Some places of the eastern Great Plains have received some rain, and the drought monitor looks a little better, but much of the Great Plains and Intermountain West are still in moderate to severe drought and areas of extreme drought are increasing. Warmer temperatures and a little moisture have caused some pastures to begin greening up, but without additional rain plant growth will be limited.
Turning out on these pastures too early will have detrimental effects on plant growth. Cattle will graze off the leaf area limiting the ability of the plant to photosynthesize sugars, which will require the plant to pull sugars from the roots. Without rain to stimulate more leaf growth the plant will rely more heavily on nutrient reserves in the roots, possibly decreasing the root zone and capacity to pull the limited moisture from the soil. This stunting of plant growth and reduction of the root zone will have negative effects on forage production in future years.
So, what can you do? Keep cattle off the pasture as long as possible with the optimism of more rain. Continue to feed hay or find other feed resources that may let you economically extend the winter feeding period. In a previous newsletter we discussed limit feeding cows. The difficulty is that lactating cows have their greatest nutrient requirements during this time from calving to rebreeding. Thus, feed expenses will be greater than the last few months. In late gestation, hay with total digestible nutrients (TDN) of 57% and crude protein (CP) of 10% will meet the nutrient requirements of a 1300-lb cow (Figure 1). But in early lactation, the same cow producing 20 lb of peak milk will require TDN of 59.5% and CP of 10.5%. To make up this nutrient deficit will require 4.5 lb/day of a supplement that has TDN of 75% and CP of 20%.
As Dr. Larson, likes to say “There is something magical about green grass.”. As a nutritionist, I am not sure about the magic, but early spring grass has a nutrient profile that will promote fleshing of early lactation cows (Figure 1). Cows that are in a positive energy balance from calving to rebreeding typically return to estrus sooner and rebreed better. There will be tough decisions to make this spring, because neither spring turnout or continued hay and supplement feeding are likely to be without consequences.