Effect of foetal number and sex on maternal thyroid and lipidic profiles in dairy goats

The study aimed to evaluate the effects of the kids’ number and sex on the thyroid and lipidic patterns of 30 dairy goats in the advanced mid-gestation and from 30 to 105 days of lactation.Blood samples were monthly collected to measure circulating thyroid stimulating hormone (TSH), total and free triiodothyronines (T3, fT3) and thyroxines (T4, fT4); triglyceride (TG), total cholesterol (tCho), and very-low-density lipoprotein cholesterol (VLDL Cho).Dams carrying a single foetus showed higher T4 concentrations (P < 0.04) at >130–150 days than those carrying twins. Dams carrying one/two males had the highest fT3 (P < 0.001) and fT4 (P < 0.03) concentrations at 95–115 days and the highest fT3 (P < 0.0001) and TSH (P < 0.002) at >115–130 days. Dams kidding male and female twins showed the highest TG and VLDL Cho concentrations (P < 0.04) at >70–105 days of lactation.Single or twin births influenced the thyroid activity of pregnant goats, with a specific effect of foetal number on T4 and of foetal sex on fT3 and fT4 concentrations. Kids’ number and sex affected TG and VLDL Cho in lactating dams. This suggests that foetal number and sex are not a random chance event but an interactive process between maternal and foetal endocrine and metabolic processes.