Genetic parameters of body weight, egg production, and shell quality traits in the Shan Ma laying duck (Anas platyrhynchos).

Three hundred and four female ducks of the Chinese indigenous Shan Ma breed, progeny of 11 sires and 104 dams, were used to study laying traits. Among them, 264 ducks were used to study the egg shell quality traits of eggs laid at 300 days of age. The mean age at first egg was 109 days with an average egg weight of 49.6 ± 3.7 g. Between 210 and 300 days of age, egg weight increased from 65.0 ± 3.9 g to 67.0 ± 4.2 g and the mean of the number of eggs laid up to 300 days was 161 ± 15.0. Egg length was 59.57 ± 3.01 mm and egg width was 45.02 ± 1.98 mm, leading to a shape index of 1.32 ± 0.08. Egg shell thickness was about 0.31 mm whatever the shell region, and the breaking strength was 28.80 ± 8.29 N. The heritability's estimated using restricted maximum likelihood ( REML: ) methodology were high for egg weights (ranging from 0.43 to 0.61), intermediate for the number of eggs laid (ranging from 0.38 to 0.43), and low for the age at first egg (0.13). Heritability's for egg shell quality traits varied from 0.20 for the breaking strength to 0.44 for egg length, with in-between values of 0.28 for shell thickness and 0.34 for the shape index. The number of eggs laid was not genetically correlated with the age at first egg or egg weight, but was correlated with body weight (rg = +0.54 ± 0.23). High positive correlations were found between egg weight and body weight traits, and both of these traits (except egg weight at first egg) were highly and positively correlated with egg length and width. Breaking strength was genetically correlated with egg shell thickness (rg = +0.54 ± 0.19) and the shape index (rg = +0.71 ± 0.23). These results suggest that an efficient selection strategy could be implemented to improve the egg production of the pure Shan Ma duck line.

Selection for Duration of Fertility and Mule Duck White Plumage Colour in a Synthetic Strain of Ducks (Anas platyrhynchos).

A synthetic strain of ducks (Anas platyrhynchos) was developed by introducing genes for long duration of fertility to be used as mother of mule ducklings and a seven-generation selection experiment was conducted to increase the number of fertile eggs after a single artificial insemination (AI) with pooled Muscovy semen. Reciprocal crossbreeding between Brown Tsaiya LRI-2 (with long duration of fertility) and Pekin L-201 (with white plumage mule ducklings) ducks produced the G0. Then G1 were intercrossed to produce G2 and so on for the following generations. Each female duck was inseminated 3 times, at 26, 29, and 32 weeks of age. The eggs were collected for 14 days from day 2 after AI. Individual data regarding the number of incubated eggs (Ie), the number of fertile eggs at candling at day 7 of incubation (F), the total number of dead embryos (M), the maximum duration of fertility (Dm) and the number of hatched mule ducklings (H) with plumage colour were recorded. The selection criterion was the breeding values of the best linear unbiased prediction animal model for F. The results show high percentage of exhibited heterosis in G2 for traits to improve (19.1% for F and 12.9% for H); F with a value of 5.92 (vs 3.74 in the Pekin L-201) was improved in the G2. Heritabilities were found to be low for Ie (h (2) = 0.07±0.03) and M (h (2) = 0.07±0.01), moderately low for Dm (h (2) = 0.13±0.02), of medium values for H (h (2) = 0.20±0.03) and F (h (2) = 0.23±0.03). High and favourable genetic correlations existed between F and Dm (rg = 0.93), between F and H (rg = 0.97) and between Dm and H (rg = 0.90). The selection experiment showed a positive trend for phenotypic values of F (6.38 fertile eggs in G10 of synthetic strain vs 5.59 eggs in G4, and 3.74 eggs in Pekin L-201), with correlated response for increasing H (5.73 ducklings in G10 vs 4.86 in G4, and 3.09 ducklings in Pekin L-201) and maximum duration of the fertile period without increasing the embryo mortality rate. The average predicted genetic response for F was 40% of genetic standard deviation per generation of selection. The mule ducklings' feather colour also was improved. It was concluded that this study provided results for a better understanding of the genetics of the duration of fertility traits in the common female duck bred for mule and that the selection of a synthetic strain was effective method of improvement.

