This study examined the effects of cobalt supplementation, given from three months prepartum to nine months postpartum, on lactation performance, reproductive efficiency, blood biochemistry, colostrum immunoglobulin levels, and hormonal profiles in she-camels, along with the growth of their calves. Twenty Maghrabi she-camels, weighing 489 ± 2.31 kg and aged 6–9 years, were used in this study. The camels were divided into four groups: one control group fed only the basal diet, and three treatment groups receiving 0.16, 0.32, and 0.48 mg of cobalt per kg of feed as cobalt glucoheptonate. Results indicated that cobalt supplementation significantly increased colostrum immunoglobulin concentrations (IgG, IgM, and IgA), as well as monthly milk yield and lactation period. Milk contents of total solids, protein, and lactose also improved in the supplemented groups, particularly at 0.32 mg/kg cobalt. Additionally, pre- and post-partum serum cobalt, vitamin B12, T3, T4, progesterone, and estradiol levels were higher in the cobalt-treated groups. Enhanced reproductive outcomes included shorter postpartum intervals to first estrus, reduced services per conception, and improved weaning weights and average daily gains of calves in all cobalt-supplemented groups. In conclusion, dietary cobalt supplementation at a level of 0.32 mg/kg from three months prepartum to nine months postpartum significantly enhanced the lactation and reproductive performance of Maghrabi she-camels, increased colostrum immunoglobulin levels, and positively affected the growth performance of their calves.