Black Grove Longevity Index
At Black Grove we continue to believe fundamentals survive fads. We try to take a long-term approach to our breeding program. We believe the Angus cow is the most efficient and productive manufacturing plant in the cattle industry. We are concerned with the trend towards statistical selection based on individual breeder reported contemporary group data and terminal trait characteristics to the exclusion of or regard for the functionality of the Angus cow. While we use the multiple trait selection tools offered by the Association, we also focus on breeding and selecting functional low input cattle.
After years of study we have determined the best measure of functionality is longevity (a trait not presently measured by the Association). We believe logic dictates that cows who live a long time would have been culled if they were not functionally sound. If a cow did not have good feet, good teeth, good udder and teats, milk well or maintain her fleshing ability, remain fertile and productive, she would have been culled. It is also logical to assume these cattle will be easy fleshing, low input and low maintenance cattle which will reduce our annual operating cost. If we can breed cattle that live for 12-15 years, we will dramatically reduce our turnover in the cow herd and the huge capital cost of raising replacement heifers.
To that end, we have developed a new longevity trait selection index which allows us to identify animals which should have a higher probability of living longer. The result is less turnover of productive females (our factories), lower capital investment in replacement heifer, and therefore, higher profitability and improved return on investment. We believe longevity/functionality is one of the most important selection traits for any commercial or registered cow-calf operation.
To come up with the score that we used to determine a cow's longevity, we sent letters to the last owners of the cow's mother, grandmothers, and great-grandmothers and asked if they are still alive and if not, when they died. In case their owners did not know, we asked for written permission to access the American Angus Association records, to see when their last registered calf was born. (The Association would not provide information without written authorization from one of the owners.) We devised a formula (available on request) to calculate a weighted average of the lifespan of the cows in our subject cow’s pedigree going back three generations. We only used cows in our calculations that were born before 2003. The numbers we came up with fall into one of the following six categories.
Cows with a pedigree average of 6.9 or less = no stars
Cows with a pedigree average of 7-8.9 = 1 star
Cows with a pedigree average of 9-10.9 = 2 stars
Cows with a pedigree average of 11-12.9 = 3 stars
Cows with a pedigree average of 13-14.9 = 4 stars
Cows with a pedigree average of 15 or higher = 5 stars
Each cow that we know is still alive in a pedigree, but is over 9 years old presents a challenge for our formula. We solved this by adding a + symbol to the stars, to indicate that the value could go up as the cow's mothers or grandmothers continue to produce cows. (Cows in the pedigree born after 2003 are not considered in any part of this formula.) For example: A cow with a score of 11 and a mother or grandmother that is 9 years old or older and still alive would get a score of +. A cow with the same score of 11, but with all of its ancestors that were born before 2003 having died would get a score of .
We also came up with an accuracy rating for each of the cows. This was necessary because we were not able to obtain permission to look at the records of all of the cows in our family tree, and some of our cows have mothers and even grandmothers that were not born before 2003, and therefore are not considered in this formula. If we were able to obtain the information on all of the cows in the pedigree, and they were all born before 2003, the cow would get an accuracy rating of 100%. For each great-grandmother not included in the calculations, the accuracy drops 8%. For each grandmother not included in the calculations, the accuracy drops by 16%, and if the mother is not old enough to be included in the calculations, the accuracy drops by 33%. To qualify for a rating, an animal can not be missing information on more than two ancestors.
We believe that star indexing the scores will provide breeders with an easy comparative analytical tool to evaluate relative probability for longevity and functionality. If you have any questions, please feel free to contact Dixon Shealy at (803) 629-1174 or Walter Shealy at (803) 924-1000.