. 2020 Jan 13;98(2):skaa005. doi: 10.1093/jas/skaa005

Table 7.

Performance, carcass traits, and economic outcomes according to the number of treatments for BRD in feedlot cattle

	Number of BRD treatments
Variable	0	1	2	≥3	Visually healthy treated¹	P-value
N	662	100	26	19	63	Chi = <0.001
Mortalities	1	3	3	11	0
In-weight, kg/animal	428.2 ± 5.97	421.3 ± 7.24	418.4 ± 11.39	414.0 ± 12.85	437.4 ± 8.52	0.260
Exit weight, kg/animal	634.6 ± 5.23^a	625.5 ± 6.35^a	581.5 ± 9.97^b	560.4 ± 11.51^b	651.3 ± 7.48^c	<0.001^L
ADG, kg/d	1.8 ± 0.05^ab	1.7 ± 0.06^b	1.3 ± 0.09^c	1.1 ± 0.10^c	1.9 ± 0.07^a	<0.001^L
Carcass weight, kg/carcass	347.9 ± 2.89^ab	344.4 ± 3.51^b	320.6 ± 5.51^c	308.3 ± 6.36^c	356.4 ± 4.12^a	<0.001^L
MSA marble score	347.5 ± 8.07^a	331.2 ± 9.78^ab	303.8 ± 15.37^b	300.2 ± 17.35^b	345.2 ± 11.53^ab	<0.001^L
MSA Index	54.3 ± 0.21	54.3 ± 0.26	53.4 ± 0.42	54.1 ± 0.48	54.1 ± 0.30	0.100
P8 fat depth²	16.3 ± 0.58^ab	15.0 ± 0.70^bc	12.2 ± 1.11^cd	11.3 ± 1.25^d	17.9 ± 0.83^a	<0.001^L
Rib fat depth	7.9 ± 0.38^a	7.0 ± 0.46^ab	6.3 ± 0.72^ab	5.3 ± 0.81^b	7.6 ± 0.54^ab	<0.001^L
Purchase price, $/animal	1,405.25 ± 18.592	1,377.37 ± 22.115	1,371.65 ± 34.475	1,344.94 ± 38.955	1,416.80 ± 26.081	0.140
Feed cost, $/animal	327.54 ± 1.426^a	314.25 ± 3.648^b	304.14 ± 7.191^bc	285.83 ± 8.412^c	335.20 ± 4.619^a	<0.001^L
BRD treatment cost, $/animal	5.67 ± 0.225^a	31.32 ± 0.578^b	43.07 ± 1.138^c	91.86 ± 1.332^d	28.86 ± 0.731^b	<0.001^C
Other treatment cost, $/animal³	25.95 ± 2.230^a	21.49 ± 4.139^a	21.67 ± 5.553^a	49.67 ± 8.780^b	13.86 ± 12.417^a	<0.001^Q
Price received, $/kg cwt	5.86 ± 0.029^a	5.89 ± 0.036^a	5.79 ± 0.056^ab	5.66 ± 0.064^b	5.85 ± 0.042^a	0.004^Q
Total slaughter value, $/animal	2,072.98 ± 6.230^a	2,044.90 + 15.956^a	1,929.62 ± 32.039^b	1,759.83 ± 37.799^c	2,115.22 ± 20.211^a	<0.001^L
Net return, $/animal⁴	182.86 ± 6.049^a	118.07 ± 15.451^b	−6.34 ± 31.056^c	−227.68 ± 35.624^d	198.10 ± 19.564^a	<0.001^Q

¹Visually healthy treated animals were initially pulled as visually healthy controls but exhibited elevated rectal temperature or lung auscultation score and therefore were treated for BRD.

²P8 fat depth: fat depth at the crest of third sacral vertebra measured on the hot carcass.

³Other treatment cost: cost of treatments for ailments other than BRD.

⁴Net return was calculated using slaughter value less the purchase price, induction processing cost of $7.30/animal, feed cost, BRD treatment cost, other veterinary treatment cost, yardage cost of approximately AUD$1.05/animal/d, transport cost (flat load rate of AU$635/load with a load weight limit of 35,500 kg/load), buyers commission, and levy.

^a–cWithin a row, means without a common superscript letter differ (P < 0.05).

^L,Q,CThe effect of increasing the number of BRD treatments was linear, quadratic, or cubic (P < 0.05).