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WEANING CALVES EARLY CAN BE A BENEFICIAL MANAGEMENT TOOL

by: Stephen B. Blezinger
Ph.D., PAS

In recent years in much of the United States, especially the South and Southwest, precipitation has been highly variable, and drought situations have become common. Cow-calf producers in this region have learned or must learn to manage cattle and pastures through times of drought in order to stay in business. Periods of below average precipitation challenge producers in three ways: 1) maintain appropriate stocking rates and levels of forage utilization, 2) maintain acceptable reproductive performance of the cow herd. 3) Off-set environmental stress effects to maintain reproduction, health and growth. In the past we have discussed early weaning and it's role in situations such as these. Early weaning of calves is a management tool that producers can implement to reduce forage needs of the cow-calf enterprise and improve cow condition and reproductive performance. The following is a discussion of this practice and is largely adapted from a very good paper by Mathis and Eninias (2006) presented at the Southwest Beef Symposium.

“Early weaning” is weaning calves anytime earlier than “normal.” Calves are typically weaned when they are 6 to 8 months old; however, calves can be weaned as early as 6 weeks of age. Early weaning can reduce the forage needed by the cow herd when implemented in response to a forage shortage. The magnitude of the shortage and extent of other management changes required dictates when calves should be weaned in order to balance forage supply and forage demand. When calves are weaned early to improve reproductive performance, they may be weaned just prior to the breeding season to impact reproduction in the breeding season that immediately follows. Or they may be weaned 30 to 90 days earlier than normal in attempt to reduce the postpartum interval during the breeding season that follows 6 to 8 months later.

Reducing Forage Needs

When forage production is low and it becomes necessary for producers to make management adjustments to reduce forage needed for the cow-calf enterprise, there are several options that can be employed:

• Sell cows

• Lease additional pasture

• Feed additional energy to reduce grazing

• Wean calves early

It can be challenging to cost effectively lease pasture, feed energy, or sell cows just to buy them back when forage production improves. Early weaning, especially when combined with one or more of the other options listed, can be a useful tool to manage forage supply while minimizing the need to feed energy or dramatically liquidate cattle. By September, or maybe even August for ranches at higher elevations, most producers in the West and Southwest have a fairly good idea of how much forage will be available at the end of the growing season. For example, in southern New Mexico precipitation that falls after the middle of September generally has minimal impact on forage production because temperatures are too cool for warm season forages to grow substantially. Thus, as early as the middle of September a forage budget can be developed in this region. If adequate forage is available to support the current stocking rate, no change is needed. However, if estimated forage supply by the end of the growing season is not sufficient to meet the demands of the cow herd until forage growth is expected to resume, producers must decide what management practices to implement to balance forage supply and forage demand. This is the predicament many producers are finding themselves in this year.

Forage needs are reduced by early weaning because calves are removed from the ranch (sold, placed in a feedlot, or moved to leased pasture), cow energy requirements decline when they stop lactating, and culls are sold earlier than normal. In the short-term, less income is generated from calf sales when they are sold at a lighter weight than normal; however, there is some price per pound advantage to selling lighter calves. Regardless of the weight of the early weaned calves or culled cows, July, August and September prices have historically been higher than the normal low prices of the year in October and November.

Improving Reproductive Performance

The relationship between reproductive success and body condition at calving is based on energy. Cows must have energy to support all bodily activities, but some functions have a higher priority for energy use than others. Cows can only direct energy toward resuming the estrous cycle after calving if energy intake exceeds the combined requirements for maintenance, growth and lactation. Energy demands of a lactating cow can be very high and varies between breed and body size. It is important that the cow is in adequate body condition at calving so that stored energy can be used to support some of her needs. If she does not have enough stored energy at calving, she must gain weight during lactation so that she will have enough energy to begin cycling again. However, it is difficult to cost effectively increase body condition of cows in early- to mid-lactation with supplemental feed. This is why body condition at calving is strongly related to the length of the postpartum anestrous period (time between calving and first heat) in beef cattle. Cows that are thin at calving take longer to resume cycling after calving and are less likely to become pregnant during the breeding season. Since body condition at calving influences reproductive performance, early weaning can be utilized to improve the chance that a cow is in acceptable body condition.

Weaning calves early can greatly lower a cow's nutrient requirements by ceasing lactation. More specifically, if the calf is weaned at 60 days of age (two months), the cow's daily energy requirement declines by 37 percent. If the calf is weaned at 6 months of age (30 days early), the cow's daily energy requirement declines by 18 percent. Reducing the nutrient requirements of lactation by weaning the calf makes early weaning an option to manage thin cows to achieve short- and long-term improvements in reproductive performance.

