Thanks for your query.
Cows milk is not recommended till one year of age .
Baby should be exclusively breast fed till 6 months of age.
Complete antibiotic as prescribed.
Give probiotic like lactobacillus
for 2 to 3 days.
Give oral rehydration solution sip by sip after each loose stool
Watch for features of dehydration
like lethargy/decreased urine output/refusal of feeds and in case you observe any get her re evaluated by pediatrician
Wishing your baby good health.