肥馬 is read as ひば (hiba) and means fat horse.
ひば
hiba
てんたかくうまこゆるあき
autumn comes with harvest time and clear weather
うまごやし
white clover (Trifolium repens)
こめつぶうまごやし
black medic (Medicago lupulina)
むらさきうまごやし
alfalfa (Medicago sativa)
ひりょう
manure
ひまん
corpulence
こえる
to grow fertile
こやし
something that will help one develop in the future
こやす
to fertilize
ひだい
hypertrophy
こえ
ひいく
fattening