EPDs are the gold standard for selection tools for a given trait as all sources of information are included. EPD calculations use pedigree information, performance data, and genomic results, with all of these sources boiled down for you into one value, reported in units of the trait. When available, EPDs should be your selection tool of choice for the traits of importance to you and your customers.
Though we spend a lot of time talking about genomics and the value that genomic tests offer in terms of improved accuracy on EPDs early in the life of Limousin seedstock, genomics do not completely describe the variation in the traits of interest. I often hear breeders suggest that genomic results are more valuable than performance data, some going so far as to suggest that perhaps it is no longer necessary to collect weights and measures (e.g., weaning weights, scan data, carcass measures). Nothing could be further from the truth. In fact, phenotypic measures may be more valuable than ever. Not only does performance data continue to be an important part in EPD calculation, but with the move to Single-step incorporation of genomics using BOLT software, your performance data is necessary to ensure the accuracy of genomic marker effects used in EPDs.
Many of you (if not already there) will be headed into calving season soon, so this article will focus on the value of submitting accurate birth weights. Of course, the economically relevant trait is actually calving ease (and I also encourage you to submit calving scores). However, birth weights are used as an indicator of calving ease in the computation of EPDs as well as a correlated trait for weaning weight and yearling weight, so they do have value. Over the years, you’ve been advised that scale weights were required. However, recent research has suggested that perhaps hoof tape measurements are a good alternative to scale weights and are certainly superior to “eye-balling” or making up a weight if you missed one. For reasons I’ll describe below, we do ask that you indicate if your weights being submitted are scale weights or hoof tape measurements.
Recently, the science team at IGS took a closer look at the scale vs hoof tape measurement issue (Adkins, 2019). Approximately 7,000 hoof-tape records and 15,000 scale weights were analyzed, and it was found that, as expected they had a high genetic correlation (0.92). As has been previously reported, there was less variation in the hoof-tape measures (meaning fewer outliers with extremely heavy or extremely light birth weights). See Figure 1, used complements of IGS.
In the Digital Beef system, you’ll now see the option to indicate the method for obtaining your birth weights in a pull-down menu in your birth queue (see Figure 2). Scale or Hoof Tape measurements are acceptable for use in EPDs. Also, it is far better to leave a blank weight than to guess on the animals if you are unable to obtain an actual measurement. As always, proper contemporary group designation is also important for accuracy of EPDs. This means animals of the same age, gender, raised in the same environment with equal opportunities to express their genetics are grouped together.
Figure 1. Variation in Hoof Tape Measurements vs Birth Weights in Beef Cattle
Figure 2. Birth Queue with Birth Weight drop-down menu in Digital Beef.
Limousin cattle deliver to your bottom line. With superior genetics, a simple crossbreeding plan and state-of-the-art selection tools, the Limousin breed will serve profit-minded cow/calf producers. In today’s competitive markets, taking advantage of all available opportunities is key. The Limousin breed offers a variety of options from Fullblood to Purebred to the Lim-Flex® hybrid (Limousin x Angus cross) to match your program’s needs and market goals. Crossbreeding for the right blend of muscle, maternal ability and profit is easy with Limousin seedstock.