Hormonal profile in rutting and non-rutting periods in dromedary camel (Camelus dromedarius)

The dromedary camel is a seasonally breeding animal. The breeding season (also called “rutting period” or “rut”) of this species coincides with the winter months and is characterized by significant changes in circulating hormonal levels. During the rutting period (winter season), the circulating levels of testosterone, cortisol and thyroid hormones are significantly higher than in the summer (non rutting season), however levels of vitamin D are very low in the winter, compared with those analyzed in non-rutting period (summer season). These changes may modulate the reproduction function and the thermoregulatory adaptation. Concentrations of circulating hormones during the rutting period vary greatly in the literature which could be explained by environmental and experimental conditions. In the camel, understanding the seasonal fluctuations of the hormonal prof le of the camels, can contribute to a fundamental knowledge of the reproduction physiology of this species, and will be of great importance to veterinarians in confirming their clinical diagnosis and enhancing the capacities of camel production and reproduction. The mechanisms of TH, glucocorticoids and vitamin D in the modulation of reproductive function and fertility in the dromedary remain to be studied

Comparative evolution of some minerals, osteocalcin, 25(OH)D and 1,25(OH)2D in the female camel and its newborn in South Morocco

Postpartum kinetics of plasma minerals (Ca, P, Mg, Na and K), osteocalcin, 25(OH)D and 1,25(OH)2D were observed in the lactating camel (n = 5) and its newborn (n = 5) in South Morocco. Ca and P plasma levels (mg/l) were higher in camel calves than in dams from birth up to day 30 of life. At birth, Mg, Na and K plasma levels (mg/l) were lower in camel calves than in dams. OC plasma levels (ng/ml) were higher in camel calves than in their mothers from birth (3.4 ± 0.3 vs. 0.7 ± 0.3, P < 0.05) up to day 30 of life (5.2 ± 0.5 vs. 0.7 ± 0.3). These levels reached their maximum at day 3 after birth in camel calves (6.8 ± 0.5) and at day 4 postpartum in dams (2.3 ± 0.4). Plasma levels (pg/ml) for 25(OH)D and 1,25(OH)2D in newborn calves were lower at birth than those in dams (58.2 ± 12.4 vs. 480 ± 59.7, P < 0.05, and 834.8 ± 61.5 vs. 1301 ± 209, P < 0.05, respectively). These neonatal levels became significantly higher compared to those of the dams as early as day 15 after birth for 25(OH)D (176.4 ± 19.6 vs. 116.1 ± 30.4, P < 0.05), and day 7 after birth for 1,25(OH)2D (1215 ± 248 vs. 571 ± 64, P < 0.05). These results show that OC could be a reliable biomarker for neonatal bone growth in camel and that 25(OH)D and 1,25(OH)2D might play a major role in calcium homeostasis regulation in newborn calves and their lactating dams

Influence of 1α,25-dihydroxyvitamin D₃ on Calcium and Phosphorus Secretion of the Mammary Gland in Lactating Camels

Plasma calcium (Ca) and inorganic phosphorus (Pi) levels, and content of these minerals in milk were measured in six thirdparity she-camels after i.v. administration of 1α,25-dihydroxyvitamin D3 [1α,25-(OH)2D3]. This steroid significantly (P < 0.05) increased plasma Ca and Pi levels from 94.2 ± 4.1 and 54 ± 2.5 mg/l, before the first calcitriol injection at 0 h, to 108.1 ± 3,4 and 63.5 ± 2.4 mg/l 24 h after end of treatment, respectively. Ca and Pi levels remained high until the end of the test. Intravenous administration of 1α,25-(OH)2D3 significantly (P < 0.05) increased Ca and Pi concentration and secretion in milk. Ca concentration and secretion of milk sampled every 12 h increased from 1080 ± 30 mg/l and 1100 ± 64 mg/12 h at 0 h, to 1218 ± 34 mg/l and 1240 ± 57 mg/12 h after the second injection, respectively. Those of Pi increased from 732 ± 66 mg/l and 754 ± 61 mg/12 h at 0 h, to 840 ± 38 mg/l and 890 ± 56 mg/12 h after the second injection, respectively. Ca and Pi contents and secretion in milk remained high (P < 0.05) until 12 h after treatment. These results showed that 1α,25-(OH)2D3 might affect the mammary gland of lactating camels. It increased Ca and Pi contents in milk without, however, significantly affecting milk production