Effectiveness of thiamin in reducing the impacts of high-sulfate water

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.