Statistical Analysis
To compare changes in BW, ADG, and BCS during
the experiment, the number of follicles and oocytes, and
oocyte quality variables (e.g., the rates of cleavage, and
morula and blastocyst formation) for control and underfed
ewes, data were analyzed using the GLM procedures
of SAS (SAS Inst. Inc., Cary, NC). For all variables,
the model included only nutritional treatment.
Absolute values for BW and BCS were analyzed using
a repeated measures design (Proc Mixed of SAS). The
model contained treatment, week of measurement, and
treatment × week interaction. Ewe within treatment
served as the error term to test for treatment responses.
Compound symmetry was used as the covariate structure.
Means were separated using the method of least
significant difference. When treatment × week interactions
were present (P < 0.05), the interaction means
were tested. In addition, data for the percentage of oocytes
cleaved and the rate of morula and blastocyst
formation (%) were analyzed by χ2. Simple correlations
between BWor BCS and blastocyst formation variables
were determined using Proc Corr of SAS.