Diagnosis of foetal number in prolific sheep

J.L. Owens, J.R. Armstrong

Invermay Agricultural Centre, Ministry of Agriculture and Fisheries, Mosgiel

Proceedings of the New Zealand Society of Animal Production. 1985, 45: 155-158

Techniques of real time ultra sound (ADR 2130), Toshiba Sonolayer-L SAL 22A) and radiography (DSIR X-ray) were assessed to determine the accuracy of identifying ewes carrying 3 or more lambs. Ewes were scanned between 62 and 75 days of gestation with ultra-sound and between 110 and 124 days with X-ray. There were 94.2% (ultra- sound) and 96.2% (X-ray) of ewes predicted to be carrying 3 or more lambs that actually lambed with 3 or more lambs. However, 21.1% (ultra-sound) and 8.4% (X-ray) of ewes which lambed with 3 or more lambs were predicted to lamb with<3 lambs. Because ultra-sonic diagnosis is carried out at an earlier stage of gestation it gives greater flexibility to apply nutritional management to ewes carrying 3 or more lambs in order to sustain foetal growth in these high litter sizes.

Keywords: NZSAPAB; Sheep prolificacy; litter size diagnosis; Booroola; pregnancy

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Last Updated 03-05-1997