Many thousands of acres of rangeland are unusable, or only minimally usable due to a lack of good, low-sulfate water sources. Water with sulfate levels in excess of 2500 ppm consumed by cattle result in poor weight gains and, in some cases, death. Hydrogen sulfide gas produced in the rumen of livestock fed high sulfate water is the primary agent implicated in the development of sulfur-induced polioencephalomalacia (sPEM), leading to poor animal performance and death. The overall goal of this project was to identify a feed additive that would negate the toxic effects of high-sulfate water thereby allowing cattle to safely graze rangelands with high-sulfate water sources. Thiamin was the initial substance evaluated, but it was not consistently effective in reducing the effects of high-sulfate water on cattle health and performance. Zeolite appeared promising due to its potential as a hydrogen sink, hypothetically preventing formation of hydrogen sulfide. It, however, also failed to reduce the impacts of high-sulfate water fed to livestock. Our research team identified an alternative, molybdenum, as a potential feed additive for reducing the negative effects of high-sulfate water consumption. Preliminary results showed molybdenum substantially reduced the production of hydrogen sulfide gas in vitro. An evaluation of the impacts of feeding molybdenum was conducted in summer 2009. The results, however, indicate that molybdenum is also ineffective in reducing the negative impacts of high-sulfate water on animal health and performance.
Water is a critical resource on semi-arid rangelands of western South Dakota, North Dakota, Nebraska, and Kansas. Livestock production on these rangelands is absolutely dependent on adequate quantity and quality of water. It is well known that inadequate water supplies limit the extent to which available forage may be utilized on rangelands, however poor quality water can be just as limiting. When a water source provides water that is lethal, producers are unable to graze livestock on the surrounding rangeland unless an alternate source of good quality water is provided. Many water sources in western South Dakota and in parts of western North Dakota, Nebraska, and Kansas provide water that is high in total dissolved solids (TDS), with sulfates as a major component. Thus, many thousands of acres of rangeland are unusable, or only minimally usable due to a lack of good, low-sulfate water sources. Water with sulfate levels in excess of 2500 ppm consumed by cattle result in poor weight gains and, in some cases, death. Hydrogen sulfide gas produced in the rumen of livestock fed high sulfate water is the primary agent implicated in the development of sulfur-induced polioencephalomalacia (sPEM), leading to poor animal performance and death. It is very expensive to provide alternative water sources for cattle grazing rangelands that support only high-sulfate water sources. It is also difficult and expensive to leave rangelands ungrazed and find alternative forage sources when good quality water cannot be provided to a pasture. Studies in the literature suggest that it is possible to ameliorate the effects of high-sulfate water using feed additives that reduce the production of H2S in the rumen.
Thus, the overall goal of this project was to identify a feed additive that would negate the toxic effects of high-sulfate water thereby allowing cattle to safely graze rangelands with high-sulfate water sources.
1. Determine the appropriate feed additive for ameliorating the effects of high-sulfate water fed to cattle, its effectiveness when supplied to cattle grazing pastures and its cost effectiveness.
2. Initiate a demonstration of the effectiveness of that feed additive on cooperator ranches.
3. Educate producers on the dangers of high-sulfate water and their options for reducing its impacts.
Summary: All studies were conducted at South Dakota State University’s (SDSU) Cottonwood Range and Livestock Research Station, near Philip, SD. In this project, several studies occurred from 2005 through 2009. The first study, in summer 2005, continued previous work to determine the efficacy of thiamin in negating the effects of high-sulfate water on animal health and performance. That study indicated that thiamin was not effective. During 2006, work was limited to a search for a substance to replace thiamin. During that year, Dr. H.H. Patterson left SDSU and this project. He was replaced by Dr. K.C. Olson. Several substances were considered, including minerals and clinoptilolite. The decision was made to evaluate clinoptilolite, a form of zeolite, as a sink for hydrogen in the rumen to reduce the production of H2S. Clinoptilolite was studied in summer 2007 (see below for specifics). Prior to summer 2008, clinoptilolite was further evaluated in vitro for reduction of H2S gas production. The results indicated that the zeolite compound was not effective at reducing H2S gas production. Molybdenum (Mo), a mineral considered in 2006, was then tested in vitro and found to significantly reduce H2S production. Logistics precluded a full study of Mo that summer (2008). In summer of 2009, two studies were conducted (see below). One was a trial evaluating the effect of Mo on animal health and production in drylot and the second, conducted on native mixed-grass prairie pastures, evaluated the level of copper (Cu) supplementation needed to offset the loss of Cu in cattle due to the presence of Mo in the feed. One of our objectives (#2, above) was to demonstrate the effectiveness of feed additives on cooperator ranches. Unfortunately, none of the feed additives tried in this project were successful, so it was determined that it would be unwise to proceed with that objective.
