Feed Lot

SEP-OCT 2018

Feedlots and cow/calf operations in the beef industry who feed 500 or more has annually on grains and concentrates; maintain 500 or more beef cows; backgrounder, stocker/grower, preconditioner; veterinarian, nutritionist, consultant

Issue link: https://feedlotmagazine.epubxp.com/i/1019360

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Page 19 of 47

20 FEED•LOT September/October 2018 COW/CALF CORNER BY CHANDA ENGEL, FORMER SDSU EXTENSION COW/CALF FIELD SPECIALIST C ow-calf pairs are getting moved to green grass and it is a good feeling to see them out grazing. While weaning may be a ways off, calf growth that leads to excellent calf weaning weights is a major goal of this phase of the cow- calf business. If someone asked you to give them $1.50 per steer calf at spring turn out, in return, for every 37 head (your cost is $56), they will give you an additional 550 lb steer calf at weaning. Would you take the deal? This is essentially the return cattleman can expect if they place a small hormone implant into the ear of each suckling steer calf at turn out. In 1997 Selk from the Oklahoma Agricultural Experiment Station summarized 23 research projects evaluating performance of suck- ling steer calves implanted be- tween 30 and 90 days of age, with 36 mg of a product containing the growth-promoting Zeranol. At the end of the experiment they docu- mented a 5.3% increase in average daily gain. Over a 130 day pasture period implanted steers would wean off 13 pounds heavier than their non-implanted counterparts. Since genetics have changed and improved over the years, it is im- portant to note that Bayliff and colleagues recently found simi- lar results when they studied a group of cattle in Oklahoma. In a 130 day pasture period, suck- ling steers weaned off 17 pounds heavier than their non-implanted counterparts. Additionally, work by Pritchard and colleagues at SDSU in 2015 documented implant technology can increase wean- ing weights of suckling steers by 22 pounds. The SDSU study looked at the effects of suckling calf perfor- mance from implants based on timing of the implant and age of dam. They implanted calves in May or August and classified dams into two groups: less than or greater than four years of age. Overall steers from mature dams weaned heavier calves than younger dams. Steers from mature dams that were implanted in May, weaned off 40 pounds heavier than their non-im- planted counterparts. However, if they were implanted in August they only added an additional 17 lbs. Conversely, steers from young dams (< 4 years of age) implanted in August weaned off 25 pounds heavier than non-implanted steers. Steers from young dams implanted in May only posted a 9 pound in- crease in weaning weight. Cow age definitely impacts the response that cattlemen can expect from using implant technology. Planning the implant timing based on the dam's age will give the best possible re- sponse in suckling calves. Implant earlier in the grazing season for steers suckling older dams or later in the grazing season for steers suckling younger dams. The amount of added gain po- tential that implants provide would make one think nearly every steer turned out should have one in its ear. However, according to the 2008 National Animal Health Monitoring System (NAHMS) survey, the use Suckling calf implants add value

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