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1. The four systems of rearing dairy heifer calves, described in Part 1 of this series are now studied for their effect on absolute and relative growth rates to maturity.2. Data on live-weights and measurements and the percentages of mature size attained by these at 44, 80, 104, 132, 182, 260 and 312 weeks of age are tabulated.3. In all groups the measurement to reach maturity earliest was circumference of metacarpus followed in order by length of back, height at withers and width of hooks.4. By 6 years of age all groups had attained approximately the same body size. Maturity in the LL group in terms of four skeletal measurements was delayed by only 9 months, and in the case of HL and LH animals by 5 and 4 months respectively.5. All groups showed the same general pattern of relative growth but the effect of restricted feeding was to increase at the younger ages the difference i n percentage of mature size between early and late maturing measurements. After 44 weeks of age the rate of growth was most rapid in those measurements which were furthest from maturity then.6. The rate of tissue deposition was markedly increased in high plane animals during early pregnancy compared with low plane. Evidence is presented to show that much of this was lost during lactation.7. At first oestrus, animals in all four treatment groups had reached the same percentage of mature size for each body dimension (except for length of back in the LL group).8. From data on 5 animals it is shown that although growth in height at withers and length of back ceased by 6 years of age there was slow but continuous growth in live-weight, middle and heart girths and width of hooks to 9 years of age.

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1. Eighteen pairs of one-egg and 6 pairs of two-egg twin calves were used in a balanced incomplete block design to examine four systems of rearing: (1) a continuous high plane of nutrition from birth to first calving (HH); (2) a high plane for the first 44 weeks followed by a low plane until 2 months before calving (HL); (3) a continuous low plane until 2 months before calving (LL); and (4) a low plane to 44 weeks followed by a high plane to first calving (LH). All animals were fed on a high plane during the two months before calving.2. Mean daily consumptions of DM, TDN, S.E. and DCP are given and the net energy intakes compared with a recently recommended standard.3. At 44, 80 and 104 weeks of age there were highly significant differences between the groups in all weights and measurements due to treatment. Low-plane feeding retarded the growth of the skeleton to only a limited extent as compared with live-weight. After the changeover, animals on the HL system lost much of the advantage in body measurements they had gained over those fed on a continuous low plane.4. All groups reached sexual maturity at the same stage of physical development but at different ages. The HL animals were the slowest to attain maturity indicating that as with growth the changeover from a high plane to a low plane of nutrition had had an adverse effect.5. Low-plane animals on poor hill pasture made better growth than their mates on good arable pasture. Evidence is presented, however, to show that part of this greater growth in live-weight was due to increased ‘fill’.

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