The potential for improving physiological, behavioural and immunological responses in the neonatal lamb by trace element and vitamin supplementation of the ewe

Abstract

Neonatal lamb mortality represents both a welfare issue (due to the considerable suffering and distress) and an important production inefficiency. In lambs, approximately 80% of mortality can be attributed to the starvation-mismothering-exposure complex and occurs in the first 3 days after birth. It was the object of this review to determine the micronutrient(s) most likely to have a positive effect on neonatal lamb survival when included above the requirement for that micronutrient. Micronutrients discussed were Co, Cu, I, Fe, Mn, Se, Zn, vitamins A and E and n-3 fatty acids. For Co, Fe, Mn and Zn, there was no evidence of positive responses to supplementation. Cu and I had toxicity thresholds that were sufficiently close to requirement that supplementing above requirement presented a risk of inducing toxicity. In the case of vitamin A, while serum concentrations indicated that sub-optimal status did exist, long-term buffering from liver stores (from grazing) makes experimentation difficult and practical benefits to supplementation unlikely. Therefore, the most likely candidates for supplementation were Se, vitamin E and fatty acids. Fatty acid supplementation with fish oils or docosahexaenoic acid-containing algal biomass consistently improved lamb vigour but it is unlikely that supplementation will be economic. Positive responses to Se supplementation throughout gestation were recorded. However, in many studies the Se status of control ewes was marginal and there is a need for more studies where control ewes are clearly adequate in Se. Positive responses to vitamin E supplementation above requirement in the last-third of gestation were observed but the optimum dietary inclusion of vitamin E and period of feeding during pregnancy still require clarification.Keywords: lamb mortality, sheep, supplementation, trace elements, vitamins IntroductionNeonatal lamb mortality is a significant welfare and production concern. Mortality of live-born offspring can be as high as 25%, which extrapolates to more than four million lamb deaths annually in the UK. Lamb mortality represents both a welfare issue (due to the considerable suffering and distress) and an important production inefficiency (Mellor and Stafford, 2004). In lambs, approximately 80% of mortality can be attributed to the starvation-mismotheringexposure complex and, as a consequence, the vast majority of pre-weaning deaths occur in the first 3 days after birth (Haughey, 1993). Thus the neonatal period is critical for ensuring pre-weaning survival. Since considerable technological and management changes have failed to improve these mortality figures, examining the behaviour and adaptations of the animals may be a more fruitful route to improving neonate survivability. The nutrition of the ewe is an important factor that may influence ewe and lamb behaviour and therefore survival of the lamb.Under-nutrition of the ewe has an important influence on the lamb at the extreme being manifested as intra-uterine growth retardation (IUGR). The effects of under (and over)...

Invited review: Improving neonatal survival in small ruminants: science into practice

“…Interpretation of many studies is difficult because the baseline status of ewes (deficient, marginal or adequate) before the study is frequently not well defined. Where the status of ewes was marginal, supplementation improved survival, or associated measures, for cobalt, selenium and vitamin E (reviewed by Rooke et al, 2008). Responses where pre-experiment ewe status was adequate have been more equivocal and there is little evidence for any benefits to supplying trace nutrients in excess of requirement but short of toxicity (Rooke et al, 2008).…”

“…Where the status of ewes was marginal, supplementation improved survival, or associated measures, for cobalt, selenium and vitamin E (reviewed by Rooke et al, 2008). Responses where pre-experiment ewe status was adequate have been more equivocal and there is little evidence for any benefits to supplying trace nutrients in excess of requirement but short of toxicity (Rooke et al, 2008). Relationship between lamb mortality rate (proportional mortality) and birthweight (in kg) for Scottish Blackface lambs, demonstrating the optimal birthweight, for this breed, lies between 3 and 5 kg.…”

Epigenetics and developmental programming of welfare and production traits in farm animals

“…Changes to both the quantity (Hammer et al 2011) and the micronutrient composition (for a review, see Rooke et al 2008) of the diet offered to the pregnant ewe can affect serum IgG content in her lambs. Such effects could be mediated by altered composition of colostrum and/or the amount ingested by the neonate, or the ability of the neonatal gut to absorb immunoglobulins.…”

Impact of contrasting fish oil concentrations in the diet on ovine embryo development <i>in vivo</i> and of corresponding diet-specific derivative sera during <i>in vitro</i> culture

“…EPA and DHA are marginal and vulnerable constituents of oocytes and embryos so their presence requires provision of (preferably fat-soluble) antioxidants and accordingly the diets used in the present study were fortified with vitamin E (alpha-tocopherol). Arguably, although sometimes overlooked, much of the perceived benefit of EPA-and DHA-rich supplements in various situations could be due to more wide-ranging benefits of concurrent antioxidant provision per se, something which should not be ignored because alteration of antioxidant status can have profound effects, not only in the context of reproduction (Breque et al, 2006;Ruder et al, 2008;Rooke et al, 2008Rooke et al, , 2012 but even in quite debilitating circumstances (Vijayaraghavan et al, 2005;Zablocka and Janusz, 2008). In the present study control diets were fortified with vitamin E to the same extent as the fish oil-enriched diets and, consequently, effects of the latter were unlikely to have been merely a reflection of enhanced antioxidant status.…”