Forty-five New Zealand White and 35 Californian doe rabbits, 8 months old and in the third parity of their 1st year of production were used in this study. Thirty-five does were concurrently pregnant and lactating, the remaining 45 does were non-pregnant. Milk samples were collected in colostrum and at the 7th, 14th, 21st, 28th and 35th days of lactation. Neither breed nor pregnancy status affected the does milk composition except for total phosphorus which was significantly lower (P < 0·05) in the pregnant does' milk. However the major components of milk except lactose, were significantly affected by stage of lactation. Both moisture: total solids and calcium: phosphorus ratios were the same (2:1) throughout the lactation. The ratio between retinol concentration in colostrum and in the 5th week was about 10:1. Specific gravity was significantly (P < 0·05) correlated with protein, lactose (positive) and fat (negative).

No abstract

This current investigation was conducted to evaluate the potential effects of housing system (battery cages versus litter floor) on growth performance, some blood parameters and carcass characteristics of broilers. A total number of 224 unsexed one day old Evian broiler chicks were randomly distributed into two treatment groups (112 per each group). Chicks of the 1P st P group were raised in cages, while those of the second one were raised on litter floor. The results of the present work could be summarize as follows: broilers reared on litter floor exceeded (P≤0.05 and 0.01) those kept in battery cages in each of body weight, daily body weight gain and feed consumption in most of the studied intervals. Each of feed conversion ratio, carcass characteristics, some blood parameters and some immunity agents were not significantly changed between broilers kept in batteries and those reared on litter floor. The present work revealed a better performance and an increase in carcass yield of birds reared on floor system, which could be recommended to increase broilers performance under Sharkia Governorate conditions.

One thousand, two hundreds and sixty eggs of Japanese quail (Coturnix coturnix Japonica) were set into the incubator maintaining 12 treatment groups in a factorial design experiment (3 × 4) including three categories of incubated quail weight eggs (lower than 11 g., light weight (L), 11-12 g., medium weight (M) and above 12 g., heavy (H)), and four egg storage periods (1, 4, 7 and 10 days). The traits studied were egg weight loss (%) during incubation, embryonic mortality percentage, incubation time, and fertility percentages. Results obtained revealed that, there was a significant (P<0.01) increase in egg weight loss (%) with increasing egg weight during incubation while, egg storage period was insignificantly affected on the same trait. Embryonic mortality percentage during the whole incubation period (1-17 days) was significantly (P< 0.05) affected by egg weight categories as it decreased by egg weight increase where the best result was obtained with heavy eggs (H) which recorded 22.01%. A significant (P< 0.01) effect on incubation time per hour due to quail egg weight was shown while, each of the egg storage periods and interaction effects were insignificant. A significant effect (P< 0.05) on fertility percentage due to quail egg weight, egg storage period (P< 0.01), while the interaction was insignificant. The best results were with medium (M) egg weight or storage period of 1 day while the highest values (95.83 and 95.12%) were obtained by interaction of 1 day storage period with each of medium (M) or Heavy (H) weights of incubated quail eggs, respectively. Conclusively, it can be concluded that, medium quail eggs and storage periods of 1 day or 4 days gave the best results of pre-hatch performance of Japanese quail under Egyptian conditions.

Peking ducklings were classified at 6 weeks of age according to their body weights in two categories: R, below the overall mean of the flock which were considered as retarded growth; and L, those of body weight equal to the overall mean and above which were considered as large. From each group, males and females were chosen to be parents of the next generation in a ratio 1:5 at 6 months of age and four systems of matings were conducted: RR, LL, RL and LR.At all ages studied the large ducklings were significantly heavier than retarded growth ones and had significantly greater body gain, during the two successive generations.The RL and LR matings were heavier than the RR and LL groups at the different ages studied, indicating an effect of heterosis and that the retarded growth character is controlled by few pairs of genes. The differences due to mating systems were not significant either in body weight or body gain, except in body weight at 18 and 24 weeks and relative gain at 6 weeks of age in which the differences were significant (P < 0-05) in the second generation.The other environmental factors studied were sex, month of hatch and 6-week body weight.Heritability estimates were 0-489, 0509, 0576, 0346, 0713, 0-809, 0-651 and 0-386 for body weight at hatch 4, 6, 8, 12, 16, 18 and 24 weeks of age, respectively, using the data which were adjusted for the effects of sex, month of hatch, 6-week body weight and mating system. The same estimates were 0-482, 0-554, 0-578, 0352, 0713, 0808, 0-650 and 0-386, respectively, using the same data but adjusted for month of hatch and sex only.Phenotypic and genetic correlations between body weights at different ages for the two sets of data were estimated. The phenotypic correlations were negative between body weight at hatch and each of the body weights at 16 and 18 weeks of age for the two corrected sets of data. The genetic correlations were negative between hatch weight and each of the other body weights for the two adjusted sets of data and between body weight at 4 weeks of age and each of the body weights at 16, 18 and 24 weeks only for the first set of data. Phenotypic and genetic correlations between the body weights in older birds were highly positive.