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Title: Cytogenetic abnormalities in early embryos of the sheep and pig
Author: Hamlet, Erica J.
ISNI:       0000 0001 3528 7484
Awarding Body: University of Glasgow
Current Institution: University of Glasgow
Date of Award: 1983
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This work was undertaken in normal sheep and pigs to elucidate the proportion of early embryos with cytogenetic abnormalities in order to determine the importance of chromosome abnormalities in early embryonic death in these species. The chromosome complement of the animals used in this study was assessed using leucocyte culture. Ewe synchronisation and surgical flushing proved to be very successful in obtaining 4 and 5 day embryos with recovery rates of 60%, 73% and 84% in the 1st, 2nd and 3rd periods of study respectively. Fertilisation rates from natural service and artificial insemination in and out of the breeding season were compared, with an average fertilisation rate of after artificial insemination and 80 after natural mating. Estimates of embryonic death were obtained and were found to be higher in August at 66% than in peak breeding season at 26%. A surgical technique was developed to repeatedly recover 4 to 7 day old embryos from gilts. A total of 218 embryos v/ere surgically recovered from 9 gilts. Morphologically abnormal pig embryos were examined under a scanning electron microscope. Embryos were cultured for chromosome analysis. The techniques used proved to be successful with pig embryos (58% analysed) but less so with sheep embryos (28% analysed). Cytogenetic abnormalities found included monosomy and trisomy, haploidy, triploidy, diploid/triploid mosaicism, tetraploidy and mixoploidy. Mixoploidy was found at the 6 cell stage in pig embryos and in leucocyte culture of normally developing 78 day foetuses. It v/as concluded that 12% of pig embryos and 9% of sheep embryos had chromosome complements likely to lead to early embryonic death.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Genetics