Growth factors and vitamin-like substances have great positive importance in most biological interactions in the cellular level. The addition of these elements in the culture media will increase the yield of the resulting embryos and improve quality. We examined the effects of epidermal growth factor (EGF) and myo-inositol (MI) on meiotic maturation and yields of blastocyst of Awassi sheep oocyte across two experiments. The oocytes obtained were subjected into three treatments: A (without EGF nor MI), B (10 ng/ml EGF + 20 mmol/l MI) and C (50 ng/ml EGF +40 mmol/l MI). Oocytes were then cultured in Ham's F-10 medium supplemented with 5% (v: v) fetal calf serum and 40 ng/ml follicle - stimulating hormone. In the first experiment, during the 27-h culture period, the oocytes were assessed for germinal vesicle break down, metaphase-I and metaphase-II stages across three-time intervals (9, 21 and 27-h). Results of the experiment showed that EGF and MI enhanced the rates of germinal vesicle break down phase (1.53%; 27-h interval; lowest value), metaphase-I (33.87%; 21-h interval) and metaphase-II (89.23%; 27-h interval). In the second experiment, the oocytes incubated in treatment B achieved the highest rates of cleavage (81.96%), 2-8 cell (62.35%) and blastocyst (45.09%). It is concluded from the present study that incubating sheep oocytes in culture media containing a cocktail of EGF (10 ng/ml) and MI (20 mmol/l) significantly improves the rates of metaphase-II, fertilization and blastocyst rates.
Many of the reproductive traits in cows are affected by a group of factors, the most important of which are climatic conditions and the management of the herds. In this paper, the reproductive status of imported Holstein - Friesian cattle breed was evaluated in terms of breeding through the investigation for some traits under the influence of some factors. The records involved cow birth to first service trait (CBFS) (1101 records), cow birth to first days open trait (CBFDO) (1091 record), and age at first calving trait (AFC) (1083 record). The results of the study showed significant differences in CBFS, CBFDO, and AFC traits according to the year and season of birth (p <0.01), the lowest values were 19.33, 21.29 and 30.29 months (the year 2000) and 19.40,21.30 and 30.32 months (winter) respectively. Also. a significant difference (p <0.01) was noticed through the interaction between the year and season of birth and between the year of birth and total milk yield level (TMYL). Estimated heritability(h2) for CBFS, CBFDO, and AFC traits were 0.22,0.25 and 0.17 respectively. The study showed variation in estimated breeding values (EBVS) across sires within the reproductive traits. The first three lowest values were achieved by the sires 13,25 and 20, the values were -1.97, -1.87 and -1.86 months (CBFS trait), -2.33, -2.21 and -2.19 months (CBFDO trait), -2.32, -2.20 and -2.18 months (AFC trait) respectively. Based on current given results, it is advised to direct and intensify births during winter and spring seasons to obtain optimal reproductive performance of the herd later.
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