The Effect of Superovulation of Javanese Thin-Tail Ewes Prior to Mating on Lamb Birth Weight and Preweaning Growth

Abstract

There is little information on optimum management of fodder tree legumes for maximum leaf production. The type of management depends on both their morphology and form of utilisation, which varies between species. As differences exist in relative growth rates and ability to persist over longer periods, their management is influenced by cutting height and cutting frequency (Horne et al., 1986). This study was undertaken at the University of Queensland to observe the responses of commonly used fodder tree legumes to cutting management. Four cutting treatments (60 cm, 100 cm, 150 cm and lopped) commencing in August, 1987 were imposed on five established tree legume species (Acacia angustissimus, Calliandra calothrysus, Albizia chinensis, Gliricidia sepium and Leucaena leucocephala). Each row of species contained five trees per treatment. Two months later the trees were cut at their respective heights and coppiced material lopped and subsequent harvests made at 1.5 monthly intervals until March. Materials harvested were separated into leaf (including flowers and pods) and stems (>6 mm diameter) and oven dried at 60C. The low spring temperatures reduced and inhibited leaf growth of all species and G. sepium respectively, but improved during summer. At 150 cm, L. leucocephala was better during spring and all species produced similar yields during summer. The overall mean leaf yields (%) at the respective heights over the period were 19, 26, 36, 19; 13, 24, 43, 19; 14, 22, 44 and 20. When lopped, leaf yield of C. calothrysus was high during spring and summer but similar to A. chinensis and G. sepium respectively in terms of forage quality. The overall mean leaf yields over the period were 7, 16, 10 and 65%. As cutting height increased, the number of remaining shoots, leaves and buds in the bottom canopy also increased from which regrowth was rapid. However, the proportion of leaves removed either by cutting, lopping or loss through leaf fall removed most photosynthetic tissues and reduced current photosynthate, resulting in reduced leaf yield. Regrowth and plant survival then depended on the reserve carbohydrate in the stem and rate of dry-matter accumulation, which varied between species. The different responses to cutting management provided some options for their use as reserve fodder in grazing systems. Horne, PM Catchpole D W and Ella A 1986 ACIAR