Key	Year	Country	Total number of dairy cows	Total number of dairy herds	Average of cows per herd	Average milk production per cow per year (kg)	Percent of fat production per cow per year (%)	Percent of protein production per cow per year (%)	Others	E-mail address of the responsible
6	2004	México	6,850,000	n.a.	n.a	1,441.42	n.a.	n.a.	n.a.	holstein2004@prodigy.net.mx
5	2003	México	6,800,000	n.a.	n.a	1,438.88	n.a.	n.a.	n.a.	holstein2004@prodigy.net.mx
4	2002	México	6,800,000	n.a.	n.a	1,420.34	n.a.	n.a.	n.a.	holstein2004@prodigy.net.mx