Effect of vitamin E supplementation to ewes in late pregnancy on the rate of stillborn lambs

- Vitamin E-supplementation increased serum concentration of α-tocopherol.
- Vitamin E-supplementation reduced stillbirth rate in ewes with litters of 3 lambs or more.
- Vitamin E-supplementation did not influence stillbirth rate in ewes with 1 or 2 lambs.

This study evaluated the effect of supplemental vitamin E to ewes in late pregnancy on the rate of stillborn lambs. Ewes in 19 flocks in 5 regions of Norway were daily supplemented the 6-7 weeks before average expected lambing date with either (1) 360 IU of vitamin E (supplemented), or (2) placebo (control). The daily supplement was given in addition to the daily basal diet of forage, concentrate and mixture of minerals and vitamins in each flock, assuming that forage contained on average 40 mg α-tocopherol/kg DM. Information about the basal diets was collected via analyses of forage samples and questionnaires. Blood was collected from a sample of ewes in each flock 1 week pre-treatment (7-8 weeks before lambing), and from some flocks 1-2 weeks after initiation of supplementation (5-6 weeks before lambing) and 1-2 weeks after lambing. The body condition score (BCS) of the ewes was assessed 4-6 weeks before lambing. Mean content (±SD) of α-tocopherol in the forage of the 19 flocks was 25 ± 17 mg/kg DM. Mean daily intake of vitamin E of the ewes from the basal diet was 153 ± 44 IU. Vitamin E supplementation increased serum concentration of α-tocopherol (P = 0.0002) 5-6 weeks before lambing. After lambing there was a higher ratio of α-tocopherol to cholesterol in serum of supplemented ewes compared with control ewes (P = 0.02). Ewes with one or more stillborn lambs had lower serum α-tocopherol concentrations than ewes without stillborn lambs in litters with ≥3 lambs (P = 0.01). For ewes with ≥3 lambs there was a significant lower stillbirth rate for vitamin E supplemented than for control ewes (P = 0.0004), while there was no effect on the stillbirth rate for ewes having ≤2 lambs. Ewes with low BCS had a higher stillbirth rate than ewes with medium or high BCS (P = 0.001). The results of this study indicate that daily supplementation of vitamin E during the last 6-7 weeks before lambing decreases the stillbirth rate of ewes having ≥3 lambs.