diff --git a/trainvel/gtfs/management/commands/update_trainvel_gtfs.py b/trainvel/gtfs/management/commands/update_trainvel_gtfs.py
index bd9e201..862436d 100644
--- a/trainvel/gtfs/management/commands/update_trainvel_gtfs.py
+++ b/trainvel/gtfs/management/commands/update_trainvel_gtfs.py
@@ -225,21 +225,23 @@ class Command(BaseCommand):
                 calendars.clear()
 
         calendar_dates = []
+        all_calendars = {calendar.id: calendar for calendar in Calendar.objects.filter(gtfs_feed_id=gtfs_code)}
+        new_calendars = {}
         with transaction.atomic():
             for calendar_date_dict in read_csv("calendar_dates.txt"):
                 calendar_date_dict: dict
                 service_id = f"{gtfs_code}-{calendar_date_dict['service_id']}"
-                date = calendar_date_dict['date']
+                date = datetime.fromisoformat(calendar_date_dict['date']).date()
 
                 calendar_date = CalendarDate(
                     id=f"{gtfs_code}-{calendar_date_dict['service_id']}-{calendar_date_dict['date']}",
                     service_id=service_id,
-                    date=date,
+                    date=calendar_date_dict['date'],
                     exception_type=calendar_date_dict['exception_type'],
                 )
                 calendar_dates.append(calendar_date)
 
-                if not Calendar.objects.filter(id=calendar_date.service_id).exists():
+                if service_id not in all_calendars:
                     calendar = Calendar(
                         id=service_id,
                         monday=False,
@@ -249,26 +251,27 @@ class Command(BaseCommand):
                         friday=False,
                         saturday=False,
                         sunday=False,
-                        start_date=calendar_date_dict['date'],
-                        end_date=calendar_date_dict['date'],
+                        start_date=date,
+                        end_date=date,
                         gtfs_feed_id=gtfs_code,
                     )
-                    calendar.save()
+                    all_calendars[service_id] = calendar
+                    new_calendars[service_id] = calendar
                 else:
-                    calendar = Calendar.objects.get(id=service_id)
-                    if calendar.start_date.isoformat() > date:
+                    calendar = all_calendars[service_id]
+                    if calendar.start_date > date:
                         calendar.start_date = date
-                        calendar.save()
-                    if calendar.end_date.isoformat() < date:
+                    if calendar.end_date < date:
                         calendar.end_date = date
-                        calendar.save()
 
                 if len(calendar_dates) >= bulk_size and not dry_run:
                     CalendarDate.objects.bulk_create(calendar_dates, batch_size=bulk_size)
                     calendar_dates.clear()
 
-            if calendar_dates and not dry_run:
+            if (calendar_dates or new_calendars) and not dry_run:
+                Calendar.objects.bulk_create(new_calendars.values(), batch_size=bulk_size)
                 CalendarDate.objects.bulk_create(calendar_dates, batch_size=bulk_size)
+                new_calendars.clear()
                 calendar_dates.clear()
 
         trips = []