Selection and crossbreeding in relation to plumage color inheritance in three chinese egg type duck breeds (anas platyrhynchos).

In China and South East Asia, the duck (common duck) is important in egg production for human consumption. Plumage color is a breed characteristic and of economic importance, together with egg production. Our aim in this study was to investigate the inheritance of plumage color in three Chinese indigenous egg-type duck breeds, Shan Ma (S), Putian White (F) and Putian black (P), and some of their crossbreds. These three breeds have different plumage color and are used in crossbreeding. The crossbred laying ducks F×(P×S) and F×(S×P) showed highly improved laying ability but heterogeneous plumage color. Genotypes at four relevant loci were investigated by studying down color and pattern in ducklings after crossbreeding. F1 ducklings from the matings F×S and S×F, P×S, and S×P were classified into four classes of plumage color (the Shan Ma plumage color, black, white, or multicolored) over three generations. Parents were selected for the Shan Ma plumage color of their progeny. In the fourth generation, P male and P female ducks were selected according to the frequency of the desired class of plumage color (Shan Ma) of their F1 progeny to obtain the so-called "Brown Putian Ma duck". The Shan Ma duck genotype was identified as having the restricted mallard color pattern (M(R)M(R)), full expression of any of the patterns or colors (CC), no extended black (ee) and no brown dilution D (D). The Putian White genotype was recessive white (cc), no extended black (ee) and no brown dilution D (D). The Putian Black genotype exhibited full expression of extended black (E gene) and no brown dilution (CCEE D [D]). It was shown that F×S and S×F tests should be implemented to eliminate the recessive white c allele in the S line and the dominant extended black E allele in the F line. It was also shown that the Brown Putian Ma obtained from Putian Black, with no extended black genotype (ee), could be used to get rid of the black plumage (E gene) in the crossbred ducks. This could provide a solution for producing 3-way crossbred ducks Putian White×(Putian-Ma ×Shan Ma) and Putian White×(Shan Ma×Putian-Ma), with the desired Shan Ma feather color.

Inheritance of duration of fertility in female common ducks (Anas platyrhynchos) inseminated in pure breeding or in inter-generic crossbreeding with Muscovy drakes (Cairina moschata).

Ducks (common, Muscovy and mule ducks) are the third most important bird species in animal production for human consumption worldwide. Our study aimed to improve the efficiency of mule duck breeding, thus contributing to the efficiency of food production in general. In the common duck, females can be bred either with males of the same species (i.e. in pure breeding (PB) subscript p) or in inter-generic crossbreeding (CB; subscript c) with Muscovy drakes to produce the hybrid mule duck. The aim of the present study was to estimate the genetic parameters of several indicators of duration of fertility, considered to be a trait of the female duck, within and between breeding schemes and, in particular, to estimate the purebred-crossbred genetic correlation (rg pc). These indicators were maximum duration of fertility (MD), that is, the time interval between insemination and the last fertilised egg, the number of fertile eggs (F) and of hatched ducklings (H) after a single artificial insemination (AI), and the fertility rate over days 2 to 12 after AI (F 2,12), taking three sub-periods (F 2,4, F 5,8, F 9,12) into account. A total of 494 females and 2655 inseminations were involved. PB resulted in longer duration of fertility (MD p = 8.1 v. MD c = 6.4 days). Heritability (h 2) was higher for MD p (estimate ± s.e.: 0.27 ± 0.04) than for MD c (0.15 ± 0.04), but both traits were highly correlated with each other (rg pc = 0.85 ± 0.07). F p and F c had similar heritability (h 2 around 0.24) and displayed a high genetic correlation (0.78 ± 0.07). The same was true for H p and H c (h 2 around 0.17 and rg pc = 0.88 ± 0.05). The heritability estimates were 0.24 ± 0.03 for F 2,12p and 0.20 ± 0.04 for F 2,12c, with a 0.80 ± 0.07 genetic correlation between each other. Permanent environmental effects influenced MD p far less than MD c, F p less than F c, but H p and H c to the same extent. The high values for rg pc (>0.78) indicated that the same genes are involved in the duration of fertility for both PB and CB. Unlike CB, initial fertility for PB (F 2,4p) was not correlated to overall fertility rate and to duration of fertility and probably involves different genes, if any. In both breeding schemes, indirect selection on F would be better than direct selection on H to improve H, and easier to implement than selection on MD. Moreover, any gain in one breeding scheme will have its correlated counterpart in the other one, because of the high values of rg pc.

