Register      Login
Animal Production Science Animal Production Science Society
Food, fibre and pharmaceuticals from animals
REVIEW

The case for pre-parturient selenium and iodine supplementation of ewes for improving lamb survival

Sabine Schmoelzl A B C and Fran Cowley B
+ Author Affiliations
- Author Affiliations

A CSIRO Agriculture, F.D. McMaster Laboratory, New England Highway, Armidale, NSW 2350, Australia.

B School of Environmental and Rural Sciences, University of New England, Armidale, NSW 2351, Australia.

C Corresponding author. Email: sabine.schmoelzl@csiro.au

Animal Production Science 56(8) 1263-1274 https://doi.org/10.1071/AN15362
Submitted: 8 July 2015  Accepted: 6 October 2015   Published: 8 March 2016

Abstract

Lamb survival is an issue of high relevance to the Australian sheep industry, as lamb-survival rates have direct bearing on overall reproductive performance of the sheep, and also constitute a main concern from an animal welfare perspective (Mellor and Stafford 2004). Both genetic and management factors play an important role in this complex issue (Hinch and Brien 2014). Ewe nutrition is of particular relevance as the intrauterine growth conditions prepare the lamb for the crucial transition to life outside the uterus. Effects of body condition of the ewe during various stages of the pregnancy have been investigated in detail, yet much less is known about the critical role of micronutrient provision to the ewe. Although several risk factors for selenium (Se) and iodine (I) subclinical deficiencies exist for sheep on pasture in Australia, determining micronutrient status in sheep or pasture is not straightforward. Several studies have separately found effects of Se and I supplementation on lamb survival. Studies investigating the interaction of Se and I supplementation have been few but results have demonstrated an interaction between Se and I. With increased twinning rates as a result of increased selection of numbers of lambs weaned, nutritional demands during pregnancy across flocks are increasing, and effects of micronutrients on lamb health and survival have greater impact. New opportunities in nutritional research are encouraging new studies into the effects of Se and I supplementation on lamb survival.

Additional keywords: goitre, growth, lamb mortality, management, neonate, pregnancy, reproduction, sheep, thermoregulation, thyroid.


References

Abdollahi E, Kohram H, Shahir MH (2013) Plasma concentrations of essential trace microminerals and thyroid hormones during single or twin pregnancies in fat-tailed ewes. Small Ruminant Research 113, 360–364.
Plasma concentrations of essential trace microminerals and thyroid hormones during single or twin pregnancies in fat-tailed ewes.Crossref | GoogleScholarGoogle Scholar |

Alexander G, Williams D (1968) Shivering and non-shivering thermogenesis during summit metabolism in young lambs. The Journal of Physiology 198, 251–276.
Shivering and non-shivering thermogenesis during summit metabolism in young lambs.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DyaF1M%2Fjs1Kmug%3D%3D&md5=2ad1f01ddb0585464cb0cf5962e85c55CAS | 5698273PubMed |

Anon (2008) Wean more lambs. In ‘Making more from sheep program’. (AWI & MLA) Available at http://www.makingmorefromsheep.com.au/wean-more-lambs/index.htm [Verified 8 February 2016]

ARC (1980) ‘The nutrient requirements of ruminant livestock.’ (Commonwealth Agricultural Bureaux: Farnham Royal, UK)

Aumont G, Levieux D, Lamand M, Tressol JC (1989) Iodine nutrition in ewes. 2. Effects of low to high iodine intake by ewes on the I content of biological fluids and plasma immunoglobulins G in newborn lambs. Reproduction, Nutrition, Development 29, 203–217.
Iodine nutrition in ewes. 2. Effects of low to high iodine intake by ewes on the I content of biological fluids and plasma immunoglobulins G in newborn lambs.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaL1MXkslKrsL8%3D&md5=17ad50d59476d193f5653eaf81a8cf46CAS | 2757760PubMed |

Azuolas JK, Caple IW (1984) The iodine status of grazing sheep as monitored by concentrations of iodine in milk. Australian Veterinary Journal 61, 223–227.
The iodine status of grazing sheep as monitored by concentrations of iodine in milk.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaL2cXmtV2mt7k%3D&md5=d45087a6b9d5a584f60c14c128462a1cCAS | 6093759PubMed |

Banchero GE, Quintans G, Martin GB, Lindsay DR, Milton JTB (2004a) Nutrition and colostrum production in sheep. 1. Metabolic and hormonal responses to a high-energy supplement in the final stages of pregnancy. Reproduction, Fertility and Development 16, 633–643.
Nutrition and colostrum production in sheep. 1. Metabolic and hormonal responses to a high-energy supplement in the final stages of pregnancy.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2cXmslaksLs%3D&md5=8baba9aa2ebd8d232ed914dbc6d660ebCAS |

