Richardson C, Hebert C N, Terlecki S
Vet Rec. 1976 Jul 10;99(2):22-6. doi: 10.1136/vr.99.2.22.
Fifty-six fetuses and 33 lambs were obtained from a flock of ewes at set gestational intervals between 50 to 180 days after conception. The fetuses and lambs were killed, disected and the sizes and weights of a wide range of skeletal and soft tissues were measured. Five morphological parameters emerged as most suitable for the determination of normal foetal developmental age. By plotting the mean value and ninety-five per cent tolerance limits, the rates of growth and the variability of each parameter were studied. Crown-anus length is useful for determining fetal developmental age from 50 to 100 days gestation; brain weight, long bone length and the number of appendicular ossification centres can be used to determine fetal development age from 50 days gestation until term.
在受孕后50至180天的特定妊娠间隔期，从一群母羊中获取了56只胎儿和33只羔羊。将胎儿和羔羊处死、解剖，并测量了一系列骨骼和软组织的大小及重量。出现了五个最适合用于确定正常胎儿发育年龄的形态学参数。通过绘制平均值和95%的耐受限度，研究了每个参数的生长速率和变异性。顶臀长有助于确定妊娠50至100天的胎儿发育年龄；脑重量、长骨长度和附属骨化中心的数量可用于确定从妊娠50天直至足月的胎儿发育年龄。
