EFFECTS OF LOW-ENERGY DIET FOLLOWED BY A COMPENSATORY DIET ON GROWTH, PUBERTY AND MILK-PRODUCTION IN DAIRY HEIFERS

Six-month-old Israeli Holstein heifers were fed on a low-energy (LE) diet with corn straw as the main feed component during the 4 months of summer, followed by a high-energy, high-protein diet for compensatory growth during the 2 months of autumn. During the same period a control group was fed to support an average daily gain of 0.65 kg. During the LE phase, the mean daily gains in heart girth, body weight and hip height were 51 to 67% lower than those of the control group. During the compensatory phase, mean daily gains in body weight, hip height and heart girth group were 197 to 225% times greater than in the control group. By the end of the compensatory phase the experimental group had the same mean body weight as the control group, but the mean hip height of the heifers was 2 cm shorter. Puberty was attained by the experimental group one month later than in the control group, but at the same body weight. Milk production was similar in the two groups. The efficiency of the metabolisable energy intake for body weight gain in both treatments was discussed.