A crossbreeding experiment was carried out using four synthesized strains of chickens involving Matrouh (MT), Mandarah (MN), Inshas (IN) and Silver Montazah (SM). The experimental work was carried out in the Poultry Breeding Research Station at Inshas, Sharkia Governorate, Animal Production Research Institute (APRI), Agriculture Research Center, Ministry of Agriculture, Egypt. The main objectives of the present study were to estimate genetic parameters (additive genetic variance, heritability and predicted breeding values) and crossbreeding effects (i.e. direct additive effect, maternal additive effect, direct heterosis and maternal heterosis), as well as to evaluate the superiority of three-way crosses versus two-way crosses. A total number of 34 sires and 230 dams from MN strain and 32 sires and 194 dams from MT strain were used. Sires and dams of the two strains were chosen randomly from 250 cocks and 600 pullets to produce purebreds of MT and MN and first generation (F1) of crossbreds (½MN½MT and ½MT½MN). In second generation of crossbreds (F2), the crossbred hens of ½MN½MT were artificially inseminated from Inshas strain (IN), while the crossbred hens of ½MT½MN were artificially inseminated from cocks of Silver Montazah strain (SM) to produce three-way crossbreds (½IN¼MN¼MT and ½SM¼MT¼MN). The studied traits were: (1) Growth traits: (body weight at 0, 4, 8, 12 and 16 weeks of age and daily gains during the intervals of 0-4, 4-8, 8-12 and 12-16 weeks); (2) Sexual maturity traits: age (ASM) and body weight (BWSM) at sexual maturity and weight of the first egg (WFE); (3) Egg production traits: egg number (EN90D), egg mass (EM90D) during the first 90-days and egg number (EN120D), egg mass (EM120D) during the first 120-days of laying and (4) partial egg recording traits such as period (in days) in which first ten eggs were laid (PF10E), egg mass for first ten eggs (EMF10E), egg number (EN2DW) and egg mass (EM2DW) for two days per week, egg number (EN1WM) and egg mass (EM1WM) for one week per month, as well as clutch size (CS90D) and pause periods (PP90D) during 90 days and (CS120D) and (PP120D) during 120 days. The methods of single trait animal model and CBE software program were used. Results of this study could be summarized as follows: For growth traits: • Heritability estimates were 0.57, 0.26, 0.24, 0.22, and 0.25 for BW0, BW4, BW8, BW12, BW16, respectively, and 0.26, 0.16, 0.13 and 0.08 for DG0-4, DG4-8, DG8-12 and DG12-16, respectively • The ranges of predicted breeding values (PBV) for body weight and daily gains in MN strain were slightly higher than that in MT strain. For simple crossbreds, ranges in PBV recorded by ½MN½MT were slightly higher than those ranges recorded by ½MT½MN. For three-way crosses, the cross fathered by IN cocks and mothered by ½MN½MT had higher ranges in PBV for body weights than those cross fathered by SM cocks and mothered by ½MT½MN. • The generalized least square means (GLM) of growth and daily gains showed superiority of MN strain over MT chickens. The GLM for body weights at 0, 4, 8, 12 and 16 weeks of age were 31.2, 208.1, 440.4, 754.3 and 1005.7g in MN and 33.2, 206.5, 430.7, 725.9 and 989 g in MT, respectively. The differences between simple cross (MN×MT) and its reciprocal (MT×MN) were insignificant for body weights and daily gains, while, the differences between ½IN¼MN¼MT and ½SM¼MT¼MN crosses were significant for only traits of BW0, BW8, BW12, BW16 and DG0-4. • The GLM solutions of the direct additive effects (GI) for body weights and daily gains were highly significant (P≤0.01) and in favour of MT strain, being 4.0, -62.1, -38.5, -20.2 and -27.2% for BW0, BW4, BW8, BW12 and BW16, respectively and -74.6, -12.7, -9.3 and -37.8% for DG0-4, DG4-8, DG8-12 and DG12-16, respectively. • The GLM solutions of the maternal additive effect (GM) for body weights and daily gains in this study were highly significant (P≤0.01) and in favour of MN strain, being -10.2, 70.5, 49.1, 29.7 and 29.9% for BW0, BW4, BW8, BW12 and BW16, respectively, and 83.7, 17.7, 13.8 and 26.4% for DG0-4, DG4-8, DG8-12 and DG12-16, respectively. Results showed that effects of GM on body weights at early ages were higher than those at later ones. • The GLM solutions of direct heterosis (HI) were highly significant (P≤0.01) for all growth traits, the percentages of HI were -4.9, 53.0, 25.7, 12.3, 23.0, 64.0, 27.7, 29.1 and 49.8% for BW0, BW4, BW8, BW12, BW16, DG0-4, DG4-8, DG8-12 and DG12-16, respectively. • Most estimates of the maternal heterosis (HM) for body weights and daily gains were highly significant (P≤0.01). The percentages of HM were 0.9, 15.9, 11.3, 8.1 and 10.6% for BW0, BW4, BW8, BW12 and BW16, respectively, and 21.8, 7.2, 5.8 and 6.5% for DG0-4, DG4-8, DG8-12 and DG12-16, respectively. Egg production and partial egg recording traits: • The heritabilities of sexual maturity traits were moderate, being 0.23 for ASM, and high (0.69) for BWSM. While the estimates of heretability were low for egg production traits, being 0.08, 0.07, 0.07, 0.04 and 0.05 for WFE, EN90D, EM90D, EN120D and EM120D, respectively. • The ranges in predicted breeding values (PBV) for MT strain were slightly higher than those for MN strain ranging from 1.4 to 416 for sexual maturity traits, 6.5 to 306 for egg production traits and 1.1 to 88.4 for partial egg recording traits. • The ranges in PBV recorded by ½MN½MT were slightly higher than those ranges recorded by ½MT½MN. The cross fathered by IN cocks and mothered by ½MN½MT had higher ranges in PBV for sexual maturity and egg production traits than those cross fathered by SM cocks and mothered by ½MT½MN. • The GLM in MN strain was slightly earlier in ASM (157 days) than MT strain (158 days). The differences between simple cross of MN×MT and its reciprocal MT×MN were insignificant for ASM, BWSM and WFE. The differences between ½IN¼MN¼MT and ½SM¼MT¼MN crosses were insignificant for ASM. The crossbred of ½SM¼MT¼MN had significantly heavier BWSM (1626 g) than ½IN¼MN¼MT cross (1381 g). • The three-way crossbreds were found to start laying at an earlier ASM by 5 days than the F1 crosses (½MN½MT and its reciprocal ½MT½MN), as well as by 8 days than the two foundations. The three-way crosses were recorded the heaviest BWSM (P≤0.01). • The GLM in MN strain were slightly higher in EN90D and EN120D compared to MT strain and consequently recorded the heaviest EM90D and EM120D, respectively. • For partial egg recording, estimates of GLM showed that MN pullets laid the first 10 eggs in 15.7 days vs. 15.8 days for MT strain and has insignificantly heavier EMF10E (421 g) than MT strain (419 g). Also, MN pullets recorded egg number and egg mass for two days per week and for one week per month higher than those of MT pullets. • In crossbreds, ½MT½MN cross have shorter period in which first 10 eggs were laid than ½MN½MT cross. In addition, the ½MN½MT cross hens recorded egg number and egg mass for two days per week and for one week per month higher than those of ½MT½MN cross hens. • In three-way crosses, means of PF10E is the same for ½IN¼MN¼MT and ½SM¼MT¼MN crosses. The cross of ½IN¼MN¼MT has slightly higher EN2DW and EN1WM and heavier EM2DW and EM1WM than ½SM¼MT¼MN cross hens. • Clutch size which contains one and three eggs was the highest in purebreds compared to in crossbreds, average of clutch size that contains more than five eggs was higher in three-way cross than those in both simple cross and purebreds. • Three-way cross have the higher number of pause that equal one day than those in both simple crossbreds and purebreds, while purebreds have slightly higher number of pause that equal more than five days than simple crossbreds and three-way cross. • The generalized least square solutions of the direct additive effects (GI) on all traits of sexual maturity, egg production and partial egg recording were highly significant (P≤0.01) and in favour of MN strain, being -4.0, 9.1, 0.8, 5.4, 4.4, 3.6, 2.5, -11.1, 1.2, 3.9, 0.1, 6.3 and 1.9% for ASM, BWSM, WFE, EN90D, EM90D, EN120D, EM120D, PF10E, EMF10E, EN2DW, EM2DW, EN1WM and EM1WM, respectively. • Effects of GI on clutch size were in favour of MT strain except for clutch contains more than five eggs. The effect of GI was associated with a decrease in the pause periods for more than five days in favour of MT strain. • Most of solutions for maternal additive effect (GM) for traits of sexual maturity, egg production and partial egg recording were non-significant and ranged from low to moderate in favour of MT strain relative to MN strain being 2.9, 8.6, -3.8, -5.8, -6.8, -2.3 and -3.3% for ASM, BWSM, WFE, EN90D, EM90D, EN120D and EM120D, respectively and -10.8, 1.8, 1.9, 3.0, -2.8 and -2.4% for PF10E, EMF10E, EN2DW EM2DW, EN1WM and EM1WM, respectively. • The GM estimates for clutch size and pause periods were in favor of pullets mothered by MT. The percentages of GM ranged from -12.5% to 35.9% for clutch size, -28.5 to 17.6% for pause periods during the first 90 days, -40.2% to 39.4% for clutch size and -32.2% to 25.6% for pause periods during the first 120-days of egg production. • The generalized least square solutions of HI were highly significant for all egg production traits. The percentages of HI were -3.8, 28.5, 29.3, 28.8, 24.9, 19.7, 17.4, 17.9, 10.6 and 8.8% for ASM, BWSM, EN90D, EM90D, EN120D, EM120D, EN2DW, EM2DW, EN1WM and EM1WM, respectively. • The estimable solutions of HI and their percentages for clutch size traits were negative and significant for clutches containing one and three eggs (-13.1 and -6.6%) during the first 90 days and (-16.5 and -23.9%) during the period of 120-days of egg production, while they were positive and significant for clutches containing more than five eggs (14.2% during first 90 days and 57.4% during 120-days). • The percentages of HI were positive and highly significant for pauses periods of one day (21.4 and 38.4%) during first 90 days and 120-days of egg production, respectively, while they were negative and highly significant for pause periods of more than five days (-20.95 and -34.38%), respectively. • Most of the generalized least square solutions of HM were highly significant for egg production traits except for only BWSM and WFE. The percentages of HM were -2.6, 1.2, 0.03, 7.8, 8.2, 7.8 and 8.1% for ASM, BWSM, WFE, EN90D, EM90D, EN120D and EM120D, respectively. • Estimates of HM on most partial recording traits were highly significant and in favor of hens-mothered by crossbred dams. The percentages of HM were -10.5, 0.2, 7.2, 0.7, 3.2 and -10.5% PF10E, EMF10E, EN2DW, EM2DW, EN1WM and EM1WM, respectively • The estimates of HM for clutch size traits were negative and significant for clutches containing one egg (-11.2 and -15.5%) during first 90 days and 120-days of egg production, respectively, while they were positive for clutches containing five eggs (24.0 and 29.4%), respectively. • Estimates of HM were positive and significant for pause periods of one day during the first 90 days (17.3%) and during the period of 120-days of egg production (31.8%), while they were negative for pause periods for five days and for more than five days (-22.7 and -5.7%) during the first 90 days, respectively, (-21.7 and -6.9%) during the period of 120-days of egg production. • Finally, from this study it is recommended that: applying genetic selection at early ages may gave rapid improvement in growth of local strains, this may be encourage the poultry breeders to using it to be short the generation intervals and consequently save money, time and effort. • Based on superiority of the three-way versus two-way crosses for all the studied traits, one can recommend that the Animal Production Research Institution (APRI) can continue in production of three-way crosses to improve growth and egg production traits of local chickens.

