Young L D
Roman L. Hruska U.S. Meat Animal Research Center, ARS, USDA, Clay Center, NE 68933-0166, USA.
J Anim Sci. 1995 Mar;73(3):711-21. doi: 10.2527/1995.733711x.
Gilts were the progeny of eight Duroc, nine Meishan, eight Fengjing, and seven Minzhu boars mated to composite (1/4 Chester White, 1/4 Landrace, 1/4 Large White, and 1/4 Yorkshire) females. Age at puberty was youngest (P < .05) for Meishan and Fengjing crosses followed by Minzhu crosses and then Duroc crosses. Fengjing crosses had a higher (P < .05) ovulation rate than Meishan or Minzhu crosses, which had a higher (P < .05) ovulation rate than Duroc crosses. Meishan and Fengjing crosses had larger (P < .05) litters than Duroc crosses at 60 and 100 d of gestation, at birth, and at weaning. Minzhu crosses also had larger (P < .05) litters than Duroc crosses at all stages but were significantly lower than Meishan and Fengjing crosses only for litter size at 100 d of gestation. Duroc crosses were heavier (P < .05) at farrowing than all three Chinese crosses. Breed groups differed (P < .05) for backfat thickness at weaning but not at farrowing. Duroc crosses were the least efficient (P < .05) in converting feed energy into litter gain from birth to weaning; Fengjing crosses were less efficient (P < .05) than Minzhu crosses but neither differed significantly from the intermediate value of the Meishan crosses. Chinese crosses returned to estrus sooner after weaning (P < .05) than Duroc crosses. Ovulation rate at second parity was highest for Fengjing crosses followed by Meishan, Duroc, and Minzhu crosses; difference among nonadjacent means were significant (P < .05). Differences among crosses were not large or significant for number of fetuses at 100 d of gestation at second parity. Results indicate Meishan and Fengjing can be used to produce crossbred gilts that have a higher level of reproductive performance than Duroc crossbred gilts; the reproductive performance of Minzhu crosses would be intermediate. However, the Chinese crosses would not be expected to have an advantage in litter size at second parity.
后备母猪是8头杜洛克公猪、9头梅山公猪、8头枫泾公猪和7头民猪公猪与杂交母猪（1/4切斯特白猪、1/4长白猪、1/4大白猪和1/4约克夏猪）交配所生的后代。梅山和枫泾杂交后代的初情期年龄最小（P < 0.05），其次是民猪杂交后代，然后是杜洛克杂交后代。枫泾杂交后代的排卵率高于梅山或民猪杂交后代（P < 0.05），而梅山或民猪杂交后代的排卵率又高于杜洛克杂交后代（P < 0.05）。在妊娠60天和100天、出生时和断奶时，梅山和枫泾杂交后代的窝产仔数比杜洛克杂交后代多（P < 0.05）。民猪杂交后代在所有阶段的窝产仔数也比杜洛克杂交后代多（P < 0.05），但仅在妊娠100天时窝产仔数显著低于梅山和枫泾杂交后代。杜洛克杂交后代的产仔体重比所有三个中国猪种杂交后代重（P < 0.05）。不同品种组在断奶时的背膘厚度存在差异（P < 0.05），但在产仔时没有差异。从出生到断奶，杜洛克杂交后代将饲料能量转化为窝增重的效率最低（P < 0.05）；枫泾杂交后代的效率低于民猪杂交后代（P < 0.05），但两者与梅山杂交后代的中间值均无显著差异。中国猪种杂交后代断奶后发情恢复得比杜洛克杂交后代快（P < 0.05）。经产母猪的排卵率以枫泾杂交后代最高，其次是梅山、杜洛克和民猪杂交后代；非相邻均值之间的差异显著（P < 0.05）。经产母猪妊娠100天时的胎儿数在不同杂交组合间差异不大且不显著。结果表明，梅山猪和枫泾猪可用于生产繁殖性能高于杜洛克杂交后备母猪的杂交后备母猪；民猪杂交后代的繁殖性能处于中间水平。然而，预计中国猪种杂交后代在经产时的窝产仔数方面没有优势。
