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Mário L. Santana Jr Rodrigo J. Pereira Annaiza B. Bignardi Lenira El Faro Maria F. Á. Pires Ricardo G. Andrade Bruno C. Perez Frank A. T. Bruneli Maria G. C. D. Peixoto 《Zeitschrift für Tierzüchtung und Züchtungsbiologie》2020,137(5):486-494
The present study evaluated the heat stress response pattern of dual-purpose Guzerá cattle for test-day (TD) milk yield records of first lactation and estimated genetic parameters and trends related to heat stress. A total of 31,435 TD records from 4,486 first lactations of Guzerá cows, collected between 1986 and 2012, were analysed. Two random regression models considered days in milk (DIM) and/or temperature × humidity-dependent (THI) covariate. Impacts of −0.037, −0.019 and −0.006 kg/day/THI for initial and intermediate stages of lactation were observed when considering the mean maximum daily temperature and humidity to calculate THI. Heritability estimates ranged from 0.16 to 0.35 throughout lactation and THI values, suggesting the possibility to expect gains from selection for such trait. The variable trajectory of breeding values for dual-purpose Guzerá sires in response to changes in THI values confirms that the genotype × environment interaction due to heat stress can have some effect on TD milk yield. Despite the high dairy performance of Guzerá cattle under heat stress, estimated genetic trends showed a progressive reduction in heat tolerance. Therefore, new strategies should be adopted to prevent negative impacts of heat stress over milk production in Guzerá animals in future. 相似文献
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Silva Roberta Polyana Araújo da Lôbo Raimundo Nonato Braga El Faro Lenira dos Santos Glaucyana Gouvêa Bruneli Frank Ângelo Tomita Peixoto Maria Gabriela Campolina Diniz 《Tropical animal health and production》2020,52(5):2513-2522
Tropical Animal Health and Production - This study aimed to estimate the genetic parameters for somatic cell count (SCC) and the genetic association between SCC and milk production traits using two... 相似文献
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Brito Laís Costa Peixoto Maria Gabriela Campolina Diniz Carrara Eula Regina Fonseca e Silva Fabyano Ventura Henrique Torres Bruneli Frank Angelo Tomita Lopes Paulo Sávio 《Tropical animal health and production》2020,52(5):2251-2257
Tropical Animal Health and Production - This study aimed to estimate the genetic parameters of milk (305-day milk yield (MY305)), growth (weaning weight (WW), yearling weight (YW), and weight at... 相似文献
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