Chein Tai

Selection responses for the number of fertile eggs of the Brown Tsaiya duck (Anas platyrhynchos) after a single artificial insemination with pooled Muscovy (Cairina moschata) semen.

A seven-generation selection experiment comprising a selected (S) and a control (C) line was conducted with the objective of increasing the number of fertile eggs (F) of the Brown Tsaiya duck after a single artificial insemination (AI) with pooled Muscovy semen. Both lines consisted of about 20 males and 60 females since parents in each generation and each female duck was tested 3 times, at 26, 29 and 32 weeks of age. The fertile eggs were measured by candling at day 7 of incubation. The selection criterion in the S line was the BLUP animal model value for F. On average, 24.7% of the females and 15% of the males were selected. The direct responses to the selection for F, and correlated responses for the number of eggs set (Ie), the number of total dead embryos (M), the maximum duration of fertility (Dm) and the number of hatched mule ducklings (H) were measured by studying the differences across the generations of selection between the phenotypic value averages in the S and C lines. The predicted genetic responses were calculated by studying the differences between the S and C lines in averaged values of five traits of the BLUP animal model. The selection responses and the predicted responses showed similar trends. There was no genetic change for Ie. After seven generations of selection, the average selection responses per generation were 0.40, 0.33, 0.42, 0.41 genetic standard deviation units for F, M, Dm, and H respectively. Embryo viability was not impaired by this selection. For days 2–8 after AI, the fertility rates (F/Ie) were 89.2% and 63.8%, the hatchability rates (H/F) were 72.5% and 70.6%, and (H/Ie) were 64.7% and 45.1% in the S and C lines respectively. It was concluded that upward selection on the number of fertile eggs after a single AI with pooled Muscovy semen may be effective in ducks to increase the duration of the fertile period and the fertility and hatchability rates with AI once a week instead of twice a week.

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.

Breeding and genetics of waterfowl

Genetic parameters of traits of interest in ducks and geese are reported. Recent achievements of research, specially to improve the Brown Tsaiya laying duck; the intergeneric crossbreeding in duck; the meat ducks Pekin and Muscovy; the goose reproduction ability; the meat and fatty liver production in geese and ducks were analysed. A linear genetic selection index based on MT-BLUP animal model of breeding values with objectives to maintain body weight, egg weight at current levels, to increase egg shell strength and egg number, used for four generations in Brown Tsaiya laying ducks was evaluated. A seven generations selection experiment was successful in increasing the duration of fertility of Brown Tsaiya female ducks by artificial insemination with pooled Muscovy semen. The genetic parameters of growth and laying traits in a selected Muscovy line in Taiwan were estimated. Favourable genetic trends for body weight at given age, without decreasing egg production, were found in this selected Muscovy line. The selection of grandparent stocks (White Tsaiya and Pekin) for white plumage mule ducks in Taiwan was efficient. The genetic parameters of laying and gosling production traits of Landaise geese and of a White plumage goose strain, bred in two systems, respectively outdoors with natural photoperiodism and in indoors with short daylight conditions were reported. The more advantageous system in selecting for laying traits in geese is discussed. Fatty liver weight was found to be highly heritable in geese and male Muscovy ducks. The genetic parameters of overfed mule duck traits were estimated in the Pekin dam population. It is concluded that future research should focus on biotechnology, quantitative trait loci detection and genome analysis.

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 (σ g) were 0·06σ g, 0·07σ g, 0·17σ g, 0·23σ g, and 0·25σ 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.

Genetic parameters of some growth and egg production traits in laying Brown Tsaiya (Anas platyrynchos)

Cinq cent trente-sept femelles de la race locale de cane Tsaiya Brune a Taiwan, issues de 156 meres, 40 peres, 4 regions de Taiwan (origine des peres), nees dans 5 lots d’eclosion, sont utilisees dans cette etude, 15 caracteres sont etudies. Les poids des adultes (âge : 30 semaines) sont de 1397 ± 120 g. Les valeurs moyennes des caracteres mesures sont les suivantes : âge au le 1er œuf, 126 ± 11 j. Pour les nombres d’oeufs pondus aux âges de 245, 280 et 360 jours, on a respectivement 107 ± 13, 139 ± 15, 207 ± 26. Pour l’epaisseur de la coquille 0,37 ± 0,02 mm et pour sa solidite, 3,8 ± 0,5 kg/cm2. Les poids de l’oeuf, respectivement aux âges de 30 et 40 semaines sont 64,2 ± 4,3 g et 67,8 ± 4,3 g. Les parametres genetiques ont ete calcules: estimation des heritabilites a partir des composantes pere (formule, voir document attache) et mere (formule, voir document attache) de la variance. Les poids corporels aux âges de 8, 16, 20, 30 et 40 semaines presentent une variabilite genetique additive forte (formule, voir document attache). Pour le poids de l’oeuf a 30 et 40 semaines d’âge, (formule, voir document attache). Pour les caracteres de production d’oeufs, les valeurs de (formule, voir document attache) sont faibles et s’accroissent avec l’âge : (formule, voir document attache). Par contre les heritabilites calculees a partir des composantes meres de la variance sont significatives : (formule, voir document attache). L’existence d’une variabilite genetique non additive pour ces caracteres conduira a envisager une selection de souches et leur croisement.