A simple crossbreeding experiment was conducted between males of APRI line (A) and females of Moshtohor line (M) rabbits. These two lines are new synthetic lines raised in Egypt for meat production. APRI line was formed in the experimental stations belonging to the Animal Production Research Institute (APRI), Agricultural Research Center, Ministry of Agriculture, Egypt, while Moshtohor line was established in the Faculty of Agriculture, Benha University, Egypt. The crossbreeding scheme was performed during two consecutive production seasons (2015/2016 and 2016/2017) at the rabbitry of the Animal Production Department, Faculty of Agriculture, Benha University. The molecular analyses were conducted at the Central Laboratory, Faculty of Veterinary Medicine, Benha University. The main objectives of the present study were: (1) to estimate variance components, heritability, direct additive, maternal additive, and direct heterotic effects for post-weaning body weights at (4, 6, 8, 10 and 12 weeks of age) and daily weight gains (during the intervals 4-6, 6-8, 8-10 and 10-12 weeks) and semen quality traits (ejaculate volume, pH semen, sperms motility, sperms concentration, live and dead sperms, normal and abnormal sperms), (2) to use the PCR-RFLP technique to genotype the C>T SNP located in the promoter region of GH gene in five genetic groups of rabbits (APRI, Moshtohor, ½A½M, V line and Sinai Gabali) and (3) to detect the polymorphic associations between (C>T( SNP genotypes of GH gene and growth or semen quality traits. A total number of 1201 weaned rabbits fathered by 179 sires and mothered by 261 dams were used in quantitative and molecular analyses of growth traits, while a total of 1050 ejaculates collected from 149 bucks were used in semen quality traits. For detecting the associations between genotypes of GH gene and growth or semen traits, the method of Generalized Least Squares (GLS) was used. The most relevant results of this study could be summarized as follows: Quantitative genetic analyses for growth and semen quality traits: • Estimates of heritability for body weights and gains were mostly low or moderate and ranging from 0.06 to 0.18 for estimates obtained from VCE software and 0.09 to 0.18 for estimates obtained from TM software. The estimates for semen quality traits resulted from TM software were very low and ranged from 0.01 to 0.03, while those estimated by VCE6 software were relatively moderate and ranged from 0.12 to 0.20. • The generalized least square solutions of direct additive effects (GI) were significantly (P

The aim of this study was to detect genetic and phenotypic trends for test day milk, fat and protein yields in Frisian cattle in Egypt applying the random regression model (RRM) and determining the genetic and phenotypic trend. Data of 5237 test days (TD) milk yield traits were recorded for 953 Friesian cows, daughters of 208 sires and 944 dams from two herds belonging to the Animal Production Research Institute, Egypt. Ten-month classes of lactation days were considered for the test-day yields. The model included the random effects of direct additive genetic, permanent environment and error, while the fixed effects were herd, year and season of calving, parity which was modeled by orthogonal Legendre polynomials. The additive genetic variance estimates at first test day for milk, fat, protein yields and age at first calving traits were respectively 2.5kg, 10g, 2.5g and 1.5month increased until the fourth (5kg, 35g, 13g and 2months), decreased thereafter, reaching the lowest value at the tenth test day for milk but fat and protein yields were reaching the lowest value at the ninth test day. Age at first calving reached at the lowest value at the sixth test day (1month) then increased until tenth test day (8months). Heritability estimates at first test day were 0.12, 0.25, 0.25 and 0.05 for TDMY, TDFY, TDPY and AFC traits respectively and increased until the third test day for TDFY, TDPY and AFC but the TDMY trait reached to fourth test day which reached to 0.25, 0.32, 0, 32 and 0.08 for TDMY, TDFY, TDPY and AFC traits respectively then TDMY, TDFY TDPY decreased until tenth test day were (0.14, 0.25, 0.25) respectively, but AFC trait reached at the lowest value at sixth test day (0.04), and increased until the tenth test day which reached to 0.2. The range in phenotypic values of TDMY decreased from the first to fifth TDMY, were 26 to 18kg then it increased until tenth test day milk yield. The range in phenotypic values of TDFY and TDPY started by 44g and 18g respectively until the fourth test day which were 38g and 110g for TDFY and TDPY respectively then decreased until ninth test day which reached to 60g and 20g respectively. The genetic trends were slightly positive for all traits instead of protein trait indicating that the selection program performs correctly. For all traits, the phenotypic trends showing deteriorating trends indicating the presence of some environmental inadequacies especially for nutritional level. Records of 180 milking cows (38 local cows and 142 Friesian cows) raised at three experimental farms (Serw, Elkarda and Sakha) belonging to APRI, Ministry of Agriculture, Egypt were used to investigate association of prolactin and lactoferrin genes with the milk, fat, protein yields and age at first calving. Traits were milk, fat and protein yields and age at first calving. PCR-RFLP method was used to get single nucleotide polymorphism (SNP). Three enzymes were used to restrict DNA product: HinfI for Lactoferrin gene and Nael and Sm/l for prolactin gene. Fixed effects were herd-year-season, parity and H, M and S genotypes and the animal additive genetic effect and permanent environmental effect of cow were used as random effects. Genotypes from restriction enzyme HinfI were AA, AB, and BB. Genotype AB was the best one for milk, fat and protein yields and was not significant for AFC trait in Frisian. In local cattle, there were no significant differences among the three genotypes for milk traits but age at first calving trait differed significantly among the three genotypes. Genotypes from restriction enzyme Nael were CD and DD in Friesian. There were no significant differences between the two genotypes in Elkarada herd for milk and fat yield, but protein yield and age at first calving were affected. In local cattle, there were no significance differences among the two genotypes for milk traits but age at first calving was significantly affected. Genotypes from restriction enzyme Sm/l were GG, GT and TT. There were significance differences among the three genotypes in Friesian for milk traits, but age at first calving was not affected. In local cattle, milk, fat, and protein yield and age at first calving traits were not significantly affected.

