It's not easy being a calf. Just about the time you're fairly sure where your next meal's coming from, somebody you've never seen before wants to stick a needle in you, slap a hot iron on your hip, clip off the nubs on your head and cut off certain unmentionables if you're blessed with the Y chromosome. Worse, you have to say so long to Mama — no hints and no goodbyes. Much of that on the same day.

You'd get sick, too.

“If we get more of these high-stress processes taken care of while the calf is on the cow, then all we have to worry about at weaning are the stresses of boostering vaccinations and separating calves from the cows,” says Shaun Sweiger, DVM. He has a beef production and medical practice at Oklahoma City, teaches part-time at Iowa State University's College of Veterinary Medicine and participates in his family's cow-calf operation in northwestern Missouri.

In other words, rather than an event, preconditioning represents a continuum that extends, in an ideal world, from marketing plans for calves when they hit the ground to their journey from the ranch.

Generally speaking, Sweiger explains the critical stages along this preconditioning continuum — defined as acclimating calves for the next stage of their production lives — are planning, pre-weaning, weaning and post-weaning. The critical control points within each of the production stages primarily revolve around effectively designed and applied vaccination protocols; adequate nutrition; and efforts to minimize and separate major stressors, such as branding and initial vaccination, dehorning, castration and weaning.

Pre-weaning sets the stage

Depending on the operation, pre-weaning could begin at branding when calves are typically 1-3 months old or as late as 2-3 weeks before removing calves from their mamas.

That's when Sweiger says calves need to be vaccinated with 4-way virals (IBR, BVD, PI3, BRSV) and Blackleg (boostered now or at weaning if first given at branding time). Pre-weaning is the time for Mannheimia (Pasteurella) vaccines, too.

Likewise, Clay Mathis, beef Extension specialist with New Mexico State University (NMSU) generally recommends following the VAC-45 and VAC-34/24 guidelines. If you're unfamiliar with them, the former describes a vaccination and management protocol for calves that will be vaccinated, weaned, booster-vaccinated and further preconditioned at least 45 days after weaning. The VAC 34, VAC 24 and related programs describe proven and industry-accepted vaccination and handling protocol standards for calves either vaccinated approximately 3-4 weeks before weaning (VAC-34) or vaccinated 2-4 months prior to weaning (VAC-24).

Pre-weaning is also the stage where marketing and retained ownership plans begin coming into play. Depending on whether calves will be sold at weaning, kept through a 45-day weaning program or retained through the feedlot, Sweiger explains effective preconditioning programs will differ.

As an example, if producers are going to keep calves around after weaning, it makes sense to deworm them at weaning so they're not sharing or re-acquiring the parasite load of the cowherd. If those calves are heading to town though, he says it's tougher for a producer to justify the cost.

Similarly, nutrition plays a larger role if calves are going to be retained at least 45 days. If calves are heading to grass after weaning, Sweiger explains there's less need to break them to a feed bunk or acquaint them with feeds other than the grass and hay they've already been picking at. On the other hand, if calves are destined for the feedyard soon after leaving the ranch, especially if you're retaining ownership, Sweiger says calves need to be acquainted with non-forage feeds and how to find them in a bunk. Though creep-feeding is an added cost — a substantial one — Sweiger says for producers willing to make the investment, the practice makes for a smoother transition to a feedlot situation.

All of that is before considering requirements for value-added specifications, such as those for natural beef programs, which further dictate which management tools a producer can use in preconditioning.

Then there's weaning

As for weaning itself, Mathis points out, “We can't avoid the psychological stress associated with separating the calf from the cow, but we can minimize it.” For instance, he explains that when it can be used practically, fenceline weaning minimizes stress and increases subsequent calf performance.”

A lack of facilities or forage prevents some producers from keeping calves after weaning. When it is possible though, and when the net economics make sense, there's no question that a 45-day program reduces sickness and increases performance.

The ongoing Texas Ranch-to-Rail (TRR) program conducted by Texas A&M University (TAMU) was the first in the industry to describe the post-weaning economic losses associated with calf sickness, using real-world, real-time performance data.

In New Mexico, four years into a similar demonstration, producers and NMSU have seen similar results. So far, cattle fed without ever becoming sick have returned an average of $14/head. Those getting sick have lost an average of $70/head, and those getting sick twice or more have lost a whopping $254/head on average.

There's also a direct correlation between the number of days calves have been weaned prior to the feedlot and their health costs once they get there. Mathis shares some unpublished data from the TRR program and the late John McNeill of TAMU that indicate calves weaned more than 45 days had an average medicine cost of $3.22/head, while those weaned 14 days or less had an average medicine cost of $13.69 (Table 1). In the NMSU Ranch-to-Rail program, the net return of calves entering the feedlot weaned 20 days or less has been $44/head less than those that had been weaned 41-60 days. The net return of calves weaned 21-40 days was $22/head less than those weaned for 41-60 days.

In research surrounding these types of studies, Sweiger explains, the power of 45-day programs has more to do with the time allowed for acclimation than the animal health products used or the combinations of them.

No one knows every reason behind the magic number, but Mathis says, “There is something critical occurring when we separate the stress of weaning from the stress of shipping by at least 45 days.”

“With high-risk (unweaned) calves coming into a stocker operation or feedlot, we don't expect to see any significant gain for the first 30 days; they're just getting healthy,” Sweiger says. “When producers try to short-change that 45-day period, the results suffer.”

Moreover, where cattle are managed can make a huge difference. In recent NMSU research, calves held and fed in a drylot 45 days gained more than those managed and fed less intensely on grass for the same period of time. However, drylot calves experienced significantly more sickness and death loss, meaning returns for the pasture-managed calves were higher.

In fact, 47% of the drylot cattle required treatment, compared to 34.3% of those managed on pasture. Worse, 7.6% of the drylot calves died, though none were lost on pasture. The net effect was that pasture calves made $15.72/head during that phase of their lives, while those in the drylot lost $28.87 on average. This was a three-year study.

“The only thing different in those calves' lives were how they spent those 45 days after weaning,” says Mathis. “By putting them into drylot, we created more stress, and did something that impaired their ability to withstand the immune challenges as well as those on pasture…From weaning to shipping, we not only want to minimize the dietary change, but also the environmental change.”

When it's possible to keep calves beyond weaning, Mathis urges producers to run a sharp pencil to evaluate the net economic potential, even with premiums for these kinds of calves running $7-$8/cwt.

More than anything, Mathis concludes, “We want to avoid stacking stressors on top of each other.”

Table 1. Impact of days weaned on subsequent health cost*
Days weaned Percent treated Medicine cost ($/head)
< 14 27% $13.69
15-21 30% $11.86
22-30 25% $8.29
31-45 23% $6.98
> 45 9% $3.22
*Texas Ranch to Rail data — 3 years — unpublished
Source: John McNeill, Texas A&M University