I use the biomaRt package for my genomic research weekly and I noticed after updating to the latest version of biomaRt that when running the following code, there is no longer a dataset listed for the Rat (Rattus norvegicus). I did test "hsapiens_gene_ensembl", and it is working I am currently running R version 4.4.0 and biomaRt version 2.60.1.

library(biomaRt)

ensemblmart113 <- useEnsembl(biomart="ensembl")
rat <- useDataset("rnorvegicus_gene_ensembl", ensemblmart113)
#Error in checkDataset(dataset = dataset, mart = mart) : 
#The given dataset:  rnorvegicus_gene_ensembl , is not valid.  Correct dataset names can be obtained with the listDatasets() function.
listDatasets(ensemblmart113) #no rnorvegicus_gene_ensembl anymore

#sessionInfo
sessionInfo()
R version 4.4.0 (2024-04-24)
Platform: aarch64-apple-darwin20
Running under: macOS 15.0.1

Matrix products: default
BLAS:   /Library/Frameworks/R.framework/Versions/4.4-arm64/Resources/lib/libRblas.0.dylib 
LAPACK: /Library/Frameworks/R.framework/Versions/4.4-arm64/Resources/lib/libRlapack.dylib;  LAPACK version 3.12.0

locale:
[1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8

time zone: America/Toronto
tzcode source: internal

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     

other attached packages:
[1] biomaRt_2.60.1

loaded via a namespace (and not attached):
 [1] bit_4.5.0               jsonlite_1.8.9          dplyr_1.1.4             compiler_4.4.0          crayon_1.5.3            filelock_1.0.3          tidyselect_1.2.1       
 [8] Biobase_2.64.0          xml2_1.3.6              blob_1.2.4              stringr_1.5.1           Biostrings_2.72.1       IRanges_2.38.1          progress_1.2.3         
[15] png_0.1-8               fastmap_1.2.0           R6_2.5.1                XVector_0.44.0          generics_0.1.3          curl_5.2.3              httr2_1.0.5            
[22] GenomeInfoDb_1.40.1     BiocGenerics_0.50.0     tibble_3.2.1            AnnotationDbi_1.66.0    GenomeInfoDbData_1.2.12 DBI_1.2.3               pillar_1.9.0           
[29] rlang_1.1.4             utf8_1.2.4              KEGGREST_1.44.1         cachem_1.1.0            stringi_1.8.4           bit64_4.5.2             RSQLite_2.3.7          
[36] memoise_2.0.1           cli_3.6.3               magrittr_2.0.3          zlibbioc_1.50.0         digest_0.6.37           dbplyr_2.5.0            rappdirs_0.3.3         
[43] hms_1.1.3               BiocFileCache_2.12.0    lifecycle_1.0.4         S4Vectors_0.42.1        prettyunits_1.2.0       vctrs_0.6.5             glue_1.8.0             
[50] stats4_4.4.0            fansi_1.0.6             httr_1.4.7              tools_4.4.0             pkgconfig_2.0.3         UCSC.utils_1.0.0

Is there an alternative method for acquiring the rat gene ensemble? Or has this been removed permanently?

If you need any further information from me, I would be happy to provide it.

The biomaRt package only queries what exists on Ensembl's Biomart database, and if you go directly to their page it's not there. So you should ask Ensembl, since it's their database, rather than asking here, as nobody here (except Mike Smith, who may have to ask Ensembl himself) is likely to have any inside information about what's going on at Ensembl.