All beef cow producers need to apply some basic principles of performance testing, as well as estimated breeding values (EBVs) and their application, to improve their herd. Some of these ideas are covered in detail below.
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1. The greater the number of animals being tested.
You must Weigh all of the animals that will be weaned, and also include those that will be killed. When just the ‘good’ ones are weighed, the range from light to heavy is narrowed, resulting in a biased picture.
2.It’s critical to have the right management grouping.
Mating groups, for example, can be put together for three months in similar pastures, then together for three or four months before weaning. If one group is given more food, those calves and their dams belong to their own management group and should be identified as such. If this is not done, the fed group’s growth EBVs will be inflated and will no longer represent a true genetic value, but a value influenced by the environment. This is common with exhibit animals who do not have their own management group.
3.Breeding seasons make performance testing easier and more accurate.
Total management, including weighing and measuring for performance attributes, becomes easier when animals are grouped in a 60- or 90-day mating and then calving phase. It should be noted that Shorter breeding seasons also put more emphasis on fertility selection.
4. Every stud and commercial breeder should have a breeding goal.
Performance testing as a tool will be basically useless if you don’t have such an objective. If you want to breed for fertility, ease of calving, or hefty weaners, for example, you’ll know to look for these traits and acquire bulls or rams with the appropriate EBVs for birth and weaning.
5. The accuracy of performance testing is improved by linking bulls or rams between seasons and breeders.
The accuracy of EBVs is improved by rolling over some bulls between seasons and with groups of females. The same is true if similar bulls are employed in active performance testing between two or three herds; for example, switching bulls between seasons while using some of the prior season’s bulls. The more bulls in the same management grouping that can be directly compared to each other, the better.
6. Weigh and measure all of your breed’s characteristics.
Features that come to mind are ease of calving, calving weight, weaning, 400-day, 600-day, and mature weights, scrotum size, sheath/navel score, carcass traits, residual feed consumption, and days to calving (fertility). Although some of them are connected, don’t rely on correlations; the more you measure, the more you’ll learn.
7. Always compare the EBVs for various qualities to the breed average to see whether the animal is better or worse than the breed average.
Some catalogs may not properly display breed averages. For example, a bull’s wean or 200-day EBV may be +12, but the breed average is +15. This indicates that the bull is 3kg less than the current breed average for that weight. The +15 for the breed usually signifies that the breed average was 220kg in 1993, and the breed as a whole has raised its average weaning weight by 15kg to 235kg since then. As a result, the weaning weight of the +12 bull is anticipated to be 232kg.
8. EBVs should always be evaluated alongside their accuracy.
EBVs are simply the average genetic value of a trait that an animal will pass down to its offspring. Pedigree, individual performance, progeny, and correlations are all factors. Because young bulls offered at sales do not yet have progeny, we must rely on their pedigrees and performance data. If this is in place, it will be possible to get accuracies of more than 60%, which are useful for selection.
When ten or more of a bull’s progeny have their own data up to weaning, the accuracy of EBVs for growth features, for example, improves considerably, and the EBV begins to stabilize. EBVs can be relied on as a selection tool to a greater extent as their accuracies improve. The following calculation shows an EBV for yearling weight based on an animal’s own performance: EBV = heredity x (individual weight) – (average weight of all animals in the group).
9. An EBV for an animal trait indicates the average performance of the progeny for that trait, not the overall performance of the progeny.
Many stud and commercial breeders believe that a bull with a high-accuracy EBV for a feature, such as weaning weight, means that all of the bull’s progeny would perform similarly for that trait. This is not the case. Because there are so many gene combinations that can occur, quantitative genetics works on averages. Every offspring (except identical twins) will be distinct.For example, the average of the progeny for, say, weaning weight, will be on or very close to the average of the dam and sire’s EBV after 25 progenies of high accuracy (80%+).
10. EBVs should always be utilized in conjunction with visual inspection.
Examine the EBVs of the animals on sale when choosing a bull, and mark those that have the EBVs you require for your herd. Then visually choose one or a couple of them. The overall appraisal of an animal is influenced by structural correctness, muscling and masculinity in bulls, femininity in females, and other visual traits. A bull or ram with great EBVs but leg issues like straight hocks and pasterns, roll claws, or weak pasterns, for example, will not last long and may breed the problem into your herd.
11. Rand indexes are essentially an economic value assigned to specific EBVs for specific production systems, and they should be used for selection purposes if they are available.
This could be a grass-fed system, a weaner, or a feedlot. If your breed has these rand indexes, choose the one that is closest to your production system when buying or using bulls with higher rand indexes. After that, examine each individual EBV.
12. Predicted breeding values with genomic enhancements are on the way, which will improve trait accuracy.
Marker genes and combinations for specific attributes will be identified as a result of DNA testing, but this will not replace traditional performance recording. Animal phenotypic performance data, on the other hand, will be required to determine which genes and gene combinations are responsible for specific qualities, such as growth up to weaning, fertility, or good residual feed consumption. A balanced approach is required.
If you attain very high weaning weights, but your herd’s mature weight is likewise higher, birthweight is higher, calving ease is lower, and overall fertility is lower, you’ve probably made no long-term gain with the amount of beef produced per hectare. If you have the right breeding goal, precise performance testing and effective use of EBVs can be extremely beneficial.