Banchero GE, Quintans G, Martin GB, Milton JTB, Lindsay DR (2004b) Nutrition and colostrum production in sheep. 2. Metabolic and hormonal responses to different energy sources in the final stages of pregnancy. Reproduction, Fertility and Development 16, 645–653.
Nutrition and colostrum production in sheep. 2. Metabolic and hormonal responses to different energy sources in the final stages of pregnancy.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2cXmslaksLg%3D&md5=495573487f0eacc905f2828b039ed201CAS |

Bianco AC, Silva JE (1987) Intracellular conversion of thyroxine to triiodothyronine is required for the optimal thermogenic function of brown adipose tissue. The Journal of Clinical Investigation 79, 295–300.
Intracellular conversion of thyroxine to triiodothyronine is required for the optimal thermogenic function of brown adipose tissue.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaL2sXnvFWlsg%3D%3D&md5=8e9d67e7bd9e8d59e5eaa1c1a18979ffCAS | 3793928PubMed |

Boland TM, Brophy PO, Callan JJ, Quinn PJ, Nowakowski P, Crosby TF (2005) The effects of mineral supplementation to ewes in late pregnancy on colostrum yield and immunoglobulin G absorption in their lambs. Livestock Production Science 97, 141–150.
The effects of mineral supplementation to ewes in late pregnancy on colostrum yield and immunoglobulin G absorption in their lambs.Crossref | GoogleScholarGoogle Scholar |

Boland TM, Hayes L, Sweeney T, Callan JJ, Baird AW, Keely S, Crosby TF (2008) The effects of cobalt and iodine supplementation of the pregnant ewe diet on immunoglobulin G, vitamin E, T3 and T4 levels in the progeny. Animal 2, 197–206.
The effects of cobalt and iodine supplementation of the pregnant ewe diet on immunoglobulin G, vitamin E, T3 and T4 levels in the progeny.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1MXitVWisbo%3D&md5=68525e869e510cb1f8d0201c77ff502aCAS | 22445013PubMed |

Brien F, Hebart ML, Hocking Edwards JE, Greeff JC, Hart KW, Refshauge G, Gaunt G, Behrendt R, Thomson K, Hinch G, Geenty KG, Van Der Werf JHJ (2009) Genetics of lamb survival: preliminary studies of the information nucleus flock. In ‘Proceedings of the eighteenth conference: matching genetics and environment: a new look at an old topic’, Barossa Valley, SA, 28 September – 1 October 2009. (Eds A Safari, B Pattie, A Restall) pp. 108–111. (Association for the Advancement of Animal Breeding and Genetics)

Brien FD, Cloete SWP, Fogarty NM, Greeff JC, Hebart ML, Hiendleder S, Edwards JEH, Kelly JM, Kind KL, Kleemann DO, Plush KL, Miller DR (2014) A review of the genetic and epigenetic factors affecting lamb survival. Animal Production Science 54, 667–693.
A review of the genetic and epigenetic factors affecting lamb survival.Crossref | GoogleScholarGoogle Scholar |

Caple IW, Andrewartha KA, Edwards SJ, Halpin CG (1980) An examination of the selenium nutrition of sheep in Victoria. Australian Veterinary Journal 56, 160–167.
An examination of the selenium nutrition of sheep in Victoria.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaL3cXlsVymtLs%3D&md5=3d3313b8693456247f1a3af37ac39456CAS | 7436915PubMed |

Clark RG, Sargison ND, West DM, Littlejohn RP (1998) Recent information on iodine deficiency in New Zealand sheep flocks. New Zealand Veterinary Journal 46, 216–222.
Recent information on iodine deficiency in New Zealand sheep flocks.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK1MXlt1ahsw%3D%3D&md5=4813ebd54970e71608974b9ca26f7e9dCAS | 16032052PubMed |

Clarke L, Symonds ME (1998) Thermoregulation in newborn lambs: influence of feeding and ambient temperature on brown adipose tissue. Experimental Physiology 83, 651–657.
Thermoregulation in newborn lambs: influence of feeding and ambient temperature on brown adipose tissue.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK1cXntFOns7w%3D&md5=1180a25d588ed778e9d8cf3815902832CAS | 9793785PubMed |

Davis PA, McDowell LR, Wilkinson NS, Buergelt CD, Alstyne RV, Weldon RN, Marshall TT (2006a) Effects of selenium levels in ewe diets on selenium in milk and the plasma and tissue selenium concentrations of lambs. Small Ruminant Research 65, 14–23.

