Beef Cattle Institute Research BULLERS Beef Cattle Institute Research BULLERS

By: J.C. Simroth, D.U. Thomson, C.D. Reinhardt, S.J. Bartle, The Beef Cattle Institute, Kansas State University

By: J.C. Simroth, D.U. Thomson, C.D. Reinhardt, S.J. Bartle, The Beef Cattle Institute, Kansas State University

The buller steer syndrome commonly observed in feedlots is an abnormal, aberrant behavioral and social condition in which steers repeatedly mount another steer. The steer being mounted is called the “buller” and the steer riding is called the “rider.”

The buller steer syndrome commonly observed in feedlots is an abnormal, aberrant behavioral and social condition in which steers repeatedly mount another steer. The steer being mounted is called the “buller” and the steer riding is called the “rider.”

As a consequence of the excessive riding, the buller steer often becomes exhausted, shows loss of hair, can develop swelling and trauma along the dorsal line and tail head, and in extreme cases can suffer from broken bones or may even die from injuries.

As a consequence of the excessive riding, the buller steer often becomes exhausted, shows loss of hair, can develop swelling and trauma along the dorsal line and tail head, and in extreme cases can suffer from broken bones or may even die from injuries.

There appears to be various degrees to bulling activity; some riding activity is relatively harmless and falls under the category of "horseplay”. On the other end of the spectrum we have serious bulling activity in which normal steers vigorously pursue the abnormal steer, the buller, who may or may not be receptive to be mounted (Ulbrich, 1981).

There appears to be various degrees to bulling activity; some riding activity is relatively harmless and falls under the category of “horseplay”. On the other end of the spectrum we have serious bulling activity in which normal steers vigorously pursue the abnormal steer, the buller, who may or may not be receptive to be mounted (Ulbrich, 1981).

The incidence of the buller steer syndrome ranks third in disease conditions occurring in U.S. feedlots (2.8 + 0.5%; USDA, 2013) only behind bovine respiratory disease and metabolic/digestive conditions. A survey conducted in Kansas in the 1970s by Brower and Kiracofe (1972) indicated that 2% of all feedlot steers in Kansas experienced the buller steer syndrome.

The incidence of the buller steer syndrome ranks third in disease conditions occurring in U.S. feedlots (2.8 + 0.5%; USDA, 2013) only behind bovine respiratory disease and metabolic/digestive conditions. A survey conducted in Kansas in the 1970s by Brower and Kiracofe (1972) indicated that 2% of all feedlot steers in Kansas experienced the buller steer syndrome.

In the same manner, Brower and Kiracofe (1978) and Irwin et al. (1979) reported that the annual incidence of buller steers within the feedlot industry fell somewhere between 2 and 4%. A 15-year summary of buller incidence in Midwest feedlots consisting of over 5 million steers reported a buller incidence of 2.45% (Edwards, 1995).

In the same manner, Brower and Kiracofe (1978) and Irwin et al. (1979) reported that the annual incidence of buller steers within the feedlot industry fell somewhere between 2 and 4%. A 15-year summary of buller incidence in Midwest feedlots consisting of over 5 million steers reported a buller incidence of 2.45% (Edwards, 1995).

Furthermore, a 2-year study by Taylor et al. (1997b) at a western Canada feedlot using 78,445 male (intact) cattle indicated a buller incidence rate ranging from 0.0 to 11.2%, with an average incidence of 2.7%.

Furthermore, a 2-year study by Taylor et al. (1997b) at a western Canada feedlot using 78,445 male (intact) cattle indicated a buller incidence rate ranging from 0.0 to 11.2%, with an average incidence of 2.7%.

Why Do Bullers Happen?

Why Do Bullers Happen?

Over time multiple factors have been implicated by feedlot managers, consulting nutritionists, consulting veterinarians, and researchers as contributing to the incidence and manifestation of the buller steer syndrome.

Suggested factors include the use of anabolic agents, improper implantation, re-implantation or double dosing, changes in weather and seasonal factors, excessive mud or dusty pen conditions, entry weights, disease, group size, improper or late castration, feeding management, presence of cycling heifers, transportation, handling, mixing, dipping, and aggressive social dominance behavior (Stookey, 1997; Taylor et al., 1997b; Irwin et al., 1979; Peck, 2005; Sprague, 1999).

Over time multiple factors have been implicated by feedlot managers, consulting nutritionists, consulting veterinarians, and researchers as contributing to the incidence and manifestation of the buller steer syndrome. Suggested factors include the use of anabolic agents, improper implantation, re-implantation or double dosing, changes in weather and seasonal factors, excessive mud or dusty pen conditions, entry weights, disease, group size, improper or late castration, feeding management, presence of cycling heifers, transportation, handling, mixing, dipping, and aggressive social dominance behavior (Stookey, 1997; Taylor et al., 1997b; Irwin et al., 1979; Peck, 2005; Sprague, 1999).

