In the Mishna in Chullin 54a Rabi Meir says that an animal whose kidneys (presumably meaning _both_ kidneys) are gone (nitlo) is kosher, while the Chachomim say that such an animal is psula (presumably due to its being a treifa). The Shulchan Aruch Yoreh Deah 44:1 and 44:6 says that if it's kidneys are gone, it is kosher, i.e., not treifa.
I spoke to a kidney specialist who said that a human whose both kidneys are gone, won't live longer than one month. I presume animals are the same. If so, how can an animal without kidneys be kosher? I should point out that the Hebrew Artscroll says something about recent studies that show that animals can live 12 months without kidneys. While I find this hard to believe, I could not find the 2 references that the Artscroll gave for this claim.
What's the story regarding an animal without kidneys?
Kol Tuv,
Chaim
The alimentary system of animals is *not* the same as that of humans.
Since Rabbi Lach (in "Chulin Illuminated") already addresses your question, I will paraphrase his words for you here:
The kidneys perform the crucial function of filtering waste materials (produced by cellular oxidation) from the bnlood, to be excreted from the body in the form of urine. Accordingly, the medical community classifies kidneys as organs that are essential for life. It is well known that kidney failure in humans quickly brings on deterioration in the body. Death soon follows, caused by the poisoning of the body by its own waste material. Nevertheless, the Mishnah states that an animal whose kidneys were removes is not Tereifah, implying that the loss of kidneys is not a fatal condition in animals. It is thus illuminating to note that in recent years, scientists have been amazed to find that ruminants who lose their kidneys are able to cope with their condition significantly better than other creatures. Ruminating animals apparently compensate by filtering out toxins into the rumen ("Keres"), to be excreted with the solid wastes.
(Dr. J.L. Katzenelson, in "Ha'Talmud v'Chochmas ha'Refu'ah," finds this Halachah one of the most difficult to explain, and thus he changes the Girsa from "kidneys" in the plural to "kidney" in the singular. This approach is very problematic, since there is no alternative Girsa in the Mishnah, and the Shulchan Aruch and all of the Poskim clearly mention both kidneys.)
Of great interest, then, is a study performed thirty years ago (cited by Rav Levinger of Switzerland in "Me'or l'Maseches Chulin"), in which a number of cows had their kidneys surgically removed and were subsequently monitored. Scientists continuously recorded the vital body functions for a full week and found, to their surprise, that the cows showed no signs of illness or irritability, with the sole exception of a loss of appetite. To quote from the actual study, entitled, "Further Studies on the Effect of Total Nephrectomy in the Bovine" by C. Watts and J.R. Campbell of the Univesity of Glasgow Veterinary School (Res. Vet. Sci. 1971, 12, 234-245):
"In the present paper, a further group of bullocks undergoing bilateral nephrectomy was more extensively studied than the previous group. A careful assessment of their clinical condition and food and water intake was made, and a more complete picture of biochemical changes was obtained by detailed analysis of blood, saliva, rumen fluid and faeces....
"Clinical Observations. None of the bullocks showed loss or increase of weight over the experimental period. In general, they were bright and of normal demeanor up to 5 days after the operation but then became slightly dull, although this was not marked even ast the time of slaughter [at the end of 7 days]. The food and water intake dropped immediately after the operation to about one-third of the pre-operation quantity and thereafter diminished still further so that at the end of the experimental period the animals were almost completely anorexic and were drinking not more than half a gallon of water per day.... No change was noted in skin elasticity or eye brightness or position. The temperature and pulse rate of the animals showed no significant variation from normal throughout the period.... No significant change was noted in the blood pressure of the bullocks....
"Discussion. Following nephrectomy, the animals showed no signs of stress or a rapid deterioration in their clinical condition. The only obvious clinical signs were onset of anorexia and reduced water intake with a gradual cessation of rumination. In contrast, anuric humans or bilaterally nephrectomized dogs show a sharp decline in clinical condition with a short life duration in the absence of palliative treatment.... One of the most obvious results of this study is that these bullocks were able to make considerable variations in the composition of their internal secretions to accommodate the changed circumstances of non-production of urine. The saliva and rumen play an important part in this. This capacity seems to be peculiar to ruminants and it is of particular interest to note that this reflects in their clinical condition where there is a slower deterioration than in non-ruminants in similar circumstances."
Y. Shaw
D.A.F.