Calves from supplemented, low E-status cows weighed 72.7 pounds more at weaning on average than calves from low E-status cows not receiving the vitamin E supplement. This would have resulted in a 25:1 return on investment at a calf price of $.65 per pound and a supplement cost of $1.90 per cow ($.02 per 1,000 IU for 95 days). This is thought to be the first time a pre-weaning growth response in calves as a result of late-gestation maternal vitamin E supplementation has been reported (see Table 1).
In beef cows, research has focused on the impact of vitamin E supplementation of cows on their calves. Studies have shown that supplementing cows with 3,000 IU of vitamin E for a month prior to calving increases vitamin E concentrations in suckling calves and enhances their immune status (Nockels et al., 1994).
The immunologic status of the newborn calf is influenced by the immunologic and nutritional status of the dam. This was demonstrated in a study by Zobell et al. (1995). They found that when cows received 1,000 IU of vitamin E per head daily for the last 60 to 100 days of pregnancy, the incidence of scours in their calves was 62 percent less than in calves from the control group.
In the Bass study, Hereford and Angus cows calving in late winter and late summer were fed supplemental vitamin E at 1,000 IU and 600 IU, respectively. This was in addition to the vitamin E contained in the normal ration, which included dry hay, silage and a mineral supplement in the winter group and green pasture and a mineral supplement in the summer group. Supplementation began 30 days before the beginning of a 65-day calving season and continued until calving.
Cows in the winter group receiving supplemental vitamin E had significantly greater concentrations of serum vitamin E at and after calving than did unsupplemented cows. Calves from multiparous supplemented cows also had higher serum vitamin E than calves from unsupplemented cows. The scientists speculated this could have been due to greater colostrum production by cows, as well as other factors.
As noted above, calves from winter-calving Hereford cows receiving the vitamin E supplement had heavier 205-day average weaning weights than calves from control Hereford dams. The scientists concluded this could have been due to increased cow milk production. Weaning weights of calves from supplemented winter-calving Angus cows were not higher than controls. The study noted that supplemented Angus had higher serum vitamin E levels at and after calving than Hereford cows. This measure approached significance in the before-calving period (see Table 2).
