Kun Jun Han and Jeremy Hebert

Louisiana experienced extremely dry summer and fall seasons in 2023. According to the National Integrated Drought Information System, the worst drought continued from June to late September in the southern U.S., including Texas, Louisiana and Mississippi. This has put a strain on quality forage production and has impacted the availability of pasture and hay for livestock. In late 2023, LSU AgCenter economist Kurt Guidry confirmed significant economic impacts on the state's livestock industry and hay production due to the weather conditions.

Conventional Forage Versus Nonconventional Alternatives

Due to mild winter weather, Louisiana livestock producers have historically had the advantage of year-round forage production, beginning with cool-season forage, which includes annual ryegrass, small grain forage and clovers, followed by warm-season forage such as bermudagrass, bahiagrass, forage sorghum and cowpeas. However, the shortage of hay caused by the dry, hot weather in 2023 led farmers and ranchers to seek alternative feeding options.

Table 1 displays the crude protein and total digestible nutrient values obtained from hay samples submitted to the LSU AgCenter Forage Testing Lab in 2023. Agricultural byproducts usable for cattle feeding were categorized as “byproduct or alternative hay” to distinguish them from conventionally produced forage. The lab received five times more alternative hay sample submissions during this time frame than before, reflecting the increase in the use of alternative hay for the year’s winter feeding.

Byproducts or alternative hays are recovered from main agricultural commodity productions, usually grains. The nongrain portions of the plant mature and contain low protein and high fiber, resulting in low-quality feeds with various nutrient values. Examples of such byproducts are cottonseed meal (approximately 45% crude protein) and cotton gin trash (approximately 10.5% crude protein). Samples sent to the lab indicate that varieties of alternative hay were utilized for livestock feeding in 2023. Barnyardgrass samples were also submitted as forage despite being known as a fast-maturing annual weed. An analysis of barnyardgrass indicated some potential as an alternative forage when fed prior to seedhead development. An analysis of multiple Johnsongrass samples indicated potential utilization of this species as well. However, Johnsongrass and sorghum forage must be used with extreme caution as both species can lead to nitrate toxification when produced in drought conditions.

With the exception of barnyardgrass, cotton gin trash and peanut residue, the crude protein and energy (total digestible nutrients) contents of the sampled alternative hays are overall insufficient to meet the nutrient requirements of actively growing cattle. The average nutrient contents in sorghum forage and bermudagrass were above 8% crude protein and 51% total digestible nutrients, which were greater quality hay than medium-quality hay, followed by hays of unidentified grass, bahiagrass, crabgrass and some native grasses (Table 1).

Potential of Rice Straw as Alternative Forage

Given that rice straw samples composed the largest group of submissions, it is presumed that rice straw is the alternative hay most readily available to weather the current low hay supply in Louisiana. Unlike countries with relatively low forage production capabilities, rice straw has rarely been considered as forage in the United States. As Table 1 shows, the crude protein and total digestible nutrients of rice straw were equivalent to or even below utility grade. Notable was the ash content in the analyzed Louisiana rice straw, which averaged around 17%, twice the average of bermudagrass hay. The silica content of ash contributed to a large portion of that number. Silica is a main component of glass and sand, and it does not have any nutrient value.

Injections of ammonia gas into plastic wrap-covered rice straw bales have been used in rice-producing countries to improve the nutrient value of rice straw. Table 2 (available at LSUAgCenter.com) indicates the substantial improvement of crude protein and total digestible nutrients resulting from the gas injection. However, this treatment is not practical in the United States, given the required injection cost, preparation and safety considerations needed.

Feeding Value Variation in Rice Straws

Rice straw is an abundant byproduct in Louisiana; therefore, it has value as an emergency feed source. A study was conducted to investigate potential feed value differences in rice straws produced from different backgrounds, such as variety, parish and nitrogen fertilization. The total digestible nutrient index may differ by rice variety, indicating potential differences in fiber characteristics in rice stems. The most significant difference was found in protein content in rice straw cultivated at the different nitrogen fertilizer application rates. The nutrient values were not influenced by parish, indicating the quality may vary but without consistency in the production regions. Despite the temporary challenges, the increased focus on alternative feed options, particularly rice straw, underscores the resilience and adaptability of Louisiana's livestock industry in the face of adverse weather conditions.

Implications

Due to extreme weather during the growing season of 2023, hay production was at a historic low. Rice straw and other agricultural byproducts are potential alternative feed sources, but the nutrient values do not meet most livestock classes' protein and energy requirements. Although chemical treatments on rice straw have been practiced in some countries to enhance nutrient value and digestibility, the economic gain of those treatments is uncertain in U.S. livestock operations. Additionally, more systematic research is required to confirm the potential variations, as rice straw quality has been found to be inconsistent with production backgrounds. In the meantime, using rice straw and agricultural byproducts as feed should be considered a temporary solution to be managed carefully with appropriate protein and energy supplements.

Kun Jun Han is an associate professor in the AgCenter School of Plant, Environmental, and Soil Sciences, and Jeremy Hebert is an extension associate based at the AgCenter H. Rouse Caffey Rice Research Station.

This article appeared in the spring 2024 edition of Louisiana Agriculture.

Soil Health Concerns

Removing rice straw from a rice field offers a couple of advantages. Notably, it enhances water quality for crawfish production by eliminating decomposing foliage material that consumes oxygen in the water, thereby improving conditions for crawfish. Additionally, employing methods like baling rice straw as baleage or postharvest mowing can lead to a more uniform ratoon crop stand, enhancing overall productivity. However, this practice comes with the drawback of depriving the field of essential nutrient material that would otherwise replenish soil fertility through natural decomposition. Thus, farmers must be vigilant about monitoring soil health and may need to supplement nutrients if a significant amount of rice straw is removed, underscoring the importance of soil sampling to inform management decisions. Jeremy Hebert

Rice straw is an abundant byproduct in Louisiana; therefore, it has value as an emergency feed source. A study was conducted to investigate potential feed value differences in rice straws produced from different backgrounds, such as variety, parish and nitrogen fertilization. AgCenter file photo

Rice straw is commonly used to feed livestock in Asia. Photo courtesy of German Müller/GIZ Thailand