It is generally recognized that anabolic implants

It is generally recognized that anabolic implants may be one of several factors involved in the buller steer syndrome; that is, greater total dosages of anabolic compounds such as estradiol, result in incremental increases in bullers. Taylor et al. (1997a) concluded that re-implanting with 20 mg of estradiol + 200 mg of progesterone did not alter buller incidence compared with cattle receiving a single dose of the same implant initially. may be one of several factors involved in the buller steer syndrome; that is, greater total dosages of anabolic compounds such as estradiol, result in incremental increases in bullers. Taylor et al. (1997a) concluded that re-implanting with 20 mg of estradiol + 200 mg of progesterone did not alter buller incidence compared with cattle receiving a single dose of the same implant initially.

In contrast, Turgeon and Koers (1997) analyzed data from a historical database involving about 48 million feedlot cattle and reported that buller incidence was substantially increased for re-implanted steers vs. nonreimplanted steers (3.21% vs 1.65%).

In contrast, Turgeon and Koers (1997) analyzed data from a historical database involving about 48 million feedlot cattle and reported that buller incidence was substantially increased for re-implanted steers vs. nonreimplanted steers (3.21% vs 1.65%).

Booker et al. (1997) conducted a field trial in Nebraska with 14,196 steers fed for an average of 147 days. These researchers reported that the overall new rider incidence was increased when the initial implant contained 28 mg of estradiol benzoate and 200 mg of trenbolone acetate compared with an initial implant with 36 mg of zeranol followed by a re-implant with either 28 mg of estradiol benzoate + 200 mg of trenbolone acetate or 24 mg of estradiol-17β + 120 mg of trenbolone acetate (9.93, 5.06, and 3.99% new riders, respectively), whereas the rider re-pull incidence did not differ.

Booker et al. (1997) conducted a field trial in Nebraska with 14,196 steers fed for an average of 147 days. These researchers reported that the overall new rider incidence was increased when the initial implant contained 28 mg of estradiol benzoate and 200 mg of trenbolone acetate compared with an initial implant with 36 mg of zeranol followed by a re-implant with either 28 mg of estradiol benzoate + 200 mg of trenbolone acetate or 24 mg of estradiol-17β + 120 mg of trenbolone acetate (9.93, 5.06, and 3.99% new riders, respectively), whereas the rider re-pull incidence did not differ.

Voyles et al. (2004) implanted cattle with a single dose of a 24 mg estradiol 17β + 120 mg trenbolone acetate implant on day 1 or a 36 mg zeranol implant on day 1 and re-implanted with a 24 mg estradiol 17β + 120 mg trenbolone acetate implant on day 50. Results show a lower incidence of new bullers when steers received only one implant on day 1 vs. steers that were re-implanted on day 50 (P = 0.01; 0.92% vs. 1.93%, respectively). However, the overall incidence of new bullers did not differ between treatments (P>0.43).

Voyles et al. (2004) implanted cattle with a single dose of a 24 mg estradiol 17β + 120 mg trenbolone acetate implant on day 1 or a 36 mg zeranol implant on day 1 and re-implanted with a 24 mg estradiol 17β + 120 mg trenbolone acetate implant on day 50. Results show a lower incidence of new bullers when steers received only one implant on day 1 vs. steers that were re-implanted on day 50 (P = 0.01; 0.92% vs. 1.93%, respectively). However, the overall incidence of new bullers did not differ between treatments (P>0.43).

Prouty and Larson (2010) reported a nonsignificant (P = 0.20) numerical difference in buller incidence when using different implanting strategies in finishing feedlot steers. Cattle received either a 14 mg estradiol benzoate + 100 mg trenbolone acetate implant (A) on day 0 and re-implanted at day 79 with the same implant or at day 70 with a 28 mg estradiol benzoate + 200 mg trenbolone acetate implant (B), or received a single dose of a 40 mg estradiol + 200 mg trenbolone acetate implant (C) on day 0. Buller incidence for “AA”, “A-B”, and “C” implanted cattle was 0.24, 0.76, and 1.65%, respectively.

Prouty and Larson (2010) reported a non-significant (P = 0.20) numerical difference in buller incidence when using different implanting strategies in finishing feedlot steers. Cattle received either a 14 mg estradiol benzoate + 100 mg trenbolone acetate implant (A) on day 0 and re-implanted at day 79 with the same implant or at day 70 with a 28 mg estradiol benzoate + 200 mg trenbolone acetate implant (B), or received a single dose of a 40 mg estradiol + 200 mg trenbolone acetate implant (C) on day 0. Buller incidence for “A-A”, “A-B”, and “C” implanted cattle was 0.24, 0.76, and 1.65%, respectively.

Irwin et al. (1979) also found that type of implant and time of implantation influenced the incidence of bullers, with a greater percentage of bullers in groups of steers implanted with a combination of progesterone and estradiol (2.46%) than in those implanted with zeranol (0.46%); 13,244 steers received the combination implant, and 1,721 steers received the zeranol implant.

Irwin et al. (1979) also found that type of implant and time of implantation influenced the incidence of bullers, with a greater percentage of bullers in groups of steers implanted with a combination of progesterone and estradiol (2.46%) than in those implanted with zeranol (0.46%); 13,244 steers received the combination implant, and 1,721 steers received the zeranol implant.