How to say “Her milk yield has dropped at this stage of lactation.” in Japanese

In Japanese

あの牛(うし)、この泌乳(ひにゅう)の時期(じき)に入(はい)ってから乳(ちち)の出(で)が落(お)ちたね。

Ano ushi, kono hinyū no jiki ni haitte kara chichi no de ga ochita ne.