AFLP fingerprinting for paternity testing in ducks.

1. The accuracy and reproducibility of AFLP fingerprinting was investigated in the duck (Anas Platyrhynchos), using a multicolour fluorescent labeling technique. The fluorescent labelling fragments were separated on a capillary electrophoresis-base ABI PRISM 3100 Genetic Analyzer. 2. A total of 337 AFLP peaks with 103 of them being polymorphic markers were generated by 16 sets consisting of EcoRI/TaqI primer pair combinations. The number and size range of AFLP polymorphisms detected per primer pair varied from 3 to 11 and 58 to 290 bp, respectively. About 30.6% (103/337) of AFLP peaks were detected polymorphisms, with an average of 6.4 polymorphic markers per primer pair. 3. The clear polymorphic peaks were amplified with EcoR+AC/Taq+AC primer combinations. The AFLP peaks showed high reproducibility. From the family testing, we found that the fingerprints of all the offspring were derived from one or other parent. Therefore, we conclude that AFLP fingerprinting might be a suitable method for duck paternity testing.

Selection responses in duration of fertility and its consequences on hatchability in the intergeneric crossbreeding of ducks.

1. From 1992 to 2003, selected (S) and control lines (C) of the laying Brown Tsaiya duck (Anas platyrhynchos) were simultaneously maintained under the same standardised conditions of feeding and management. 2. The selection objective was to increase the number of fertile eggs after a single artificial insemination (AI) with pooled Muscovy semen. From generations G1 to G11, 2452 and 2022 female ducks, in S and C lines, respectively, were measured and recorded. In the S line, the percentage selected varied between 20.2 and 34.3% in females and between 7.2 and 20.8% in males. 3. Selection for number of fertile eggs had a correlated effect of increasing the parameter tau of the logistic curves which fitted the daily variations (d 2 to 15) in fertility or hatchability on the basis of eggs set. The differences S-C for the estimates of the times of half maximal fertility and hatchability increased by 0.41 and 0.37 d per generation between G1 and G11, respectively. 4. The highest increases of fertility per day rates after a single AI were observed between d 5 and 11. Moreover, in the selected line, fertility rate was higher than, or equal to, 90% in d 2 from G8. The same tendencies were observed for the changes in the evolution of hatchability on the basis of eggs set. 5. Selection increased fertility and hatchability according to the egg set rates, especially for d 2 to 8 after AI. Hatchability of fertile eggs was not impaired, confirming that selection for one AI per week was possible in this strain of laying ducks.

Investigation of chromosome abnormalities and early embryonic mortality in goose lines.

Early embryonic mortality and chromosome abnormalities were studied in three goose lines: Grey Landes (line 7), White Polish (line 4) and their synthetic line (line 9). Eggs laid at the beginning, in the middle and at the end of the laying season were set. At candling at 5th day after egg set, all eggs (2847) were examined and those showing no normal embryonic development were opened 2847. Dead embryos were classified phenotypically and karyotyped. The mean ratio of embryonic mortality (EM) among fertile eggs was 9.4%, 5.2%, 7.3% in the lines 4, 7 and 9, respectively. The mean ratio of embryos with chromosomal abnormalities (CA) among the dead embryos was 8.0%, 14.8% and 13.1% in the lines 4, 7 and 9, respectively. Gander effect and layer within gander effect on embryo mortality were significant, indicating genetic factors. Father and mother of the layer effects were also significant, showing family effects. Animals producing dead embryos and embryos with chromosome abnormalities in high proportion were selected. In the selected groups the mean EM was 17.7-22.9%, and the mean CA was 11.7-34.7% among the three lines. The repetition of CA was not observed in the reproductive season of following year, while animals repeated the high EM (repeatability coefficient of 0.54). This shows that some part of EM may be resulted from other genetic factors. Ganders and layers progeny of these selected animals showed also high EM. It was concluded that culling pairs giving high EM value in their embryos could increase the average level of embryo viability and that the study of genetic determinism of that trait should be continued in geese.