Davis PA, McDowell LR, Wilkinson NS, Buergelt CD, Van Alstyne R, Weldon RN, Marshall TT (2006b) Tolerance of inorganic selenium by range-type ewes during gestation and lactation. Journal of Animal Science 84, 660–668.

de Jesus LA, Carvalho SD, Ribeiro MO, Schneider M, Kim S-W, Harney JW, Larsen PR, Bianco AC (2001) The type 2 iodothyronine deiodinase is essential for adaptive thermogenesis in brown adipose tissue. The Journal of Clinical Investigation 108, 1379–1385.
The type 2 iodothyronine deiodinase is essential for adaptive thermogenesis in brown adipose tissue.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3MXot12ktb0%3D&md5=9faa8d4f9c1e5d8e6ac7e91f80f791b9CAS | 11696583PubMed |

Delange F (2001) Iodine deficiency as a cause of brain damage. Postgraduate Medical Journal 77, 217–220.
Iodine deficiency as a cause of brain damage.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BD3Mzgs1KjtA%3D%3D&md5=0ab636c100cc9fababef8bd7ff1c29c0CAS | 11264481PubMed |

Dhillon KS, Dhillon SK (2003) Distribution and management of seleniferous soils. Advances in Agronomy 79, 119–184.
Distribution and management of seleniferous soils.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3sXltlGqsrw%3D&md5=6529ed6ae9872de6eb32617ca399bd56CAS |

Donald G, Langlands J, Bowles J, Smith A (1993) Subclinical selenium insufficiency. 4. Effects of selenium, iodine, and thiocyanate supplementation of grazing ewes on their selenium and iodine status, and on the status and growth of their lambs. Australian Journal of Experimental Agriculture 33, 411–416.
Subclinical selenium insufficiency. 4. Effects of selenium, iodine, and thiocyanate supplementation of grazing ewes on their selenium and iodine status, and on the status and growth of their lambs.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK2cXhs1agsb0%3D&md5=9738dacac7087a3aa42af7bef2409166CAS |

Donald GE, Langlands JP, Bowles JE, Smith AJ (1994) Subclinical selenium insufficiency. 6. Thermoregulatory ability of perinatal lambs born to ewes supplemented with selenium and iodine. Australian Journal of Experimental Agriculture 34, 19–24.
Subclinical selenium insufficiency. 6. Thermoregulatory ability of perinatal lambs born to ewes supplemented with selenium and iodine.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK2cXlslynsr0%3D&md5=80d9875372a9da682b2e7041e6ba95bbCAS |

Ducker MJ, Kendall PT, Hemingway RG, McClelland TH (1981) An evaluation of feedblocks as a means of providing supplementary nutrients to ewes grazing upland/hill pastures. Animal Science 33, 51–57.

Dwyer CM, Lawrence AB (1998) Variability in the expression of maternal behaviour in primiparous sheep: effects of genotype and litter size. Applied Animal Behaviour Science 58, 311–330.
Variability in the expression of maternal behaviour in primiparous sheep: effects of genotype and litter size.Crossref | GoogleScholarGoogle Scholar |

Dwyer CM, Lawrence AB, Bishop SC, Lewis M (2003) Ewe-lamb bonding behaviours at birth are affected by maternal undernutrition in pregnancy. British Journal of Nutrition 89, 123–136.
Ewe-lamb bonding behaviours at birth are affected by maternal undernutrition in pregnancy.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3sXhsFWlsr0%3D&md5=01b5da395b9e7bb608fb1989b05379a2CAS | 12568672PubMed |

Dwyer CM, McIlvaney KM, Coombs TM, Rooke JA, Ashworth CJ (2010) Undernutrition in early to mid pregnancy causes deficits in the expression of maternal behaviour in sheep that may affect lamb survival. In ‘Proceedings of the 44th International Society for Applied Ethology (ISAE): coping in large groups’. (Ed. L Lidfors, H Blokhuis, L Keeling) p. 45. (Wageningen Academic Publishers: Wageningen, The Netherlands)

Dwyer CM, Conington J, Corbiere F, Holmoy IH, Muri K, Nowak R, Rooke J, Vipond J, Gautier JM (2015) Invited review: Improving neonatal survival in small ruminants: science into practice. Animal
Invited review: Improving neonatal survival in small ruminants: science into practice.Crossref | GoogleScholarGoogle Scholar | 26434788PubMed |

