July 2014
Cool-season-dominated pastures and rangelands in the Nebraska Panhandle have produced many pounds of forage this year, thanks to abundant moisture in May and June. Native grass species such as western wheatgrass and needle-and-thread have done extremely well.
While the quantity of grass is very welcome, the quality of this forage going into mid- to late summer has declined significantly as these plants have matured and set seed. This decline in forage quality, especially for cool season dominated pasture and rangelands, could have a detrimental effect on conception rates for late spring calving replacement heifers and young cows being bred now through late summer.
Nutrition important for conception rates
Research from the University of Nebraska–Lincoln has shown that the status or plane of nutrition right prior to and through the breeding season is important for conception rates of growing and developing replacement heifers and young cows. Heifers and young cows on a decreasing plane of nutrition during the breeding season tend to have lower conception rates than those on an increasing plane of nutrition.
Providing the equivalent of 1 to 2 pounds per head per day of fiber-based energy/protein supplement to these high-risk females right prior to and through the early part of the breeding season can significantly improve conception rate when forage quality is decreasing. This supplement could be provided every-other- day (two to four pounds per head per day). A recent significant price decrease in distillers grains products makes this a cost-effective source of both protein and energy that would complement well the forage from these mature cool-season grasses.
Additional resources
Further information on the importance of plane of nutrition during the breeding season is available from a NebGuide titled "Reducing Replacement Heifer Development Costs Using a Systems Approach" (PDF version, 1.04MB) as well as a webinar by Dr. Rick Funston titled "Cost Effective Replacement Heifer Development".
Economic benefits
Getting heifers and cows to conceive early in the breeding season has tremendous economic benefits. Under current market conditions bred heifers and cows are very valuable. Strategically providing a fiber-based energy/protein supplement right prior to and through the breeding season to these high-risk females could provide a tremendous return to the supplement dollars spent.
It is great to see cows belly deep in grass this year, especially after the drought conditions of 2012 and 2013. However, this abundance of forage quantity has also resulted in a decrease in forage quality that may challenge heifers and young cows breeding in late summer.
Aaron Berger
UNL Extension Educator