The metabolic and reproductive responses of lactating dairy cows to supplementation with choline

Shahsavari, Arash (2012). The metabolic and reproductive responses of lactating dairy cows to supplementation with choline MPhil Thesis, School of Agriculture and Food Sciences, The University of Queensland.

       
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Author Shahsavari, Arash
Thesis Title The metabolic and reproductive responses of lactating dairy cows to supplementation with choline
School, Centre or Institute School of Agriculture and Food Sciences
Institution The University of Queensland
Publication date 2012
Thesis type MPhil Thesis
Supervisor Michael D'Occhio
Rafat Al Jassim
Neil Gannon
Total pages 92
Total colour pages 1
Total black and white pages 91
Language eng
Subjects 070204 Animal Nutrition
070206 Animal Reproduction
Abstract/Summary Negative energy balance is a common metabolic condition as parturition approaches and during early lactation in dairy cows. It variably affects metabolic homeostasis and subsequently postpartum reproductive performance. Fatty liver syndrome and ketosis are two major metabolic disorders in transition dairy cows that result from the attempt by cows to respond to the energy imbalance in early lactation. Choline has been introduced to dairy feeding system basically because of its positive impact on productive parameters including milk composition, yield and postpartum reproductive function. The mechanisms by which choline is involved in metabolic pathways is not fully understood. However, there is evidence that choline has lipothrophic characteristics and contributes to the exportation of accumulated triglyceride (TG) in hepatic tissue, mostly very low density lipoprotein. Therefore, choline may have a key role in ameliorating the detrimental effects of fatty liver syndrome and ketosis in early lactation. This could be associated with improvements in postpartum reproductive function including a reduction in the postpartum anoestrus interval, higher conception rate and pregnancy rate. In the first study in this thesis, feeding 120 g/day rumen- protected choline (providing 30g choline chloride) to Holstein-Friesian cows during the transition period (3 weeks before to 6 weeks after calving) improved the metabolic state and postpartum reproductive function in dairy cows. Cows that received choline had greater plasma concentrations of leptin in early lactation and they showed a lesser decline in plasma insulin. Body condition was marginally better in cows that received choline and a greater proportion conceived to AI in the first 100 days after calving, although the latter was not significantly different to cows that did not receive choline. In the second study, Holstein-Friesian cows received 240 g/day rumen-protected choline (providing 60g choline chloride) from the time of calving to 6 weeks postpartum. Cows that received choline had lesser plasma concentration of β-hydroxybutyrate than cows that did not receive choline at Week 6 postpartum. The size of the dominant follicle was greater at Weeks 3 and 6 postpartum in cows fed choline and a greater proportion of these cows had ovulated by Week 6, compared with cows not fed choline. It was concluded that the provision of choline can influence both metabolic hormones and metabolic substrates in early lactation dairy cows and there can be beneficial effects on reproductive function.
Keyword Negative energy balance
High-producing dairy cows
Fatty liver syndrome
Ketosis
Choline
Metabolic homeostasis
Reproduction

 
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Created: Thu, 06 Sep 2012, 10:58:19 EST by Mr Arash Shahsavari on behalf of Scholarly Publishing and Digitisation Service