Everett-Hincks JM, Dodds KG (2008) Management of maternal-offspring behavior to improve lamb survival in easy care sheep systems. Journal of Animal Science 86, E259–E270.
Management of maternal-offspring behavior to improve lamb survival in easy care sheep systems.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BD1c3lsVyqsw%3D%3D&md5=d60279827db413ce4a5cee8988704e42CAS | 17965331PubMed |

Everett-Hincks JM, Mathias-Davis HC, Greer GJ, Auvray BA, Dodds KG (2014) Genetic parameters for lamb birth weight, survival and death risk traits. Journal of Animal Science 92, 2885–2895.
Genetic parameters for lamb birth weight, survival and death risk traits.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BC2cjgt1ersg%3D%3D&md5=aae64481a36b19271541152789f58940CAS | 24802039PubMed |

Geenty KG, Brien FD, Hinch GN, Dobos RC, Refshauge G, McCaskill M, Ball AJ, Behrendt R, Gore KP, Savage DB, Harden S, Hocking-Edwards JE, Hart K, van der Werf JHJ (2014) Reproductive performance in the Sheep CRC Information Nucleus using artificial insemination across different sheep-production environments in southern Australia. Animal Production Science 54, 715–726.
Reproductive performance in the Sheep CRC Information Nucleus using artificial insemination across different sheep-production environments in southern Australia.Crossref | GoogleScholarGoogle Scholar |

Gereben B, Zavacki AM, Ribich S, Kim BW, Huang SA, Simonides WS, Zeöld A, Bianco AC (2008) Cellular and molecular basis of deiodinase-regulated thyroid hormone signaling. Endocrine Reviews 29, 898–938.
Cellular and molecular basis of deiodinase-regulated thyroid hormone signaling.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1MXmt1yjtQ%3D%3D&md5=80170f0b528bdce896c0824ff1db1a3aCAS | 18815314PubMed |

Grace ND (1994) Iodine. In ‘Managing trace element deficiencies: the diagnosis and prevention of selinium, cobalt, copper and iodine deficiencies in New Zealand grazing livestock’. pp. 53–59. (AgResearch: Palmerston North, NZ)

Grace ND, Knowles SO (2012) Trace element supplementation of livestock in New Zealand: meeting the challenges of free-range grazing systems. Veterinary Medicine International 2012, 639472
Trace element supplementation of livestock in New Zealand: meeting the challenges of free-range grazing systems.Crossref | GoogleScholarGoogle Scholar | 23316417PubMed |

Grace ND, Knowles SO, West DM (2006) Dose-response effects of long-acting injectable vitamin B12 plus selenium (Se) on the vitamin B12 and Se status of ewes and their lambs. New Zealand Veterinary Journal 54, 67–72.
Dose-response effects of long-acting injectable vitamin B12 plus selenium (Se) on the vitamin B12 and Se status of ewes and their lambs.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD28Xkt1Kmu7Y%3D&md5=c764b63c2e72fce9d30223653ef722fcCAS | 16596157PubMed |

Greenwood PL, Bell AW (2014) Consequences of nutrition during gestation, and the challenge to better understand and enhance livestock productivity and efficiency in pastoral ecosystems. Animal Production Science 54, 1109–1118.

Guinan M, Harrison G, Boland TM, Crosby TF (2005) The effect of timing of mineral supplementation of the ewe diet in late pregnancy on immunoglobulin G absorption by the lamb. Animal Science 80, 193–200.
The effect of timing of mineral supplementation of the ewe diet in late pregnancy on immunoglobulin G absorption by the lamb.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2MXktVOnsr0%3D&md5=e982bd8f90fad01b03f5a7f9333bfacfCAS |

Hall DG, Egan AR, Foot JZ, Parr RA (1990) The effect of litter size on colostrum production in crossbred ewes. Proceedings of the Australian Society of Animal Production 18, 240–243.

Hall JA, van Saun RJ, Bobe G, Stewart WC, Vorachek WR, Mosher WD, Nichols T, Forsberg NE, Pirelli GJ (2012) Organic and inorganic selenium: I. oral bioavailability in ewes. Journal of Animal Science 90, 568–576.
Organic and inorganic selenium: I. oral bioavailability in ewes.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC38XitVeltLo%3D&md5=7e0670cea97c60481790914b9d5a3012CAS | 21965451PubMed |

Hatcher S, Atkins KD, Safari E (2009) Phenotypic aspects of lamb survival in Australian Merino sheep. Journal of Animal Science 87, 2781–2790.
Phenotypic aspects of lamb survival in Australian Merino sheep.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1MXhtFSqu7nJ&md5=a4e49b9c9257a210776060055150400bCAS | 19502501PubMed |

