How to read NTM and breeding values for traits in NTM? • Breeding values are estimated by the independent scientific breeding institute NAV (Nordic Cattle Genetic Evaluation) • Rolling base, cows 3-5 years old (for each genetic evaluation use a new group of cows) VERAGE GOOD • Average 0 for NTM, average 100 for breeding values • Standard deviation 10 units SUPER UPERIOR A S NTM=0 EBV=100 NTM>+10 EBV>110 NTM>+20 EBV >120 NTM>+30 EBV>130 NTM and breeding values for different traits is not just numbers but an important tool to compare the bulls. These numbers reveal what genetic potential is actually hidden in a bull. By looking at NTM and the estimated breeding values (EBV) for a specific bull, you could know what to expect from his daughters. The numbers will tell you all about their performance in your herd. The bell curve shows what each standard deviation represents. One standard deviation (10 units) away from the mean in either direction (the light blue area) accounts for about 68 % of the bulls. This means that bulls with NTM over 20 and breeding values over 120 represent the top 2.5% of the breed. Everything is relative and we know there is a difference between bulls on the genetic level. In our total merit index – NTM, a bull with NTM 0 is an average bull. A bull with NTM +10 is labelled as Good, while a bull with NTM +20 is a Super bull. A bull with NTM +30 is even better, he is a Superior specimen and represents the top 0.1% (1 out of 1,000) of the bulls. A top ranking genomic VikingHolstein bull with +40 in gNTM is 1 out of 30,000 bulls. Not hard to understand how rare and special that is! How are the indexes in NTM expressed? Estimated breeding values (EBVs) of all animals are adjusted in such a way that animals in the base population have an average index of 100. For all traits a rolling base consisting of cows from Denmark, Sweden and Finland that are 3-5 years of age at the date of publication is applied. That means that a new group of cows that satisfy the condition is used for each genomic evaluation. The Standard Deviation is a statistic that tells you how widely spread from the average the scores of all bulls are for any particular trait. Using Standard deviation makes it possible to know what is normal, and what is extra good or what is not so good. Just relying on averages can be misleading. Without using standard deviation, you have no way of knowing how spread out the values are around the average. 34.1% 34.1% 13.6% 13.6% 2.1% 0.1% NTM -30 -20 Index 70 80 -10 0 +10 90 100 110 2.1% 0.1% +20 +30 120 130 They are simply the elite specimens. If we compare with other international indices, a breeding value of 120 on the Nordic scale is comparable with a US bull at +2.00 (PTA Type) and 108 in the Dutch proofs. 4
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