Phenotypic profiles for body weight, body condition score, energy intake, and energy balance across different parities and concentrate feeding levels

摘要

The objective of this study was to investigate potential differences in lactation profiles for body weight (BW), body condition score (BCS), net energy intake (NET) and energy balance (EB) across different parities and concentrate feeding levels. Records collected from the research farm in southern Ireland from 1995 to 2002 were analysed using random regression methodology. A total of 27,126 and 8212 records were available for BW and BCS, respectively; 1861 and 1835 records were available for NEI andEB, respectively. Significantly different lactation profiles existed for BW, BCS, NET and EB across parities one to three. First parity cows were lighter, lost more BCS in early lactation, had lower NEI and were in negative energy balance for longer compared to later parity cows. Average NEI across the first 225 days of lactation was 15.4, 19.5 and 21.0 UFLs/day for first, second and third parity cows, respectively. Energy balance turned positive at days 71, 60 and 73 of lactation for first, second andthird parity cows, respectively. Cows on the higher feeding levels were heavier, mobilised less body condition in early lactation and had higher NEI than cows on the lower feeding level. No significant difference in height of the EB profile existed between the cows on the low and high feeding level indicating that the duration and extent of NEB was not influenced by the concentrate feeding levels adopted in this study.