Beef Research Beef Cattle Cattle Institute Institute Research
BULLERS BULLERS
By: D.U.Thomson, Thomson, C.D. Reinhardt, By:J.C. J.C. Simroth, Simroth, D.U. C.D. Reinhardt, S.J. S.J. Bartle,The TheBeef Beef Cattle Cattle Institute, Bartle, Institute,Kansas KansasState StateUniversity University Thebuller buller steer steer syndrome The syndrome commonly commonlyobserved observedin feedlots is an abnormal, aberrant behavioral and in feedlots is an abnormal, aberrant behavioral andsocial social conditionininwhich whichsteers steersrepeatedly repeatedlymount mountanother anothersteer. steer. condition The steer being mounted is called the “buller” and the The steer being mounted is called the “buller” and the steerriding ridingisiscalled calledthe the“rider.” “rider.” steer As a consequence riding, the the As a consequence of ofthe theexcessive excessive riding, buller steer often becomes exhausted, shows loss of hair, buller steer often becomes exhausted, shows loss of hair, can develop swelling and trauma along the dorsal line can develop swelling and trauma along the dorsal line and andhead, tail head, andextreme in extreme cases suffer from tail and in cases cancan suffer from broken broken bones or may even die from injuries. bones or may even die from injuries. Thereappears appears to to be bulling There be various variousdegrees degreestoto bulling activity; some riding activity is relatively harmless activity; some riding activity is relatively harmlessand and fallsunder underthe thecategory categoryofof“horseplay”. "horseplay”. On Onthe theother otherend end falls of the spectrum we have serious bulling activity in which of the spectrum we have serious bulling activity in which normalsteers steersvigorously vigorously pursue pursue the the abnormal normal abnormal steer, steer, the the buller, who may or may not be receptive to be mounted buller, who may or may not be receptive to be mounted (Ulbrich, 1981). (Ulbrich, 1981). The incidence of the buller steer syndrome ranks incidence of theoccurring buller steer syndrome ranks third inThe disease conditions in U.S. feedlots (2.8 third in disease conditions occurring in U.S. feedlots (2.8 + 0.5%; USDA, 2013) only behind bovine respiratory +disease 0.5%; and USDA, 2013) only behind bovineArespiratory metabolic/digestive conditions. survey disease and metabolic/digestive conditions. A survey conducted in Kansas in the 1970s by Brower and conducted in Kansas in the 1970s byof Brower and Kiracofe Kiracofe (1972) indicated that 2% all feedlot steers in (1972) indicated that 2% of all feedlot steers Kansas experienced the buller steer syndrome.in Kansas experienced thesame buller steer syndrome. In the manner, Brower and Kiracofe (1978) In the same manner, Brower (1978) and Irwin et al. (1979) reported thatand the Kiracofe annual incidence and Irwin steers et al. (1979) thatindustry the annual of buller within reported the feedlot fell incidence somewhere ofbetween buller steers within the feedlot industry fell somewhere 2 and 4%. A 15-year summary of buller between 2 and 4%. A 15-year summary of buller incidence incidence in Midwest feedlots consisting of over 5 inmillion Midwest feedlots consisting of over 5 million steers reported a buller incidence of 2.45%steers reported a buller incidence of 2.45% (Edwards, 1995). (Edwards, 1995). Furthermore, Furthermore,aa2-year 2-yearstudy studyby byTaylor Tayloretetal.al. (1997b) at a western Canada feedlot using (1997b) at a western Canada feedlot using78,445 78,445male male (intact) cattle indicated a buller incidence rateranging ranging (intact) cattle indicated a buller incidence rate from from0.0 0.0toto11.2%, 11.2%,with withananaverage averageincidence incidenceofof2.7%. 2.7%. Why DoDo Bullers Happen? Why Bullers Happen? Over time multiple been implicated implicated Over time multiple factors factors have have been by byfeedlot feedlotmanagers, managers, consulting consulting nutritionists, nutritionists, consulting consulting veterinarians, researchersasascontributing contributing to the veterinarians, and and researchers to the incidence incidenceand andmanifestation manifestationofofthe thebuller bullersteer steersyndrome. syndrome. Suggested factors factors include of of anabolic Suggested include the theuse use anabolic agents, improper implantation, re-implantation or double agents, improper implantation, re-implantation or dosing,dosing, changes in weather and seasonal factors, factors, double changes in weather and seasonal excessivemud mud or or dusty excessive dusty pen penconditions, conditions,entry entryweights, weights, disease,group groupsize, size, improper improper or or late disease, late castration, castration, feeding feeding management, presence of cycling heifers, transportation, management, presence of cycling heifers, transportation, handling, mixing, and and aggressive social social handling, mixing,dipping, dipping, aggressive dominancebehavior behavior(Stookey, (Stookey,1997; 1997;Taylor Tayloretetal., al.,1997b; 1997b; dominance Irwinetetal., al.,1979; 1979;Peck, Peck,2005; 2005;Sprague, Sprague,1999). 1999). Irwin generally recognized recognized that that anabolic ItItisisgenerally anabolic implants implants