A selection experiment was carried out for four generations (base and three selected generations) during the period from November 2011 to May 2015 in the Faculty of Agriculture, Benha University to improve egg production and quality traits in Benha chickens. A total of 18 cockerels and 180 pullets were selected according to their BLUP values for egg number during 90 days of laying from Benha base generation (G0). Each selected cock was mated with 10 selected hens and housed separately in breeding pen to produce the first generation of selection (G1). Then, selection was practiced for two generations to produce the 2nd (G2) and 3rd (G3) generations of selection. The pedigreed eggs from each individual breeding pen for the three selection generations (G1, G2 and G3) were collected daily for fifteen days and then incubated. The selection effects and correlated responses across generations were quantified and the genetic and phenotypic trends for egg production and quality traits in Benha chickens were clarified applying the updated approach of the animal model program of BLUPF90. Data of 756 hen produced by 69 sires and 484 dams were used to estimate heritabiliets, genetic and phenotypic correlations and BLUP estimates for age (ASM) and body weight at sexual maturity (BWSM), weight of the first egg (WFE), egg number (EN), rate of laying (RL), egg mass (EM) recorded during 90-days (EM90D) and 120-days (EM120D) of production after sexual maturity. Partial recording for egg number and egg mass during two days per week (EN2DW, EM2WM) and one week per month, (EN1WM, EM1WM) were identified. Pause periods in days during the first 90 days and 120 days (PP90D and PP120D) of egg production were recorded. A 4242 eggs were collected from all generations to study egg quality traits such as: egg weight (EW), albumen weight (AW), yolk weight (YW), shell weight (SW), Haugh unit (HU), egg shape index (ESI), albumen index (AI), yolk index (YI) and shell thickness (STH). Body weights of 4916 chicks were recorded at hatch (BW0), 4 weeks (BW4), 8 weeks (BW8), 12 weeks (BW12), and 16 weeks (BW16) of age, while the daily gains in weight for these chicks were calculated during the periods of 0-4 (DG4), 4-8 (DG8), 8-12 (DG12) and 12-16 (DG16) weeks of age. The aims of this study were: 1) to estimate the genetic parameters for egg production, egg quality and growth traits in such selection experiment, 2) to estimate BLUP values across generation, 3) to quantify the selection effects on different traits using generation contrasts estimated by generalized least square procedure, 4) to detect the phenotypic and genetic trends across generations, and 5) to estimate the direct selection response in egg number during the first 90-days of laying and the correlated responses in some egg and growth traits over three generations of selection in Benha chickens. The results of this selection experiment can be summarized as follows: First: Egg production traits: 1. The estimates of h2 were mostly moderate; being 0.27, 0.32, 0.42, 0.31, 0.34, 0.28, 0.33, 0.14 and 0.19 for egg production traits of ASM, BWSM, WFE, EN90D, EM90D, EN120D, EM120D, RL90D and RL120D, respectively. 2. ASM was closely positively genetically correlated with BWSM, WFE, PP120, with magnitudes of 0.65, 0.20, 0.25, respectively, but negatively correlated with EN120D (-0.32). Genetic correlation (rG) between EN90D and EM90D was 0.18 and 0.19 between EN120D and EM120D. The estimates of rG among EN90D & PP90D and EN120D & PP120D were -0.99 and -0.99, respectively. 3. The ranges in BLUP for most egg production and partial egg recording traits were moderate or high in all generations; the ranges in the control, 1st, 2nd, and 3rd generations being 5.8, 5.8, 5.5 and 5.5 days for ASM, 317, 337, 360 and 345 g for BWSM, 4.7, 4.1, 4.7 and 1.45 g for WFE, 26, 25, 26 and 24 egg for EN90D, 702, 700, 740 and 745 g for EM90D, 25, 27, 25 and 25 egg for EN120D and 744, 740, 765 and 765 g for EM120D, respectively. 4. The three generations of selection were superior in most egg production and partial egg recoding traits than the base generation (P

This study aimed: 1) to investigate the genetic improvement possibilities for test-day milk yield traits and their lactation curve parameters, 2) to determine the genetic and phenotypic trends for test-day milk, fat and protein yields in the Egyptian buffalo applying a random regression model (RRM) and finally 3) to construct sets of generating selection indices for milk production and persistency traits using eigenvector indices derived from RRM and comparing these results with the traditional selection index based on the breeding values of milk yield to the end of lactation. The data set used in this study contained 4971 test-day milk, fat and protein yield traits collected at monthly intervals (alternate a.m. / p.m. system) over the period from 1999 through 2009 and recorded for 691 Egyptian buffalo cows, daughters of 120 sires and 532 dams from four herds (El-Nattafe El-Gadid, El-Nattafe El-Kadim, Mahalet Mousa, and Gemmiza) belonging to the Animal Production Research Institute, Egypt.Ten-month classes of lactation days were considered for the test-day yields. Buffalo cows with less than 4 TD records per lactation were excluded from the data. The results of this study can be summarized as follows: (1) Lactation curve parameters: * Genetic and phenotypic lactation curve parameters were estimated using multiple-trait animal model including direct additive genetic, permanent environment and error as random effects and herd-test day, year and season of calving and parity as fixed effects as well as days in milk as a covariable. Test-day milk yield (TDMY) averaged 7.00 kg while TDFY and TDPY were 45.6 and 26.9 g, respectively. The means for initial milk yield (a), ascending slope (b), descending slope (c), persistency (P), and maximum milk production during lactation (Ymax) for milk were 5.59, 0.99, 0.19, 6.09 and 10.77 kg, respectively. The corresponding means for test-day fat parameters were 3.79, 1.06, 0.33, 2.38 and 4.68 g, respectively while those for test-day protein parameters were 3.31, 1.01, 0.32, 2.33 and 3.92 g, respectively. Peak test day (PY) milk, fat and protein were 54.97, 3.47 and 3.31 days in milk, respectively. Heritabilities estimated for TDMY, a, b, c, P, PY and Ymax were 0.22, 0.37, 0.38, 0.39, 0.37, 0.37 and 0.38, respectively. The corresponding heritabilities for TDFY parameters were 0.21, 0.41, 0.40, 0.39, 0.38, 0.36 and 0.42, while those for TDPY parameters were 0.22, 0.38, 0.40, 0.40, 0.38, 0.40 and 0.43, respectively. Genetic correlation between a and b curve parameters for TDMY was -0.8 and between a and c was -0.43. Ymax had a favorable high genetic correlation with TDMYs (0.87). PY had a relatively high genetic correlation with TDMY (0.48). TDMY was positively correlated with parameter a. Genetic correlation coefficient between TDMY and parameter a was moderate (0.31). Genetic and phenotypic correlations in milk yield between parameter b and c were 0.5 and 0.88, respectively. The rate of milk yield increase was negatively correlated with parameter P of lactation (-0.71). Genetic correlation in TDMY between PY and P was 0.87. A genetic correlation in TDMY between parameter c and PY was -0.48. The genetic correlation between TDMY and P was 0.52. Phenotypic correlations followed their corresponding genetic ones both in the value and direction. Genetic and phenotypic correlations between all yield traits (milk, fat and protein) were high (0.98 to 0.99) and so as the genetic and phenotypic correlations between curve parameters for milk, fat and protein (0.71 to 0.96). Genetic selection for curve parameters (a, P and Ymax) especially persistency would improve total milk, fat and protein yields. (2) Plotting the genetic and phenotypic trend: The genetic and phenotypic trends for test day milk, fat and protein yields in Egyptian buffalo were plotted applying the random regression model (RRM). The model included the random effects of direct additive genetic, permanent environment and error, while the fixed effects were herd-test day, year and season of calving and parity as well as days in milk as a covariable, which was modeled by orthogonal Legendre polynomials. The additive genetic variance estimates at the first test day for milk, fat and protein yields were 0.035kg2, 2.26 g2, 0.80 g2, respectively. Estimates increased until the fourth test (0.807kg2, 30.52g2, 12.52g2), decreased thereafter, reaching the lowest value at the ninth test day for milk and protein yields (0.238 kg2, 0.97 g2) and at the tenth one for fat yield (7.28 g2). Heritability estimated at first test day for milk yield was 0.05, increased until the fourth test day (0.30), and decreased thereafter and reached the lowest value at the tenth test day (0.06). The highest heritabilities were found to be 0.29 and 0.31 for fourth test day in fat and protein yields, respectively. The range in phenotypic values change decreased from 7.99 to 5.66kg, 53.37 to 35.07g and 30.86 to 21.54g, while the respective genetic values change increased from -0.22 to 0.17kg, -1.41 to 1.36g and -0.82 to 0.70g for milk, fat and protein yields, respectively. The genetic trends were slightly positive for all traits indicating that the selection program performs correctly. For all traits, the phenotypic trends showing deteriorating trends indicating the presence of some environmental inadequacies. (3) Selection indices constructed: The genetic gains were estimated for milk production and persistency, derived from random regression models (RRM), using eigenvector indices, and they were compared with the traditional selection index based on the breeding values of milk yield until 301 day of lactation (IMY301). Eigenvalues decomposition, the first and the second eigenvalues explained 73.1 and 22.9% of the variation of the random regression coefficients, respectively, whereas the 3rd and 4th eigenvalues accounted for a combined total of only 4.0%. Both of the first and the second eigenvalues explained 96.0% of the variation in the breeding goal of improving milk yield and persistency, suggesting that the use of the first two eigenvalues is sufficient. Individual eigenvector indices, genetic responses in total milk yield based on the first eigenvector index ( ) and that based on the conventional selection (IMY) have close gain of about 171 kg in each index. The second eigenvector index ( ) showed an increase in total milk yield (9.91 kg), and thus an increase in the persistency (0.86 kg). The Third eigenvector index ( ) decreased milk yield and persistency; these results suggest that the was highly related to the change of the lactation curve. The fourth eigenvector index ( ) showed an increase with small amount in milk yield (0.15 kg), but with decrease in persistency. Therefore, the combined results of both the and indices play a minimal role in the genetic improvement of milk yield and persistency. Sequential eigenvector indices, the second eigenvector index (I*2) is the best with the persistency (0.045 kg). The genetic gain in milk yield using the sequential eigenvector indices with 1, 2, 3 or 4 eigenvectors (I1, I2, I3, or I4, respectively) for improving milk yield alone was almost the same as the traditional selection index. The lactation milk yield and persistency are the two economically important traits in dairy production. If the breeding goal is to improve both milk yield and persistency, additional genetic gains in persistency and high genetic gain for milk yield could be obtained using the 2nd eigenvector index (I*2) with the relative economic value of 1:25 for TMY and persistency, respectively.

