Many grass finish beef operations utilize a spring calving season and market the finished animals coming off of grass at 18-21 months of age. This system requires forages that are of excellent quality to obtain weight gain through the winter feeding period and the subsequent grazing season. Finishing beef cattle on grass that are born during the fall months allows cattle to grow slower, yield higher dressing percentages, achieve higher quality grades and receive a high percentage of total feed coming from grazing forages, as opposed to the mechanically harvested winter feed supply.
Feeding cattle to USDA choice quality grade has been a standard of acceptability in the cattle feeding business. Increasing the age of cattle from 18 to 24 months of age at harvest, increases the chance of cattle grading choice if fed to the same fat endpoint. As cattle are fed to older ages, muscle accretion decreases and fat deposition increases. Feeding fall born calves to 24 months of age has the potential of resulting in cattle reaching a higher fat endpoint and is positively correlated with cattle yielding higher dressing percentages.
Feeding cattle to 24 months on grass allows producers to grow them at a slower growth rate (1.75 pounds/day) on a slightly lower plane of nutrition as opposed to cattle harvested at 18 months (2.2 pounds/day). Feeding cattle for a longer time period does result in a longer term investment on money and will add interest cost. Also, the winter feeding period of fall born calves as yearlings will require about 10-15 percent more stored feed than that of the spring born calves. Feeding cattle to 24 months of age will require more total forage to be consumed as opposed to feeding cattle for 18 months; however a higher percentage of the forage will come from grazing, rather than harvested feed for winter.
Utilizing a fall calving season to produce grass finished beef offers an opportunity to produce heavier cattle of higher quality than spring born calves with a slightly lower quality forage. Cost of production will be higher using the fall born system, but the potential for higher income may increase profits. For more information about feeding fall born beef calves to finish on grass contact Frank Wardynski, Ruminant Educator with Michigan State University Extension at firstname.lastname@example.org.