Thermogenesis and physiological maturity in neonatal lambs: a unifying concept in lamb survival
K. J. Plush A B C , F. D. Brien A , M. L. Hebart A and P. I. Hynd A
+ Author Affiliations
- Author Affiliations
A School of Animal and Veterinary Sciences, The University of Adelaide, Roseworthy, SA 5371, Australia.
B Present address: South Australian Research and Development Institute, Roseworthy, SA 5371, Australia.
C Corresponding author. Email: kate.plush@sa.gov.au
Animal Production Science 56(4) 736-745 https://doi.org/10.1071/AN15099
Submitted: 23 February 2015 Accepted: 1 September 2015 Published: 18 February 2016
Abstract
Lamb mortality represents reproductive wastage and an animal welfare concern. While lambs are thought to be at a thermogenic advantage following birth in comparison to other species, death from exposure can still be a major contributor to lamb mortality, largely because of the inclement conditions often prevailing at lambing. For this reason, thermogenesis has been studied extensively in neonatal lambs. Heat is produced in the neonatal lamb by shivering and non-shivering thermogenesis. The latter is heat generated by metabolism of brown adipose tissue (BAT) found largely in the thorax and peri-renal areas of the newborn lamb. Brown adipose tissue differs from normal adipose tissue in that it contains densely packed mitochondria, a high cytochrome c content and a vast vascular network. Heat is generated in BAT by uncoupling of the proton conductance mechanism from ATP production, resulting in heat production instead of stored energy. The ability of lambs to resist cooling differs among individuals and this is likely to be due to both genetic and phenotypic factors. The heritability of cold resistance is moderate-to-high and polymorphic gene markers associated with energy homeostasis and cold-related mortality have been identified. Additionally, several aspects of the phenotype of the lamb have been associated with cold resistance. Most relate to properties of the coat, skin and bodyweight, the latter being particularly important, presumably through effects on surface area to volume ratios and subsequent heat loss. The ability of the neonate to achieve the transition from intra- to extra-uterine life has been termed physiological maturity and is associated with the ability to activate appropriate neuro-endocrinological and behavioural changes that are consistent with homeostasis of energy metabolism. Ways to alter physiological maturity of the lamb, such as nutrition, pharmacology and genetic selection, have been identified, and while these show promising results with regards to thermoregulation, a key limitation of their application has been the lack of a repeatable, representative model of neonatal cold stress. An estimation of the non-shivering component potential of a lamb’s ability to thermoregulate can be derived from norepinephrine challenges, but more useful models of real-world cold stress are climate chambers or controlled water bath tests. Further use of repeatable test models such as these with appropriate neuroendocrine and metabolic metrics will identify key components and markers of physiological maturity associated with lamb thermogenesis and survival.
Additional keywords: cold exposure, lamb mortality.
References
Alexander G (1961a) Temperature regulation in the new-born lamb. II. A climatic respiration chamber for the study of thermoregulation, with an appendix on a correction for leaks and imperfect measurement of temperature and pressure in closed circuit respiration chambers. Australian Journal of Agricultural Research 12, 1139–1151.| Temperature regulation in the new-born lamb. II. A climatic respiration chamber for the study of thermoregulation, with an appendix on a correction for leaks and imperfect measurement of temperature and pressure in closed circuit respiration chambers.Crossref | GoogleScholarGoogle Scholar |
Alexander G (1961b) Temperature regulation in the new-born lamb. III. Effect of environmental temperature on metabolic rate body temperatures, and respiratory quotient. Australian Journal of Agricultural Research 12, 1152–1174.
| Temperature regulation in the new-born lamb. III. Effect of environmental temperature on metabolic rate body temperatures, and respiratory quotient.Crossref | GoogleScholarGoogle Scholar |
Alexander G (1962a) Energy metabolism in the starved new-born lamb. Australian Journal of Agricultural Research 13, 144–164.
| Energy metabolism in the starved new-born lamb.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaF38XnsFClsA%3D%3D&md5=eddc8b38c2e3e6184bdcd2512adef7acCAS |
Alexander G (1962b) Temperature regulation in the new-born lamb. IV. The effect of wind and evaporation of water from the coat on metabolic rate and body temperature. Australian Journal of Agricultural Research 13, 82–99.
