The Cow-Calf Manager
Livestock Update, April 2006
John B. Hall, Extension Animal Scientist, Beef, Virginia Tech
Selenium Supplementation Strategies for Cow/Calf Herds
Most beef producers know that selenium is important for beef cattle, but quite often they are unsure as to how much selenium is needed or what form to provide. Selenium (Se) is an essential trace mineral for cattle. It is involved in proper immune function, acts as an antioxidant, and helps activate thyroid hormones. Symptoms of selenium deficiency include muscle damage, increased illness, impaired growth and decreased reproductive efficiency.
The most common ailment noticed by cattlemen in selenium deficient cattle is white muscle disease. This disease causes calves to be stiff and have damage to their muscles especially in the hind legs. In addition, sudden death can result from cardiac failure in calves deficient in selenium. Sudden death can happen a few days after birth or a few weeks later.
Impact of dietary selenium The soils of the Mid-Atlantic and Southeastern US are extremely deficient in selenium, therefore, pasture, hay, and grains from this region supply inadequate amounts of selenium. Selenium must be supplemented in mineral or injectable form. The focus of the rest of this article will be when, how, and in what form do we supplement Se to the cow-calf herd.
Selenium is stored in the liver so calves born to properly supplemented dams will have enough selenium available for the first 30-60 days of life. However, transfer of selenium from dam to the developing calf has some inefficiency. So, cows need to be supplemented with high levels of Se prepartum to obtain adequate levels of Se in the newborn calf. Research indicates that calves from cows fed free-choice mineral with 60 ppm or 120 ppm Se had greater blood Se concentrations than calves from dams fed mineral with 20 ppm Se (Awadeh et al., 1998). In addition, cows on high Se supplementation produced higher quality colostrum with greater antibody levels. Unfortunately, free-choice cattle minerals are limited by FDA to 26 ppm or 52 ppm depending on the expected consumption of mineral.
Selenium transfer from dam to calf through the milk is relatively poor. Even if calves are born with adequate levels of selenium, they usually become selenium deficient before they begin to eat a significant amount of mineral. A study was conducted to examine if well supplemented cows could supply enough selenium through their milk if calves could not get access to mineral (Davis et al., 2005). The optimum blood levels of selenium are still a point of discussion among scientists, but > 100 ug/L is generally agreed to be adequate. In all supplementation strategies except Se-Yeast, transfer of Se from milk to calf was insufficient to keep calves from becoming Se deficient or at least low in Se (Table 1). Remember in this study calves were not able to reach the mineral and were not given injections.
Several important points are illustrated in Table 1.
Table 1. Blood selenium levels in calves from cows supplemented with different forms of Se from mid-gestation through weaning.*
|Age of Calf, days|
|Supplemental Se Source||0||30||90||205|
|Control (no Se)||Adequate||Marginal||Low||Deficient|
|Barium selenate (Deposel), one injection at start||High||Marginal||Low||Deficient|
|Sodium selenate (Mu-Se®), injection at start & every 40 d||High||Marginal||Deficient||Deficient|
|Free-choice mineral mix (sodium selenate); 26 ppm with 1.5 oz per day consumption||High||Marginal||Marginal||Low|
|Free-choice mineral mix (Sel-plex®;SeYeast); 26 ppm with 1.5 oz per day consumption||Very High||High||High||High|
Another study examined effect of the source of Se in a free-choice mineral for the cow-calf herd on immune function in backgrounded calves. Calves and cows were allowed free access to the mineral from mid-gestation through weaning. Minerals were 1) no supplemental Se; 2) 26 ppm Se from sodium selenate; 3) 26 ppm Se from Se-yeast. Regardless of mineral consumed, performance of cows and calves through weaning was not affected. However, only Se-yeast mineral calves had blood levels of Se that were not low by weaning (Gunter et al., 2003).
During backgrounding feeding a diet that was marginal to adequate in selenium was not enough to overcome the selenium deficiency acquired in the pre-weaning phase as indicated by immune response (Gunter et al., 2003). However, calves that had adequate Se levels from the Se-yeast mineral had good immune responses. Research from Virginia Tech indicated that Se deficient backgrounding calves fed high levels of Se (> 80 ppm in mineral) or fed a 20 ppm Se mineral and given an injection of Se-Vit E had improved immune response (Swecker et al., 1989). Therefore, selenium supplementation both before and during the backgrounding phase is important.
It is not surprising that Se-yeast (Sel-Plex®) or other organic forms of Se are able to enhance selenium status in calves. Organic mineral complexes have long been recognized for their high absorption rate and improvements in circulating mineral concentrations. Producers need to weigh the cost of these organic minerals against their current supplementation strategies and animal performance.
How to supplement the cow-calf herd
Producers can follow one of three supplementation strategies - traditional inorganic strategy, organic supplementation strategy, or combination strategy.
Traditional inorganic strategy (Standard VT recommendations):
Organic supplementation strategy
With all strategies it is essential that even young calves (60+ days) can access mineral. This may mean lowering the mineral feeder, especially if you are using a barrel feed hung from a tree. Remember to check you label on you mineral supplement to ascertain if you are feeding sufficient selenium. If you have other questions about mineral supplementation of cow-calf herds contact your county agent or nutritionist.
Awadeh, F.T., R.L. Kincaid, and K.A. Johnson. 1998. Effect of level and source of dietary selenium on concentrations of thyroid hormone and immunoglobulins in beef cows and calves. J. Anim. Sci. 76: 1204-1215.
Beck P.A., T.J. Wistuba, M.E. Davis, and S.A. Gunter. 2005. Case Study: Effects of Feeding Supplemental Organic or Inorganic Selenium to Cow-Calf Pairs on Selenium Status and Immune Responses of Weaned Beef Calves. Prof. Anim. Sci. 21:114-120.
Davis P.A., L.R. McDowell, R. Van Alstyne, T.T. Marshall, C.D. Buergelt, R.N. Weldon, and N.S. Wilkinson. 2005. Case Study: Tissue and Blood Selenium Concentrations and Performance of Beef Calves from Dams Receiving Different Forms of Selenium Supplementation. Prof. Anim. Sci. 21:486-494.
Gunter, S.A., P.A. Beck, and J.M. Phillips. 2003. Effects of supplementary selenium source on the performance and blood parameters in brood cows and their calves. J. Anim.Sci. 81:856-862.
Swecker, Jr., W.S., D.E. Eversole, C.D. Thatcher, D.J. Blodgett, G.G. Schurig, and J.B. Meldrum. 1989. Influence of supplemental selenium on humoral immune responses in weaned beef calves. Am. J. Vet. Res. 50:1760.