Effect of transient high-energy diets just after ovulation on ovarian performance and metabolic status in cyclic ewes

The aim of this study was to investigate the influence of short-term treatment of high-energy diet after ovulation on ovarian function and metabolic status in ewe. Cycling ewes Ossimi were divided into treatment group (TG; n = 6) and control group (CG; n = 6). After ultrasonographic detection of ovulation (day 0), a high-energy diet (12.55 MJ DE/kg diet; 125% of maintenance) was fed to TG from day 1 to day 4 after ovulation (4 days). The high-energy diet consisted of 850 g concentrate mixture and 150 g alfalfa hay, plus ad libitum access to wheat straw. The CG was offered as maintenance diet (10 MJ DE/kg diet) throughout the experiment. Follicular development was observed ultrasonographically every other day while blood samples were collected daily throughout the experiment for the analysis of glucose, total cholesterol, urea, triglycerides, total proteins, aspartate aminotransferase (AST), alanine transaminase (ALT) and glutamate oxaloacetate transaminase (GOT). Transient feeding of high-energy ration during early luteal phase of estrous cycle significantly influenced the concentration of glucose and some metabolic profiles. Total proteins were greater at first, third and fourth day after ovulation (ovulation is day 0) in TG when compared to CG ewes. Blood glucose concentration was greater in TG than that of CG at days 1, 2, 3 and 4 postovulation. The average number of small follicles (2-2.9 mm) of the first follicular wave after ovulation was greater in TG ewes (23.3 follicles) than that of CG (2.2). There was no difference in the number of medium (3-5 mm) and large sized follicles (>5 mm) between CG and TG ewes. Moreover, the maximum size of large follicles did not differ between CG (5.6 mm) and TG ewes (5.9 mm). In conclusion, high-energy diet may improve number of small follicles and alter energy metabolite during early luteal phase in cycling ewes.