The aim of this study was to determine the extent of variations
in composition and physico-chemical properties of bulk milk from
a commercial herd in the UK throughout the year.
Seasonal variations were found for some properties and correlations
between some physical properties and milk composition
have been highlighted. PCA was used to distinguish between the
samples and was able to differentiate between autumn and spring
milk samples.
The novelty of this study is that these milk samples were then
used to produce a range of products under standardised conditions
in order to determine how selected quality attributes of the products
were influenced by milk composition and other properties.
The observed variation in different parameters could be related
to seasonal effects in some cases but seemed to be more difficult to
explain. Much of the data was consistent with earlier studies on
seasonal variation, while other parameters varied less widely or
displayed less seasonality than may have been expected. This
may be because previous studies were from different geographical
areas, or employed different, in some cases outdated, farming practices
such as diets or calving patterns.
Many interrelationships in physical and chemical parameters
were observed and it is clear that the milk supply would be more
suited to the manufacture of different products at different times
of the year or even on a day to day basis. Subsequent studies will
report on variation in production and quality of products manufactured
from the same milk samples described in the current study.
In this way it is hoped to provide some clearer guidelines on the
relationships in milk composition, properties and product manufacture,
including seasonal factors.