Abstract

The objective of this research was to evaluate the suitability of six published equations to fit lactation curves to milk yield records of Hanwoo (Korean Beef Cattle) cows. Milk was collected from 102 heads of Hanwoo by milking machine from two teats every ten days for 180 days from 1986 to 1990, while the other two teats were suckled by her calf simultaneously. The following five lactation curve models were compared. 1) Wood, 2) Wood weighted, 3) Jenkins, 4) Nelder and 5) Multiphase (MP/). Two variants of multiphase curves (mono-phase (MPi, n=l) and di-phase (MP2, n=2)) were estimated. The mean deviations between observed milk yield and predicted equations by Wood, Nelder and mono-phase were ranged -0.2 to 0.2 kg during 10 days to 180 days after calving. The Wood weighted was over estimated, but MP2 was under estimated during the whole period of lactation. The Jenkins showed markedly different shape of curve from the others. The multiphase estimated earlier day of peak yield than the others.

N. S Kim, J. C Ju, Y. S Won, S. B Choi, Y. L Choi

Proceedings of the World Congress on Genetics Applied to Livestock Production, Volume 24: Sheep and goats (fibre); sheep and goats (meat and milk); poultry; horses; buffaloes., , 90–93, 1998
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