Effects of replacing grass silage with either maize silage or concentrates during late pregnancy on the performance of breeding ewes fed isonitrogenous diets

Abstract

A study was undertaken to investigate the performance of breeding ewes fed a range of forage and concentrate-based diets in late pregnancy, balanced for supply of metabolizable protein (MP). For the final 6 weeks before lambing, 104 twin-bearing multiparous ewes were offered one of four diets: ad libitum precision-chop grass silage 1 0.55 kg/day concentrates (GS); ad libitum maize silage 1 0.55 kg/day concentrates (MS); a 1 : 1 mixture (on a dry matter (DM) basis) of grass silage and maize silage fed ad libitum 1 0.55 kg/day (GSMS); or 1.55 kg/day concentrates 1 50 g/day chopped barley straw (C). The CP content of the concentrates was varied between treatments (157 to 296 g/kg DM) with the aim of achieving a daily intake of 130 g/day MP across all treatments. Compared with ewes fed GS, forage DM intake was higher ( P , 0.05) in ewes fed MS (10.21 kg/day) and GSMS (10.16 kg/day), resulting in higher ( P , 0.001) total DM intakes with these treatments. C ewes had the lowest total DM intake of all the treatments examined ( P , 0.001). C ewes lost more live weight (LW; P , 0.001) and body condition score (BCS; P , 0.05) during the first 3 weeks of the study but there were no dietary effects on ewe LW or BCS thereafter. The incidence of dystocia was lower ( P , 0.01) in C ewes compared with those offered silage-based diets (7.5% v. 37.4% ewes), and was higher ( P , 0.01) in ewes fed MS compared with GS or GSMS (50.7%, 34.7% and 26.9%, respectively). There were no significant dietary effects on the plasma metabolite concentrations of ewes in late pregnancy, pre-weaning lamb mortality, weaned lamb output per ewe or on lamb growth rate. The results of this study demonstrate that both maize silage and all-concentrate diets can replace grass silage in pregnant ewe rations without impacting on performance, provided the supply of MP is non-limiting. The higher incidence of dystocia in ewes fed maize silage as the sole forage is a concern.

Pengaruh substitusi fodder jagung pada silase rumput alam terhadap konsumsi dan kecernaan serat, konsentrasi VFA dan kadar glukosa darah pada pedet jantan sapi persilangan ongole x brahman lepas sapih

“…Dalam penelitian ini terjadi peningkatan protein dari 5% pada ransum yang hanya terdiri dari silase rumput menjadi 12% pada ransum dengan fodder jagung. Kandungan PK silase rumput alam dalam penelitian ini sebesar 5.38% (Tabel 3), jauh lebih rendah dari yang dilaporkan Annett et al (2013) yaitu sebesar 119 g/kg BK (11,9%). Moss et al (1995) mencatat protein kasar silase rumput (Lolium perenne) pada 2 penelitian berbeda berturutturut sebesar 142 dan 149 g/kg BK (14,2% dan 14,9%).…”