Effects of a long-acting, trace mineral, reticulorumen bolus on range cow productivity and trace mineral proﬁles 1 J. E. Sprinkle,* 2 S. P. Cuneo,* H. M. Frederick,* R. M. Enns,† D. W. Schafer,* G. E. Carstens,‡ S. B. Daugherty,‡ T. H. Noon,* B. M. Rickert,* and C. Reggiardo* *University of Arizona, Tucson 85721; †Colorado State University, Fort Collins 80523; and ‡Texas A & M University, College Station 77843 ABSTRACT: The objectives were to determine if strategic supplementation of range cows with a long- acting (6 mo), trace mineral, reticulorumen bolus con- taining Cu, Se, and Co would: (1) increase cow BCS and BW, and calf birth, weaning, and postweaning weights, or weight per day of age (WDA); (2) increase liver concentrations of Cu or Zn in cows, or blood Se, Cu, or Zn concentrations in cows and calves; and (3) vary by cow breed for any of these response variables. There were 192 control and 144 bolused Composite cows (C; 25% Hereford, Angus, Gelbevieh, and Senepol or Barzona); 236 control and 158 bolused Hereford (H) cows; and 208 control and 149 bolused Brahman cross (B) cows used in a 3-yr experiment. Cows were weighed and scored for body condition in January, May, and September, and all bolused cows received boluses in January. Each year, from among the 3 breed groups a subset of 15 control and 15 bolused cows (n = 90) had samples obtained in January and May for liver Cu and Zn, blood Se, and serum Cu and Zn. As for cows, blood and serum from the calves of these cows were sampled each year in May and September for Cu, Se, and Zn. There was a signiﬁcant breed × year × treatment inter- action (P = 0.001) for cow weight loss from January to Key words: beef cattle, breed, copper, mineral, range, selenium 2006 American Society of Animal Science. All rights reserved. J. Anim. Sci. 2006. 84:1439–1453 INTRODUCTION A large area of central Arizona from Roosevelt Lake eastward to New Mexico has been reported to be deﬁ- 1 We acknowledge the support of the Arizona Experiment Station; Texas Agricultural Experiment Station; Mesquital Livestock Service, Tucson; and Telsol Ltd., manufacturer of Cosecure, P. O. Box HH7, Leeds, UK LS8 2YE. Mention of a proprietary product does not consti- tute a guarantee or warranty of the product by Arizona Experiment Station, University of Arizona, Texas Agricultural Experiment Sta- tion, Texas A & M University, Colorado State University, or the authors and does not imply its approval to the exclusion of other products that may also be suitable. 1439 May. Calf WDA, weaning, and postweaning weights did not differ (P > 0.40) between bolused and control cows, but there was a signiﬁcant (P = 0.022) breed × year × treatment interaction for birth weight. Liver Cu was deﬁcient (<75 ppm; P < 0.001) in control cows and ade- quate (>75 to 90 ppm) for bolused cows. Liver Cu dif- fered by year (P < 0.001). Blood Se was adequate (>0.1 ppm) for all cows except in January 2001 and 2002. There was no difference (P > 0.50) in blood Se between treatment groups in January, but bolused cows had greater (P < 0.01) blood Se in May. Breed differences for blood Se concentrations existed for bolused cows, with B having greater (P < 0.05) blood Se than either C or H cows. Breed differences also existed for control cows, with H having less blood Se (P < 0.04) than B or C cows. Calves from bolused cows had greater blood Se than calves from control cows (P = 0.01). Supplementa- tion via a long-acting trace mineral bolus was successful in increasing liver Cu in cows and blood Se in cows and calves, but the responses varied by year. Bolus administration had variable effects on BW change in early lactation, depending on breed and year, which may indicate the need for breed- and year-speciﬁc sup- plementation programs. cient in Se (Kubota et al., 1967). With additional sam- pling, it seems that almost all of the broken Mogollon Rim country with volcanic-derived or granitic soils are Se deﬁcient. Additionally, many of these areas appear to be Cu deﬁcient during some time periods (our unpub- lished observations). Due to the rugged topography of many of these rangelands and due to posted wilderness areas allowing no vehicle access, delivery of traditional trace mineral supplements can be problematic. 2 Corresponding author: sprinkle@ag.arizona.edu Received May 11, 2005. Accepted January 9, 2006.