Cow Age: When Is She Too Old?11 November 2014
Sky high cattle prices are prompting ranchers to keep cows that may have one more calf in them, but how can you tell is she is good for another year?
Rainfall is key to supporting forage growth, but keeping older cows is 'tempting', writes Dr Glenn Selk of Oklahoma State University.
Cow culling time always presents producers with tough decisions, but the extension livestock specialist advises that there is 'great variability' in beef cow longevity.
Breed and geography may have some influence, adds Dr Selk. Region of the country and soil type may affect how long the teeth remain sound and allow the cow to consume roughages such as pasture and hay.
Records kept by a very large ranch in Florida in the 1980's and published in the 33rd Annual Proceedings of the Beef Cattle Short Course by the University of Florida Animal Science Department show how productivity changes over the life of the beef cows.
These large data sets, (19500 cows, and 14000 cows in two separate years) were plotted to indicate the average percentage of cow determined to be pregnant based on their age in years.
These cows were not pampered but expected to produce in the environment in which they were kept.
The data would indicate that cows are consistent in the rebreeding performance through about 8 years of age. A small decline was noted in 1983 as cows aged from 8 to 10 years of age.
However the most consistent decline in reproductive performance was noted after cows were 10 years of age.
A steeper decline in reproductive performance was found as they became 12 years of age.
This data, collected in Florida on cows with some Brahman influence, represents one of, if not the largest data set on this subject.(Source: Genho, 1984 Proceedings of the Beef Cattle Short Course. Animal Science Department, University of Florida.)