The conventional weaning age of beef calves at 200 to 220 days of age (about 7 months) generally coincides with the lack of forage growth for spring-born calves. There are many research studies that have examined the results of weaning at an earlier age—as early as 30 days of age, but usually 150 to 170 days of age—on the subsequent performance of cows and calves. The effect on cow performance is pretty consistent, while the results from feedlot growth and carcass traits of early-weaned calves is anything but consistent.
It is a reasonable conclusion that it would be more efficient to wean the calf and use feed resources directly to the calf to produce weight gain compared to using those feed resources to feed cows to produce milk for calf weight gain. Secondly, when there is no calf nursing the cow, it eliminates a nutritional stress on that cow that can affect her ability to cycle, get bred and even produce milk in the next lactation. This feature will be significantly more important in young cows. Consider the results of research trials that evaluated cow reproductive performance and weight gain after calves were weaned early (Table 1). These results clearly show cows will have a higher pregnancy rate, gain more body weight and have a higher condition score if the calf is removed at an earlier age (Table 2). In addition, Odhiambo et al (2009) has shown these cows are more likely to stay in the herd longer and will have a calf with a higher weaning weight in the next calving and lactation.
In summary, there is significant evidence to show early weaning calves will increase performance of beef cows, particularly for young cows and when there is a nutritional stress on the cow.
Growth and carcass traits of early-weaned calves
While the results for cows is more clear-cut, there is no such consistency with performance and carcass traits in early-weaned calves. Reports from Meyer et al. (2005) and Story et al. (2000) indicated there would be a higher percentage of Choice carcasses from early-weaned calves, while Comerford et al (2007) and Fluharty et al. (2000) indicated there would be more Choice carcasses from normal-weaned calves. Why this discrepancy? The answer appears to be in how the calves were managed after weaning. In the table below, the report from Comerford et al. (2007) with calves sired by bulls with a higher genetic potential for marbling shows one reason for this variation when some calves were backgrounded with corn silage for a short time prior to entering the feedlot (Table 3).
As shown by these results, the nutritional regimen for calves prior to entry in a feedlot has a significant effect on the ability for marbling to be expressed, and this is true for early weaning as well as for normal weaning. The report from Bruns et al. (2004) indicated marbling accretion is a function of animal growth and not fattening rate. When calves are weaned earlier than 7 months, it will be important to maintain a consistent growth pattern comparable to remaining with the cow on pasture to allow marbling to be effectively expressed after feeding. Therefore, the nutritional program for the early weaned calf is important and cannot be discounted.
Early-weaning calves will be an effective management tool for many breeders. This will allow more efficient use of feed resources, improve reproductive rate in young cows and improve subsequent performance of the cow herd. Lack of forage from drought, poor body condition in young cows and lack of growth of calves while nursing cows are signs early weaning can be used effectively. However, subsequent production of the calf in the feedlot will be predicated on an effective nutritional program for that calf. Growth rate must be maintained to allow marbling accretion to occur at an effective rate. An early weaning program can also allow access to calf marketing programs that require weaning and calves eating dry feed before marketing.
Dr. John Comerford is associate professor of dairy and animal science at the Pennsylvania State University.
Bruns, K. W., R. H. Pritchard, and D. L. Boggs. 2004. The relationships among body weight, body composition, and intramuscular fat content in steers. J. Anim. Sci. 82:1315.
Comerford J. W., H. W. Harpster, K. B. Bryan, E. H. Cash, and V. H. Baumer. 2007. Evaluation of production systems for progeny of beef sires with higher marbling expected progeny differences. Prof. Anim. Sci.23:4.
Fluharty, F. L., S. C. Loerch, T. B. Turner, S. J. Moeller, and G. D. Lowe. 2000. Effects of weaning age and diet on growth and carcass characteristics of steers. J. Anim. Sci. 78: 1759.
K. S. Lusby, R. P. Wettemann and E. J. Turman. 1981. Effects of Early Weaning Calves from First-Calf Heifers on Calf and Heifer Performance. J. Anim. Sci. 53:1193.
Odhiambo, J. F., J. D. Rhinehart, R. Helmondollar, J. Y. Pritchard P. I. Osborne E. E. Felton and R. A. Dailey. 2009. Effect of weaning regimen on energy profiles and reproductive performance of beef cows. http://jas.fass.org/cgi/content/abstract/jas.2008-1138v1?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&fulltext=early+weaning&sea. Accessed June, 2009.
Meyer, D. L., M. S. Kerley, E. L. Walker, D. H. Keisler, V. L. Pierce, T. B. Schmidt, C. A. Stahl, M. L. Linville, and E. P. Berg. 2005. Growth rate, body composition, and meat tenderness in early vs. traditionally weaned beef calves. J. Anim. Sci. 83: 2752.
Myers, S. E., D. B. Faulkner, F. A. Ireland, L. L. Berger, and D. F. Parrett. 1999. Production systems comparing early weaning to normal weaning with or without creep feed for beef steers. J. Anim. Sci. 77:300.
Story, C. E., R. J. Rasby, R. T. Clark and C. T. Milton. 2000. Age of calf at weaning of spring-calving beef cows and the effect on cow and calf performance and production economics. J. Anim. Sci. 78: 1403.