The Ag News and Views contained an excellent article by Chan Glidewell discussing how overstocking leads to increased hay feeding. I wanted to add a comment to that article. On some ranches, hay feeding is caused by the calving season, regardless of the stocking rate. This is because cows in late gestation and early lactation have nutrient requirements that often dramatically exceed the nutrient content of available forage.
I recently worked with a client on this situation. He has a demanding job in town and wants to minimize the labor input into his cow herd. He also is interested in improving and using the native range on his place. We recommended, and he adopted, an appropriate stocking rate for no hay feeding. However, the calving season of his cows is almost requiring him to feed hay, even though there is abundant native range. He purchased some young bred cows scheduled to calve in February. The cows were a little thin, and he needed to improve body condition on these cows. When evaluating supplement programs, I quickly came to the conclusion that cows in this situation might need more than 10 lbs. of 20 percent cubes per cow per day. While that may be physically possible, it didn't strike me as a good idea. Feeding this much supplement would cost $10 per cow per week, not to mention loading, unloading, reloading and feeding 84 bags per week. That is a lot of money and a lot of work. When you consider this rancher really doesn't have time to feed cows every day, this program becomes impossible.
Although we could possibly devise some other supplement program, the real culprit here is the calving season. If these cows were going to calve in May instead of February, this impossible situation becomes easy to manage. In January, cows that are still four months away from calving can simply be fed about 1 lb. of 38 percent cubes per day, even if they are slightly thin and grazing low quality forage. Before they calve, they will have several weeks of high quality spring grazing, and the grass will be getting better while they calve, lactate and breed back. Feeding 1 lb. of feed per day is much easier (and cheaper) than 10 lbs. of feed per day. Further, these cows can easily be fed the needed supplement just two or three days per week, further reducing labor input. The rancher also won't have to worry about the newborn calves in May because they won't be cold-stressed. For this rancher, the advantages to May calving begin to stack up.
There may be a few disadvantages to moving the calving season to May, such as reduced weaning weights in the fall. A quick analysis at current calf prices indicates that May-born calves could be worth $100 less than February-born calves in the fall. Further, it is possible that the cows might suffer from reduced conception rates due to heat stress during the breeding season. However, both of those issues could be managed around at relatively low cost.
Calving season should be an individual decision for each ranch, based on available resources. Certainly the costs will vary due to forage base, labor costs, cow type, etc. However, timing of calving dictates many other management decisions so consider it carefully. Don't set your calving season because that is what you've always done or because that is what your neighbors do. For the most part, if you calve when your neighbors do, you'll get the same results and do the same amount of work that they do.