|MCMANUS, CONCEPTA - University Of Brasilia|
|HERMUCHE, POTIRA - University Of Brasilia|
|PAIVA, SAMUEL - Embrapa|
|GUIMARAES, RENATO - University Of Brasilia|
|CARVALHO, O - University Of Brasilia|
Submitted to: Livestock Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/3/2021
Publication Date: 11/6/2021
Publication URL: https://handle.nal.usda.gov/10113/7565969
Citation: McManus, C.M., Hermuche, P.M., Paiva, S.R., Guimaraes, R.F., Carvalho, O.A., Blackburn, H.D. 2021. Gene bank collection strategies based upon geographic and environmental indicators for beef breeds in the United States of America. Livestock Science. 254. Article e104766. https://doi.org/10.1016/j.livsci.2021.104766.
Interpretive Summary: The geographic location where gene bank samples are sourced can influence various types of genetic adaptation to environmental stress, for example, heat stress. Geographic Information Systems was used to compare how environmental factors differed for different breed types of cattle sampled for the gene bank. Environmental indicators included the thermal heat index (an indicator of heat stress typically placed on cattle in different regions), altitude, and vegetation productivity. Also changes in geographic location of beef cattle populations over time were mapped. Gene bank collections of cattle breeds from the United Kingdom, Africa and east Asia were found to be primarily derived from the mid-west and inter-mountain west. Breeds in the collections of continental European decent tended to be sourced from locations with higher precipitation and greater forage productivity. Brahman and Brahman composites were sourced from the Gulf Coast region. Thermal heat index zones were created running from east to west, and increased in heat stress from north to south. While the collection was represented across all zones, opportunities exist to fill collection gaps from each zone among the different cattle types and breeds. With the baseline of environmental factors developed, opportunity exists to initiate genotyping of animals from different environmental zones to evaluate genetic resistance to environmental stress.
Technical Abstract: As gene bank collections develop, there are opportunities to collect germplasm using criteria other than random sampling or genetic relationships. For Brazil and the US, it has become apparent that sampling based upon environmental adaptability could enrich germplasm collections. Combining current US beef cattle germplasm collection with Geographical Information System (GIS) approaches, sample concentration and underrepresented areas were identified for Bos taurus taurus and Bos taurus indicus (BI). BI samples were principally derived along the Gulf Coast region (not necessarily close to freshwater sources). In contrast, continental Europe (BTCE) and British, Africa and Asia (BAA) breed samples were more concentrated among the Great Plains/Mid-West (close to major rivers and lakes), with some samples being derived from the south-west and Gulf Coast areas. BTCE and BAA have been extensively sampled, but more is needed in the more westerly states of New Mexico, Nevada, California and Utah. In addition, BI sampling should increase in the more northerly states of Tennessee and Kentucky to capture allele frequencies that may better enable those breeds to perform outside the Deep South. The methods used in this evaluation can be extended to using genotypes within or among breeds to promote sampling in environmentally unique areas.