- Agronomic: sugarbeets
- Animals: sheep
- Animal Production: animal protection and health, feed rations, preventive practices
- Education and Training: demonstration, on-farm/ranch research
- Farm Business Management: whole farm planning, risk management
- Sustainable Communities: sustainability measures
The first half of gestation is critical for placental growth, differentiation and vascularization as well as fetal organogenesis. Placentomes are the functional units of placental exchange in the ewe, and are classified as A, B, C or D types (Figure 1), associated with increasing placentomal efficiencies. We compared two groups of multiparous Rambouillet ewes: 1) adapted to a nomadic existence (grazed ~250 miles/year); Baggs ewes and 2) relatively sedentary ewes supplied with more than adequate nutrition (UW ewes). Equal numbers of UW and Baggs ewes were fed to 50% (nutrient restricted, NR) or 100% (control fed, CF) of NRC requirements from day 28 to 78 of gestation. A ~30% reduction of fetal weight was observed in the NR vs. CF UW ewes, but not Baggs ewes on day 78. Further, placentome type was more advanced in NR Baggs ewes (B,C and D) than NR UW ewes (vertially all A). Conversion to more advanced placentomal types resulted in similar placentomal efficiencies (fetal weight/ placentomal weight) for NR and CF Baggs ewes, while placentomal efficiency of NR UW ewes declined markedly. These data suggest that selection of ewes under different production schemes can alter the negative impacts of early maternal undernutrition on fetal growth and development. The impacts of these maternally dependent changes in placentomal and fetal growth and development on the resultant offspring are currently under investigation.
Measurements taken in this study included diet-associated changes in maternal body weight and body condition, fetal size and organ weights, placentomal numbers, weights and morphologies, and fetal blood glucose concentrations.