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Title: The effect of dietary energy and body reserves on the partitioning of nutrients in lactating sows
Author: Jones, G. M.
Awarding Body: University of Aberdeen
Current Institution: University of Aberdeen
Date of Award: 2000
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Milk nutrient output in modern lean genotype sows is potentially impaired by their genetic drive to deposit body protein. This is thought to be particularly true for young sows, whose body protein mass at farrowing is far from their mature body protein. The present series of experiments investigated possible factors involved in the regulation of the partitioning of nutrients in lactating modern lean genotype sows. In experiment 1, milk composition of sows was manipulated by dietary means and the effects on daily milk nutrient output and piglet performance pre- and post-weaning were measured. Experiment 2 compared starch and fat at isocaloric levels in sow lactation diets in terms of sow and piglet performance in association with the metabolic state of sows at peak lactation. Experiment 3, a long-term study, compared gilts of two different genotypes, allowed to select their own pattern of nutrient intake during rearing and pregnancy with those fed conventionally, in terms of body composition at farrowing and subsequent effects on sow metabolic state and performance in lactation. Milk energy content in sows was responsive to dietary fat. However, milk nutrient output was much more related to the availability of dietary glucose. Body composition of piglets at weaning could be manipulated via changes in sow milk composition, but had little effect on post-weaning performance. High fat diets increased the metabolic stress of sows in lactation. Gilts selected a lower dietary protein content than offered in conventional commercial practice, irrespective of genotype. The choice-feeding regime was of no advantage for lactation performance in sows. There were differences between genotypes in metabolic state and performance in lactation. In conclusion fat should only be regarded as a supplementary dietary energy source for sow lactation diets, since its effect is influenced by the availability of dietary glucose. Choice-feeding does not appear to be a suitable method to determine appropriate feeding regimes for modern genotype breeding gilts.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available