My blood... my precious

Its my second day of my final year laboratory project and it's pretty stressful, there are many things to note, to learn, and to remember, and on top of that, my project supervisor is strict and my friends and I have already got reprimanded a few times in two days. Nevertheless, it may be good training for the working society in future. We have to use some blood for our project, and if animal's blood can't be bought, human blood may be used instead, though scientifically and strictly speaking that would be considered unethical.

Images of inverted-hanging farm animals with blood gushing out from their slit throats filled my mind. What makes our blood so much precious than that of an animal? What makes it unethical for us, yet "ethical" for them? I am afraid to let blood flow out of me, likewise, the animals would feel so, they will not be willing to die and sacrifice themselves. Unfortunately, their lives are of little value in the eyes of many. Do not to others what you will not do to yourself, may the day of alternatives to all the animal products come soon.