Heritabilities and genetic correlations of laying performance in Muscovy ducks selected in Taiwan.

1. Genetic parameters in the base population of a closed experimental strain of Muscovy ducks, selected for body weight at 10 weeks of age, were estimated from data in 8 successive generations, for the following traits: age at first egg (AGE1EGG), total number of eggs laid at 40 and 52 weeks of age (NEGG40 and NEGG52), number of eggs laid during 15 and 22 weeks in the first laying cycle (NEGG15W and NEGG22W), and their Box-Cox transformed data. 2. The method of multi-trait restricted maximum likelihood with an animal model was used to estimate genetic parameters. Only the results obtained with non-transformed data are shown. 3. Heritability estimates for laying performance showed moderate values, increasing little with age: 0.20+/-0.03 (AGE1EGG), 0.23+/-0.03 (NEGG40), 0.27+/-0.03 (NEGG52), 0.20+/-0.03 (NEGG15W), and 0.22+/-0.03 (NEGG22W). 4. Genetic correlations between laying traits were high. Genetic correlation between AGE1EGG and egg number was negative, it was positive between total numbers of eggs at 40 and 52 weeks and egg numbers in the first laying cycle. 5. Body weight at 10 weeks of age exhibited positive genetic correlations (0.46+/-0.06) with age at first egg and negative with egg production traits (-0.28+/-0.06 to -0.41+/-0.06). 6. The cumulated predicted genetic gains, after 7 generations of selection, expressed per genetic standard deviation unit (sigma(g)) were 0.06 sigma(g), 0.07 sigma(g), 0.17 sigma(g), 0.23 sigma(g), and 0.25 sigma(g) for AGE1EGG, NEGG40, NEGG52, NEGG15W, and NEGG22W, respectively. 7. Selecting Muscovy ducks to improve laying in Taiwanese climatic conditions would be possible using the number of eggs laid up to 52 weeks of age as the selection criterion. Because unintended selection effects for laying traits were present, the selection experiment for body weight at 10 weeks of age was not antagonistic with laying traits.

Female-specific DNA sequences in geese.

1. The OPAE random primers (Operon Technologies, Inc., CA) were used for random amplified polymorphic DNA (RAPD) fingerprinting in Chinese, White Roman and Landaise geese. One of these primers, OPAE-06, produced a 938-bp sex-specific fragment in all females and in no males of Chinese geese only. 2. A novel female-specific DNA sequence in Chinese goose was cloned and sequenced. Two primers, CGSex-F and CGSex-R, were designed in order to amplify a 912-bp sex-specific polymerase chain reaction (PCR) fragment on genomic DNA from female geese. 3. It was shown that a simple and effective PCR-based sexing technique could be used in the three goose breeds studied. 4. Nucleotide sequencing of the sex-specific fragments in White Roman and Landaise geese was performed and sequence differences were observed among these three breeds.

Genetic parameters of reproductive traits in Brown Tsaiya ducks artificially inseminated with semen from Muscovy drakes.

A selection experiment on maximum duration of fertility of Brown Tsaiya ducks after artificial insemination (AI) with pooled Muscovy semen has been conducted since 1992. The Brown Tsaiya ducks were divided into two lines: a control line (T) with no selection and a selected line (S). The traits measured were the number of eggs set that were laid from Days 2 to 15 after one AI (NES), the number of fertile eggs at candling (NEF), the total number of dead embryos (NED), the maximum duration of fertility (MD), and the number of hatched mule ducklings (NEH). The selected trait was NEF. Six generations with a total of 2,127 females were measured. The variance components were estimated for each line in a multiple-trait animal model, using the restricted maximum likelihood (REML) methodology, which yields estimates free of bias caused by selection and inbreeding. Estimates of the heritability and genetic correlation from the two lines were very similar. Heritabilities in the S and T lines, respectively, were 0.14 and 0.10 for NES, 0.30 and 0.26 for NEF, 0.06 and 0.09 for NED, 0.28 and 0.21 for MD, and 0.18 and 0.19 for NEH. High and favorable genetic correlations existed between NEF and MD (0.96 and 0.92), between NEF and NEH (0.86 and 0.91), and between MD and NEH (0.90 and 0.82). The results suggested that selection for NEF could improve the maximum duration of fertility, but it could be useful to check the estimates of genetic parameters in a meat-type female duck.

