You mentioned grass hay for the horses and for sure that lines up with what we'd do too. I should have said it better than "cold" feed - meant low alfalfa content for the horses.
I wasn't sure if you changed up the feed for cattle or just increased the ration - as you say you do. Makes sense.
When we first got into horses I was fortunate to be mentored by a chap who'd grown up looking after logging camp horses in New Brunswick way back in the day. To say Earl was a fount of knowledge was an understatement and we surely were enriched by the horse tips and knowledge he shared with us.