The experimental work of this study was carried out at the Poultry Research Farm, Department of Animal Production, Faculty of Agriculture, Benha University, Egypt, started in March 2008 and terminated in October 2010. Number of 1500 egg from White Leghorn and 300 eggs from Golden Montazah were chosen randomly and came from El-Takamoly chicken project, Alazab, El-Fayoum Governorate, Egypt. These eggs were incubated and hatched in the laboratory of Poultry Research Farm, Benha University, Egypt. The F2 chicken population was developed by crossing a broiler male strain Golden Montazah (GM) with a layer breed White Leghorn (WL). A total number of 18 cockerels and 180 pullets were chosen randomly from the GM and WL strains, respectively. Each cock was mated with 10 hens housed in separately breeding pen to produce F1 crossbred (½GM½WL), consequently inter-se matings were practiced for two generations to produce F2 with genetic structure of (½GM½WL)2. Also, purebreds from the two strains were produced. The pedigreed eggs from each individual breeding pen for the four mating groups, two foundations of GM and WL, two crossbreds of (½GM½WL) and (½GM½WL)2 were collected daily for fifteen days and then incubated. The studied traits were phenotyping growth, egg production and egg quality traits in the parental and F2 generations in such crossbreeding program, detect and localize QTL affecting growth and egg production and egg quality traits at different ages in the F2 population using specific microsatellite markers. Results obtained in this study could be summarized as follows: 1) The overall performance of the crossbred chickens of (1/2GM1/2WL) and (1/2GM1/2WL) 2 was found to be better than local chickens of GM. 2) The estimate in (½GM½WL) 2 for BW at hatch was higher than that at later ages except (at 12 weeks). The estimates are 0.51 for BW0, 0.52 for BW12 and 0.43 for BW16. The largest estimate for DG is 0.51 for DG812, 0.46 for DG04, 0.45 for DG48 and 0.47 for DG1216. 3) The genotypic and phenotypic correlations between growth traits in the F2 population in the QTL analysis were high positive correlations between each two growth traits. 4) The total chromosomal map length was 1901 cM ranging from 25 cM on chromosome 11 to 568 cM on chromosome 1, with an average marker spacing of 24.39 cM and that ranging from 7.8 cM on chromosome 8 to 24.3 cM on chromosome 1. 5) The flanking markers, position of QTL relative to the first marker (cM), F-ratio and significant for each QTL at chromosome-wise level along with the proportion of phenotypic variance explained by each QTL for body weights and daily gains in weight. 6) The position of QTL relative to the first marker (cM) indicated that QTL were located in the region of 0 to 502 cM, 0 to 233 cM, 0 to 179 cM and 12 to 555 cM for body weights at 4, 8, 12 and 16 weeks of age, respectively. For daily gains, the position of QTL relative to the first marker (cM) indicated that QTL were located in the region of 67 to 452 cM, 0 to 436 cM, 26 to 512 cM and 17 cM for daily gain intervals at 0-4, 4-8, 8-12 and 12-16 weeks, respectively. 7) For body weights evaluated in F2 cross, a total of 34 QTL were detected and these QTL were distributed over five distinct regions on 10 chromosomes. A total of 19 genome significant QTL that affecting body weight were located on seven macro-chromosomes (chromosomes 1, 2, 3, 4, 6, 8 and Z) and one micro-chromosome (chromosome 11). There was statistical evidence for two QTL on chromosome 4 for body weight at 8 and 12 weeks of age. A further 15 suggestive QTL were identified for body weight at different ages on chromosomes 2, 6, 9 and 13. 8) For daily body gains (DG), a total of 14 QTL were detected. These QTL were distributed over 7 distinct regions on 6 chromosomes. A total of 11 genome significant QTL that affected daily gain were located on five macro-chromosomes (1, 2, 3, 4 and 8). There was statistical evidence for two QTL on chromosome 4 for daily gains at 0-4, 4-8 and 8-12 weeks of age. A further three suggestive QTL were identified for daily gain at DG4-8 and DG0-4 on chromosomes 1, 8 and 13. 9) For confidence intervals of 4-week body weight, four significant QTL were located on chromosomes 2, 4, 6 and 11 at position of 292, 145, 29 and 0 cM, respectively, in which 95% confidence intervals were 43–367, 12–183, 0-42 and 0-10 cM, respectively. For 8-week body weight, another significant QTL was located on chromosomes 1, 3, 4, 11 and Z sex chromosome at position of 128 , 48, 0, 159, 0 and 117 cM, respectively with 76-219, 14-219, 0-69, 140-183, 0-57 and 14-127 cM of the 95% confidence interval. For 12-week body weight, six significant QTL were located on chromosomes 1, 3, 4, 8 and Z sex chromosome at position of 133, 37, 0, 179, 59 and 120 cM respectively, in which 95% confidence intervals were 67-227, 155-183, 0-177, 155-183, 12 and 8-127 cM, respectively. Moreover, at 16-week body weight significant QTL for was located on chromosomes 4, 8 and Z sex chromosome at position of 139, 12, and 125 cM, respectively, with 19-169, 0-86 and 0-125 cM of the 95% confidence intervals. 10) The largest proportion of the phenotypic variation explained by a QTL was 13.8% for 12-week body weight at 179 cM on chromosome 4. The proportions of phenotypic variation explained by significant and suggestive QTL for body weight at 4, 8, 12 and 16 weeks were 21.1, 30.8, 29.3 and 25.4%, respectively, while the proportions explained by significant and suggestive QTL for daily gain 0-4, 4-8, 8-12 and 12-16 weeks were 25.9, 29.1, 9.35 and 3.9%, respectively. The largest proportion of the phenotypic variation explained by a QTL was 8.88% for DG 4-8 week at 428 cM on chromosome 4. 11) The additive effects detected in the study showed positive values, as expected, while the dominance effects were generally negative or not significant with the exception of body weight at 4, 8, 12 and 16 weeks of age (QTL on chromosomes 2, 3, 4, 8, 11 and Z). The largest additive effect (369.6 ± 64.6 g) was for QTL of body weight at 16 weeks of age on chromosome 4 at 179 cM. The largest dominance effect (−188.1 ± 55.0 g) was for a QTL of body weight at 16 weeks on chromosome 4 at 139 cM. 12) The percentage of additive variance explained by each QTL for body weights ranged from 2.6% to 24.8%. While, the percentage of dominance variance ranged from -12.8 % to 15.7%. 13) The estimates of the additive effects explained by QTL were positive and of moderate magnitude ranging from 1.20 g on chromosome 2 to 1.77 g on chromosome 4 for DG 0-4 weeks, from 1.39 g on chromosome 1 to 3.89 g on chromosome 4 for DG 4-8 weeks, from 1.38 g on chromosome 2 to 3.84 g on chromosome 4 for DG 8-12 weeks and 1.21 g on chromosome 8 for DG 12-16 weeks. On the other hand, the estimates of dominance effects attributable to QTL were mostly negative, i.e. nine estimates out of 14 QTL were negative. The smallest dominant effect was recorded on chromosome 3 for DG 8-12 week (-2.09 g), while the largest dominant effect was recorded on chromosome 4 for DG 4-8 week (1.44 g). 14) The percentage of additive variance explained by each QTL for daily gains ranged at different intervals from 6.8% to 34.3%. While, the percentage of dominance variance ranged from -14.8 % to 12.7%. 15) The crossbreds were superior for egg production traits than purebreds. In general, results in the present study indicated that growth and egg production traits in local chickens in Egypt could be improved by crossbreeding. 16) For egg production and egg quality traits total chromosomal map length was 1949 cM ranging from 52 cM on chromosome 11 to 542 cM on chromosome 1, with an average marker spacing of 43.3 cM and that ranging from 15.3 cM on chromosome 4 to 71.5 cM on chromosome 6. 17) For confidence intervals of WFE, four significant QTL were located on chromosomes 2, 4, 8 and Z sex chromosome at position of 322, 156, 61 and 102 cM, respectively, in which 95% confidence intervals were 244-422, 144-185, 0-75 and 60-127 cM, respectively. 18) For AFE, two significant QTL was located on chromosomes 3 and Z sex chromosome at position of 189 and 128 cM, respectively with 155-200 and 65-135 cM of the 95% confidence interval. 19) The additive effect is −4.9 ± 1.8, 1.9 ± 0.6 and -0.5 ± 0.6 HU, QTL explains 6.5%, 4.3% and 4.5% respectively of the total phenotypic variance of the F2 population. For dominance effect is -3.5 ± 3.3, -3.1 ± 1 and 4.2 ± 1.1 HU. 20) The ES a QTL at the end of the chromosome Z was detected. The additive effect was −0.15 ± 0.04 that explains 5% of the total phenotypic variance. The confidence interval ranged from 77 to 134 cM with no dominance effect. 21) A QTL affecting WFE was found on chromosome 2, 4, 8 and Z. The additive effect is 85 ±17.6, 830 ±44.8, 109 ±22.9 and 95 ±30.5, QTL explains 1.4%, 6.9, 1.4% and 1% respectively of the total phenotypic variance of the F2 population. For dominance effect is 5 ±28.8, 164± 169.5, 36 ±46.9 and 15.4±8.5 respectively. 22) QTL effects on egg weight were found on the chromosome 4 and Z, explaining 13% and 5.6%, of the phenotypic variance, respectively. The additive effect is 3.2 ±0.5 and 1.5±0.3 g. For dominance effect is -0.8 ±0.6 g of chromosome 4 and with no dominance effect for chromosome Z. 23) QTL affecting egg number were found in the chromosome 4 and Z. There are two QTL on chromosome 4 explaining 7.2% of the phenotypic variance and 5% for chromosome Z. The additive effect is -6.5 ±1.9, -3.5±2.2 and -4.3± 1.3. For dominance effect is -0.9 ±2.3 and 14.3 ±4.5 of chromosome 4 and with no dominance effect for chromosome Z. 24) QTL effects on AFE were found on the chromosome 3 and Z, explaining 5% and 7.2%, of the phenotypic variance, respectively. The additive effect is -2.5 ±1.1 and 2.77 ±0.6 day. For dominance effect is 6.5 ±2.2 day of chromosome 3 and with no dominance effect for chromosome Z. 25) The QTL effects expressed as the percentage of phenotypic variance is explained by each QTL were mostly of considerable importance ranging from 1 to 6.9 % of the phenotypic variation for WFE, from 5 to 7.2 % for AFE from 5.6 to 13 % for EW, from 3.6 to 5 % for EN, from 4.3 to 6.5 % for HU and 5 % for ES. The largest proportion of the phenotypic variation explained by a QTL was 13% for EW at 191 cM on chromosome 4. The proportions of phenotypic variation explained by significant and suggestive QTL for WFE, AFE, EW, EN, HU and ES were 10.7, 12.2, 18.6, 12.2, 15.3 and 5%, respectively.

