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Application of multiple trait analysis in animal breeding research
I.L. MAO
Department of Animal Breeding and Genetics
Swedish University of Agricultural Sciences, S-750 07 Uppsala, Sweden
The circumstances under which the use of multiple trait analysis is of advantage are discus-
sed. The basic model for such analysis, as well as models and mixed model equations for six
case studies, are formulated for the prediction of breeding values and the estimation of variances
and covariances. The case studies revealed several patterns of equations. For each pattern, a
computing strategy is suggested.
Relationships between lifetime milk production, productive life,
level of production and a lifetime profit function in cows
A. ESSL
Institute of Animal Production, University of Bodenkultur,
Gregor Mendelstrafie 33, A-II80 Vienna, Austria
Regarding the Austrian conditions a simple function for the profit per lactation of herdlife was
derived. Some intersting results in connection with lifetime production criteria obtained from mo-
dell calculations were as follows : 
’
For a given level of milk production per lactation the profit decreases progressively when
herdlife gows down. consequently, the primary breeding task is here to avoid a decrease in herdlife
at all events.
Further, there is a quite remarkable variation of the expected profit per lactation for a given
lifetime production. Hence, pure lifetime production can not be designated as an ideal economic
measurement for dairy cows as it is sometimes interpreted.
Variation in lipolysis in milk from individual cows
P. SKIPENES
Department of Animal Genetics and Breeding,
Agricultural University 1432 As, NLH, Norway
The free fatty acid (FFA) content in milk from 60 cows were determined. Fresh and stored
samples from both evening and morning milkings were analysed. The results can be summarized
as follows :
a) There are considerable differences between cows in FFA-content of stored milk.
b) The correlations between fresh samples collected within a 24 hour interval are low,
0.16-0.22, whereas the correlations for stored samples are high, 0.69-0.74. The correlation
between fresh and stored samples from the same milking is low, 0.17.
c) Within-cow correlations between testing weeks are in average found to be 0.75.


Relationships between lifetime milk production, productive life, level of production and a lifetime profit function in cows

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Relationships between lifetime milk production, productive life, level of production and a lifetime profit function in cows

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