No description available.

No description available.

Experiments were carried out to test the effects of maternal nutrition (0.5 versus 1.0 x maintenance) during early foetal life and peri-ovulatory nutrition on the reproductive performance and associated parameters of Scottish hillbreeds (North Country Cheviot and Scottish Blackface) crossed with Texel sires carrying or not carrying the X-linked Inverdale (<i>FecX^I</i>) gene. Undernutrition of the dam resulted in reduced birthweights of single male lambs, reduced plasma progesterone concentrations of ewe lambs and a tendency for reduced ovulation rates in ewe lambs and shearlings (non-carriers) but litter size was not affected. Heterozygous carriers of the Inverdale gene showed a mean increase in ovulation rate of approximately 0.35 as ewe lambs, and approximately 0.65 the following year, the latter resulting in a mean litter size increase of approximately 0.6. Plasma progesterone concentrations were lower for <i>FecX^I</i> gene-carriers as ewe lambs and also as adults in a flock that had been flushed prior to mating, suggesting that the increased feed intake could have had a suppressing effect on the concentrations of this hormone. It is postulated that this could have resulted in the large number of peri-natal losses associated with gene-carrier ewes in the same flock, since neonatal vigour of offspring of gene-carriers was not affected in the SAC experimental flock that had not been flushed pre-mating. Presence of the <i>FecX^I</i> gene is associated with a reduction in birthweight of approximately 0.5 kg which could be due to the reduced placental efficiency of gene-carrier dams. At puberty and as shearlings gene-carriers remained lighter than their non-carrier counterparts. Throughout the shearling breeding season the increase in ovulation rate associated with this prolificacy gene remained constant.

"March 2004" / Bibliography: leaves R1-24 / xix, 209 p., A54, R24 leaves : ill. (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / "This thesis describes two models developed to investigate the effect of maternal feed intake on muscle cellularity and myogenic gene expression of fetal sheep." --p. vi.

Thesis (Ph. D.)--University of Missouri-Columbia, 2002. / Typescript. Vita. Includes bibliographical references (leaves 96-114). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 2002. / Typescript. Vita. Includes bibliographical references (leaves 96-114). Also available on the Internet.

No description available.

No description available.

No description available.

Thesis (M.Sc.(Agric.))(Food Science)--University of Pretoria, 2009. / Abstract in English. Includes bibliographical references.