The objective of the present study was to determine the effects of dietary inclusion of different levels of pawpaw seeds powder (PSP) at different periods on the growth performance, survival rate, feed utilization and carcass composition of fry and fingerlings of Nile tilapia (Oreochromis niloticus). The experiment was divided into two periods; the first was feeding period of Nile tilapia fry with PSP for 71 days; and, the second was rearing period where the Nile tilapia fingerlings fed control diet (0 g/kg diet from PSP) for 84 days. Apparently-healthy 1200 Nile tilapia fry of one day old with an average initial body weight 0.012 g/fry were randomly distributed to 20 treatments. Each treatment was referred to three aquaria. The PSP was added to the basal diet at levels of 0, 2, 4, 6 and 8 g/kg diet for 15, 30, 45 and 60 days, different periods. The results of the first period showed no significant (P ≥ 0.05) differences in all growth performance parameters and feed conversion ratio (FCR) during all periods (15, 30, 45 and 60 day); however, different levels of PSP showed significant (P ≤ 0.01) improvement in all growth performance, survival (intervals SR and final SR) and feed utilization (FI and FCR) by increasing level of PSP till 6 g PSP/ kg diet, then significantly decrease (P ≤ 0.01) till 8 g PSP / kg diet. In case of the second period, all growth performance parameters and feed utilization (FI and FCR) gradually (P ≤ 0.01) improved with increasing feeding periods until 45 day, and then decreased with increasing feeding period (60 day). The interaction between levels of PSP and different periods of treatment indicated that 6 g PSP/kg diet for 45 day had the best (P ≤ 0.01) values of FW, TWG and ADG compared with other treatments. Thus, the results of this study lead to useful and safety recommended use of 6 g PSP /kg diet for 45 day, to be economic and efficient for fish farms.

The present study was carried out to evaluate the ability of using Pawpaw (Carica papaya) seeds powder (PSP) as natural reproductive inhibitor for Nile tilapia (Oreochromis niloticus) to control their propagation. The experiment was divided into two periods; the first was the treating period (1 st) during which the Nile tilapia fry were treated with PSP for 71 days and the second was the rearing period whereas the Nile tilapia fingerlings (2 nd) obtained from the first period until sexual maturation stage for 84 days. The PSP was added to the basal diet at levels of 0, 2, 4, 6 and 8 g/kg diet for 15, 30, 45 and 60 days, different periods (1 st). Results of the 2 nd period showed that there were no significant (P ≥ 0.05) effects on total cholesterol, testosterone and progesterone hormones among all periods; however the testosterone and progesterone hormones were decreased (P ≤ 0.0 1) by increasing levels of PSP. Also, the high levels of PSP (4, 6 and 8 g / kg diet) and increasing exposure periods (30, 45 and 60 day) caused obvious histological alternations of testes and ovaries of O. niloticus which reduce the fertility of both males and females. Consequently, it could be recommended that the effectiveness use of PSP as a natural reproductive inhibitor for O. niloticus.

This research was conducted to evaluate the Friesian cattle performance and study the relationship among different days open periods, total milk yield and days in milk at the first lactation of Friesian cows under different Egyptian conditions. Milk productive and reproductive data were collected from 3258 Friesian cows of six farms. Farm No.1 is a governmental, while other farms are commercial farms located in Kafr El-Sheikh, Cairo-Alexandria desert road, Gharbia, Sharqia, Daqahlia, Beheira governorates and were named from 1, 2, … to 6, respectively. Days open (DO) was classified to 10 classes, each class of 30 days (from < 60 to ≥ 300 d). The overall average of age at first calving, days open, calving interval, days in milk (DIM) and total milk yield (TMY) of all farms were 29.4 mo, 174.4, 472.0 and 359.2 d and 6173.5 kg, respectively. Results of this study showed that, in all examined farms, the 1 st lactation TMY and DIM significantly differed by the differences of the DO lengths. The study recommended that the most appropriate length of DO could be from 60 to <120 d, for Friesian cows under different managerial conditions in Egypt.

This study conducted to evaluate some of non-genetic and genetic parameters that affect the productive and reproductive traits. Total of 3596 records of 1021 Holstein Friesian cows in the first five parities were collected during the period from 2002 to 2016 from a commercial farm. The details values of productive traits (total milk yield (TMY, kg), lactation period (LP, day) and dry period (DP, day)), as well as, details values of reproductive traits (days open (DO, day), number of services per conception (NSC), age at first calving (AFC, months) and calving interval (CI, day)) were considered. The effects of season of calving and parity on productive and reproductive traits were also examined. The results revealed that the season of calving and parity had significant effect on all the studied traits. Heritability estimates for TMY, LP, DP, DO, CI, NSC and AFC are 0.110, 0.089, 0.071, 0.100, 0.103, 0.123 and 0.168, respectively. The phenotypic correlations of all studied traits were positive and ranged from 0.016 to 0.989, except that between TMY and all the reproductive traits as well as DP were negative. The values of genetic correlations among all studied productive and reproductive traits were positive and ranged from 0.031 to 0.998, except DP and TMY was negative. The present study is an effective way for using in improving programs for milk yield of Holstein Friesian cows in commercial farms.

No abstract