Observations on dystocia in a Romney flock.
Observations on dystocia in a Romney flock.
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对罗姆尼鸡群难产的观察。
DOI：
10.1080/00480169.1977.34419
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发表时间：
1977
影响因子：
1.4
通讯作者：
E. D. Fleiden
中科院分区：
文献类型：
--
作者：
K. Mcsporran;R. Buchanan;E. D. Fleiden
摘要调查了一只罗姆尼种马在1964-1972年间的交配和产羔记录，该种马一直经历着严重的难产问题。1970年之前，有20%到31%的母羊在产羔时需要帮助，但这一水平随后下降到1971年的18%、1972年的11%、1973年的3.3%和1974年的4.0%。在调查的最后几年，难产明显减少，这被认为主要是由于在分娩时反复得到帮助的母羊被淘汰，以及选择出生体重较低的绵羊来繁殖。羊群难产与单只羔羊初生重高度相关(r=0.84，p<；0.01)。59%的受助单身羔羊是公羊；公羊羔羊出生时比母羊羔羊重。除了1966年，初产母羊需要的援助不比年长的母羊多，除了那一年，生单胎的母羊需要的援助水平与生双胞胎的母羊相同。文中还讨论了胎次对难产发生率的影响。
Summary The mating and lambing records for 1964–1972 of a Romney stud that had been experiencing a serious dystocia problem were investigated. Until 1970 between 20 and 31% of ewes required assistance at lambing but this level then fell to 18% in 1971, 11% in 1972, 3.3% in 1973 and 4.0% in 1974. The decline in dystocia evident in the latter years of the investigation is considered to have been brought about largely by the culling of ewes that were repeatedly assisted at parturition and by the selection of rams that sired lambs of lower birth weight. Dystocia in this flock was highly correlated with the mean birth weight of single lambs ( r =0.84, p<0.01). Fifty nine percent of assisted single lambs were males; ram lambs were heavier at birth than ewe lambs. Apart from the year 1966, primiparous ewes required no more assistance than older ewes and, except for that year, ewes bearing singles required the same levelof assistance as those bearing twins. An effect of the sire on the incidence of dystocia was d...