An attempt to develop a new strain pig of Duroc breed: Performance in the fourth generation
2005
Kawai, K.(Gifu-ken. Livestock Research Inst., Kiyomi (Japan)) | Naganawa, T. | Yoshioka, G. | Shimabe, N. | Imaeda, N.
We have attempted to develop a new strain pig of Duroc breed from Duroc pigs imported from the USA since 1999. This experiment was to examine the reproductive ability in the third generation (G3), and growth and meat production in the fourth generation (G4). 1) By non-likeness crossing between G3 on the basis of the breeding value of back fat thickness (BF), the next generation, G4 was produced. 2) Litter size in G3 was smaller by 1.5 piglets than in the basal generation. 3) In G4, daily body gain was 987+-76g in males and 901+-77g in females, which was greater by 5g in males and smaller by 41g in females than in G3. BF was 1.8+-0.2 cm in males and 1.9+-0.3 cm in females. There was a 0.2 cm increase in BF for males above its G3 level but no change for females. Coefficient of variation of BF was smaller than in G3. 4) Crude lipid content of the longissimus muscle in G4 was 4.6+-0.9% across both sexes, and it increased with an increase in the generation. 5) Total score for assessment of leg hoof shapes in G4 was 16.8+-3.1 in males and 17.1+-2.6 in females. In G4 selected to produce the next generation, the scores in males and females were 19.5+-1.6 and 17.7+-2.7, respectively. These results indicate that most traits in question are making a shift toward the expected ones.
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