Drought effect on birth weights

[Dusty Britches]

Ok, so I learned how much a severe drought can affect birth weights.

Until last year, our average birth weight for the whole cow herd was 75 pounds. The average this spring has been 60. The other day, one was born that weighed 48 pounds to a momma that averaged 70 in the last 3 years.

The cows all look good and have had mineral supplements. All of the calves are healthy.

I'm sure this will generate some discussion.

 

[Texas Gal]

Besides having mostly heifers the last two years (06 & 07), we haven't seen any changes from non-drought years. I was expecting a drop in birthweights due to the conditions - short grass or no grass, loss of condition while nursing previous calf, less than good hay, etc.- but not so. The only big difference I noticed was in my 06 heifers that we retained. It seemed like they grew like weeds but never put on a lot of pounds until just recently. They were in good flesh just not roly-poly as others were in the past.

 

[KNERSIE]

Droughts do play a big role in BW, but this wouldn't neccesarily mean calving ease in equal proportion. If the cows and especially heifers lose a lot of condition in the last three months of gestation, they often lack the desire to push the calve out or tire quickly, ofsetting the advantage of lower BW.

There is a definate advantage in calving before optimum grazing conditions to avoid excessive foetal growth due to the spring early summer flush's high proteien and also the calf growing with the grazing conditions are better able to utilise the extra milk resulting from the cow grazing on the lush early summer pasture.