M. Y. Sumaryadi

Effect of fetal number on the concentrations of circulating maternal serum progesterone and estradiol of does during late pregnancy

Abstract Twenty Etawah-cross does with similar body weights (20–22 kg) and ages (2–3 years) were used to study the effects of fetal number (single or twin) on serum concentrations of progesterone and estradiol during the last two months of pregnancy. Average serum progesterone concentrations during the last two months of gestation period in the single- and twin-bearing markedly increased (P

Maternal serum progesterone concentration during gestation and mammary gland growth and development at parturition in Javanese thin-tail ewes carrying a single or multiple fetuses

Fifteen pregnant ewes were used to study maternal serum progesterone concentration during pregnancy and mammary gland growth at parturition in ewes carrying single (n = 9) and multiple fetuses (n = 6) as compared to five nonpregnant ewes. The experimental ewes were sacrificed at parturition to determine mammary gland growth and development indices (mammary dry fat-free tissue [DFFT], DNA, RNA, collagen, protein, and glycogen). Nonpregnant ewes serum progesterone concentrations (2.89 ± 0.27 ng/ml) and mammary DFFT (2.34 ± 0.21 g), total mammary DNA (0.10 ± 0.01 g), RNA (0.03 ± 0.003 g), collagen (0.11 ± 0.01 g), protein (1.26 ± 0.15 g) and glycogen (0.02 ± 0.002 g) were lower (P < 0.01) than in pregnant ewes. Ewes carrying multiple fetus had higher average serum progesterone concentrations (18.56 ± 1.55 vs. 12.02 ± 1.44 ng/ml), mammary DFFT (45.88 ± 10.56 vs. 26.39 ± 2.02 g), total mammary DNA (1.51 ± 0.30 vs. 0.92 ± 0.09 g), total mammary RNA (0.94 ± 0.23 vs. 0.30 ± 0.05 g), total mammary protein (36.49 ± 9.64 vs. 19.35 ± 1.74 g), and total mammary glycogen (0.23 ± 0.08 vs. 0.09 ± 0.01 g) as compared to those carrying a single fetus, without a significant difference in total mammary collagen (0.35 ± 0.04 vs. 0.30 ± 0.04 g). The results of the experiment indicated that ewes carrying higher number of fetuses could have higher secretion of pregnancy-related mammogenic hormones that stimulated greater mammary gland growth and development during gestation.

Correlations between lamb birth weight and the concentrations of hormones and metabolites in the maternal serum during pregnancy

Maternal serum hormones (progesterone, oestradiol, triiodothyronine and cortisol) and blood metabolites (β-hydroxy butyric acid [BHBA] and blood urea nitrogen [BUN]) concentrations at weeks 0, 4, 8, 12, 16 and 20 of pregnancy were measured in 39 pregnant Javanese thin-tail ewes (20 and 19 carrying single and multiple [2-3] foetuses, respectively), and six non-pregnant ewes as controls, to evaluate their correlations with lamb birth weight at parturition. All hormones and metabolites changed with the advance of pregnancy. Regression analyses showed that concentrations of triiodothyronine, cortisol, BHBA, and BUN in the maternal circulation during pregnancy had lower correlations with lamb birth weight at parturition than those of progesterone and oestradiol. Progesterone and oestradiol concentrations in the maternal circulation at week 8 of pregnancy had the greatest correlations with lamb birth weight at parturition. The higher the concentrations of progesterone and oestradiol in the maternal circulation at week 8 of pregnancy, the higher the lamb birth weight at parturition. The results suggested that raising maternal serum progesterone and oestradiol concentrations during early pregnancy in sheep, either by exogenous administration or superovulation, might improve prenatal growth and lamb birth weight.