library(rvest)
suppressPackageStartupMessages(library(dplyr))

url <- "http://madb.europa.eu/"

# r <- html("http://madb.europa.eu/madb/atDutyOverviewPubli.htm?option=1&display=20&language=all&year1=&year2=&sector=all&country=all&langId=en&datacat_id=AT&showregimes=&countryid=US&submit=Search&countries=US&hscode=5515110045")

r <- html(url,
           path ="madb/atDutyOverviewPubli.htm",
           query = list(option = 1,
                         display = 20,
                         language = "all",
                         year1 = "",
                         year2 = "",
                         sector = "all",
                         country = "all",
                         langId = "en",
                         datacat_id = "AT",
                         showregimes = "",
                         countryid = "US",
                         submit = "Search",
                         countries = "US",
                         hscode= "01012000"))


html_nodes(r,, "//table[1]") %>% html_table(fill = T, header = T) %>% 
  as.data.frame(stringsAsFactors = F) %>% 
  select(hs = 1, desc = 2)
##               hs                                   desc
## 1           <NA>                                   <NA>
## 2             01                 CHAPTER 1 LIVE ANIMALS
## 3           0101 Live horses, asses, mules and hinnies:
## 4                                             - Horses:
## 5        0101.21        - - Pure-bred breeding animals:
## 6  0101.21.00.10                             - - - Male
## 7  0101.21.00.20                           - - - Female
## 8        0101.29                             - - Other:
## 9  0101.29.00.10 - - - Imported for immediate slaughter
## 10 0101.29.00.90                            - - - Other
## 11       0101.30                                - Asses
## 12       0101.90                               - Other:
## 13    0101.90.30   - - Imported for immediate slaughter
## 14    0101.90.40                              - - Other