Columbia subject headings:
Livestock--Reproduction--Congresses.
Ruminants--Reproduction--Congresses.
Harvard subject headings:
Livestock--Reproduction--Congresses.
Ruminants--Physiology--Congresses.
Ruminants--Reproduction--Congresses.
Princeton subject headings:
Livestock--Reproduction--Congresses.
Ruminants--Reproduction--Congresses.