Dual‐purpose Guzerá cattle exhibit high dairy performance under heat stress
| Autor: | Annaiza Braga Bignardi, Lenira El Faro, Rodrigo Junqueira Pereira, Ricardo Guimarães Andrade, Mário Luiz Santana, B. C Perez, Maria Gabriela Campolina Diniz Peixoto, F. A. T. Bruneli, Maria de Fátima Ávila Pires |
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| Rok vydání: | 2019 |
| Předmět: |
0301 basic medicine
Hot Temperature Genotype Breeding Biology Heat Stress Disorders 03 medical and health sciences Animal science Food Animals Lactation Covariate medicine Animals Guzera cattle Gene–environment interaction 0402 animal and dairy science Genetic Variation food and beverages Humidity 04 agricultural and veterinary sciences General Medicine Heritability Zebu 040201 dairy & animal science Heat stress 030104 developmental biology medicine.anatomical_structure Cattle Female Animal Science and Zoology Heat-Shock Response |
| Zdroj: | Journal of Animal Breeding and Genetics. 137:486-494 |
| ISSN: | 1439-0388 0931-2668 |
| Popis: | 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. |
| Databáze: | OpenAIRE |
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