Estimation of genetic parameters for growth, carcass and overfeeding traits in a white geese strain.

In an experimental strain of white plumage geese created in 1989, two experiments were carried out from 1993 to 1995 in order to estimate genetic parameters for growth, and carcass composition traits in non-overfed animals, and genetic parameters for growth and fatty liver formation in overfed animals. Four hundred and thirty-one non-overfed animals were bred and slaughtered at 11 weeks of age; they were measured for forearm length, keel bone length, chest circumference and breast depth before and after slaughtering. The carcasses were partly dissected in order weigh breast, breast muscle and skin + fat, and abdominal fat. Four hundred and seventy-seven overfed animals were slaughtered at 20 weeks of age; they were measured for "paletot" (breast meat, bone and meat from wings, bone and meat from thigh and legs) weight and liver weight. In these two experiments, the weights had moderate to high heritability values. Breast depth measured on live animals showed a low heritability value. In overfed animals, liver weight showed a high heritability value. Liver weight could be increased by selection without a great effect on "paletot" weight. Thus, obtaining a white plumage geese strain for fatty liver production by selection would be difficult because only 20% of overfed animals had fatty liver. The results did not allow to conclude on the influence of selection on liver weight on carcass traits such as muscle or fatty tissue weight.

Heritabilities and genetic correlations of body weights and feather length in growing Muscovy selected in Taiwan.

1. Heritabilities and genetic correlations in the base population of a closed strain of Muscovy duck, moderately selected for body weight at 10 weeks of age, have been estimated from the data of 9 successive generations for the following traits: male and female body weight at 10 and 18 weeks of age (BW10m, BW18m, BW10f, BW18f) and length of the 8th primary feather at 10 weeks of age (F110m, F110f). 2. Multivariate REML with an animal model was used, pooling data from the 9 generations (3283 and 3289 male and female offspring respectively). The same trait expressed in male and female was considered as 2 different traits. 3. The 8th primary feather was longer in females than in males by 6% to 22% at 10 weeks of age. Body weight was heavier in males than in females by 42% to 58% at 10 weeks of age and by 57% to 75% at 18 weeks of age. 3. The heritability estimates for body weight traits showed moderate values, being a little higher for females than for males at the same age, increasing with age from h2=0.24 at BW10m to h2=0.43 at BW18f. 4. The heritability estimates for feather length showed that a greater response would be obtained in selection for male feather length (h2=0.37) than for female length (h2=0.14). Both have high genetic correlations with body weight so they could be indirectly improved. 5. Heritabilities of the difference in body weights between males and females at 10 weeks (h2=0.07) and 18 weeks of age (h2=0.10) were small, as well as for feather length (h2=0.10). It would probably be difficult to modify sexual dimorphism in body weight through selection. 6. Genetic correlations between BW10m, BW18m and BW10f, BW18f were respectively r(g)=0.77 and r(g)=0.80. They were larger for body weight at the same ages between males and females, r(g)=0.90 (r(g)=0.88 between F110m and F110f). Body weight in males and females at the same age should be better considered as 2 different traits in a selection programme. 7. The cumulated predicted genetic gains expressed per unity of the genetic standard deviation (sigma(g)) over the 8 generations of selection were 1.3 sigma(g) and 1.4 sigma(g) respectively for the BW10m and BW10f. The predicted correlated responses were 1.2 sigma(g) for body weights at 18 weeks of age, 0.9 sigma(g) and 0.7 sigma(g) for F110f and F110m respectively.

Crossbreeding effects on reproductive traits in two strains of duck (Anas platyrhynchos): brown Tsaiya and Pekin.

