ABSTRACT

The objective was to determine the effect of grazing fodder beet versus ryegrass-dominant pasture from mid-to-late gestation on dam and offspring performance under practical farming conditions. Twin-bearing ewes were randomly allocated to grazing regimes of either fodder beet plus ad libitum ryegrass/clover hay (FB; n = 100) or ryegrass-dominant pasture plus ad libitum ryegrass/clover hay (RG; n = 100) with three replicates per group, from pregnancy day (P) 100–110 to birth. At P135, 10 ewes per treatment were randomly selected from each replicate, slaughtered and back fat and eye muscle depth and fetal body weight and composition were measured. Samples were evaluated for selected blood metabolites. Ewe BW and BCS change and lamb growth were measured, and lamb survival from birth to weaning calculated. Compared with RG, FB ewes had lower ADG and overall lower BCS resulting from increased mobilisation of both fat and muscle. Lambs born to FB-ewes had lower BW and postnatal growth rates and increased mortality from birth to weaning (29% versus 12%). Body composition and blood parameters indicated that FB compared to RG ewes were subject to undernutrition. This study provides new insights into the consequences of FB grazing regimes, as an alternative to ryegrass pasture, on animal performance.

摘要

目的是确定在实际耕作条件下，从中后期妊娠放牧甜菜与黑麦草为主的牧场对水坝和后代性能的影响。双轴承母羊随机分为饲料甜菜的放牧制度加随意黑麦草/三叶草干草（FB; ñ = 100）或黑麦草显性牧场加随意黑麦草/三叶草干草（RG; Ñ= 100），每组三个重复，从怀孕日（P）100-110到出生。在P135处，从每个重复试验中随机选择10头母羊，进行宰杀，测量背部脂肪和眼肌的深度以及胎儿的体重和组成。评价样品中所选的血液代谢产物。测量母羊体重和BCS的变化以及羔羊的生长，并计算从出生到断奶的羔羊存活率。与RG相比，FB母羊的脂肪和肌肉增加了运动，因此ADG降低，BCS总体降低。FB-母羊出生的羔羊的体重和产后增长率较低，从出生到断奶的死亡率更高（分别为29％和12％）。身体成分和血液参数表明，FB与RG母羊相比营养不足。这项研究提供了有关FB放牧制度后果的新见解，