This work aimed to o study the effect of crossing between Gabali and Spanish V-line rabbits on genetic diversity and genetic stability for Moshtohor line (M-line) rabbits in later generation as an Egyptian line along with French Giant Papillon as a reference breed using two different molecular markers (16 Microsatellite markers and one SNP marker specific to one candidate gene). A total of one hundred animals were used in this study, 25 animals from each breed. The samples were taken randomly from two rabbitry (Moshtohor and Inshas). Genomic DNA was extracted from leukocytes and fur only from Papillon and PCR amplification was performed. The amplification products were resolved by electrophoresis; Images were captured and analyzed, then the results were statistically analyzed. In the present study, microsatellite markers were used to assess the genetic diversity and phylogenetic relationship of three rabbit breeds; Spanish V-line (V-line), Gabali (G) and Moshtohor line (M-line) in addition to French Giant Papillon (FGP) as a reference population with Sixteen microsatellite markers. All microsatellite loci typed were polymorphic. The average number of alleles per locus was 4.984±0.176 and ranging from 4 in (SAT2 and SAT7) to 10 in (SAT16 and SOL33). Mean observed heterozygosity was 0.651 ± 0.024 and that was ranged from 0.370 in SAT4 to 0.790 in SOL44 and D6Utr4. While, the mean expected heterozygosity was 0.711± 0.015 and that was ranged from 0.660 in SAT2 to 0.878 in SOL33. The average PIC was 0.7645 ranged from 0.595 at locus SAT2 to 0.861 at locus SOL33. All studied loci showed differentiation in Hardy-Weinberg Equilibrium, one hand the loci (SAT2,SAT3, SAT4, SAT5, SAT7, SAT12, SOL30 and D7Utr5) showed deviations with highly significant level from Hardy-Weinberg Equilibrium. On the other hand, the loci (INRACCDDV0003, SAT8, SAT16, SOL44, D3Utr2, SOL33 and D6Utr4 showed non-significant level from Hardy-Weinberg Equilibrium. These results might be attributed to disequilibrium created by selection which conducted on Moshtohor line to develop reproductive traits in the case of the first group of loci. While results of the other loci could be attributed to inbreeding practiced on pure breeds (Gabali and Papillon) which used in this study. The inbreeding coefficient of individuals relative to the total population (FIT) was 0.180. The overall within-population heterozygote deficit (FIS) was 0.083±0.043, and ranging from 0.266±0.055 in Gabali to -0.032±0.064 in M-line. The overall variation between populations (FST) was 0.107. The highest pairwise FST value was recorded between M-line and French Giant Papillon (0.157) while, the lowest pairwise FST value was recorded between Gabali and French Giant Papillon (0.056). The Neighbor-Joining tree showed close relation between V-line and M-line. The close relation between V-line and M-line which reflect high genetic similarity between this parent (V-line) and its progeny might be explained by selection processes which conducted in direction of V-line to improve reproductive traits specially litter traits in M-line. While the genetic distance between M-line and the other parent (Gabali) was 0.269. Also, analysis of population structure indicated that the V-line and M-line clustered together forming one admixed cluster. Single Nucleotide polymorphism (SNP) technique was used for association litter size in rabbit owing to existence SNP(G/A2464) located in the promoter region in Progesterone receptor gene (PGR) for detect different genotypes by PCR- RFLP analysis. Three genotypes (AA, GG and AG) were identified, counted, and the genotype and allele frequencies were calculated in three population (V-line, Gabali, M-line) in addition to French Giant Papillon as a reference population .The genotype frequency of AG ranged from (0.680) in V-line to (0.880) in French Giant Papillon, was higher than AA and GG in all populations. The A allele frequency was also higher than G allele in all populations except in M-line (A= 0.460), (G= 0.540). Chi-square tests showed that genotypic frequencies were not in Hardy-Weinberg equilibrium (P

The main objectives of this study were to assess the genetic diversity and phylogenetic relationship among three Egyptian rabbit breeds (Gabali, Baladi Red and Baladi Black) along with New Zealand White breed as a reference breed by using two different molecular markers (RAPD markers and microsatellite markers ). A total of one hundred and twenty animals were used in this study, 30 animals from each breed. The samples were taken randomly from pedigreed animals with the least relationship (avoiding full-sib and half-sibs) to decrease the genetic similarity between the genotyped animals. Genomic DNA was extracted from leukocytes and PCR amplification was performed the amplification products were resolved by electrophoresis; Images were captured and analyzed, then the results were statistically analyzed. In the present study, RAPD technique was used to assess the genetic variability and phylogenetic relationship among four rabbit breeds. Fourteen random primers were tested to amplify pooled genomic DNA from these breeds. Ten of them were chosen for further analysis, on the basis of the presence of reproducible and distinct RAPD profiles in one or more rabbit breeds. Out of 131 bands scored using these primers, 74(56.48%) were recognized as Polymorphic and 57 (43.52%) as monomorphic bands. The highest percentage of polymorphic bands was recognized for primers OPB-02 (94%) and OPB-07 (92%). While, the lowest percentage of polymorphic bands was recognized for primers OPA-02(16%) and OPF-12 (28%). The band sharing frequencies (BSF) was found higher between Baladi Red -Baladi Black (0.80± 0.038 ) , followed by Gabali - Baladi Black (0.71±0.079 ), New Zealand White- Baladi Black (0.70±0.096 ), New Zealand Whit- Baladi Red (0.69±0.088 )and the least BSF was found between New Zealand Whit- Gabali (0.64±0.081 ) . Overall, there was no significant difference (P>0.05) in BSF values between breeds. The highest genetic distance was found between Baladi Red -Baladi Black (0.87) followed by Gabali, Baladi Red (0.86), Gabali, Baladi Black(0.82), New Zealand White, Gabali (0.80), New Zealand White, Baladi Red (0.75) and the lowest genetic distance was found between New Zealand White, Baladi Black(0.73). One primer (OPA-20) in Gabali, two primers (OPA-02, OPB-14) in Baladi Red, three primers (OPA-02, OPB-14, OPA-20) in New Zealand White and Baladi Black were found to be specific for these breeds. The study suggests that RAPD can be successfully utilized for detecting genetic variation among the studied rabbit breeds. Also, microsatellite markers were used in the present study to investigate the genetic diversity of three native rabbit breeds; Gabali (G), Baladi Red (BR) and Baladi Black (BB) in addition to New Zealand White (NZW) as a reference population by using twelve microsatellite markers. All microsatellite loci typed were polymorphic. The average number of alleles per locus was 5.250 ± 0.232 ranging from 4 in SAT2 to 9 in SAT4 and SAT16 .Mean observed heterozygosity was 0.616 ± 0.021 ranging from 0.358 in SAT2 to 0.725 in SOL33 while the mean expected heterozygosity was 0.682± 0.021 ranging from 0.372 in SAT2 to 0.864 in SAT16. The average PIC was0.7096 ranging from 0.351 at locus SAT2 to 0.846 at locus SOL33.All studied loci except SAT7 and Sat2 showed deviation from Hardy-Weinberg Equilibriumwith highly significant level. The inbreeding coefficient of individuals relative to the total population (FIT) was 0.071. The overall within-population heterozygote deficit (FIS) was 0.068±0.035, ranging from 0.141±0.068in BaladiRed to 0.015±0.084in Baladi Black breed. The overall variation between populations(FST) was 0.138, The highest pairwise FST value was recorded between Baladi black and New Zealand white (0.071) while, the lowest pairwise FST value was recorded between Baladi Red and both of Gabali (0.038) and Black Baladi (0.039). The Neighbour-Joining tree showed close relation between Baladi Red and Baladi Black breeds. The close relation between Baladi Red and Baladi Black breeds may be explained as they had a common ancestor. Also, the three Egyptian breeds (BR, BB and G) are structurally separated from the NZW breed. Analysis of population structure indicated that the New Zealand White and Baladi Black were assigned independently into their respective clusters while the remaining two populations (Baladi Red and Gabali) were clustered together forming admixed mosaic cluster.