maybebeone one of several factors involved the steer buller may of several factors involved in theinbuller steer syndrome; is, greater total dosages of anabolic syndrome; that is,that greater total dosages of anabolic compoundssuch such as estradiol, in incremental compounds as estradiol, resultresult in incremental increases in bullers. Taylor et al. (1997a) concluded increases in bullers. Taylor et al. (1997a) concluded that that re-implanting with of estradiol + 200 re-implanting with 20 mg20 of mg estradiol + 200 mg of mg of progesterone progesteronedid didnot notalter alterbuller buller incidence incidence compared compared with with cattle cattlereceiving receivingaasingle singledose dose of of the the same same implant implant initially. initially.In contrast, Turgeon and Koers (1997) analyzed In contrast, Turgeon andinvolving Koers (1997) data from a historical database aboutanalyzed 48 million data fromcattle a historical database that involving 48 million feedlot and reported bullerabout incidence was feedlot cattle and reportedforthat buller incidence substantially increased re-implanted steerswas vs. nonsubstantially for re-implanted reimplanted increased steers (3.21% vs 1.65%). steers vs. nonreimplanted steers (3.21% vs Booker et al. (1997)1.65%). conducted a field trial in Booker al. (1997) conducted trial in Nebraska withet14,196 steers fed for aanfield average of 147 Nebraska withresearchers 14,196 steers fed for an of 147new days. These reported thataverage the overall days. researchers reported when that the rider These incidence was increased theoverall initialnew implant rider incidence was increased when the initial implant contained 28 mg of estradiol benzoate and 200 mg of contained mg of compared estradiol benzoate and 200 mg of with trenbolone28acetate with an initial implant trenbolone acetate compared with an initial implant with28 36 mg of zeranol followed by a re-implant with either 36 mg of zeranol followed by a re-implant with either 28 mg of estradiol benzoate + 200 mg of trenbolone acetate mg of estradiol benzoate + +200 or 24 mg of estradiol-17β 120mg mgofoftrenbolone trenboloneacetate acetate or(9.93, 24 mg of estradiol-17β + 120 mg of trenbolone acetate 5.06, and 3.99% new riders, respectively), whereas (9.93, 5.06, and 3.99% newdid riders, respectively), whereas the rider re-pull incidence not differ. the riderVoyles re-pulletincidence did not differ. al. (2004) implanted cattle with a single Voyles et al. (2004) implanted with a acetate single 17β + 120 mgcattle trenbolone dose of a 24 mg estradiol dose of a 24 mg estradiol 17β + 120 mg trenbolone implant on day 1 or a 36 mg zeranol implant on day 1 acetate implant on day zeranol17β implant onmg with1aor24a 36 mgmg estradiol + 120 and re-implanted day 1 and re-implanted with a 24 mg estradiol 17β + 120 trenbolone acetate implant on day 50. Results show a mg trenbolone acetate implant on day 50. Results show a lower incidence of new bullers when steers received only lower incidence of new bullers when steers received only oneimplant implantononday day 1 vs. steers were re-implanted one 1 vs. steers thatthat were re-implanted on on day 50 (P = 0.01; 0.92% vs. 1.93%, respectively). day 50 (P = 0.01; 0.92% vs. 1.93%, respectively). However,the theoverall overallincidence incidence bullers did not However, of of newnew bullers did not differbetween betweentreatments treatments(P>0.43). (P>0.43). differ Prouty and Larson (2010) Prouty and Larson (2010)reported reportedaanon-significant non(P = 0.20) numerical difference in buller incidence significant (P = 0.20) numerical difference in buller when using different implanting strategies in finishing feedlot incidence when using different implanting strategies in steers. Cattle received either a 14 mg estradiol benzoate finishing feedlot steers. Cattle received either a 14 mg + 100 mg trenbolone implant (A) on day 0 and estradiol benzoate + 100acetate mg trenbolone acetate implant re-implanted at day 79 with the same implant or at (A) on day 0 and re-implanted at day 79 with the sameday 70 withora at 28day mg 70 estradiol + 200 mg trenbolone implant with a benzoate 28 mg estradiol benzoate + acetate implant (B), or received a single of a 40 200 mg trenbolone acetate implant (B), ordose received a mg estradiol 200 mgmg trenbolone implant (C) on day single dose+ of a 40 estradiolacetate + 200 mg trenbolone 0. Buller incidence for “A-A”, “A-B”, and “C” implanted acetate implant (C) on day 0. Buller incidence for “Acattle was 0.24, 0.76, and 1.65%, respectively. A”, “A-B”, and “C” implanted cattle was 0.24, 0.76, and Irwin et al. (1979) also found that type of implant 1.65%, respectively. and time ofetimplantation influenced Irwin al. (1979) also found thatthe typeincidence of implantof bullers, a greater percentage bullers in groups and time with of implantation influencedofthe incidence of of steers implanted with a combination of progesterone and bullers, with a greater percentage of bullers in groups of estradiol (2.46%) thana combination in those implanted with zeranol steers implanted with of progesterone and (0.46%);(2.46%) 13,244 steers the combination implant, estradiol than inreceived those implanted with zeranol and 1,721 steerssteers received the zeranol implant. implant, (0.46%); 13,244 received the combination and 1,721 steers received the zeranol implant. 14
