In a kinder and gentler world they're called bullers. These cattle, for which pen riders have their own not-so-kind names, can be defined as steers that will stand to be ridden. Whatever you want to call them though, bullers are a significant problem throughout the cattle feeding industry.

Late-'90s data indicates that in most feedyards, 1-4% of all steers are identified as bullers. But, in some regions and at some times of the year, buller cattle can attract other steers like flowers attract bees. The economic impact of buller steers has been empirically estimated at $25-$35/buller animal due to performance, and mortality and morbidity issues.

“Bullers are just a horrible animal to have in a feedyard,” says Chris Hitch, Hitch Enterprises, Inc., Guymon, OK. “You can't treat a buller like you can a sick animal, yet you have to get him out of the pen and deal with him in some manner.”

Hitch says bullers also complicate things when determining billing charges for a customer. He contributes to a list of why bullers are so hated:

  • Losses due to injury or death.

  • Reduced final weight of the bullers and the cattle riding them.

  • Bruising, leading to excessive carcass trim.

  • Labor required to segregate bullers.

  • Complicated pen utilization.

  • Increased paperwork and recordkeeping.

No one knows for sure why bullers act the way they do. Published data indicates the following factors contribute to bulling activity:

  • Mixing of cattle or put-together groups.
  • Crowding — limited pen space.
  • Pens greater than 150 head.
  • Placement weight — favoring heavier steers.
  • Crushed or bunched hormone implants.
  • Abscessed implant sites.
  • Implants containing trenbalone acetate (TBA).
  • Animal size variation with a pen.
  • Seasonal and climactic variations.
  • Presence of cycling heifers.

The implant effect

The implant-effect concept drew Hitch's attention when feedyard employees began seeing bullers decrease after a switch from the feedyard's traditional implant program. Hitch veterinarian Shawn Blood reports that in early 2001 when Hitch Enterprises changed to Component® with Tylan®, buller rates began to drop unexpectedly.

“We switched implants for other reasons,” Blood says. “But, it didn't take long before we saw buller rates drop like a rock.”

Hitch's feedyard data showed the frequency of bullers decreased by 41% across each of their three feeding facilities. Overall buller rate* (see end of article) was 1.25% before and 0.64% after inclusion of Component with Tylan.

The implants are patented, differentiated growth promotants that include a localized antibacterial agent (tylosin tartrate) as the first pellet of each dose. While reducing bullers is not a label use of the implant, Hitch's observations corroborated Kansas State University (KSU) research on the implants.

Hitch says that while other factors could be involved, the only potential causative factor that's been identified is the transition to Component and Tylan implants.

“None of the yards changed nutritional programs or made major changes in animal health or other management during this period of time,” Blood adds.

The favorable effects appear to have been the greatest in the situations that typically produce the highest frequency of bullers — big pens, heavy cattle and/or late summer placements.

The first scientific evidence of reduced buller rates was generated by Brandon Depenbusch in 2003. He's an animal science graduate student and assistant manager of KSU's research feedlot. The work he led shows feedyard buller rates dropped from 3.83% to 1.71% — a 55% reduction (see Table 1).

“In this study, we found the inclusion of a pellet of the antibiotic Tylan within Component TE-S implants seems to result in significant reductions in the incidence of buller activity among feedlot steers,” Depenbusch says.

The research data also fits the Hitch buller data in big steers placed in June and July, which might be expected to have a high buller incidence.

Depenbusch notes the Tylan addition to the implant regime did not have significant impact on normal feedyard performance measures like average daily gain, feed efficiency or final weight.

Insight into implants

Iowa State University research shows that when an animal is implanted, the animal responds by initiating an inflammatory response. Over time, this results in a capsule of connective tis sue around every implant.

The research shows that as the level of contamination increases, so does the thickness of the capsule. A reduction in bullers due to use of Component with Tylan is likely the result of a healthier implant site and more consistent consumption of the implant's active ingredients.

Since Component with Tylan results in a thinner capsule of connective tissue around the implant, contact between the animal and the implant could be greater. In addition, it would be expected that consumption of active compounds would be more consistent both across animals (one animal compared to another) and within animals (from day to day in the same animal).

An infection due to an ear abscess may cause an increase in localized blood flow to the infected ear, resulting in rapid payout of the active ingredient. This could result in abnormal behavior, including increases in the incidence of buller-related activity.

Depenbusch points out that aseptic techniques, such as cleaning the surface of ears and using clean needles, are important factors contributing to effectiveness of implants. Even with proper techniques and visually clean ears and needles though, problems can still exist.

“It's plausible that the cattle implanted with Component with Tylan had fewer abscesses and resulting scar tissue immediately surrounding the implant site,” he says. “It's also possible that the addition of Tylan to implants may reduce variation in uptake of the growth-promoting compound.”

This improved consistency would likely result in a less frequent need to re-establish the social order within the pen, resulting in greater behavioral stability and fewer bullers.

However it works, the Hitch crew is happy having fewer bullers to deal with these days.

“This implant program has really helped the manpower situation around here,” Blood says. “Anyone who's had to deal with bullers in a feedyard knows how something like that can make life easier for everyone.”

*The Hitch data actually characterized as the buller-head-day rate — the ratio of buller-head-days/total head days.

Table 1. Finishing performance and carcass characteristics of yearling steers implanted with Component TE-S or Component TE-S with Tylan
Item Component TE-S Component TE-S with Tylan
No. of head 919 924
No. of pens 6 6
Days on feed 116 116
Initial weight, lb. 826 828
Final weight, lb. 1,289 1,297
Dry matter intake, lb./day 21.6 22.0
Average daily gain, lb./day 3.84 3.86
Feed:gain 5.61 5.69
Bullers, % 3.83 1.71
Hot carcass weight, lb. 818 824
Depenbusch et al. 2003, Kansas State University
To access the complete study “Growth performance and Carcass characteristics of finishing beef steers implanted with Component TE-S or Component TE-S with Tylan” go to www.oznet.ksu.edu/library/lvstk2/SRP923.pdf for the proceedings of the K-State Cattlemen's Day 2004.