Conservation Reserve Program Hay Quality in North Dakota in 2002

Kevin Sedivec, Extension Rangeland Specialist and Greg Lardy, Extension Beef Specialist, Animal and Range Sciences Department, NDSU

All of North Dakota’s Conservation Reserve Program (CRP) lands were open to emergency haying and grazing in 2002. Throughout the state, many CRP fields were hayed or grazed because of cost efficiency, had very few restrictions, and, in many cases, was the only standing forage in a county. NDSU Extension Service collected a number of CRP hay samples to determine its nutritional quality.

In 1996, when we also collected CRP samples, the primary restriction on haying CRP was timing (no earlier than July 15). This year, fields were open as early as July 2. In order to achieve a more representative analysis of the fields, samples were categorized by the amount of alfalfa they contained. Also, assuming that later clippings would have a lower nutritional value due to the maturity of the plants, samples were divided by clipping date. County agents collected samples from 131 CRP fields in 16 counties, mainly from the southern tier counties of North Dakota. Samples were sent to NDSU for analysis.

The average cutting date across North Dakota was July 20. Only 15 % of CRP fields were harvested by July 10, with 77 % cut between July 11 and August 1. Over 92 % of all stands in this study were harvested by August 1. Over 44 % of the samples had 10 % or less alfalfa and 82 % of all samples contained less than 40 % alfalfa. Average forage production per CRP stand was 3,775 lb per acre, ranging from 1,000 to 10,000 lb per acre. The highest producing CRP stands were found in central North Dakota and lowest producing stands in Adams County.

All samples were analyzed for crude protein (CP), acid detergent fiber (ADF), ash, and dry matter (DM), with total digestible nutrients (TDN) calculated using ADF. Fields were categorized as having 1) less than 10% alfalfa, 2) 10-40% alfalfa, or 3) more than 40% alfalfa. Percent crude protein content was highest on those CRP fields with more than 40% alfalfa, averaging 21% higher CP than fields with 10 to 40% alfalfa, and 43% higher than fields with less than 10% alfalfa (Table 1). Total digestible nutrients followed the same trend, with a slightly higher value found in CRP stands with greater levels of alfalfa.

The CP content and TDN were compared by date of clipping: cut prior to July 10, cut between July 11 and 20, cut between July 21 and August 1, and cut after August 1. Stands cut prior to July 10 had a higher CP content than all stands cut after July 10 (Table 2). Conservation Reserve Program stands cut in late July and August were similar in CP content. The TDN did not differ between clipping dates.

Clipping date and amount of alfalfa played an important role in determining the quality of CRP hay. Most hay samples with less than 10% alfalfa in the stand and cut in late July or August were lower in nutritional quality, achieving an average CP content around 7.0 to 7.5%. These stands would provide adequate nutrient content when fed to beef cows in the second trimester of pregnancy (assuming cows are not lactating); however, this level of CP would be inadequate during the third trimester of pregnancy and lactation.

If the CRP stand was cut in early to mid July and/or had greater than 10% alfalfa, average CP content was between 8 and 10%. This type of CRP hay would meet the minimum requirements of a beef cow throughout much of her pregnancy; however, it would be deficient during lactation unless alfalfa composition was greater than 30 to 40% of the stand. This CRP hay would be very similar to other grasses and alfalfa in terms of energy supplied, which is inadequate from the last trimester of pregnancy and during lactation.