Henry BA, Blache D, Rao A, Clarke IJ, Maloney SK (2010) Disparate effects of feeding on core body and adipose tissue temperatures in animals selectively bred for Nervous or Calm temperament. American Journal of Physiology. Regulatory, Integrative and Comparative Physiology 299, R907–R917.
Disparate effects of feeding on core body and adipose tissue temperatures in animals selectively bred for Nervous or Calm temperament.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3cXht1WgurnI&md5=a477c66c4007e789169ab31122c68c03CAS | 20573991PubMed |

Hidiroglou M (1980) Trace elements in the fetal and neonate ruminant: a review. The Canadian Veterinary Journal. La Revue Veterinaire Canadienne 21, 328–335.

Hinch GN, Brien F (2014) Lamb survival in Australian flocks: a review. Animal Production Science 54, 656–666.
Lamb survival in Australian flocks: a review.Crossref | GoogleScholarGoogle Scholar |

Hocking Edwards JE, Copping KJ, Thompson AN (2011) Managing the nutrition of twin-bearing ewes during pregnancy using Lifetimewool recommendations increases production of twin lambs. Animal Production Science 51, 813–820.
Managing the nutrition of twin-bearing ewes during pregnancy using Lifetimewool recommendations increases production of twin lambs.Crossref | GoogleScholarGoogle Scholar |

Holst PJ, Hall DG, Allan CJ (1996) Ewe colostrum and subsequent lamb suckling behaviour. Australian Journal of Experimental Agriculture 36, 637–640.
Ewe colostrum and subsequent lamb suckling behaviour.Crossref | GoogleScholarGoogle Scholar |

Judson GJ, Reuter DJ (1999) Selenium. In ‘Soil analysis: an interpretation manual’. (Eds KI Peverill, LA Sparrow, DJ Reuter) pp. 325–329. (CSIRO Publishing: Melbourne)

Kenyon PR (2008) A review of in-utero environmental effects on sheep production. Proceedings of the New Zealand Society of Animal Production 68, 142–155.

Kenyon PR, Blair HT (2014) Foetal programming in sheep: effects on production. Small Ruminant Research 118, 16–30.
Foetal programming in sheep: effects on production.Crossref | GoogleScholarGoogle Scholar |

Kenyon PR, Hickson RE, Hutton PG, Morris ST, Stafford KJ, West DM (2012) Effect of twin-bearing ewe body condition score and late pregnancy nutrition on lamb performance. Animal Production Science 52, 483–490.
Effect of twin-bearing ewe body condition score and late pregnancy nutrition on lamb performance.Crossref | GoogleScholarGoogle Scholar |

Kerslake JI, Kenyon PR, Stafford KJ, Morris ST, Morel PCH (2010) Can maternal iodine supplementation improve twin-and triplet-born lamb plasma thyroid hormone concentrations and thermoregulation capabilities in the first 24–36 h of life? The Journal of Agricultural Science 148, 453–463.
Can maternal iodine supplementation improve twin-and triplet-born lamb plasma thyroid hormone concentrations and thermoregulation capabilities in the first 24–36 h of life?Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3cXotFeisbo%3D&md5=229ee8f637a6d727c75cdb509624dbfdCAS |

Kleemann DO, Walker SK, Walkley JRW, Ponzoni RW, Smith DH, Grimson RJ, Seamark RF (1993) Effect of nutrition during pregnancy on birth weight and lamb survival in FecB Booroola × South Australian Merino ewes. Animal Reproduction Science 31, 213–224.
Effect of nutrition during pregnancy on birth weight and lamb survival in FecB Booroola × South Australian Merino ewes.Crossref | GoogleScholarGoogle Scholar |

Knights G, O’Rourke P, Hopkins P (1979) Effects of iodine supplementation of pregnant and lactating ewes on the growth and maturation of their offspring. Australian Journal of Experimental Agriculture 19, 19–22.
Effects of iodine supplementation of pregnant and lactating ewes on the growth and maturation of their offspring.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaE1MXhs1Krtbc%3D&md5=53264192a2a2f3b6a724fbcc0482bf29CAS |

Knowles SO, Grace ND (2007) A practical approach to managing the risks of iodine deficiency in flocks using thyroid-weight:birthweight ratios of lambs. New Zealand Veterinary Journal 55, 314–318.