A crossbreeding experiment was executed between local strain of Golden Montazah (GM) and foreign breed of White Leghorn (WL) at the Poultry Research Farm, Department of Animal Production, Faculty of Agriculture, Benha University, Egypt, during the period from March 2008 to October 2010. After producing F1 (GM × WL) cross, inter-se mating was practiced to produce F2 (GM × WL)2, F3 ((GM× WL)2)2 crossbreds. Data on 996 pullets fathered by 79 sires and mothered by 441 dams produced from five genetic groups (two purebreds and three crossbreds) were used. It was intended to: estimate non-genetic effects (e.g. genetic group and year or month-year) affecting egg production and egg quality traits, estimate genetic parameters (additive genetic variance, permanent environmental variance, heritability and correlations (genetic and environment) for these traits in purebred and crossbred chickens, estimate crossbreeding effects (direct additive effects, direct and maternal heterosis, and direct recombination), and to try producing a synthetic line of chickens under hot climate conditions in Egypt. The studied egg production traits were: age (ASM) and body weight (BWSM) at sexual maturity, weight of the first egg (WFE), egg number (EN90D) and egg mass (EM90D) during the first 90-days, total egg number (EN120D) and total egg mass (EM120D) during the 120-days of laying, and rate of laying egg per day during 90 days (RL90D) and 120 days (RL120D). Partial recording traits such as period (days) in which first ten eggs were laid (PF10E), egg mass for first ten eggs (EMF10E), egg number (EN2D/W) and egg mass (EM2D/W) for two days per week, egg number (EN1W/M) and egg mass (EM1W/M) for one week per month, as well as pause periods during 90 days (PP90D) and 120 days (PP120D) were studied. Numbers of 6103 eggs were collected from all genetic groups to study egg characteristics. The studied egg quality traits were: egg weight (EW), albumen weight (AW), yolk weight (YW), shell weight (SW), Haugh units (HU), egg shape index (ESI), albumen index (AI), yolk index (YI) and shell thickness (STH). Single - trait animal model analysis was used to analyze the data. The results obtained can be summarized as follows: First: Egg production traits: 1. Breed of WL had superiority (P

The present study were carried out using records of 2257 off-spring of New Zealand White (NZW) and 1748 of Californian (CAL) rabbits collected from the experimental rabbitry of Faculty of Agriculture at Moshtohor, Zagazig University for four consective years started in September, 1989. Postweaning body weights at 5, 6, 8, 10 and 12 weeks and livabilities at the intervals of 5-6, 6-8, 8-10 and 10-12 weeks were studied. Variance components and heritabilities were estimated for these traits using Henderson’s method and Restricted Maximum Likelihood procedure (REML). Linear mixed models were used for analyzing such data. Transmitting abilities for sire and dam (with and without records) were estimated using two procedures. The first procedure was using the sire model (SM) or was using the dam model (DM). The second method was carried out by the animal model (AM). The results obtained could be summarized: (i) Means and Variation: Postweaning body weights and livabilities in NZW were slightly higher than those in CAL rabbits. For both breeds, percentages of phenotypic variation (V%) for body weights at earlier ages in NZW and CAL were higher than at older ages where V% ranged from 17.4 to 25.4% for body weights and 17.9 to 35.4% for livabilities in NZW, respectively and from 14.6 to 26.5% for body weights and 17.9 to 20.5% for livabilities in CAL, respectively. (ii) Sire variance components (2s): For both breeds (i.e. NZW and CAL), sire variance components estimated using Henderson’s and REML were low. Percentages of sire component of variance using REML were higher than those obtained using Henderson’s method for most postweaning body weights and livabilities. For both methods, percentages of 2s for postweaning body weights were relatively higher in CAL than those obtained in NZW. In NZW, they averaged 6.4 and 1.9% for body weights and livabilities, respectively using Henderson’s method vs 7.9 and 2.8 % in CAL in the same order. The percentages of 2s in NZW using REML method averaged 9.2 and 0.9% for body weights and livabilities, respectively vs 11.9 and 3.6% for respective traits in CAL. (iii) Dam variance components (2d): Generally, dam components of variance (2d) estimated by REML were relatively higher than those obtained by Henderson’s method. For both methods (Henderson and REML), percentages of 2d for postweaning body weights and livabilities were higher in NZW than in CAL rabbits. They averaged 15.2 and 5% for body weights and livabilities in NZW rabbits, respectively vs 14.2 and 4.0% in CAL rabbits. With NZW rabbits, percentages of 2d using Henderson’s method ranged from 14.1 to 16.5% for body weights and 0.0 to 11.8% for livabilities, while the respective traits ranged from 17.9 to 23.1% and 0.1 to 13.9% when using REML method. (iv) Sire heritability h2s: Estimates of h2s obtained using REML method were higher than those obtained using Henderson’s method for most postweaning body weights and livabilities in both NZW and CAL. With NZW, estimates of h2s obtained using Henderson’s method ranged from 0.177 to 0.452 with an average of 0.256 for body weights and from 0.006 to 0.177 with an average of 0.069 for livabilities. While they ranged from 0.258 to 0.354 with average 0.393 for body weights and from 0.043 to 0.150 with an average of 0.103 for livabilities in CAL rabbits. Estimates of h2s when using REML in NZW ranged from 0.228 to 0.718 with an average of 0.379 for body weights and from 0.002 to 0.112 with an average of 0.034 for livabilities, while the respective estimates ranged from 0.266 to 0.552 with an average of 0.549 and from 0.055 to 0.177 with an average of 0.1 in CAL. (v) Dam heritability: Estimates of h2d obtained using REML method were higher than those obtained using Henderson’s method for most postweaning body weights and livabilities in both NZW and CAL. With NZW, estimates of h2d obtained using Henderson’s method ranged from 0.565 to 0.660 with an average of 0.608 for body weights and from 0.002 to 0.428 with an average of 0.202 for livabilities. While they ranged from 0.5 to 0.605 with average 0.567 for body weights and from 0.043 to 0.288 with an average of 0.165 for livabilities in CAL rabbits. Estimates of h2d when using REML in NZW ranged from 0.716 to 0.925 with an average of 0.815 for body weights and from 0.004 to 0.569 with an average of 0.209 for livabilities, while the respective estimates ranged from 0.544 to 0.830 with an average of 0.732 and from 0.004 to 0.230 with an average of 0.111 in CAL. (vi) Sire transmitting ability (STA): The ranges in estimates of STA for body weights in NZW rabbits at 5, 6, 8, 10 and 12 weeks were 110.9, 77.9, 127.3, 560.0 and 291.1 grams using the sire model (SM with A-1 ) vs 41.2, 28.7, 35.2, 139.5 and 206.5 grams using the animal model (AM) in the same order. For livabilities in NZW, the ranges in STA were 1.6, 11.7, 1.7 and 0.3% at 6, 8, 10 and 12 weeks of age when using the sire model vs 0.5, 2.2, 0.8 and 0.2% in the same order. In CAL rabbits, the ranges in estimates when using the sire model were 205.5, 209.0, 267.5, 239.1 and 199.2 grams for body weights at 5, 6, 8, 10 and 12 weeks, repectively vs 216.1, 181.4, 213.5, 207.6 and 232.7 grams when using the animal model. For livabilities in CAL rabbits, they were 5.5, 13.8 and 5.1% at 6, 8 and 12 weeks when using the sire model vs 3.8, 12.6 and 4.1% when using the animal model. For all sires list in both breeds, the largest ranges in STA were obtained when using the sire model in most traits followed by the animal model. Generally, ranges in estimates of STA in both methods of sire evaluation were relatively higher in CAL rabbits than those recoded in NZW rabbits for most body weights, while the reverse trend was observed for livabilities. In both two methods of sire evaluation, CAL rabbits recorded generally the largest ranges in estimates of STA followed by NZW rabbits for most traits studied when considering all the sires or the top 10% of sires. Ranges in estimates of transmitting abilities for dams of sires (animals without records) were lower than those obtained for transmitting abilities of sires (animals with records) in most traits. About 50% of the sires recorded positive transmitting abilities. For most traits studied in both methods of sire evaluation numbers and percentages of sires with transmitting abilities of positive signs in CAL breed were relatively higher than in NZW breed. The overall ranking of sires changes much between both methods of sire evaluation. (vii) Dam transmitting abilities (DTA): The ranges in estimates of STA for body weights in NZW rabbits at 5, 6, 8, 10 and 12 weeks were 307.9, 333.4, 324.3, 478.7 and 446.2 grams when using the dam model (DM with A-1 ) vs 137.8, 131.5, 143.6, 214.5 and 241.1 grams using the animal model (AM) in the same order. For livabilities in NZW, the ranges in DTA were 4.7, 40.2 and 0.4% at 6, 8 and 10 weeks of age when using the dam model vs 5.0, 22.7 and 0.6 when using the animal model in the same order. In CAL rabbits, the ranges in estimates when using the dam model were 197.2, 276.6, 278.7, 284.6 and 320.3 grams for body weights at 5, 6, 8, 10 and 12 weeks, repectively vs 197.2, 154.7, 167.7, 172.4 and 186.2 grams when using the animal model. For livabilities in CAL rabbits, they were 0.4, 11.6, 8.0 and 16.1% at 6, 8, 10 and 12 weeks when using the dam model vs 11.4, 5.5, 5.0 and 4.2% when using the animal model. For all dams list in both breeds, the largest ranges in DTA were obtained when using the dam model in most traits followed by the animal model. Generally, ranges in estimates of DTA in both methods of dam evaluation were relatively higher in NZW rabbits than those recoded in CAL rabbits for most body weights. In both two methods of dam evaluation, NZW rabbits recorded generally the largest ranges in estimates of DTA followed by CAL rabbits for most traits studied when considering all the dams or the top 30% of dams. Ranges in estimates of transmitting abilities for sires of dams (animals without records) were lower than those obtained for transmitting abilities of dams (animals with records) in most traits. About 50% of the dams recorded positive transmitting abilities. For most traits studied in both methods of dam evaluation numbers and percentages of sires with transmitting abilities of positive signs in CAL breed were relatively higher than in NZW breed. The overall ranking of dams changes much between both methods of dam evaluation.