Clinoptilolite (Zeolite) study: This study was conducted in summer 2007. Yearling steers (n = 96; 318.2 ± 2.1 kg of BW) were randomly assigned to 1 of 4 treatments for a 77-d trial period: control with low-S water (566 mg of SO4/kg of BW), high-S water (3,651 mg/kg of SO4), or high-S water plus clinoptilolite supplemented at 2.5 or 5.0% of the diet DM. Each treatment was assigned to 3 pens of 8 animals per pen in a randomized complete block design. Steers were fed a diet of 50% chopped crested wheatgrass (Agropyron desertorum) and 50% pellets. Pellets were 88% wheat middlings and the remaining 12% was made up of the appropriate amount of clinoptilolite for each treatment and limestone. Feed and water were provided ad libitum; consumption was measured daily, and all steers were weighed on d ?2, ?1, 29, 53, 76, and 77. Plasma samples were collected on d 0, 58, and 77, and liver samples on d 0 and 77.
Molybdenum study: This study was conducted in summer 2009. Yearling steers (n=96) were randomly assigned to one of three treatment groups, providing four pen replicates with eight steers per pen for each treatment group, for a 56-d trial: low-S water (LS, 375 ppm), high-S water (HS, 2,218 ppm) and high-S water with 100 mg Mo•kg-1 of feed DM (HSMO, 2,218 ppm). All steers received 10 mg•kg-1 DM of supplemental Cu as tribasic copper chloride (TBCC). Copper was included in treatments because its availability to the animal has been shown to be decreased in the presence of Mo and S. Steers were fed, ad libitum, a diet of 50% ground hay (grass hay to mimic nutritive value of summer pasture) and 50% pelleted supplement formulated from wheat middlings and supplemental minerals, including Mo and Cu as appropriate for the treatment. Water and feed consumption were measured daily. Cattle were monitored for health and symptoms of sPEM three times daily. Rumen gas cap H2S was collected on d -1, 29 and 57. Weights were recorded on d -2, -1, 29, 56 and 57.
Molybdenum and copper grazing study: This study was conducted in summer 2009. Yearling steers (n=120) were assigned randomly to 9 replicate groups, 3 replicates of 3 treatments for a 52 d experiment. All steers in the 9 native mixed-grass prairie pastures were provided with high-S water containing on average 2,201 ppm of sulfate. Additionally, all treatment groups received 100 ppm of supplemental Mo as an antagonist that would bind excess S. Unfortunately, Mo also binds copper (Cu), indicating that supplemental Cu may be necessary. Therefore treatments differed in level of supplemental copper: treatments 1 through 3 received 0, 75, or 150 mg of supplemental Cu, respectively. Mo and Cu were provided in wheat middling-based pellet provided to the steers daily at 2 lb/hd/d. All steers readily consumed the supplement. Prior to the trial, mid-trial and at the conclusion of the trial, ruminal H2S gas cap levels were collected. Animal weights were recorded d -2, -1, 28, 52 and 53.
Clinoptilolite (Zeolite) study: There was a greater (P ? 0.046) frequency of sPEM in high-S steers than control steers, but no differences among high-S treatment groups. In total, 12 cases of sPEM were confirmed by the presence of cortical lesions in steers consuming high-S water. Daily DMI (P = 0.002) and daily water intake (P = 0.001) were less in high-S water steers than control steers. No differences (P > 0.05) in ADG or G:F were observed. Plasma Cu decreased (P = 0.029) to a greater magnitude in high-S water steers than the control steers over the 77-d trial period. Mineral analyses of hepatic tissue from randomly selected healthy steers from each treatment group (n = 10 per treatment) showed an interaction (P ? 0.034) of sample time and treatment for Cu, Se, and Zn concentrations. These results suggest that clinoptilolite does not negate the effects of high-S water, and administration of high-S water decreases herd health through an increased incidence of sPEM and reduced nutritional status.
Molybdenum study: Overall in this trial we found differences between treatments in DM feed intake (P= 0.002), with the Mo supplemented steers consuming less feed than the low-S and high-S treatments. There were no differences between treatments in water intake (P= 0.703). At the end of the trial there was a significant difference in ruminal H2S due to treatment (P= 0.004), with higher ruminal H2S in the steers receiving the supplemental Mo. Steers receiving the Mo supplement had lower ADG than steers in the other treatments (P= 0.0001). Throughout the duration of the trial, two steers were removed from the trial due to advanced symptoms of sulfur-induced PEM (sPEM) from the high-S treatment with no supplemental Mo. These results suggest the use of a Mo supplement was not effective to bind S in the rumen. In addition, there were no differences in water consumption between treatments but there was a marked decline in feed consumption in animals on high-S water with the Mo supplement. Also, ADG in HSMO steers was greatly inhibited. Mo did not provide relief from the negative effects of high-S consumed by forage-fed steers.
Molybdenum and copper study: Over the entire course of the experiment there was a significant difference in ADG due to treatment (P< 0.001), with steers provided Cu gaining more weight per day than those receiving no Cu. There were no differences in water consumption as a result of treatment (P= 0.618). No differences were observed in ruminal H2S due to treatment. No animal losses occurred due to the consumption of high-S water in this trial. Thus, while the addition of Cu provided greater animal weight gains, there was no benefit of Cu in H2S production in the rumen.
