Effect of supplemental safflower seed and vitamin E to late gestating ewes on lamb growth and thermogenesis
Fifty-one twin bearing Targhee ewes (Trial 1) and 1182 single and twin bearing white face range ewes (Trial 2) were used in a 2 x 2 factorial arrangement of treatments to determine the effect of supplemental energy source and level of vitamin E on lamb serum metabolites and thermogenesis (Trial 1), and lamb growth (Trial 2). During the last 30 d of gestation, ewes were individually (Trial 1) or group (Trial 2) fed a daily supplement. Supplements were: 226 g safflower seeds (SS) and either 350 (VE) or 0 (VC) IU vitamin E or 340 g of a grain-based supplement (GC) and either VE or VC. One h postpartum in Trial 1, twin born lambs were placed in a 0oC dry cold chamber for 30 min. Lamb rectal temperature was recorded every 60 s and blood samples were taken immediately before and after cold exposure. . In Trial 2 lambs were weighed at birth, turnout and weaning. Ewes were weighed at turnout and weaning. During the cold exposure in Trial 1, lambs from SSVC ewes had the lowest (P = 0.01) body temperature, a decrease (P < 0.08) in NEFA concentration, and an increase (P = 0.06) in serum glucose while lambs born to GCVC ewes had a decrease in serum glucose.The SS lambs tended to have lower (P < 0.11) levels of BUN and T4 at 0 min than lambs born to GC ewes. After 30 min of cold exposure, SS lambs increased and GC lambs decreased in BUN, T3, and T3T4 concentration (P < 0.10). At turnout in Trial 2, GC lambs weighed more and had higher survival rates than SS lambs (P< 0.07). Based on lower body temperature in at birth of lambs born to ewes fed safflower seeds and vitamin control, the greater change in BUN during the cold exposure and the higher mortality rate for lambs born to ewes fed safflower seeds than lambs born to ewes fed grain control, it appears that safflower seed and vitamin control supplemented ewes gave birth to lambs with an apparent decrease in basal metabolic rate. This may compromise the newborn lamb's ability to adapt to extreme environmental conditions. This study was unable to demonstrate an increase in lamb production due to feeding supplemental safflower seeds during late gestation.