The present field data were collected from an investment company of rabbits in Ismalia governorate for three years (1987, 1988 and 1989). Two exotic breeds of New Zealand White (NZW) and Californian (CAL) raised under the Egyptian commercial conditions were included in the investigation. Data on 4702 litters was used to evaluate genetically some litter traits and reproductive intervals for these two breeds. The traits investigated were litter size at birth (LSB), number born alive (NBA), number born dead (NBD), litter size at weaning (LSW), number dead at weaning (NDW), litter weight at weaning (LWW) and average bunny weight at weaning (AWW), while reproductive traits included number of services till conception (NSC), days open (DO) and kindling interval (KI). Variance components and sire heritabilities within breed and parity were estimated for these traits using Henderson method and Restricted Maximum Likelihood (REML). A comparison between estimators obtained from the two methods was attempted. A linear mixed models were used for analyzing such data. The results obtained could be summarized as: (i) Litter traits The performance of litter traits within parity for NZW and CAL rabbits did not show any definite pattern. The performance of the first two parities was the best for litter size at birth and number born alive, whereas litter size at weaning of the second and third parities were the best. The number dead either at birth or at weaning was maximum in the first parity and in later ones (from six and later parities). The performance of NZW does at birth and at weaning was slightly higher than those of CAL does with values of 8.4 vs 7.8, 7.4 vs 6.8, 1.95 vs 1.45, 5.6 vs 5.7, 2983 vs 2868 and 534 vs 512 for LSB, NBA, NBD, NDW, LSW, LWW and AWW, respectively. For both breeds, the percentages of phenotypic variation (V%) for litter traits were generally high and ranged from 15.5 to 38.7% at birth and from 6.9 to 137% at weaning. Litter traits at birth and at weaning were not significantly affected by sire of doe, whereas they were significantly affected by year-season effect. (ii) Reproductive traits Reproductive performance within parity for both breeds did not show any clear pattern. The averages were 1.6 for NSC, 18.8 day for DO and 48.9 day for KI. The reproductive performance of NZW does were generally better than those of CAL does with averages of 18.1 vs 19.5 days for DO and 47.9 vs 49.9 days for KI. The percentages of phenotypic variation (V%) for reproductive traits were high and ranged from 16.3 to 53.9%. The phenotypic variability of reproductive traits in NZW rabbits were generally higher than those in CAL rabbits. These estimates were 40.9 vs 38.9% for NSC, 53.9 vs 46.5% for DO and 17.2 vs 16.3% for KI in NZW and CAL rabbits, respectively. Reproductive traits were not significantly affected by sire of doe and also most of these traits were not significantly affected by year-season effect. (iii) Additive genetic variance The sire of doe has inconsistent effect on litter traits and reproductive intervals in different parities. For both breeds, estimates of sire variance component within parity were low and ranged from 3.6 to 6.8% for LSB, 1.8 to 3.5% for NBA, 1.2 to 5.7% for NBD, 2.6 to 6.4% for NDW, 1.1 to 3.3% for LSW, 0.8 to 4.3% for LWW and 4.7 to 6.2% for AWW. The estimates for reproductive performance were also low and ranged from 0.9 to 3.0% for NSC, 1.3 to 3.9% for DO and 1.6 to 2.3% for KI. The additive genetic variance for litter traits and reproductine intervals obtained from using Henderson method in NZW rabbits were generally higher than those in CAL rabbits in almost traits. The estimates were 5.9% vs 3.6% for LSB, 2.3% vs 1.8% for NBA, 5.7% vs 1.2% for NBA, 6.4% vs 2.7% for NDW, 5.7% vs 4.7% for AWW, 2.8% vs 2.3% for DO and 2.3% vs 2.1% for KI. The same notations were also observed when using REML procedure. Sire variance components resulted from REML procedure had larger estimators in 50% of the traits than those obtained using Henderson method. The two procedures gave nearly the same estimates in 20% of the traits, while there was unexpected increase in estimates of Henderson than in REML by only 30% of the traits. (iv) Heritabiltiy For both breeds, sire heritabilities (h2) estimated using Henderson’s method within parity ranged from 0.011 to 0.235 for LSB, 0.069 to 0.153 for NBA, 0.056 to 0.31 for NBA, 0.069 to 0.138 for NDW, 0.045 to 0.131 for LSW, 0.031 to 0.258 for LWW, 0.137 to 0.248 for AWW, 0.032 to 0.140 for NSC, 0.08 to 0.155 for DO and 0.058 to 0.091 for KI. The sire heritabilities estimated using Henderson method within parity for litter traits in NZW rabbits were generally larger than those in CAL rabbits in almost traits. The estimates were 0.235 vs 0.144 for LSB, 0.092 vs 0.069 for NBA, 0.096 vs 0.069 for NDW, 0.219 vs 0.187 for AWW, 0.114 vs 0.081 for DO and 0.091 vs 0.085 for KI. The same trend was also observed for h2 estimated using REML method. Comparing h2 estimated using Henderson’s method with REML procedure, estimates show that REML had larger estimates than those for Henderson method in 45% of the traits. The two procedures gave nearly the same estimates in 5%, while there was unexpected increase in estimates of Henderson than in REML by 50% of the traits.

Purebred cows of local cattle (Domiati) and three European breeds (Friesian, Dairy Shorthorn and Jersey) along with their up-graded crosses resulting from up-grading of Domiati cows with bulls of these European breeds, were used to quantify the heterotic components of direct additive effect (GI), Maternal additive effect (GM), direct heterosis (HI), maternal heterosis (HM), direct recombination loss (RI) and maternal recombination loss (RM) for milk traits in three up-grading trials raised in hot climate condition. Data of each crossbreeding trial were analysed separately using mixed model procedure. The traits included were initial 90-day milk yield (M90), 305-day milk yield (M305), total milk yield (TMY), lactation period (LP), dry period (DP), 305-day milk yield divided by calving interval (MCI1), and total milk yield divided by calving interval (MCI2). For milk traits, foreign breeds (Friesian, Shorthorn and Jersey) always surpassed Domiati breed in their individual (direct) GI and maternal GM additive effects. For milk production traits, foreign breeds (Friesian, Shorthorn and Jersey) always surpassed Domiati breed in their direct (GI) and maternal (GM) additive effects. For most traits, estimates of GI and GM in Friesian trial were higher than those of GI and GM in Jersey and Shorthorn trials. For DP, Friesian breed showed the lowest GI and GM, followed by Shorthorn and Jersey. Heterotic superiority (HI) of crossbred cows over their purebred parents are evidenced. In most milk traits, Jersey trial (Jersey, Domiati and their up-grades) showed higher estimates and percentages of HI then Friesian and Shorthorn trials. Results of heterotic maternity HM obtained in the three trials show the superiority of Friesian maternity for milk production followed by maternities of Shorthorn and Jersey in a descending order. A positive and significant RI and RM for these milk traits indicate that crossbred dams mothered heifers with higher milking ability than did purebred dams of European breed when both groups were mated to bulls of the same purebred Eropean breed. Insignificant negative estimates of RI for DP were observed. The insignificant effect of RI indicates that there should be little difference in heterosis as measured and expected in a particular cross. In the three trials, direct heterotic superiority (HI) of crossbred cows over their purebred parents are evidenced. In most milk production traits, Jersey trial showed higher estimates and percentage of HI than Friesian and Shorthorn trials. Positive estimates of HI for milk production traits ranged from 1.2 to 13.3% in Friesian trial, 1.0 to 26% in Shorthorn trial and 0.3 to 47.4% in Jersey trial. Results of heterotic maternity (HM) obtained in the three trials show that Friesian maternity for milk production ranked first, followed by maternities of Shorthorn and Jersey in a descending order. Estimates of HM ranged from 3.7 to 23.3% in Friesian trial, 1.8 to 20.1% in Shorthorn trial and 5.0 to 43.5 in Jersey trial. Estimates of HM for most milk production traits in up-grades of Friesian trial were generally higher than in up-grades of Shorthorn and Jersey trials. Also, Friesians and their up-grades recorded higher HM for LP along with favorable lower HM for DP. Estimates of RI and RM for milk production traits were positive and significant and indicating that crossbred dams mothered heifers with higher milking ability than did purebred Friesian dams where both groups were mated to the same purebred Friesian bulls. Insignificant negative estimates of RI for DP were observed. Genetic evaluation of each up-graded group relative to purebreds (i) Additive effect For the three milk production traits (M305, TMY and LP) in the three trials, estimates of GI and GM for each breed-group were in favour of the foreign breed, i.e. Friesian, Shorthorn and Jersey. Also, estimates of GI and GM increased with the increase of foreign blood