Langlands J, Donald G, Bowles J, Smith A (1991a) Subclinical selenium insufficiency. 1. Selenium status and the response in liveweight and wool production of grazing ewes supplemented with selenium. Australian Journal of Experimental Agriculture 31, 25–31.
Subclinical selenium insufficiency. 1. Selenium status and the response in liveweight and wool production of grazing ewes supplemented with selenium.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK38XlsF2r&md5=6da8e4265af7af300f37b5deaf1a2d60CAS |

Langlands J, Donald G, Bowles J, Smith A (1991b) Subclinical selenium insufficiency. 2. The response in reproductive performance of grazing ewes supplemented with selenium. Australian Journal of Experimental Agriculture 31, 33–35.
Subclinical selenium insufficiency. 2. The response in reproductive performance of grazing ewes supplemented with selenium.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK38XlsF2q&md5=e57632a34bd64300c64fb7be5cfbb5d2CAS |

Lee J, Knowles SO, Judson GJ (2002) Trace element and vitamin nutrition of grazing sheep. In ‘Sheep nutrition’. (Eds M Freer, H Dove) pp. 285–311. (CABI: Wallingford, UK)

Li M, Eastman CJ (2012) The changing epidemiology of iodine deficiency. Nature Reviews. Endocrinology 8, 434–440.
The changing epidemiology of iodine deficiency.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC38Xos1yms7w%3D&md5=d4c720e23ff073e352c7035db183e1b5CAS | 22473332PubMed |

Li M, Eastman CJ, Waite KV, Ma G, Byth K, Zacharin MR, Topliss DJ, Harding PE, Walsh JP, Ward LC, Mortimer RH, Mackenzie EJ, Doyle Z (2008) Are Australian children iodine deficient? Results of the Australian national iodine nutrition study. The Medical Journal of Australia 184, 165–169.

Lyons GH, Judson GJ, Ortiz-Monasterio I, Genc Y, Stangoulis JCR, Graham RD (2005) Selenium in Australia: selenium status and biofortification of wheat for better health. Journal of Trace Elements in Medicine and Biology 19, 75–82.
Selenium in Australia: selenium status and biofortification of wheat for better health.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2MXht1yntL3K&md5=a4f9056128d94cc3486cf11b03a8196fCAS | 16240676PubMed |

Mackerras DEM, Eastman CJ (2012) Estimating the iodine supplementation level to recommend for pregnant and breastfeeding women in Australia. The Medical Journal of Australia 197, 238–242.
Estimating the iodine supplementation level to recommend for pregnant and breastfeeding women in Australia.Crossref | GoogleScholarGoogle Scholar |

McCoy MA, Smyth JA, Ellis WA, Kennedy DG (1997) Experimental reproduction of iodine deficiency in cattle. The Veterinary Record 141, 544–547.
Experimental reproduction of iodine deficiency in cattle.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DyaK1c%2FnsVKjsA%3D%3D&md5=2bf36048665a040d54f5290e5372898bCAS | 9413122PubMed |

McNeill DM, Murphy PM, Lindsay DR (1998) Blood lactose v. milk lactose as a monitor of lactogenesis and colostrum production in Merino ewes. Australian Journal of Agricultural Research 49, 581–587.
Blood lactose v. milk lactose as a monitor of lactogenesis and colostrum production in Merino ewes.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK1cXjtVSjtLo%3D&md5=3941e2d244bcc2bc5364146754fdb287CAS |

Mehdi Y, Hornick JL, Istasse L, Dufrasne I (2013) Selenium in the environment, metabolism and involvement in body functions. Molecules (Basel, Switzerland) 18, 3292–3311.
Selenium in the environment, metabolism and involvement in body functions.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3sXlt1Git74%3D&md5=97124aacd04982e62d65550f0b9bb090CAS |

Mellor DJ (1983) Nutritional and placental determinants of foetal growth rate in sheep and consequences for the newborn lamb. The British Veterinary Journal 139, 307–324.

Mellor DJ, Stafford KJ (2004) Animal welfare implications of neonatal mortality and morbidity in farm animals. Veterinary Journal (London, England) 168, 118–133.
Animal welfare implications of neonatal mortality and morbidity in farm animals.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BD2czpvFWntQ%3D%3D&md5=838374ba13f57b04411b8e4349087b70CAS |

Muñoz C, Carson AF, McCoy MA, Dawson LER, O’Connell NE, Gordon AW (2008a) Nutritional status of adult ewes during early and mid-pregnancy. 1. Effects of plane of nutrition on ewe reproduction and offspring performance to weaning. Animal 2, 52–63.

Muñoz C, Carson AF, McCoy MA, Dawson LER, O’Connell NE, Gordon AW (2008b) Nutritional status of adult ewes during early and mid-pregnancy. 2. Effects of supplementation with selenised yeast on ewe reproduction and offspring performance to weaning. Animal 2, 64–72.

