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Abstract. The aim of the study was to carry out crossing of the local breeds with a known prolific breed with the hope to be a beginning to develop improved synthetic lines under the sub-tropical conditions. In the present study, the data represented 4 genotypes: 2 pure Egyptian local fat-tailed breeds [Ossimi (O) and Rahmani (R)], one back-cross [1/4 Finnish Landrace (F) 3/4 O] and one 3-breed-cross [1/4 F 1/4 O 1/2 R]. The lambs resulted from two accelerated systems: 3 lambings/2 years and 2 lambings/1 year. The results showed that in 3 lambings/2 years and 2 lambings/1 year systems, the crossbred lambs were significantly (P<0.01 or 0.05) higher in most of the growth traits, carcass characteristics and weight of ewe lambs at first mating, and were significantly (P<0.01) lower in percentages of the tail and bone and age of ewe lambs at first mating than in their maternal (local) breeds. Spring born lambs were significantly (P<0.01 or 0.05) higher than those born in the other seasons of the year in body weights at 16 and 24 weeks of age and daily gain weight during 0–<8 weeks in 3 lambings/2 years system, and in daily gain weight during the period 8–<16 weeks of age in 2 lambings/1 year system. When using some indices based on combining a number of economic traits of the study (including slaughter weight, feed efficiency, dressing percentage, percentage of lean in the carcass, conception rate, lambing rate and average litter size) to compare the crossbreds with the local ones, the obtained values were not in favour of the crossbreds, which may throw some shadows on feasibility of applying crossing of the Egyptian local sheep with the Finnsheep. Comparison between the two mating systems showed that the 3 matings/2 years surpassed the 2 matings/1 year system in all the indices developed. When calculating the productive efficiency per one year by combining the traits: survivals ratio – that equals: 1 − (mortality rate at 8 weeks) – and frequency of lambing per one year, the values were 15.0 and 13.2 % in the two systems, respectively, confirming the previous results.

SummaryThirty Ossimi lambs were used in an experiment to compare those whose tail was docked shortly after birth with controls. After weaning at 4 months of age the groups were further subdivided and two of the four groups closely shorn according to a 2 × 2 factorial design.Male lambs at 20 kg were subjected to intensive finishing until the age of 50 weeks and nine were then slaughtered to determine carcass characteristics.There was a trend for increased live-weight gain in the docked lambs in the preweaning stage (up to 16 weeks).This trend was also present, although not statistically significant, in the final phase of intensive feeding from 20 kg weight to 50 weeks. Shearing significantly improved daily gain in this final period (P < 0·05). These increases in gain were also apparently associated with improvements in efficiency, as judged on a group basis.Docking and shearing also tended to cause increases in body measurements: height, chest girth and abdomen girth in the case of docking (P < 0·05) and chest girth, chest depth and abdomen girth in the case of shearing (P < 0–05).Carcass characteristics, measured on a relatively small sample, indicated several effects of docking and shearing on carcass traits although most of these were consistent with the expected differences stemming from the higher carcass weights acheived at 50 weeks of age by docked and sheared lambs.

The study was conducted to evaluate the effects of magnetized water (2000 Gauss) and season on semen and blood constituents in rabbit bucks. A total number of 32 New Zealand White (NZW) rabbit bucks were used in the experimental work during winter and summer seasons (16 in each). In each season animals were divided into 2 sub-groups (8 bucks in each). One sub group received magnetized water (MW) and the other received non magnetized water (NMW). Semen was collected weekly for 8 weeks using an artificial vagina. Reaction time (RT) was recorded during semen collection. Blood was collected and some common parameters were assayed. Semen was evaluated for ejaculate volume, mass motility, progressive motility, sperm concentration, live, dead and abnormal spermatozoa. Results showed that electrical conductivity, dissolved oxygen content, salinity, particularly sodium and calcium contents, and pH value in MW increased as compared to NMW. Ejaculate volume, mass motility, progressive motility, reaction time and sperm concentration were not affected by season, while live, dead and abnormal spermatozoa were affected (P≤0.001). Bucks consumed MW showed significantly improved (P≤0.001) physical semen characteristics in terms of increasing mass motility, progressive motility, sperm concentration, live spermatozoa and ejaculate volume as well as reaction time compared to NMW. Dead and abnormal spermatozoa were significantly (P≤0.001) lower in bucks received MW than in NMW. Consumption of MW led to an increase of red blood cells (RBC), hemoglobin (Hb) and hematocrit (HCT) as compared to NMW. However RBC, Hb and Platelet count (PLT) were considerably higher (P≤0.001) in winter than in summer. In general as, magnetic treatment improved water quality, physical semen characteristics and blood constituents in rabbit bucks.

With the global demand for rabbit meat steadily increasing, commercial rabbit breeding has become more dependent on artificial insemination (AI) rather than traditional natural mating. The study aimed to compare coconut milk (CME) as a novel extender for rabbit semen with Tris Yolk-Glucose (TYG) and Lactose Yolk-Citrate (LYC), to evaluate the in vitro presrevability of rabbit spermatozoa stored at 5°C for 48 hr. Twelve New Zealand White (NZW) rabbit bucks were used to collect semen. Semen was pooled, partioned to three portions and then diluted with one of three different extenders; Tris Yolk-Glucose, Lactose Yolk-Citrate or Coconut Milk. The dilution rate was 1:4 (volume: volume) and stored at 5°C for 48 hr., the experiment lasted for 8 weeks. Sperm motility, dead sperms, abnormal sperms and acrosome loss percentage were evaluated in chilled semen at 0, 24 and 48hr. of storage. The results showed that sperm motility was the highest at both 24 and 48hr. storage with TYG compared with LYC and CME without significant statistical differences between them. There were significant differences between extenders at 24hr. of storage with respect to the percentage of dead spermatozoa; the lowest percentages were recorded in semen stored with TYG. The CME extender gave significantly the highest values of abnormal sperms (29.16%) at 48hr. than TYG and LYC (23.16 and 26.33%, respectively). At 48hr. of storage, higher acrosome loss values were found with CME (27%) compared with TYG and LYC extenders (21.16 and 21.50%), respectively. The lowest values for the acrosome loss (21.16%), during the 48 hr., storage were obtained with TYG.