Fun with Calving

Well we are off to a sprinting start-- Heifers are coming as scheduled according to the breeding notes from last year, but everything is BIG this spring.  I have had to pull several, which is a bummer.  I made sire selections to not be big and have good CE numbers.  I am a believer to a degree that the cold winter weather makes the calves bigger.  Even my Red Angus heifers are having monsters- and they are all from LBW stock.  Now I know that you can't count on just because they are Red Angus they are all going to calve out fine or have smaller calves.  Just making a statement that I was trying to "stack the deck" in my favor for LBW. 
My cows have gotten together at the bale ring and decided amongst themselves to totally screw with me this spring-- I have them all written down for April 1 start-- but no-- I have 1/3 of them dropped babies with no warning at all over the last week-- fortunately they are ok on their own-- no big monsters there except the one or two I expect to have monster calves each year-- they are big cows- bigger than I normally keep, but they came in a package deal a few years ago and they have pretty decent calves, so they have stuck around.
Just sharing my fun so far!
Anyone else have any stories?
;D
EF

No problems here so far.
Last winter was quite a bit colder - and for a longer time; and, due to poor hay quality, we were feeding nearly double the amount of DDG... no calving issues, but calves were a lot bigger than normal ...by same bulls, out of same cows.  BWs on SH-sired calves averaged 96 lb., out of mature ANxSimAngus cows - and while these were not 'heifer' bulls, CE/BW epds were still pretty moderate..

Extended cold does result in larger BWs, due to peripheral vasoconstriction to conserve heat, resulting in shunting of more blood to internal organs, like the uterus. 
Increased protein feeding in the last trimester will give bigger BWs - but usually not an increase in dystocias.

were having monsters as well. our earlier calves were fine, 70-80's. as the weather got much colder, cows ate more, are BWS increased. had two calves, 1 mercesdes benz 122 pound bull, 1 monopoly heifer 116. as the weather broke out bws went back down to 70 pounders