| Temperature regulation in the new-born lamb. IV. The effect of wind and evaporation of water from the coat on metabolic rate and body temperature.Crossref | GoogleScholarGoogle Scholar |
Alexander G (1962c) Temperature regulation in the new-born lamb. V. Summit metabolism. Australian Journal of Agricultural Research 13, 100–121.
| Temperature regulation in the new-born lamb. V. Summit metabolism.Crossref | GoogleScholarGoogle Scholar |
Alexander G, Bell AW, Williams D (1970) Metabolic response of lambs to cold. Effects of prolonged treatment with thyroxine, and of acclimation to low temperatures. Biology of the Neonate 15, 198–210.
Alexander G (1975) Body temperature control in mammalian young. British Medical Bulletin 31, 62–68.
Alexander G (1978) Quantitative development of adipose tissue in foetal sheep. Australian Journal of Biological Sciences 31, 489–504.
Alexander G, McCance I (1958) Temperature regulation in the new-born lamb. I. Changes in rectal temperature within the first six hours of life. Australian Journal of Agricultural Research 9, 339–347.
| Temperature regulation in the new-born lamb. I. Changes in rectal temperature within the first six hours of life.Crossref | GoogleScholarGoogle Scholar |
Alexander G, Williams D (1962) Temperature regulation in the new-born lamb. VI. Heat exchanges in lambs in a hot environment. Australian Journal of Agricultural Research 13, 122–143.
| Temperature regulation in the new-born lamb. VI. Heat exchanges in lambs in a hot environment.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 |
Bassett JM (1989) Hormones and metabolic adaptations in the newborn. The Proceedings of the Nutrition Society 48, 263–269.
| Hormones and metabolic adaptations in the newborn.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK3cXnt1c%3D&md5=52ab68ed61bfa713491ca3a1f87387e7CAS | 2678122PubMed |
Bianco AC, Silva JE (1987a) 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 |
Bianco AC, Silva JE (1987b) Nuclear 3,5,3ʹ-triiodothyronine (T3) in brown adipose tissue: receptor occupancy and sources of T3 as determined by in vivo techniques. Endocrinology 120, 55–62.
| Nuclear 3,5,3ʹ-triiodothyronine (T3) in brown adipose tissue: receptor occupancy and sources of T3 as determined by in vivo techniques.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaL2sXnvFWmug%3D%3D&md5=7610239a95cbf5920d0cb27802c1a09bCAS | 3780570PubMed |
Bloomfield FH, Oliver MH, Hawkins P, Campbell M, Phillips DJ, Gluckman PD, Challis JRG, Harding JE (2003) A periconceptional nutritional origin for noninfectious preterm birth. Science 300, 606
| A periconceptional nutritional origin for noninfectious preterm birth.Crossref | GoogleScholarGoogle Scholar | 12714735PubMed |
Brien FD, Hebart ML, Smith DH, Hocking Edwards JE, Greeff JC, Hart KW, Refshauge G, Bird-Gardiner TL, Gaunt GM, Behrendt R, Robertson MW, Hinch GN, Geenty KG, van der Werf JHJ (2010) Opportunties for genetic improvement of lamb survival. Animal Production Science 50, 1017–1025.
| Opportunties for genetic improvement of lamb survival.Crossref | GoogleScholarGoogle Scholar |
Bu’Lock F, Woolridge MW, Baum JD (1990) Development of co-ordination of sucking, swallowing and breathing: ultrasound study of term and preterm infants. Developmental Medicine and Child Neurology 32, 669–678.
| Development of co-ordination of sucking, swallowing and breathing: ultrasound study of term and preterm infants.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DyaK3M%2Fgs12jsw%3D%3D&md5=a6de61bfdd2f151f3f459ccb667ca6a6CAS | 2210082PubMed |
Budge H, Edwards LJ, McMillen IC, Bryce A, Warnes K, Pearce S, Stephenson T, Symonds ME (2004) Nutritional manipulation of fetal adipose tissue deposition and uncoupling protein 1 messenger RNA abundance in the sheep: differential effects of timing and duration. Biology of Reproduction 71, 359–365.