Nowak R, Poindron P (2006) From birth to colostrum: early steps leading to lamb survival. Reproduction, Nutrition, Development 46, 431–446.
From birth to colostrum: early steps leading to lamb survival.Crossref | GoogleScholarGoogle Scholar | 16824451PubMed |

Nowak R, Keller M, Val-Laillet D, Lévy F (2007) Perinatal visceral events and brain mechanisms involved in the development of mother–young bonding in sheep. Hormones and Behavior 52, 92–98.
Perinatal visceral events and brain mechanisms involved in the development of mother–young bonding in sheep.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2sXmtVGqsb8%3D&md5=b32d58eb114d01a217c51d268bc326c3CAS | 17488646PubMed |

N.R.C. (1985) ‘Nutrient requirements of small ruminants; sheep, goats, cervids, and New World camelids.’ (National Academies Press: Washington, DC)

Pitts MW, Byrns CN, Ogawa-Wong AN, Kremer P, Berry MJ (2014) Selenoproteins in nervous system development and function. Biological Trace Element Research 161, 231–245.
Selenoproteins in nervous system development and function.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC2cXhtVKrs7jE&md5=c3639b82d943d20f8b2c905d432cac3dCAS | 24974905PubMed |

Poindron P, Levy F, Keller M (2007) Maternal responsiveness and maternal selectivity in domestic sheep and goats: the two facets of maternal attachment. Developmental Psychobiology 49, 54–70.
Maternal responsiveness and maternal selectivity in domestic sheep and goats: the two facets of maternal attachment.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2sXhtF2ksLk%3D&md5=ce87652ff498ade523bbcd561c786c6fCAS | 17186516PubMed |

Rayman MP, Infante HG, Sargent M (2008) Food-chain selenium and human health: spotlight on speciation. British Journal of Nutrition 100, 238–253.

Rita Cardoso B, Silva Bandeira V, Jacob-Filho W, Franciscato Cozzolino SM (2014) Selenium status in elderly: relation to cognitive decline. Journal of Trace Elements in Medicine and Biology: Organ of the Society for Minerals and Trace Elements (GMS) 28, 422–426.
Selenium status in elderly: relation to cognitive decline.Crossref | GoogleScholarGoogle Scholar |

Rock MJ, Kincaid RL, Carstens GE (2001) Effects of prenatal source and level of dietary selenium on passive immunity and thermometabolism of newborn lambs. Small Ruminant Research 40, 129–138.
Effects of prenatal source and level of dietary selenium on passive immunity and thermometabolism of newborn lambs.Crossref | GoogleScholarGoogle Scholar | 11295395PubMed |

Rodinova H, Kroupova V, Travnicek J, Stankova M, Pisek L (2008) Dynamics of IgG in the blood serum of sheep with different selenium intake. Veterinarni Medicina 53, 260–265.

Rooke JA, Robinson JJ, Arthur JR (2004) Effects of vitamin E and selenium on the performance and immune status of ewes and lambs. The Journal of Agricultural Science 142, 253–262.
Effects of vitamin E and selenium on the performance and immune status of ewes and lambs.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2cXhtVGitrnM&md5=eadfb2b210793bee79220bcb42fa3d9dCAS |

Rooke JA, Arnott G, Dwyer CM, Rutherford KMD (2015) The importance of the gestation period for welfare of lambs: maternal stressors and lamb vigour and wellbeing. The Journal of Agricultural Science 153, 497–519.
The importance of the gestation period for welfare of lambs: maternal stressors and lamb vigour and wellbeing.Crossref | GoogleScholarGoogle Scholar |

Rose MT, Wolf BT, Haresign W (2007) Effect of the level of iodine in the diet of pregnant ewes on the concentration of immunoglobulin G in the plasma of neonatal lambs following the consumption of colostrum. British Journal of Nutrition 97, 315–320.
Effect of the level of iodine in the diet of pregnant ewes on the concentration of immunoglobulin G in the plasma of neonatal lambs following the consumption of colostrum.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2sXhtV2qu7fP&md5=fa2ad8b0fa58ad3c867fc71b2dcaef84CAS | 17298700PubMed |

Safari E, Fogarty NM, Gilmour AR, Atkins KD, Mortimer SI, Swan AA, Brien FD, Greeff JC, van der Werf JHJ (2007) Across population genetic parameters for wool, growth, and reproduction traits in Australian Merino sheep. 2. Estimates of heritability and variance components. Australian Journal of Agricultural Research 58, 177–184.

