http://www.extension.org/pages/9859/manejo-seguro-del-ganado-lechero
http://www.infocarne.com/bovino/vacas_lecheras.asp
http://www.engormix.com/MA-ganaderia-leche/nutricion/foros/alimentacion-vaca-lechera-alta-t8951/141-p0.htm
http://html.rincondelvago.com/vacunas-en-bovinos.html