| Nutritional manipulation of fetal adipose tissue deposition and uncoupling protein 1 messenger RNA abundance in the sheep: differential effects of timing and duration.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2cXltFKrsrw%3D&md5=916e1e88fcadde8d335c7ea291955340CAS | 15056567PubMed |
Cabello G (1983) Endocrine reactivity (T3, T4, cortisol) during cold exposure in preterm and full-term lambs. Neonatology 44, 224–233.
| Endocrine reactivity (T3, T4, cortisol) during cold exposure in preterm and full-term lambs.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaL3sXlsFalt7k%3D&md5=75f177a352417b2c3ef1fee835a2b056CAS |
Cannon B, Nedergaard J (2004) Brown adipose tissue: function and physiological significance. Physiological Reviews 84, 277–359.
| Brown adipose tissue: function and physiological significance.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2cXotl2qsQ%3D%3D&md5=d8f45975d290ab916622d2708481ce70CAS | 14715917PubMed |
Cannon B, Nedergaard J (2011) Nonshivering thermogenesis and its adequate measure in thermogenic studies. The Journal of Experimental Biology 214, 242–253.
| Nonshivering thermogenesis and its adequate measure in thermogenic studies.Crossref | GoogleScholarGoogle Scholar | 21177944PubMed |
Cannon B, Romert L, Sundin U, Barnard T (1977) Morphology and biochemical properties of perirenal adipose tissue from lamb (ovis aries). A comparison with brown adipose tissue. Comparative Biochemistry and Physiology. Part B, Biochemistry & Molecular Biology 56, 87–99.
| Morphology and biochemical properties of perirenal adipose tissue from lamb (ovis aries). A comparison with brown adipose tissue.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaE2sXhtVemt7g%3D&md5=270354d0e4bf1f8f7e3d6230a9bfb2b7CAS |
Clarke L, Heasman L, Firth K, Symonds ME (1997) Influence of route of delivery and ambient temperature on thermoregulation in newborn lambs. American Journal of Physiology. Regulatory, Integrative and Comparative Physiology 272, 1931–1939.
Clarke IJ, Heasman L, Symonds ME (1998) Influence of maternal dexamethasone administration on thermoregulation in lambs delivered by caesarean section. The Journal of Endocrinology 156, 307–314.
| Influence of maternal dexamethasone administration on thermoregulation in lambs delivered by caesarean section.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK1cXhtV2ktL0%3D&md5=ec6561b1b201b95e5b16ec6338914a80CAS |
Cloete SWP, Scholtz AJ (1998) Lamb survival in relation to lambing and neonatal behaviour in medium wool Merino lines divergently selected for multiple rearing ability. Australian Journal of Experimental Agriculture 38, 801–811.
Duyne CMV, Parker HR, Havel RJ, Holm LW (1960) Free fatty acid metabolism in fetal and newborn sheep. American Journal of Physiology – Legacy Content 199, 987–990.
Dwyer CM (2008) The welfare of the neonatal lamb. Small Ruminant Research 76, 31–41.
| The welfare of the neonatal lamb.Crossref | GoogleScholarGoogle Scholar |
Dwyer CM, Morgan CA (2006) Maintenance of body temperature in the neonatal lamb: effects of breed, birth weight, and litter size. Journal of Animal Science 84, 1093–1101.
Eales FA, Gilmour JS, Barlow RM, Small J (1982) Causes of hypothermia in 89 lambs. The Veterinary Record 110, 118–120.
| Causes of hypothermia in 89 lambs.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DyaL2c%2FhvFWgug%3D%3D&md5=4da0824f268a34e2ae681bad440d3df5CAS | 6892265PubMed |
Edwards LJ, McMillen IC (2002) Impact of maternal undernutrition during the periconceptional period, fetal number, and fetal sex on the development of the hypothalamo–pituitary adrenal axis in sheep during late gestation. Biology of Reproduction 66, 1562–1569.
