Age-related changes in arterial blood-gas variables in Holstein calves at moderate altitude

Figures & data

Table 1 The sampling dates, mean calf ages, and number of calves sampled according to test

Test	Altitude, m	n^a	n^b	Dates when sampled	Mean age ± SD, days
1	1,601 (5,252 ft)	62	55	August 17–September 1, 2012	9.8±4.0
2	1,601	62	55	September 21–28, 2012	38.4±6.3
3	1,601	54^c	54^c	January 4-20, 2013	150.3±4.2
4	1,696 (5,565 ft)	55	55	May 3, 2013	260.5±8.0

Notes:

a Number of calves sampled;

b number of calves included in the analysis;

c one calf during the third test was missing at the time of sampling and subsequently found to be in another pen.

Abbreviation: SD, standard deviation.

Table 2 Nasal discharge and cough scoring criteria

Nasal or cough score	Clinical signs of nasal discharge	Clinical signs of coughing
1	Clear serous fluid	No coughing
2	Unilateral cloudy discharge	Induced cough (one cough only)
3	Bilateral cloudy discharge or excessive mucous or both	Induced cough (≥ two coughs)
4	Copious bilateral, mucopurulent discharge	spontaneous, noninduced coughing

Note: A separate score was assigned for nasal discharge and coughing.

Table 3 Mean ± SD values obtained from calves that had not been treated for respiratory disease prior to the test and had a cough score of 1 (neither spontaneous nor induced cough)

Item	Test	n*	Mean ± SD
Age, days	1	52	10.0±4.1
	2	32	36.9±6.0
	3	40	150.2±4.4
	4	41	259.0±7.7
Body temperature, Celsius	1	52	38.6±0.3
	2	32	39.1 ±0.6
	3	40	38.8±0.3
	4	41	39.0±0.3
A-a O2, mmHg	1	52	22±8^a
	2	32	19±9^a
	3	40	8±8^b
	4	41	7±8^b
pH	1	52	7.45±0.05^a
	2	32	7.47±0.05^b
	3	40	7.48±0.03^b
	4	41	7.49±0.04^c
PacO2, mmhg	1	52	35.9±5.2
	2	32	37.1 ±3.1
	3	40	35.3±3.3
	4	41	35.3±2.9
PaO2, mmHg	1	52	58.9±9.1^a
	2	32	61.2±8.4^a
	3	40	74.0±8.9^b
	4	41	75.3±9.1^b
Hematocrit, %	1	15	Not tested
	2	31	23.4±4.6^a
	3	12	26.1 ±4.3^b
	4	25	25.3±4.6^b
HCO3, mmol/L	1	52	25.3±4.6^a
	2	32	27.0±3.6^a
	3	40	26.5±3.1^a
	4	41	27.3±2.8^b
L-lactate,** mmol/L	1	52	(0.37, 0.68, 0.91, 1.41, 3.22)^a
	2	11	(0.32, 0.75, 1.66, 2.34, 9.43)^b
	3	36	(0.35, 0.78, 1.54, 2.06, 5.21)^a
	4	16	(1.07, 2.15, 3.20, 4.05, 5.98)^b
Oxyhemoglobin saturation,** %	1	52	(74.7, 88.7, 91.5, 93.4, 97.4)^a
	2	32	(79.4, 90.2, 92.2, 94.5, 96.1)^a
	3	40	(89.5, 94.8, 95.8, 97.0, 97.8)^b
	4	41	(91.0, 95.1, 95.9, 97.1, 98.2)^b

Notes: ^a–cMeans for a common variable with different superscripts differ (P<0.006); *Number of calves sampled that met the inclusion criteria; **Minimum, 25th percentile, median, 75th percentile, and maximum values; Data not normally distributed.

Abbreviations: A-a O₂, alveolar-arterial pressure gradient; HCO₃, bicarbonate; PaCO₂, arterial CO₂ tension; PaO₂, arterial O₂ tension; SD, standard deviation.

Figure 1 Alveolar-arterial oxygen pressure gradient in calves by age.

Notes: Dots represent estimated values; Values less than 0 mmHg are physiologically impossible and indicate measurement error; The respiratory quotient used was most likely unsuitable for older calves; The dashed line represents predicted alveolar-arterial oxygen (mmHg) =24.6 − 0.16*age + 0.0004*age².

Figure 2 Arterial oxygen tension in calves by age.

Notes: Dots represent measured values; Dashed line represents predicted arterial oxygen tension fitted values (mmHg) =56.10 + 0.16*age − 0.0003*age².

Table 4 The number of calves according to the number of treatments received for respiratory disease and age of first treatment

Number of treatments	Number of calves	Age at first treatment, days
0	41 (75%)	–
1	12 (22%)	(7, 31.5, 43.5, 91.5, 102)^a
2	1 (2%)	25
3	1 (2%)	27

Note: ^aMinimum, 25th percentile, median, 75th percentile, and maximum values.

Figure 3 Percentage of calves with nasal scores 1 to 4 during test periods 1 to 4.

Figure 4 Percentage of calves with cough scores 1 to 4 during test periods 1 to 4.