Sargison ND, West DM, Clark RG (1998) The effects of iodine deficiency on ewe fertility and perinatal lamb mortality. New Zealand Veterinary Journal 46, 72–75.
The effects of iodine deficiency on ewe fertility and perinatal lamb mortality.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK1cXjslemtbg%3D&md5=bbeb6fb27f1718be3146c8ba365ce29aCAS | 16032020PubMed |

Schweizer U, Bräuer AU, Köhrle J, Nitsch R, Savaskan NE (2004) Selenium and brain function: a poorly recognized liaison. Brain Research. Brain Research Reviews 45, 164–178.
Selenium and brain function: a poorly recognized liaison.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2cXltVChu7g%3D&md5=b56c648f4f0ccc806e0646bf51fe4e26CAS | 15210302PubMed |

Sher L (2001) Role of thyroid hormones in the effects of selenium on mood, behavior, and cognitive function. Medical Hypotheses 57, 480–483.
Role of thyroid hormones in the effects of selenium on mood, behavior, and cognitive function.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3MXoslaltrc%3D&md5=347db38dc0f9707756d78b9171fc3884CAS | 11601874PubMed |

Smith LC, Morton JD, Catto WD (1999) The effects of fertiliser iodine application on herbage iodine concentration and animal blood levels. New Zealand Journal of Agricultural Research 42, 433–440.
The effects of fertiliser iodine application on herbage iodine concentration and animal blood levels.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3cXpt1Ontg%3D%3D&md5=a7677fa6494ef20a484321e68bccf835CAS |

Stewart WC, Bobe G, Pirelli GJ, Mosher WD, Hall JA (2012a) Organic and inorganic selenium: III. Ewe and progeny performance. Journal of Animal Science 90, 4536–4543.

Stewart WC, Bobe G, Vorachek WR, Pirelli GJ, Mosher WD, Nichols T, van Saun RJ, Forsberg NE, Hall JA (2012b) Organic and inorganic selenium: II. Transfer efficiency from ewes to lambs. Journal of Animal Science 90, 577–584.
Organic and inorganic selenium: II. Transfer efficiency from ewes to lambs.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC38XitVeltLs%3D&md5=d797bc63d203ea24fbbebdc5f680594aCAS | 21965446PubMed |

Stewart WC, Bobe G, Vorachek WR, Stang BV, Pirelli GJ, Mosher WD, Hall JA (2013) Organic and inorganic selenium: IV. Passive transfer of immunoglobulin from ewe to lamb. Journal of Animal Science 91, 1791–1800.

Towery BT (1953) The physiology of iodine. Bulletin of the World Health Organization 9, 175–182.

Underwood EJ (1966) ‘The mineral nutrition of livestock.’ (Commonwealth Agricultural Bureaux: Farnham Royal, Slough, UK)

Van Ryssen JBJ, Deagen JT, Beilstein MA, Whanger PD (1989) Comparative metabolism of organic and inorganic selenium by sheep. Journal of Agricultural and Food Chemistry 37, 1358–1363.
Comparative metabolism of organic and inorganic selenium by sheep.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaL1MXltlaqu78%3D&md5=89a0772329c64ce5bb8cb8b03c47aca7CAS |

Whanger PD (2002) Selenocompounds in plants and animals and their biological significance. Journal of the American College of Nutrition 21, 223–232.
Selenocompounds in plants and animals and their biological significance.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD38Xlt1Orurw%3D&md5=8468c7cb7aad7da8c5355133578ad25dCAS | 12074249PubMed |

Wichtel JJ (1998) A review of selenium deficiency in grazing ruminants. Part 1: new roles for selenium in ruminant metabolism. New Zealand Veterinary Journal 46, 47–52.
A review of selenium deficiency in grazing ruminants. Part 1: new roles for selenium in ruminant metabolism.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK1cXjslemt7w%3D&md5=1ef6e4d162d85be0986e2b4aabff4ae0CAS | 16032015PubMed |

Young JM, Saul G, Behrendt R, Byrne F, McCaskill M, Kearney GA, Thompson AN (2014a) The economic benefits of providing shelter to reduce the mortality of twin lambs in south-western Victoria. Animal Production Science 54, 773–782.
The economic benefits of providing shelter to reduce the mortality of twin lambs in south-western Victoria.Crossref | GoogleScholarGoogle Scholar |

Young JM, Trompf J, Thompson AN (2014b) The critical control points for increasing reproductive performance can be used to inform research priorities. Animal Production Science 54, 645–655.
The critical control points for increasing reproductive performance can be used to inform research priorities.Crossref | GoogleScholarGoogle Scholar |