Table 2.

Linear regression models assessed the association between the timing of lameness case occurrence in lactation milk yield in grazing dairy cows (n = 6685 lactations for MILK150 and 4298 lactations for MILK305) from a commercial dairy herd evaluated for 7.5 years (January 2010–June 2017).

		n	LSM 1	95% CI 2	p	Contrast 1 3	Contrast 2 4
			MILK150 6
Lame group 5					<0.001
	LG0	4789	5037	5006–5037		<0.001
	LG1	989	4821	4763–4821			<0.001
	LG2	469	4979	4903–5055
			MILK305 7
Lame group 5					<0.001
	LG0	2927	9766	9703–9829		<0.001
	LG1	732	9566	9452–9680			0.855
	LG2	416	9608	9472–9744

¹ LSM: least squared means were estimated with Proc Glimmix of SAS using normal distribution and identity link function; ² 95% CI: 95% confidence intervals; ^{3, 4} orthogonal contrasts (1: LG0 vs. LG1 and LG2, and 2: LG1 vs. LG2); ⁵ lame group: cows not diagnosed as lame during the entire lactation (healthy cows, L0), cows diagnosed as lame between calving and first service (L1), and cows diagnosed as lame between first service and first pregnancy (L2).⁶ MILK150: accumulated milk yield to 150 DIM; ⁷ MILK305: accumulated milk yield to 305 DIM. The models were also controlled by year (2010 through 2018), season (summer (21 December to 20 March), fall (21 March to 20 June), winter (21 June to 20 September), and spring (21 September to 20 December)), and parity (1st vs. 2nd vs. ≥3rd).