Profit Tip: Balancing Timing of Hay Harvest on Subsequent Forage Productivity
Keeping the beef female grazing, harvesting her nutrient needs, is the most economical approach to lowering feed costs. However, in some management systems or in some areas of the United States, harvested forages are needed to feed the cow herd. Are there management practices where grazing and hay harvesting practices can be optimized?
What Determines Forage Quality and Yield
It is safe to say that stage of maturity of forage is the primary factor that influences forage quality. As plants mature or advance in maturity, forage quality declines. As the plant matures, a larger portion of the plant is stem as compared to leaves. Also, as the plant matures the fiber components of the plant increases causing a decline in quality and digestibility. Just as the fiber components increase as the plant matures, so does the lignin content increase. Lignin is a cell wall component of the plant that is not digested by ruminants.
On the flip side of forage quality is forage yield. As the plant matures, more plant material is produced and forage yield increases.
So this is a balancing act for producers, to optimize forage quality and yield. If the producer maximizes quality, then forage yield is minimized. If forage yield is maximized, then forage quality suffers.
Harvesting Time Effect on Quality and Subsequent Productivity
This experiment was conducted in the Sandhills of Nebraska. Crude protein of the grass harvested on June 1 was 11.9%, forages harvested on July 1 were 8.0% crude protein, and forages cut on August 1 were 6.4% crude protein. There are huge differences in forage yield based on first harvest date. There is about a ton (2,026 lb/acre) difference in forage yield when comparing the cutting date of June 1 to July 1. There is only about half the yield (1,046 lb/acre) difference between July 1 (4,679 lb/acre) compared to August 1 (5,725 lb/acre) cutting dates. There is not much difference in yield between August 1 and August 15. Early cut hay would be a good protein and energy source for females after calving when the nutrient requirements are high. The early cut hay would also be forage that could be targeted to first-calf-females during their first lactation. If the forage source doesn't meet the requirement, then only minimal supplementation would be needed.
Interesting in this experiment, is that forage availability and forage quality was determined at a fixed time in the fall. In these cases, forage availability and crude protein were determined in September on the same locations that the different cutting dates were performed. It is interesting that in September, forages quality increased as cutting date increased. In other words, the forage in September that was on the area that was harvested on June 1 (9.10% CP) was lower in crude protein compared to the protein content in the area that was harvested on August 1 (16.53% CP). After you think about it, this makes sense, because on September, the forage cut in that area on June 1 is more mature compared to the forage first harvested on August 1 then re-cut in September.
The forage available in September is much greater when the cutting date was June 1 (3,099 lb/acre) compared to August 1 (611 lb/acre). September yield when first cutting date was June 15 (1,921 lb/acre) is not different than that cut on July 1 (1,669 lb/acre).
One of the management practices that keeps the cow harvesting her needs is dormant season grazing. Forage available for dormant season grazing is 2.7 times greater when first cutting was taken as hay on July 1 compared to the forage cut as hay on August 1. Will the dormant standing forage meet the cow's nutrient needs? Maybe, maybe not as it will depend on her stage of production. If it doesn't, then a little strategic supplementation may be warranted.
Two factors that would impact forage quality and yield are precipitation and fertilization. Do these calculations for your area and response expected for different rates of application.
High Quality Meadow Hay as a Winter Supplement for Gestating Beef Cows in the Sandhills of Nebraska. 1993 Beef Cattle Report, Page 8.
Dr. Rick Rasby, Professor of Animal Science
Animal Science, University of Nebraska - Lincoln, Lincoln, NE