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SummaryTo investigate the effects of physiologically relevant heat shock during oocyte maturation, buffalo cumulus-oocyte complexes (COCs) were cultured at 38.5°C (control) or were exposed to 39.5°C (T1) or 40.5°C (T2) for the first 6 h of in vitro maturation (IVM), followed by 38.5°C through the next 18 h/IVM and early embryonic development up to the blastocyst stage. Gene expression analysis was performed on selected target genes (HSF-1, HSF-2, HSP-70, HSP-90, BAX, p53, SOD1, COX1, MAPK14) in denuded oocytes and their isolated cumulus cells resulting from control COCs as well as from COCs exposed to a temperature of 39.5°C (T1). The results indicated that heat shock significantly (P < 0.01) decreased the maturation rate in T1 and T2 cells compared with the control. After in vitro fertilization (IVF), cleavage rate was lower (P < 0.01) for oocytes exposed to heat stress, and the percentage of oocytes arrested at the 2- or 4-cell stage was higher (P < 0.01) than that of the control. The percentage of oocytes that developed to the 8-cell, 16-cell or blastocyst stage was lower (P < 0.01) in both T1 and T2 groups compared with the control group. mRNA expression levels for the studied genes were decreased (P < 0.05) in treated oocytes (T1) except for HSP-90 and HSF-1, which were increased. In cumulus cells isolated from COCs (T1), the expression for the target genes was upregulated except for BAX, which was downregulated. The results of this study demonstrated that exposure of buffalo oocytes to elevated temperatures for 6 h severely compromised their developmental competence and gene expression.

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This work aims at studying the enterprise of Baladi fattening farms in Egypt under the system of controlled feeding as affected by average daily gain (ADG). Different scenarios are discussed to maximize the return of fattening farms of Baladi. Seven normally distributed herds with different ADG (g) are simulated. All herds have initial body weight (IBW) of 230 kg and marketing body weight (MBW) of 400 kg. Based on the results of previous experiment, two scenarios are tested to maximize the return of fattening Baladi farms enterprise, the first is the MBW and the second is early culling rate. Prices of the inputs are calculated based on the price list of year 2010 in Egyptian bounds (LE). Output /input ratio, net return (%), annual return of investment (ROI, %), gross margin (GM) , number of fattening cycles/ year and cost of producing one kg gain, are calculated as economic indicators. Economic indicators measured on the seven simulated herds show increasing output /input ratio (from 0.91 to 1.16), net profit per cycle (from-8.63 to 15.67 %) and ROI (from-10.25 to 38.77%). With increasing ADG from 550 to 1150 g, this accompanied by decreasing cost of producing 1 kg gain by 52.4%. Herds having ADG less than 750g show negative values of output / input ratio, net profit per fattening cycle, ROI. This is because of the break-even point is between ADG of 650 and 750 g. However, comparing ROI of the simulated herds with annual bank interest (7%) indicate the break-even point is achieved when ADG is not less than 810 g. ROI shows reverse trend with increasing MBW from 400 to 550 kg, regardless the ADG. ROI value increased with increasing culling rate (from 5 to 20%), however, ROI reaches a value of more than 7% (the bank interest) under culling rate of 15% (9.3%). In conclusion, ADG of less than 850 g is not profitable if compared with annual bank interest rate. MBW of 400 kg and early culling rate of 15% at least are two scenarios to maximize the ROI of Baladi fattening enterprise. Increasing ADG by 100 g at herd level increases net profit per cycle by 5.22 % and decreases cost of producing one kg gain by 3.6%.