Long-Term Effects of Feeding Plans Initiated at Birth on Growth and Performance of Gir Dairy Heifers: Evaluation During the Rearing Period

This study represents the second phase of a longitudinal experiment evaluating the long-term cumulative effects of feeding strategies initiated at birth on the body development, metabolic profile, and feed efficiency of Gir dairy heifers during the rearing period. Thirty-four Gir dairy heifers participated in this study, which took place over a period of 133 days (21 days of adaptation and 112 days of data collection). A randomized block design was used with two treatments applied at birth: a conventional feeding plan (CF), offering 4% of body weight (BW) as dry matter (DM), and an optimized feeding plan (OF), offering 5% of BW as DM. Growth, feed efficiency, metabolic profile, and vulvar and teat morphometry were evaluated. Data were analyzed using linear and generalized mixed models. Average DM intake was 2.51% and 2.46% of BW for OF and CF, respectively. Heifers on OF showed a greater average chest circumference than those on CF. No differences were observed between treatments for residual feed intake, feed efficiency and feed conversion, teat and vulvar morphometry, or blood parameters. Our findings indicate that the growth differences established under the feeding plan initiated at birth were maintained throughout the rearing period, with no effects on feed efficiency, metabolic profile, or mammary gland development.