from 1/2 to 15/16, i.e. breed group with blood proportion of 15/16 Friesian or Shorthorn or Jersey recorded the highest estimates of GI and GM relative to the proportion of 1/2 or 3/4 or 7/8. Percentages of additive effect relative to least-square mean of the trait (i.e. GI/LSM or GM/LSM) were high and increased with the increase of foreign blood from 1/2 to 15/16. In Freisian and Shorthorn trials, inter-se mating groups of (3/4E1/4D)2 and (7/8E1/8D)2 showed higher estimates of GI and GM than those of their corresponding breed groups of 3/4E1/4D and 7/8E1/8D. The inter-se matings in Shorthorn trial only had higher estimates of GI and GM than for all other breed groups in this trial. (ii) Heterotic effect For both estimates of HI + HM (i.e. total heterosis), the estimates in Friesian, Shorthorn and Jersey trials respectively averaged 8.6, 6.7 and 17.9% for 1/2E, 8.9, 6.7 and 8.4% for 3/4E, 4.0, 1.2 and 4.5% for 7/8E and 3.6, 1.6 and 2.1% for 15/16E. Estimates or percentages of heterosis (HI or HM or both together) decreased with the increase of the proportion of foreign blood from 1/2 to 15/16 in Friesian trial, 1/2 to 7/8 in Shorthorn trial and 1/2 to 15/16 in Jersey trial. A breed group with blood proportion of 3/4F in Friesian trial, (3/4S1/4D)2 in Shorthorn trial and 1/2J in Jersey trial recorded the highest total heterotic superiority, while 15/16F in Friesian trial, 7/8S in Shorthorn trial and 15/16J in Jersey trial recorded the lowest total heterotic superiority. Also, inter-se mating groups of (3/4E1/4D)2 and (7/8E1/8D)2 recorded higher heterortic superiority than groups of 3/4E1/4D and 7/8E1/8D, respectively. In the meantime, inter-se mating group of (3/4E1/4D)2 showed higher heterosis than group of (7/8E1/8D)2. For estimates of total heterosis (i.e. HI+HM) relative to total additive (i.e. GI+GM), the estimates in Friesian, Shorthorn and Jersey trials respectively averaged 14.9, 30.1 and 35.2% for blood proportion of 1/2E, 15.7, 25.1 and 18.9% for 3/4E, 6.3, 4.7 and 9.0% for 7/8E and 5.1, 4.7 and 3.8% for 15/16E. (iii) Recombination effect For the three milk production traits (M305, TMY and LP), estimates of RI for inter-se mating groups of (3/4E1/4D)2 and (7/8E1/8D)2 in Friesian and Shorthorn trials were higher than those estimates of HI. RI and RM for milk traits in these two crossbreeding trials decreased with the increase of foreign blood from 3/4F or 3/4S to 7/8F and 7/8S. Therefore, inter-se mating groups of (7/8E1/8D)2 showed lower recombination effect than groups of (3/4E1/4D)2. Percentages of recombination effect relative to additive effect (i.e. RI/GI or RM/GM or both RI+RM relative to GI+GM) were positive and higher in groups of 3/4E1/4D than in groups of 7/8E1/8D. In dairy industry, such favorable recombination effect in groups of 3/4E1/4D and 7/8E1/8D for milk traits indicate that epistatic recombination losses in these inter-se mating groups were negligible and therefore there is a potential advantage to use crossbred cows or dams including foreign blood (Friesian or Shorthorn) to develop parental strains to be used in crossbreeding stratification systems in Egypt. Methodology comparison of breed-group models with regression models The comparisons between the two analyses suggest that the additional genetic effects (e.g. nonlinear effects of additive x dominance and linkage) did not significantly reduce the error variance. For most traits in the first four lactations and all lactations, insignificant differences between the two analyses were observed, indicating that additive x dominance and linkage (i.e. non-linear effects) were not important in the two up-grading trials (F and S trials). Consequently, the amount of heterosis estimated for these different traits were basically due to dominance. Also, the present results reveal that prediction of different up-grades between Domiati and each of Friesian or Shorthorn or Jersey are similar and using any simple analysis of breed-group model or regression-analysis model is quite efficient, i.e. both analyses gave the same accuracy in estimating genetic components.

An experiment on New Zealand White (NZW) and Californian (CAL) rabbits was carried out to evaluate genetically some fur and postweaning growth traits of these two breeds raised under the Egyptian conditions. Data on 1234 offspring of NZW and 520 of CAL for postweaning fur traits along with 2291 offspring of NZW and 1628 of CAL for postweaning growth traits were collected from the experimental rabbitry of the Faculty of Agriculture at Moshtohor, Zagazig University, Banha Branch, Egypt for three consecutive years started in September 1989. Postweaning fur traits investigated were hair length and diameter, medulla diameter and percentage of medullation of down and guard hair. Postweaning growth traits investigated were body weight (at 5,6,8,10 and 12 weeks), daily gains (at the age intervals of 5-6, 6-8, 8-10 and 10-12 weeks) ,and livability (at the age intervals of 5-6, 6-8, 8-10 and 10-12 weeks). Variance components and sire heritabilities were estimated for these traits once by using Henderson's method and another time by using the Restricted Maximum Likelihood (REML). A comparison between estimators obtained from the two methods was attempted. Linear method mixed models were used for analyzing such data. Sire transmitting abilities (STA) for these traits were estimated using two procedures the first was the best linear unbiased predictor (BLUP) and the second was the Animal Model (AM). Estimates of variance components estimated by REML were used in both procedure. The results obtained could be summarized as: Most postweaning fur traits in CAL were slightly higher than those in NZW. The estimates at 8 and 12 weeks respectively, were of 2.37 vs 2.36 cm and, 3.05 vs 3.02 cm for hair length, 12.21 vs 12.18 *m, and 18.87 vs 18.83 *m for diameter of down hair , 62.28 vs 62.13 *m at 8 weeks for diameter of guard hair, 10.17 vs 10.15 *m, and 16.40 vs 16.35 *m for medulla diameter of down hair, 51.53 vs 51.41 *m at 8 weeks for medulla diameter of guard hair, 83.55 vs 82.17% and 82.57 vs 82.25% for percentages of medullation of down and guard hair at 8 weeks, respectively. Percentages of phenotypic variations in NZW and CAL for fur traits at earlier ages were slightly higher than at older ages with exception of hair length. For most fur traits, the variance components estimated using Henderson's 3 and REML methods in both breeds were low. Estimates of sire component of variance obtained using REML method for most fur traits in NZW and CAL rabbits are relatively higher than those obtained using Henderson's method. For fur traits except hair length in both breeds, sire heritabilities estimated using Henderson's and REML methods were low or somewhat moderate. For hair length in both breeds, heritabilities estimated using Henderson's and REML methods are generally moderate or high. In NZW rabbits, sire heritabilities estimated using Henderson's method were smaller than the corresponding estimates obtained by REML, while a reverse trend was observed for CAL rabbits. For both breeds and both ages, heritabilities estimated using Henderson's and REML methods from 0.139 to 0.962 vs 0.357 to 0.832 for hair length, 0.032 to 0.109 vs 0.038 to 0.304 for diameter of down hair, 0.038 to 0.058 vs 0.051 to 0.142 for diameter of guard hair, 0.041 to 0.129 vs 0.046 to 0.356 for medulla diameter of down hair, 0.042 to 0.070 vs 0.057 to 0.174 for medulla diameter of guard hair, 0.009 to 0.087 vs 0.008 to 0.132 for percentages of medullation of down hair and 0.033 to 0.050 vs 0.047 to 0.074 for percentages of medullation of guard hair. For most fur traits in both methods of sire evaluation, the largest differences were recorded by NZW and the lowest differences were observed for CAL. The STA estimated for NZW and CAL rabbits using BLUP are nearly similar to those estimated using Animal Model for fur traits except hair length . For STA estimated for all sires using BLUP and Animal Model in both ages of the study in NZW rabbits, there was a little average difference of 0.151 vs 1.53 cm for hair length, 0.95 vs 0.99 *m for diameter of down hair, 3.37 vs 3.45 *m for diameter of guard hair, 1.0 vs 1.03*m for medulla diameter of down hair, 3.47 vs 3.49 *m for medulla diameter of guard hair, 1.25 vs 1.68% for percentages of medullation of down hair and 0.93 vs 1.39% for percentages of medullation of guard hair. For BLUP method, the largest absolute differences in STA for most fur traits in NZW and CAL rabbits were recorded by the smallest number of sires. An opposite trend was observed by Animal Model procedure where the largest absolute differences were recorded by the largest number of sires. Among all sires, percentages of sires which had positive estimates of STA using BLUP and Animal Model in both breeds and both ages were, the largest average of percentages of positive estimates of STA recorded by Animal Model, followed by BLUP. Among all fur traits, the largest percent of positive STA was recorded for hair diameter of down hair followed by hair length, medulla diameter of down hair, medulla diameter of guard hair, while the lowest percent was recorded for hair diameter of guard hair.