Effect of supplementation on growth of heifers and post partum reproductive performance of pregnant horro cows at Bako Research Center

Two experiments were conducted at Bako research Centre to see the response of weaned female calves and pregnant Horro cows to different types and levels of supplementation under two separate experiments. In the first experiment, 24 weaned female Horro calves at the age of six months were randomly assigned to three treatments. The treatments were grazing only, grazing plus hay supplementation and grazing plus hay plus half kilogram concentrate per head per day offered at night. The calves were fed for 18 months until the age of 24 months. Treatment significantly (p0.01) affected growth of the calves at all ages. Heifers supplemented with concentrate had better growth performance at all ages compared with other two treatments. The effect of treatment on the daily weight gain of the calves was significant (p0.01). The effect of hay supplementation started to be significant at the age of 24 months. Weaning weight that is the weight at the start of the experiment was also considered in the model as a coveriate. The effect of this factor was significant at the age of one year. In the sedond experiment, 40 pregnant Horro cows were randomly assigned to five levels (0, 1, 2, 3 and 4 kg)) concentrate per head per day to a basal diet of 8 hrs grazing and ad libtum hay supplementation. Accordingly, the result indicated that treatment (p0.05), season (p0.05) and parity (p0.05); affected gestation length significantly (p0.05). But it is only parity that significantly (p0.05) affected calf birth weight. Treatment and season affected (p0.05) post partum anoestrus interval significantly (p0.05. However, treatment had no effect on days to conception and calving interval. the results of treatment had no effect on days to conception and calving interval, The results of both experiments demonstrated the need of supplementation for high growth rate, early age at first calving and better postpartum reproductive performances. Besides, up to the age of 24 months, high concentrate feeds resulted in better performance.