Real-time ultrasonic scanning in the diagnosis of pregnancy and the determination of fetal numbers in sheep

Abstract

Two trials were conducted on a total of 1120 ewes of four breeds to evaluate the use of real-time ultrasonic scanning as a means of diagnosing pregnancy, differentiating barren, single- and multiple-bearing ewes and determining actual fetal numbers in pregnant ewes. In trial 1 (566 ewes) the accuracy of an inexperienced operator, as judged against assessments of an experienced operator, improved from 81 to 100 per cent for the classification of ewes as carrying no, one or more than one fetus, and from 69 to 100 per cent for the determination of actual fetal numbers more than one. In trial 2 the accuracies of the same operator, judged against the lambing performance of 267 ewes, ranged from 90 to 97 per cent for both types of assessment, and for an experienced operator from 95 to 100 per cent (554 ewes). In both trials pregnancy was diagnosed with an accuracy of 100 per cent. It is concluded that real-time ultrasonic scanning of sheep between days 50 and 100 of gestation offers a safe and practicable means of diagnosing pregnancy and of determining fetal numbers. Accuracies of diagnosis of pregnancy of more than 99 per cent, of differentiation of barren, single- and multiple-bearing ewes of 98 per cent, and of determination of actual fetal numbers of 97 per cent can be achieved in practice at scanning rates of at least one ewe per minute. Some of the benefits to flock management and performance likely to result from the use of the technique are considered.

Mortality determination and gender identification of conceptuses in pregnancies of Santa Ines ovine by ultrasound

“…This confirms the recommendations made by White et al (1984) on the use of transrectal ultrasound examination in sheep as being a precise, rapid and safe method. Examinations were carried out during a phase of pregnancy that favours the determination of the number of embryos and the visualisation of important ultrasound parameters, such as foetal movement or heartbeat.…”

“…The accuracy on days 50 and 60 of pregnancy was more compromised South African Journal of Animal Science 2009, 39 (4) © South African Society for Animal Science 311 by the foetal position, which impaired gender identification, than on day 40. Probably, if examinations had been repeated, as is recommended by Bürstel (2002) and Reichenbach et al (2004), the percentage of correct diagnoses would be higher, especially in multiple pregnancies, where diagnosis is more difficult (White et al, 1984;Gearhart et al, 1988;Haibel, 1990). In the case of multiple pregnancies, Bürstel et al (2001) propose two examinations, the first between days 50 and 56 of pregnancy, and the second between days 66 and 70.…”

Pregnancy diagnosis, fetal quantification and gender estimation by ultra-sonography in ewes

“…There was one gestation diagnosed as double, which actually yielded the birth of a single offspring. However, this error could have occurred from fetal death during gestation as related by White et al (1984) Gearhart et al (1988) and Santos et al (2006a and (Table 2). This apparently high error rate (White et al, 1984) may have occurred, in part, by the limited operator experience (Haibel, 1990) together with the difficulty in obtaining the image of all fetuses during the exam.…”

“…P. 3037 -37200-000 -Lavras, Animal Scientist, master student -Departamento de Zootecnia/DZO -Universidade Federal de Lavras/UFLA -Cx. P. 3037 -37200-000 -Lavras, MGmila_zoo@yahoo.com.br and survival (White et al, 1984;Gearhart et al, 1988;Santos et al, 2004 and2007b).…”

Migration time of the genital tubercle in caprine and ovine fetuses: Comparison between breeds, sexes and species

“…Ultrasound pregnancy diagnosis contributes to improving the reproductive handling of herds, allowing for the commercialisation of females that did not conceive in the last matting station, and the separation of females with simple and multiple pregnancies into specific feeding programs (White et al, 1984;Davey, 1986). Furthermore, ultrasound enables sexing of fetuses, when scanning is performed in an adequate period of pregnancy (Santos et al, 2005a(Santos et al, , 2006a(Santos et al, , 2006b.…”