Sheep Extension Program
The Influence of Vitamin E Supplementation During Late Pregnancy On Lamb Mortality and Ewe Productivity
R.W. Kott1, V.M. Thomas1, P.G. Hatfield1, T. Evans2 and K.C. Davis1
1Montana State University, Bozemanand and 2Roche Vitamins & Fine Chemicals, Nutley, NJ.
Mature Rambouillet and Targhee ewes over a three year period (approximately 430 ewes per year) were randomly allocated within breed and age to either a vitamin E supplemented group or a control group receiving no supplemental vitamin E. Beginning approximately three weeks prior to the first expected lambing date all ewes were fed 2.3 kg/d of alfalfa-grass hay and .23 kg/d of a barley based supplemental pellet. The pellet with added vitamin E contained 1450 mg of d-l-alpha tocopherol acetate/kg and provided an additional 330 IU/hd/d of vitamin E. Selenium was incorporated into a trace mineral salt and fed free choice to all ewes throughout pregnancy. Supplemental vitamin E had no affect (P>.05) on ewe weight or body condition score at turnout to summer range (approximately 30 d post lambing) or at weaning (approximately 4 months post lambing). Ewe fertility and prolificy did not differ (P>.05) between groups. In ewes lambing in the early part of the lambing season, vitamin E supplementation reduced (P<.05) lamb mortality (17 vs 12 percent lamb mortality for untreated vs vitamin E supplemented ewes, respectively). Consequently, these ewes weaned 2.9 kg more lamb per ewe lambing (P<.05). No differences were observed (P>.05) in lamb mortality or kg of lamb weaned per ewe lambing among ewes lambing during the late lambing period.
Feeding of vitamin E in late pregnancy reduced lamb mortality during first half of the lambing season. As a result of this reduced lamb mortality, ewes lambing in the first part of the lambing season weaned 2.9 kg more lamb when supplemented with vitamin E. The cost of the supplemental vitamin E for the test period is about $0.60 (330 IU/hd/d or $0.0132/hd/d for a feeding period of 45 days).
Supplemental vitamin E levels utilized in this study (330 IU/hd/d) were about 10 times NRC recommended levels. In a recent review, Roche (1994) indicated that daily vitamin E intakes of 2 IU/Kg body weight (about ½ of those used in this study) improved immunocompetency and general health in dairy cattle.