Progesterone concentrations in milk of CIDR-treated goats

When using hormonal treatments to stimulate animal reproduction, it is of interest to identify possible hormone residues in milk. Progesterone levels were herein determined in the milk of CIDR-treated goats. A total of 18 animals were synchronized with prostaglandin; once in estrus, they were treated with the vaginal CIDR device for a period of 15 days (CIDR group, n = 9) or left untreated (control, n = 9). A third group of pregnant goats (90–120 days of pregnancy, n = 9) was used to compare milk progesterone values under different physiological conditions. Progesterone levels were determined in a daily sample of milk taken for 15 days after estrus from both the CIDR and control groups, and for 8 days from pregnant goats. Mean milk progesterone levels in the CIDR group were not higher than in controls or pregnant animals (P > 0.05). Total amount of milk progesterone showed no significant differences between groups (P > 0.05). In conclusion, milk progesterone levels of CIDR-treated goats did not exceed those of dioestrous or pregnant animals. Assuming that progesterone levels in milk of naturally cycling or pregnant animals are safe for human consumption, then the milk of CIDR-treated goats should also be safe