Livestock Improvement Association in Japan

Tokyo, Japan

Livestock Improvement Association in Japan

Tokyo, Japan
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Togashi K.,Livestock Improvement Association in Japan | Hagiya K.,Japan National Agriculture and Food Research Organization | Osawa T.,National Livestock Breeding Center | Nakanishi T.,National Livestock Breeding Center | And 6 more authors.
Asian-Australasian Journal of Animal Sciences | Year: 2012

We first sought to clarify the effects of discounted rate, survival rate, and lactation persistency as a component trait of the selection index on net merit, defined as the first five lactation milks and herd life (HL) weighted by 1 and 0.389 (currently used in Japan), respectively, in units of genetic standard deviation. Survival rate increased the relative economic importance of later lactation traits and the first five lactation milk yields during the first 120 months from the start of the breeding scheme. In contrast, reliabilities of the estimated breeding value (EBV) in later lactation traits are lower than those of earlier lactation traits. We then sought to clarify the effects of applying single nucleotide polymorphism (SNP) on net merit to improve the reliability of EBV of later lactation traits to maximize their increased economic importance due to increase in survival rate. Net merit, selection accuracy, and HL increased by adding lactation persistency to the selection index whose component traits were only milk yields. Lactation persistency of the second and (especially) third parities contributed to increasing HL while maintaining the first five lactation milk yields compared with the selection index whose only component traits were milk yields. A selection index comprising the first three lactation milk yields and persistency accounted for 99.4% of net merit derived from a selection index whose components were identical to those for net merit. We consider that the selection index comprising the first three lactation milk yields and persistency is a practical method for increasing lifetime milk yield in the absence of data regarding HL. Applying SNP to the second- and third-lactation traits and HL increased net merit and HL by maximizing the increased economic importance of later lactation traits, reducing the effect of first-lactation milk yield on HL (genetic correlation (r G) = -0.006), and by augmenting the effects of the second- and third-lactation milk yields on HL (rG = 0.118 and 0.257, respectively).


Yamazaki T.,Japan National Agriculture and Food Research Organization | Togashi K.,Livestock Improvement Association in Japan | Iwama S.,Livestock Improvement Association in Japan | Matsumoto S.,Livestock Improvement Association in Japan | And 4 more authors.
Animal Science Journal | Year: 2014

The effectiveness of the incorporation of genomic pre-selection into dairy cattle progeny testing (GS-PT) was compared with that of progeny testing (PT) where the fraction of dam to breed bull (DB) selected was 0.01. When the fraction of sires to breed bulls (SB) selected without being progeny tested to produce young bulls (YB) in the next generation was 0.2, the annual genetic gain from GS-PT was 13% to 43% greater when h2=0.3 and 16% to 53% greater when h2=0.1 compared with that from PT. Given h2=0.3, a selection accuracy of 0.8 for both YB and DB, and selected fractions of 0.117 for YB and 0.04 for DB, GS-PT produced 40% to 43% greater annual genetic gain than PT. Given h2=0.1, a selection accuracy of 0.6 for both YB and DB, and selected fractions of 0.117 for YB and 0.04 for DB, annual genetic gain from GS-PT was 48% to 53% greater than that from PT. When h2=0.3, progeny testing capacity had little effect on annual genetic gain from GS-PT. However, when h2=0.1, annual genetic gain from GS-PT increased with increasing progeny testing capacity. © 2014 Japanese Society of Animal Science.

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