T7 respectively.