1. The reproductive performances of 211 domestic duck females (Anas platyrhynchos) from the pure breeds Brown Tsaiya (Ts) and Pekin (Pk) and their two reciprocal crossbreds were analysed. 2. Differences in the 4 genotypes, additive direct and maternal crossbreeding effects and heterosis were estimated on the following traits: age at first egg, egg production to the ages of 30, 35, 40 and 52 weeks of age, egg weight at 30 weeks of age, and (egg) fertility by artificial insemination with Muscovy drakes' pooled semen. 3. Egg production up to 52 weeks of age was higher in Ts than in Pk (respectively 214 +/- 7 and 150 +/- 8 eggs), but not statistically different from that of the reciprocal crossbreds. The ratio of settable eggs to total eggs was nearly 90%, without any difference between genotypes. 4. Average egg weight at the age of 30 weeks was 75 +/- 0.9 g for Pk, which was higher than the corresponding values for Ts (62 +/- 0.8 g), but not significantly different from the crossbreds. 5. An effect of genotype was found on egg fertility: the Pk strain exhibited the lowest value, 71.3 +/- 3.1% compared with 75.9 +/- 2.1% for Ts, 80.6 +/- 2.6% for Ts x Pk and 74.6 +/- 1.9% for Pk x Ts. 6. Crossbreeding genetic variables showed favourable direct genetic effects for egg production and (egg) fertility in Ts, while Pk had favourable direct genetic effects on egg weight. The Pk genotype had a favourable maternal effect on fertility. Direct heterosis was 34% and 10% for egg production up to 30 and 52 weeks of age respectively, 8.8% for egg weight and 5.4% for (egg) fertility. 7. Crossing Ts with Pk seems profitable for the production of mule ducklings.

Genetic parameters from factorial cross breeding in two duck strains (anas platyrhynchos) Brown Tsaiya and Pekin, for growth and fatty liver traits.

1. A total of 655 mule ducklings were produced in three hatches by artificial insemination of common duck females Brown Tsaiya and Pekin "Alienor" and of their 2 reciprocal crossbreds with Muscovy semen. 2. They were fed ad libitum until 6 weeks, then restricted to one meal per day until day 75 and afterwards preforce fed until day 84 and subsequently forced fed by 2 crammers, twice a day, from the age of 85 d and for a maximum of 13 d. 3. Body weight at hatching, 28 d, 56 d, 75 d, 84 d and at slaughter, the number of force-fed meals, the "paletot" weight, the fatty liver weight, the fat release rate after sterilisation of a 60 g portion of liver and the serous melting rate were measured individually. 4. Significant dam genotype and hatch effects were present for all traits. The crammer effect on force feeding traits was also significant. For mule ducks from Brown Tsaiya, Tsaiya x Pekin, Pekin x Tsaiya and Pekin dams respectively, mean body weight was 2356, 3219, 3137 and 3801 g at 12 weeks, "paletot" weight was 1585, 2111, 2110 and 2470 g, fatty liver weight was 441, 585, 563 and 641 g, fat release rate was 35.1, 40.5, 38.2 and 46.0%. 5. The estimated differences between Pekin and Tsaiya genetic effects in their mule progeny were significant and in favour of the Pekin, except for the number of force fed meals and for the serous melting rate.(ABSTRACT TRUNCATED AT 250 WORDS)

Heritabilities for duration of fertility traits in brown Tsaiya female ducks (Anas platyrhynchos) by artificial insemination with pooled muscovy (Cairina moschata) semen.

1. Fertility traits in 348 Brown Tsaiya female ducks were analysed following intergeneric crossbreeding by artificial insemination (AI) with pooled Muscovy semen. The females descended from 18 sires and 107 dams. At 50 weeks of age, the ducks were intra-vaginally inseminated once with 0.03 ml of pooled Muscovy semen. Subsequently eggs were collected for 15 d and set for incubation up to candling 10 d later. 2. Average fertility decreased from 87% at day 2 after AI to 53% at day 6 and less than 7% from day 10 onwards. 3. The best criterion of selection for duration of fertility seems to be the number of fertile eggs from 2nd day up to the 15th day after AI. Heritability estimates for this trait were hs2 = 0.29 +/- 0.18., hD2 = 0.38 +/- 0.22.