Although this study has not yielded a feed additive that counteracts the effects of high-sulfate water on cattle health and performance, it has evaluated and eliminated from further consideration several options that had been thought to have great potential for resolving this problem. There has been considerable interest in this project by colleagues at other universities, which has led to collaborations with other scientists. Dr. Cody Wright at South Dakota State University has collaborated by collecting liver biopsies on all cattle in the study to evaluate copper levels in the liver, providing further information on the effects of sulfates on cattle. Dr. Kristi Cammack of the University of Wyoming has been studying the effect of high-sulfur water on gene expression of the cattle in this study since 2007. These studies, and others, will provide information to not only better understand the mechanisms by which high sulfur levels affect cattle, but also to potentially identify genetic traits in cattle that might allow ranchers to select cattle that are more resistant to the effects of excess sulfur in feed and water.
While this research has not been able to provide ranchers in the region with supplementation strategies to reduce high-sulfate water issues, it has been very successful in making ranchers aware of the problem. Every county Extension office in western South Dakota has an electrical conductivity meter that provides a good first estimate of the total dissolved solids in water, which correlates well with the level of sulfates in water. Ranchers bring water samples in for free testing, and any samples that are suspect are sent to a lab for further analysis. Many ranchers with water sources that have been identified as having a history of high sulfates have their own meters and monitor their water carefully. Water development, including rural water systems, have been expanded to provide low-sulfate water to areas with sulfate problems.
Studies on sulfur issues are expanding in the region and elsewhere. While high-sulfate water is an issue in other regions, considerable impetus to study the issue is also coming from concerns over the sulfur levels of feeds, especially byproducts of ethanol production, including distillers grains.
It was our intent to perform an economic analysis to evaluate a successful feed additive with alternatives (e.g. no grazing, development of other water sources, timing grazing for lowest S intake, etc.). Without a successful feed additive, however, such an analysis could not be accomplished.
As mentioned above, ranchers in the region have become very aware of the consequences of high-sulfate water, and many have had their water sources tested by SDSU Extension offices for free. Some have even purchased their own electrical conductivity meter so that they can test their water more frequently. Our work has been followed closely by area ranchers, and interest in any options to reduce the negative effect of high-sulfate water is still very high.
Educational & Outreach Activities
Peer reviewed journal:
Kessler, K.L., K.C. Olson, C.L. Wright, K.J. Austin, P.S. Johnson, R.R. Cockrum, and K.M. Cammack. Hepatic gene expression in steers administered high-sulfur water. J. Anim. Sci. (in review).
Cammack, K.M., C.L. Wright, K.J. Austin, P.S. Johnson, P.A. Ludden, R.R. Cockrum, and K.C. Olson. 2010. Effects of High-sulfur Water and Clinoptilolite on Health and Growth Performance of Steers Fed Forage-based Diets. J. Anim Sci. 88:1777-1785.
Knight, C.W., K.C. Olson, C.L. Wright, K.J. Austin, K.M. Cammack, and R. Cockrum. 2008. Sulfur-induced polioencephalomalacia in roughage-fed feedlot steers administered high-sulfur water. Proc. West. Sec. Amer. Soc. Anim. Sci. 59:364-366.
Kessler, K.L., K.C. Olson, C.L. Wright, K.J. Austin, P.S. Johnson, K.M. Cammack. 2010. Effect of supplemental molybdenum on forage-fed steers receiving high-sulfur water. J. Anim. Sci. 88: (in press).
Kessler, K.L., K.C. Olson, C.L. Wright, K.J. Austin, P.S. Johnson, and K.M. Cammack. 2009. Effects of high-sulfur water and clinoptilolite on growth performance and gene expression of steers fed forage-based diets. J. Anim. Sci. Vol. 87(E-Suppl. 3):72.
Kessler, K.L., K.C Olson, C.L. Wright, K.J. Austin, K. McInnerney, P.S. Johnson, and K.M. Cammack. 2009. Effects of high-sulfur water on growth performance and gene expression of steers fed forage-based diets. J. Anim. Sci. 87(E-Suppl. 2):73:533.
Richter, H.A., K.C. Olson, P.S. Johnson, and Cody Wright. 2009. Clinoptilolite as a supplement to reduce the toxic effects of high sulfate water. 62nd Society for Range Management Annual Meeting. Paper No. 2030-18.
Kessler, K.L., K.C. Olson, C.L. Wright, K.J. Austin, P.S. Johnson, and K.M. Cammack. 2009. Effects of molybdenum supplementation on performance of forage-fed steers receiving high-sulfur water. In: 2009 South Dakota State University Beef Report.
Kessler, K.L., K.C. Olson, C.L. Wright, K.J. Austin, P.S. Johnson, and K.M. Cammack. 2009. Copper supplementation of grazing yearling steers supplemented with molybdenum while consuming high-sulfur water. In: 2009 South Dakota State University Beef Report.
Areas needing additional study
There is a critical need for further study. This can be approached on several fronts:
1) Continue the search for feed additives to reduce the effects of sulfur that is consumed as feed or water.
2) Develop cost-effective methodologies to eliminate sulfur problems from water prior to livestock consumption.
3) Continue to evaluate gene expression work to potentially identify animals less susceptible to the effects of high sulfates.