Table 7.

Lactation responses of beef cows that received diets containing supplemental INR (n = 95) or AAC (n = 95) during gestation¹

Item	INR	AAC	SEM	P-value
Days in milk	42.6	42.2	0.7	0.69
Milk yield, kg/d	6.62	6.98	0.70	0.70
Milk mineral profile2
Co, mg/kg
Colostrum	0.0052	0.0055	0.0003	0.50
Milk	0.00030	0.00035	0.00004	0.40
Cu, mg/kg
Colostrum	0.985	0.997	0.014	0.58
Milk	0.049	0.062	0.007	0.19
Mn, mg/kg
Colostrum	0.061	0.055	0.007	0.53
Milk	0.014	0.016	0.002	0.42
Zn, mg/kg
Colostrum	15.3	13.7	1.6	0.48
Milk	4.21	4.26	0.30	0.89

¹INR and AAC cows received the same amount of supplemental Co, Cu, Mn, and Zn from sulfate sources or Availa 4 (Zinpro Corporation, Eden Prairie, MN). Cows were assigned to the experiment at 117 ± 2 d of gestation (day 0). Colostrum samples were collected manually upon calving. Milk production was estimated via the WSW method (Aguiar et al., 2015), and milk samples were manually collected the day after WSW. Colostrum and milk samples were collected from 30 cows of each treatment randomly selected on each sampling day.

²Concentrations of Co, Cu, Mn, and Zn were determined by the Michigan State University Diagnostic Center for Population and Animal Health (East Lansing, MI; Braselton et al., 1997).