Effect of nutrition on follicle development and ovulation rate in the ewe

摘要: The general aim of this thesis was to gain further knowledge on the effect nutrition endocrine response and follicular dynamics in cyclic ewe. Paper I presents an investigation low high body condition profiles ewes. study showed that ewes had a constant pattern three follicle waves, while developed two or waves during cycle. Individual tracking by ultrasonography (US) made it possible growing profile each relation its milieu. Oestradiol FSH levels were implicated regulation turnover. Ewes higher ovulation rate, which associated with lower oestradiol concentrations phase There lack information regarding limitations US evaluate follicles different size could replace more invasive techniques. objective II assess accuracy evaluating number corpora lutea (CL) compared observations at post-mortem examination ovaries. predictive value sensitivity 100% for presence 96% absence CL. 80% determination (90-95%) ³4 mm. (62%) (71%) smaller classes (2 3 mm, respectively) may explain inconsistent results found literature. Overall, demonstrated is good tool counting CL rate under field conditions. In III we evaluated if short-term nutritional supplementation before ovulatory wave emergence increase recruited into wave, condition. supplement increased proportion three-wave pattern, but neither nor recruitment increased. supplemented group feed intake induced decrease progesterone concentrations, prolonged life span largest present beginning treatment. A trail performed same treatment rate. moderate-high than conclusion, last non-ovulatory promoted 3-wave development inter-ovulatory interval. Supplementation also active dominant single ovulation. Short-term from Day 8 14 oestrous cycle moderate IV hypothesis tested glucose, insulin, leptin IGF-I are supplementation. Acute changes peripheral glucose metabolic hormones related time feeding measured. insulin third day after commenced. similar among groups. Thus, ewe be mediated through leptin.