Weaning Prior to or During the Breeding Season

When calves are weaned prior to or during the breeding season (45 to 100 days of age), reproductive performance can be improved. Weaning prior to breeding is practiced among females that are at high risk of conceiving late in the calving season or not conceiving at all. These are usually thin cows or first-calf heifers. Research on first-calf heifers whose calves were weaned early had a 38-percentage unit advantage in conception rate during the breeding season that immediately followed; plus, the first-calf heifers were 87 pounds heavier on the normal weaning date. Average calving date was 18 days earlier the following calving season; thus their calves were 18 days older at weaning the next year. In addition to raising more calves, there is substantial long-term benefit to maintaining a relatively short calving season that in some cases may only be practically achieved by early weaning. Assuming 1.75 pounds average daily gain for the last 18 days prior to weaning, this would equate to 32 more pounds per calf at weaning the following year. If the calves were worth $100/cwt., females whose calves were early weaned would produce 38 more calves per 100 females, plus generate over $30 more per calf weaned the following year.

The improved reproductive performance comes at a cost. Calves must either be sold at a very light weight, or retained and sold later. Neither of these options will likely generate as much short-term net income as leaving the calves with their mothers until normal weaning time; however, the long-term benefits of early weaning may well exceed the reduction in short-term profit.

30 to 90 Day Earlier Weaning

Reproductive performance may also be improved by weaning calves less than 90 days earlier than normal. For example, weaning calves in August or September when they would normally be weaned in October or November. This approach allows the cows to gain extra weight before winter. In turn, cows are in better body condition on the normal weaning date, and the need for supplemental feeding to maintain adequate body condition at calving is reduced.

By weaning early, but after the breeding season, improved reproductive performance is not realized until the following breeding season. Consider the following financial comparison of calf income made with the following assumptions.

1) A 500 lb. calf is worth $100/cwt on November 1.

2) A 421 lb. calf is worth $108/cwt on September 17th (based on historical relative monthly prices at regional auctions).

3) Cows gain 0.6 BCS (~50 lb.) by normal weaning date if the calf is weaned 45 days early.*

4) Increase of 1 BCS increase pregnancy rate by 9 percentage units if cows are initially thin.*

5) Increase of 1 BCS increases calf age at weaning by 10 days if cows are initially thin.*

* Several of these assumptions are based on specific research. Contact author for references.

Based on these assumptions, weaning calves 45 days early yields $45/cow less gross income initially, but the calf crop conceived during the breeding season following early weaning generates 32 more pounds of calf weaned/cow (about $32/cow). Therefore, the monetary benefits of early weaning are a reduction in winter feed cost, and an increase in weaning rate and calf weaning weight two years after early weaning. The important point to note is that on the financial side, the difference in gross income is relatively small, being less than $13 per cow in this hypothetical example. However, the risk of poor reproductive performance and costs associated with broad herd liquidation and expansion is reduced when early weaning is employed. In this scenario, early weaning provides enterprise stability by reducing risk.

Management Options for Early Weaned Calves

Producers have several options for managing early weaned calves. The strategy chosen depends upon the availability of alternative resources and the reason that early weaning was implemented. Some options include:

• Place calves on another owned pasture for grow-out.

• Sell the calves immediately

• Growing calves on lease pasture

• Growing calves in a feedlot

• Finishing calves in a feedlot

• Combination of the above

If the calves are weaned early to reduce forage needs by the herd, then the calves need to be removed from the ranch. It is generally less expensive to grow calves on grass than feeding them in a feedlot; however, calf gain on pastures is usually lower as well. Calves managed on pasture verses calves weaned at 210 days of age. Early weaned calves were weaned at 65 days of age and grazed native range pasture and fed 2.5 pounds per day of a 25 percent protein pellet. The early weaned calves weighed 62 pounds less than calves weaned at 210 days of age.

On the other hand, early weaned calves placed in a feedlot can be fed to weigh more on the normal weaning date, especially if they are weaned more than 90 days early. Rate of gain for early weaned calves placed in a feedlot can be programmed to most cost-effectively take advantage of feed commodity prices and market seasonality. It is also important to note that early weaned calves often have improved feed efficiency when placed on feed and finished immediately after weaning, but usually have lighter carcasses when harvested.

Conclusion

Early weaning is a management tool that producers can use to balance the forage needs of the cow-calf enterprise and avoid overgrazing. At the same time this practice helps in reducing supplemental feed costs and the need for herd liquidation. Early weaning also reduces nutrient requirements of the cows and enables them to recover body weight more easily and with less energy intake. The additional weight gain achieved by early weaning shortens the postpartum interval and can improve pregnancy rate among cows that are otherwise nutritionally stressed. Early weaning can have some short term costs but has also show long term benefits that must be considered.

Dr. Steve Blezinger is a nutritional and management consultant with an office in Sulphur Springs, TX. He can be reached at 667 CR 4711 Sulphur Springs, TX 75482, by phone at (903) 885-7992 or by e-mail at sblez@hughes.net.

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