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Biblioteca (s) : |
INIA Las Brujas. |
Fecha : |
21/02/2014 |
Actualizado : |
04/11/2019 |
Tipo de producción científica : |
Artículos en Revistas Indexadas Internacionales |
Autor : |
AGUILAR, I.; MISZTAL, I.; TSURUTA, S. |
Afiliación : |
IGNACIO AGUILAR GARCIA, Instituto Nacional de Investigación Agropecuaria (INIA), Uruguay; I. MISZTAL, Animal and Dairy Science Department, University of Georgia,United States; S. TSURUTA, Animal and Dairy Science Department, University of Georgia,United States. |
Título : |
Short communication: Genetic trends of milk yield under heat stress for US Holsteins. |
Fecha de publicación : |
2010 |
Fuente / Imprenta : |
Journal of Dairy Science, 2010, v.93, no.4, p. 1754-1758. |
DOI : |
10.3168/jds.2009-2756 |
Idioma : |
Inglés |
Notas : |
Article history: Received September 21, 2009. / Accepted December 4, 2009. |
Contenido : |
ABSTRACT.
Data included 90,242,799 test-day milk records from 5,402,484 Holstein cows in the first 3 parities and 9,326,754 animals in the pedigree. Additionally, daily temperature-humidity indexes from 202 weather stations were available. Analyses were done by a random regression model in which each parity was treated as a separate trait and that accounted for heat stress. The fixed effects included herd test-day, age at calving, milking frequency, and days in milk classes. Random effects included additive genetic, permanent environment, and herd-year effects, all fit as random regressions. Five covariates in the random regressions included linear splines with 4 knots at 5, 50, 200, and 305 DIM and a function of a temperature-humidity index (THI). Mixed model equations were solved by using an iteration on data approach with a preconditioned conjugate gradient algorithm. Genetic trends for daily milk yield in absence of heat stress (intercept) were 0.140 kg/yr, 0.172 kg/yr, and 0.168 kg/yr for the first, second, and third parity, respectively. Genetic trends for decline of milk yield at temperature of 5°C THI over the threshold of sensitivity to heat stress were -0.002 kg/yr, -0.035 kg/yr, and -0.038 kg/yr, for first, second, and third parity, respectively. Genetic profiles were created by contrasting the 100 most and 100 least heat-tolerant bulls for the official proofs. The most heat-tolerant bulls transmitted lower production and dairy form but higher fertility, productive life, and type, especially udder and locomotion traits. In later parities, the type advantages were smaller. Test-day records capture only a fraction of information due to heat stress, and the real trends for heat stress may be stronger. Studies on heat stress for production should include records on later parities.
© 2010 American Dairy Science Association. MenosABSTRACT.
Data included 90,242,799 test-day milk records from 5,402,484 Holstein cows in the first 3 parities and 9,326,754 animals in the pedigree. Additionally, daily temperature-humidity indexes from 202 weather stations were available. Analyses were done by a random regression model in which each parity was treated as a separate trait and that accounted for heat stress. The fixed effects included herd test-day, age at calving, milking frequency, and days in milk classes. Random effects included additive genetic, permanent environment, and herd-year effects, all fit as random regressions. Five covariates in the random regressions included linear splines with 4 knots at 5, 50, 200, and 305 DIM and a function of a temperature-humidity index (THI). Mixed model equations were solved by using an iteration on data approach with a preconditioned conjugate gradient algorithm. Genetic trends for daily milk yield in absence of heat stress (intercept) were 0.140 kg/yr, 0.172 kg/yr, and 0.168 kg/yr for the first, second, and third parity, respectively. Genetic trends for decline of milk yield at temperature of 5°C THI over the threshold of sensitivity to heat stress were -0.002 kg/yr, -0.035 kg/yr, and -0.038 kg/yr, for first, second, and third parity, respectively. Genetic profiles were created by contrasting the 100 most and 100 least heat-tolerant bulls for the official proofs. The most heat-tolerant bulls transmitted lower production and dairy form but higher fertility, producti... Presentar Todo |
Thesagro : |
ESTRES CALORICO; GANADO LECHERO. |
Asunto categoría : |
L01 Ganadería |
URL : |
http://www.ainfo.inia.uy/digital/bitstream/item/3652/1/Aguilar-I.-2010-Jr.Dairy-Sc.v.93-p.1754-1758.pdf
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Marc : |
LEADER 02506naa a2200193 a 4500 001 1012836 005 2019-11-04 008 2010 bl uuuu u00u1 u #d 024 7 $a10.3168/jds.2009-2756$2DOI 100 1 $aAGUILAR, I. 245 $aShort communication$bGenetic trends of milk yield under heat stress for US Holsteins.$h[electronic resource] 260 $c2010 500 $aArticle history: Received September 21, 2009. / Accepted December 4, 2009. 520 $aABSTRACT. Data included 90,242,799 test-day milk records from 5,402,484 Holstein cows in the first 3 parities and 9,326,754 animals in the pedigree. Additionally, daily temperature-humidity indexes from 202 weather stations were available. Analyses were done by a random regression model in which each parity was treated as a separate trait and that accounted for heat stress. The fixed effects included herd test-day, age at calving, milking frequency, and days in milk classes. Random effects included additive genetic, permanent environment, and herd-year effects, all fit as random regressions. Five covariates in the random regressions included linear splines with 4 knots at 5, 50, 200, and 305 DIM and a function of a temperature-humidity index (THI). Mixed model equations were solved by using an iteration on data approach with a preconditioned conjugate gradient algorithm. Genetic trends for daily milk yield in absence of heat stress (intercept) were 0.140 kg/yr, 0.172 kg/yr, and 0.168 kg/yr for the first, second, and third parity, respectively. Genetic trends for decline of milk yield at temperature of 5°C THI over the threshold of sensitivity to heat stress were -0.002 kg/yr, -0.035 kg/yr, and -0.038 kg/yr, for first, second, and third parity, respectively. Genetic profiles were created by contrasting the 100 most and 100 least heat-tolerant bulls for the official proofs. The most heat-tolerant bulls transmitted lower production and dairy form but higher fertility, productive life, and type, especially udder and locomotion traits. In later parities, the type advantages were smaller. Test-day records capture only a fraction of information due to heat stress, and the real trends for heat stress may be stronger. Studies on heat stress for production should include records on later parities. © 2010 American Dairy Science Association. 650 $aESTRES CALORICO 650 $aGANADO LECHERO 700 1 $aMISZTAL, I. 700 1 $aTSURUTA, S. 773 $tJournal of Dairy Science, 2010$gv.93, no.4, p. 1754-1758.
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INIA Las Brujas (LB) |
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