Reporting

The statistical analysis can be summarised by a simple statement as follows. One does not necessarily need to describe each step in the process of finding the appropriate model.

Statistical analysis
Milk offtake was analysed by analysis of variance fitting separate regression lines to the data from Bilisa and Assa.

The results of the statistical analysis can then be put simply as follows:

Results
Average milk offtake was higher in cows sampled in villages in Bilisa than in villages in Assa, a drier, more arid region (Table 1), especially during early lactation (Fig. 1). For cows in Bilisa milk offtake declined linearly by an average of 0.096 litres per month with increasing age of the cow´s calf (P<0.001). However, no trend was evident for cows in Assa where milk offtake remained low at about 1 litre per day throughout lactation.

Fig1.Association between milk offtake and age of calf in Orma Boran cows sampled in Bilisa and Assa locations in Tana River district, Kenya