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Intake, in vivo and in vitro digestibility’s, and seed survival following ingestion of annual medic pods by sheep

R. Valizadeh, E.D. Carter and N.G. Yates

Departments of Plant Science and Agricultural Technology, University of Adelaide, SA 5000

Pods of annual medic, Medicago spp.), are important components of dry pasture residues for sheep during summer and autumn. In addition, medic pods are being harvested in some districts for direct pelleting as sheep feed. However, the nutritive value of medic pods and their constituents is largely unknown. Furthermore, it is important to know the extent of seed survival following ingestion by livestock so that knowledge of seed-seedling dynamics can be incorporated into the management of pastures.


The voluntary intake, in vivo digestibility and seed survival following ingestion of three medic cultivars were studied. These were: Medicago scutellata cv. Sava and Parabinga and M. truncatula cv. Paraggio. Eighteen Merino wethers (6 per treatment) were offered pure pod diets individually with a 10-day preliminary period and a 10-day collection period in a completely randomised design.A two-stage method (3) was used for in vitro digestibility determinations of ground whole pods, seeds and hulls.

Results and discussion

The results are summarised in Tables 1 and 2. The intakes of Sava and Parabinga were similar to M. truncatula cvs. Jemalong and Commercial and M. littoralis cv. Harbinger (1). The intake of Paraggio pods was only about 30% of that of the other cultivars: the low intake may reflect a poor season with pods smaller than normal. Also the pods appeared to have some attached fungal residues. In vivo dry matter digestibilities were 36.7, 26.9 and 32.6 percent for Sava, Parabinga and Paraggio respectively. Organic matter and energy digestibilities followed the same ranking as the dry matter digestibilities. Seed survival was generally less than 3%.The in vitro digestibilities of ground whole pods was similar to that of whole pods in vivo, and the in vitro digestibilities of seeds varied between 67 and 78%. Apparently the low digestibility of hulls found in this study, supported in the findings of Denney et al. (3), limited the nutritional value of the pods.

Table 1. Voluntary dry matter intake, in vivo digestibilities and seed survival of medic pods.


1. Carter, E.D. 1980. Proc. 1st Aust. Agron. Conf., Lawes, p. 178.

2 Denney, G.D., Hogan, J. P. and Lindsay, J.R. 1979. Aust. J.Agric. Res. 30, 1177-1184. 3. Tilley, J .M.A. and Terry, R.A. 1963. J. Br. Grassld Soc. 18, 104-111.

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