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Title: Sources of variation in voluntary feed intake and nutrient utilization for milk production of dairy cows
Author: Kabuga, Joseph Dabien
ISNI:       0000 0001 3593 7379
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 1986
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The influence of animal characteristics immediately post-partum on the voluntary feed intake and nutrient utilization for milk production during 24 weeks of lactation was studied in two trials, one involving cows and the other cows plus heifers. The influence of eating behaviour on daytime voluntary feed intake was studied in early lactation (weeks 1-8) using 33 animals and in middle and late lactation with 40 animals. It was shown that environmental factors (years and months of calving), parity, calving liveweight, calving condition score, milk yield in lactation week 2 and liveweight change within the period of lactation explained the following proportion of the variation in voluntary feed intake 41.3-60.1 and 48.0-74.996; in milk yield 23.3-58.9 and 33.3-91.5%; in energy balance 30.1-69.0 and 28.6 - 50.696; gross efficiency 25.5-69.0 and 35.5-62.2%; in net efficiency 27.5- 68.0 and 32.6-42.9% and in nitrogen efficiency 19.3-48.1 and 20.8-58.9% for different stages of lactation in Trials 1 and 2 respectively. In the behaviour study the animals were found to have a two-peak pattern of eating; the hour immediately after fresh feed offering and milking. Fifty per cent of the within day variation between animals in voluntary feed intake was due to differences in the time spent eating. The selection of animals for high milk yields has resulted in animals with high appetites and efficiency, and the ability to mobilize body reserves in early lactation. Animal to animal variation in the mobilization and storage of body reserves was the main cause of differences between animals in energetic and nitrogen efficiency for milk production. Calving condition score was not related to voluntary feed intake or to nutrient utilization after lactation week 12; and milk yield. It was concluded that calving condition score can be manipulated to improve voluntary feed intake without affecting milk yield. Areas of further research are suggested.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Animal husbandry & farm animals & pets