Short communication: Implementation of a breeding value for heat tolerance in Australian dairy cattle
| Autor: | Benjamin J. Hayes, Phil J. Bowman, Thuy T. T. Nguyen, Mekonnen Haile-Mariam, Jennie E. Pryce, Gert J. Nieuwhof |
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| Rok vydání: | 2017 |
| Předmět: |
0301 basic medicine
Male Thermotolerance Animal breeding Single-nucleotide polymorphism Biology Breeding Standard deviation 03 medical and health sciences Animal science Genetic variation Genetics Animals Lactation Selection (genetic algorithm) Dairy cattle business.industry 0402 animal and dairy science Australia Temperature food and beverages Reproducibility of Results Humidity 04 agricultural and veterinary sciences Milk Proteins 040201 dairy & animal science Breed Biotechnology 030104 developmental biology Milk Genetic Techniques Trait Animal Science and Zoology Cattle Female business Food Science |
| Zdroj: | Journal of dairy science. 100(9) |
| ISSN: | 1525-3198 |
| Popis: | Excessive ambient temperature and humidity can impair milk production and fertility of dairy cows. Selection for heat-tolerant animals is one possible option to mitigate the effects of heat stress. To enable selection for this trait, we describe the development of a heat tolerance breeding value for Australian dairy cattle. We estimated the direct genomic values of decline in milk, fat, and protein yield per unit increase of temperature-humidity index (THI) using 46,726 single nucleotide polymorphisms and a reference population of 2,236 sires and 11,853 cows for Holsteins and 506 sires and 4,268 cows for Jerseys. This new direct genomic value is the Australian genomic breeding value for heat tolerance (HT ABVg). The components of the HT ABVg are the decline in milk, fat, and protein per unit increase in THI when THI increases above the threshold of 60. These components are weighted by their respective economic values, assumed to be equivalent to the weights applied to milk, fat, and protein yield in the Australian selection indices. Within each breed, the HT ABVg is then standardized to have a mean of 100 and standard deviation (SD) of 5, which is consistent with the presentation of breeding values for many other traits in Australia. The HT ABVg ranged from −4 to +3 SD in Holsteins and −3 to +4 SD in Jerseys. The mean reliabilities of HT ABVg among validation sires, calculated from the prediction error variance and additive genetic variance, were 38% in both breeds. The range in ABVg and their reliability suggests that HT can be improved using genomic selection. There has been a deterioration in the genetic trend of HT, and to moderate the decline it is suggested that the HT ABVg should be included in a multitrait economic index with other traits that contribute to farm profit. |
| Databáze: | OpenAIRE |
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