Table 1.

Biological parameters evaluated during the experiment of N-methyl-N-nitrosourea-induced mammary cancer. A score from 0 to 3 was attributed for each of parameter. A severe alteration in some biological parameters was indication for euthanasia

Score		Parameters
General appearance and mental status	Body condition
	0	Well-conditioned
	1	Under conditioned
	2	Emaciated (Euthanasia)
	Body weight
	0	Normal
	1	Weight loss < 10 %
	2	Weight loss 10-20 %
	3	Weight loss > 20 % (Euthanasia)
	Food intake
	0	Normal (≈ 5-10 g/100 g of body weight)
	1	Decreased (< 5 g/100 g of body weight)
	Water intake
	0	Normal (≈ 10-15 mL/100 g of body weight)
	1	Decreased (<10 mL/100 g of body weight)
	Posture
	0	Normal position
	1	Changed position (eg. orthopneic position)
	Coat and grooming
	0	Normal
	1	Lack of grooming
	2	Rough coat, chromodachryorrhea
	3	Very rough coat, piloerection, severe chromodachryorrhea
	Mucosal
	0	Normal
	1	Mild anemic
	2	Moderate anemic
	3	Severe anemic (Euthanasia)
	Eyes, ears and whiskers
	0	Normal
	1	Partial closed eye, droopy ears, forward whiskers
	2	Complete closed eye, droopy and curved ears, forward and bunched whiskers
	Mental status
	0	Normal (alert, curious, eyes bright)
	1	Lethargic
	2	Stupor
	3	Moribund / Coma (Euthanasia)
Behavior	Response to external stimuli (hand clapping above the cage)
	0	Normal
	1	Mild response
	2	Moderate response with vocalization
	3	Violent response
Clinical signs	Hydration status
	0	Normal (< 2 sec.)
	1	Abnormal skin pinch test (> 2 sec.)
	Respiratory rate
	0	Normal (66-115 breaths/min)
	1	Abnormal (decreased: < 66 breaths/min or increase: > 115 breaths/min)
	2	Abdominal breathing (Euthanasia)
	Heart rate
	0	Normal (250-450 beats/min)
	1	Abnormal (decreased: < 250 beats/min or increased: > 450 beats/min)
	Body temperature
	0	Normal (35.6-38.9°C)
	1	Abnormal (hypothermia: < 35.6ºC or hyperthermia: > 38.9°C)
	Hematocrit
	0	Normal (35-51%)
	1	Abnormal (decreased: < 35% or increased: > 51%)
	Urine specific gravity
	0	Normal (1.040-1.070)
	1	Abnormal (decreased: < 1.040 or increased: > 1.070)
Mammary tumors	Tumors location
	0	Do not interfere with animals’ bodily functions
	1	Interfere with animals’ bodily functions (eat or drink) (Euthanasia)
	2	Tumor in contact with cage floor (Euthanasia)
		Tumors macroscopic evaluation
	0	Normal
	1	Erosion
	2	Ulceration (Euthanasia, when combined with a size > 35 mm in a 250 g rat)
	3	Persistent self-induced trauma (Euthanasia)
		Tumors burden
	0	< 10% of the animal’s body weight (<35 mm in a 250 g rat)
	1	>10 % of the animal’s body weight (>35 mm in a 250 g rat) (Euthanasia, when combined with tumor ulceration)