| Impact of maternal undernutrition during the periconceptional period, fetal number, and fetal sex on the development of the hypothalamo–pituitary adrenal axis in sheep during late gestation.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD38XjtFWnsLY%3D&md5=248f44457b351a5c8f06e2084e7edd4cCAS | 11967224PubMed |
Edwards LJ, McFarlane JR, Kauter KG, McMillen IC (2005) Impact of periconceptional nutrition on maternal and fetal leptin and fetal adiposity in singleton and twin pregnancies. American Journal of Physiology. Regulatory, Integrative and Comparative Physiology 288, R39–R45.
| Impact of periconceptional nutrition on maternal and fetal leptin and fetal adiposity in singleton and twin pregnancies.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2MXhtVCqtbc%3D&md5=09f12f4f1a97302e6dd59e2a6b98ea99CAS | 15191901PubMed |
Erenberg A, Phelps D, Lam R, Fisher D (1974) Total and free thyroid hormone concentrations in the neonatal period. Pediatrics 53, 211–216.
Forrest RH, Hickford JGH, Hogan A, Frampton C (2003) Polymorphism at the ovine beta 3-adrenergic receptor locus: associations with birth weight, growth rate, carcass composition and cold survival. Animal Genetics 34, 19–25.
| Polymorphism at the ovine beta 3-adrenergic receptor locus: associations with birth weight, growth rate, carcass composition and cold survival.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3sXit1Kjsbg%3D&md5=be3c0e366a12d22dbfa51d54f4a88138CAS | 12580782PubMed |
Forrest RH, Hickford JGH, Frampton CM (2007) Polymorphism at the ovine beta 3-adrenergic receptor locus (ADRB3) and its association with lamb mortality. Journal of Animal Science 85, 2801–2806.
| Polymorphism at the ovine beta 3-adrenergic receptor locus (ADRB3) and its association with lamb mortality.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2sXhtlWitbrN&md5=95f0dc752050003bcdf59e0b4cb04f49CAS | 17644783PubMed |
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 |
Gemmell RT, Bell AW, Alexander G (1972) Morphology of adipose cells in lambs at birth and during subsequent transition of brown to white adipose tissue in cold and in warm conditions. The American Journal of Anatomy 133, 143–163.
| Morphology of adipose cells in lambs at birth and during subsequent transition of brown to white adipose tissue in cold and in warm conditions.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DyaE38%2FpsFCktA%3D%3D&md5=bb89ece2d8c849fd00ca9c4c17b04d73CAS | 5009244PubMed |
Girard J, Ferre P, Pegorier JP, Duee PH (1992) Adaptations of glucose and fatty acid metabolism during perinatal period and suckling-weaning transition. Physiological Reviews 72, 507–562.
Greenwood PL, Hunt AS, Slepetis RM, Finnerty KD, Alston C, Beermann DH, Bell AW (2002) Effects of birth weight and postnatal nutrition on neonatal sheep: III. Regulation of energy metabolism. Journal of Animal Science 80, 2850–2861.
Hahn P, Novak M (1975) Development of brown and white adipose tissue. Journal of Lipid Research 16, 79–91.
Hamadeh SK, Hatfield PG, Kott RW, Sowell BF, Robinson BL, Roth NJ (2000) Effects of breed, sex, birth type and colostrum intake on cold tolerance in newborn lambs. Sheep and Goat Rsearch Journal 16, 46–51.
Haughey KG (1991) Perinatal lamb mortality: its investigation, causes and control. Journal of the South African Veterinary Association 62, 78–91.
Himms-Hagen J (1984) Nonshivering thermogenesis. Brain Research Bulletin 12, 151–160.
| Nonshivering thermogenesis.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DyaL2c3gsVyksw%3D%3D&md5=e9ba456bb7cf7373f1d5bc813c16a72cCAS | 6722594PubMed |
Himms-Hagen J (1985) Brown adipose tissue metabolism and thermogenesis. Annual Review of Nutrition 5, 69–94.
| Brown adipose tissue metabolism and thermogenesis.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaL2MXltVans7Y%3D&md5=7269972c1b1c55fa37d912187f5ac271CAS | 2992550PubMed |
Himms-Hagen J (1989) Brown adipose tissue thermogenesis and obesity. Progress in Lipid Research 28, 67–115.
