allowing us to determine the volume at which the abomasal capacity
would be exceeded. Between- and within-patient RSP designs are generally
analysed with isotonic regression analysis [17,20]. However, no
meal size in the current study turned out to cause milk to enter the
rumen. This means that there were no quantiles to estimate and
hence isotonic regression could not be applied to determine an optimal
dose level based on abomasal capacity.
Milk is easily digestible and abomasal emptying in young calves normally
starts within a few minutes [21]. Radiographs were taken during
and immediately after the milk intake when backflow is most likely to
occur. Ruminal emptying can take up to 48 h [3]. To avoid confusion
from barium sulphate potentially remaining in the forestomachs, test
sessions were performed with 48 h intervals.