Published online by Cambridge University Press: 02 September 2010
Friesian/Holstein dairy heifers require an average daily live-weight gain of about 0·68 kg/day from birth to calving if they are o t reach a target live weight of 540 kg before first calving at 2 years of age. For autumn- born cattle the diet during their second winter is usually based on silage, hay or straw and the level of supplementation depends on the forage quality. When supplementation is necessary the aim should be to feed a least-cost diet. One possible supplementary food is fodder beet which, if grown without the use of purchased fertilizer (West of Scotland Agricultural College, 1984), can be a relatively cheap source of energy and compares favourably with other crops in yield per ha. In the two experiments reported here fodder beet was used for feeding dairy youngstock. The objective of experiment 1 was to evaluate the substitution of barley by fodder beet in straw-based diets. In experiment 2, fodder beet was fed as a partial substitute for silage.