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Data on sex ratio in swine were collected from 14, 111 young in six experiment stations of animal husbandly in Nagano (Nn), Aichi (Ai), Toyama (Ty), Ishikawa (Is), Kagawa (Kg) and Kochi (Ko) Prefec-tures. The young were composed of Large White (W), Yorkshire (Y), Landrace (L), Hampshire (H), and Durock (D) and their hybrids (Hyb). There was only one breed (L), and generations (Go-G5) were clear in Ty. Therefore, sex ratio was analyzed in each generation in Ty. Analysis was performed by the same method as mentioned previously0. The classes which showed a shift of sex ratio to either sex are cited mainly in tables. The results obtained are summarized as follows.<BR>A shift of total sex ratio was seen in one station (Ko), and in six stations as a whole. A sig-nificant difference in total sex ratio was noted only in two cases; that is, between Ko and Ty, and Ko and Kg (Table 1). The percentage of boars and sows which showed a shift of sex ratio in their offspring ranged from 0 to 3.7 and from 0 to 9.8, respectively (Tables 2 and 3). Only negative results15 were obtained from the survey of pedigree of these parental individuals.<BR>With regard to litter series, shifts of sex ratio were found in two classes in Nn, and in one class in Ko (Table 4). A shift of sex ratio was noticed in only two classes of litter size in Ko (Table 5).<BR>A shift of sex ratio was noted in Ai and Ko in summer (Table 6-1). A significant seasonal difference in sex ratio was recognized in Is between spring and winter, in Ko between spring and summer, and summer and autumn (Table 6-2).<BR>A shift of sex ratio was seen in one class of paternal age in Nn and in Ko (Table 7). With regard to the age of sows, shifts of sex ratio were found in one class in Ty, and in two classes in Ko (Table 8). No shift of sex ratio was shown in any class of age difference between parents in two stations (Ty and Kg). Shifts of sex ratio to the same sex of older parent, and also to the opposite sex were recognized in the remaining four stations (Table 9). There was no shift of sex ratio accord-ing to the maternal age at the first mating in any station.<BR>A shift of sex ratio was observed in only one class of calendar year in Nn and Ko (Table 10).
- 日本繁殖生物学会の論文
日本繁殖生物学会 | 論文
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