1. Braude, R., 1971. Pig Production Univ. of Nottingham 18th Easter School in Agric. Sci.
2. Bryant, M.J. and Ewbank, R., 1973. Br. Vet. J. 130, 139.
3. Close, W.H. and Mount, L.E., 1978. Br. J. Nutr. 40, 413.
4. Ford, J.J., Teague, H.S., 1978. J. Anim. Sci. 47, 828.
5. Gehlbach, G.D., Becker, D.E., Cox, J.L., Harmon, B.G. and Jensen, A.H., 1966. J. Anim. Sci. 25, 386.