Peri-conception and first trimester diet modifies reproductive development in bulls

Area of Science:

• Reproductive Biology
• Animal Science
• Nutritional Science

Background:

• Maternal nutrition during gestation affects fetal development.
• Cattle reproductive development differs from rodents and sheep.
• Impact of peri-conception and early gestation nutrition on bull reproductive development is understudied.

Purpose of the Study:

• To investigate the effects of maternal dietary protein perturbation during peri-conception and first trimester on bull reproductive development.
• To assess fetal testis development and later reproductive performance in bulls exposed to different maternal diets.

Main Methods:

• 360 heifers fed high- or low-protein diets from 60 days pre-conception.
• Dietary changes post-conception (24-98 days) created four treatment groups (2x2 factorial).
• Fetal testis development assessed at 98 days; progeny reproductive development assessed until 598 days of age.

Main Results:

• Low peri-conception protein diet delayed puberty and reduced sperm quality in bulls.
• Lower FSH concentrations observed in bulls from dams on low peri-conception diets.
• Fetal testes showed increased seminiferous tubules and decreased vascular area with low peri-conception diet; adult testes showed increased vascularity with low first-trimester diet.

Conclusions:

• Maternal dietary protein manipulation around conception and early gestation alters male bovine reproductive development.
• Low protein intake during critical early developmental windows can negatively impact bull reproductive health and pubertal attainment.