| Brown adipose tissue thermogenesis and obesity.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaL1MXltlWksrg%3D&md5=0dae3fbcf7153b153a9326885de14bdfCAS | 2692032PubMed |
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 |
Holst PJ (2004) ‘Lamb autopsy: notes on a procedure for determining cause of death.’ (NSW Agriculture and Australian Sheep Industry Co-operative Research Centre: Armidale, NSW)
Hull D (1966) The structure and function of brown adipose tissue. British Medical Bulletin 22, 92–96.
Kleemann DO, Kelly JM, Rudiger SR, McMillen IC, Morrison JL, Zhang S, MacLaughlin SM, Smith DH, Grimson RJ, Jaensch KS, Brien FD, Plush KJ, Hiendleder S, Walker SK (2015) Effect of periconceptional nutrition on the growth, behaviour and survival of the neonatal lamb. Animal Reproduction Science 60, 12–22.
| Effect of periconceptional nutrition on the growth, behaviour and survival of the neonatal lamb.Crossref | GoogleScholarGoogle Scholar |
Kumarasamy V, Mitchell MD, Bloomfield FH, Oliver MH, Campbell ME, Challis JRG, Harding JE (2005) Effects of periconceptional undernutrition on the initiation of parturition in sheep. Regulatory. Integrative and Comparative Physiology 288, R67–R72.
| Effects of periconceptional undernutrition on the initiation of parturition in sheep. Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2MXhtVCqur0%3D&md5=57441db31b68779104f24d1adc473822CAS |
Liggins GC (1994) The role of cortisol in preparing the fetus for birth. Reproduction, Fertility and Development 6, 141–150.
| The role of cortisol in preparing the fetus for birth.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK2cXlvFKjs7w%3D&md5=cbd7eb28c8d1a9c497e8953dad28720aCAS |
McCoard SA, Henderson HV, Knol FW, Dowling SK, Webster JR (2014) Infrared thermal imaging as a method to study thermogenesis in the neonatal lamb. Animal Production Science 54, 1497–1501.
McCutcheon SN, Holmes CW, McDonald MF (1981) Lambs will die as quick as look at you. New Zealand Journal of Agriculture May, 7–11.
Mellor DJ, Cockburn F (1986) A comparison of energy metabolism in the new-born infant, piglet and lamb. Quartlery Journal of Experimental Physiology 71, 361–379.
| A comparison of energy metabolism in the new-born infant, piglet and lamb.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaL28XlsFShtbs%3D&md5=a84cbc89ae605bdece633ac204be2167CAS |
Miller DR, Jackson RB, Blache D, Roche JR (2009) Metabolic maturity at birth and neonate lamb survival and growth: the effects of maternal low-dose dexamethasone treatment. Journal of Animal Science 87, 3167–3178.
| Metabolic maturity at birth and neonate lamb survival and growth: the effects of maternal low-dose dexamethasone treatment.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1MXht1WksL%2FN&md5=0056f8b8d6bf5aeff293bda6e7855be9CAS | 19542513PubMed |
Montaldo HH, Meza-Herrera CA (1998) Use of molecular markers and major genes in the genetic improvement of livestock. Electronic Journal of Biotechnology 1, 83–89.
| Use of molecular markers and major genes in the genetic improvement of livestock.Crossref | GoogleScholarGoogle Scholar |
Mostyn A, Pearce S, Budge H, Elmes M, Forhead AJ, Fowden AL, Stephenson T, Symonds ME (2003) Influence of cortisol on adipose tissue development in the fetal sheep during late gestation. The Journal of Endocrinology 176, 23–30.
| Influence of cortisol on adipose tissue development in the fetal sheep during late gestation.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3sXhtFaktbk%3D&md5=0f6381079cf270dba15a9652f610e358CAS | 12525246PubMed |
Munoz C, Carson AF, McCoy MA, Dawson LER, O’Connell NE, Gordon AW (2007) 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.
Nicholls DG (1983) The thermogenic mechanism of brown adipose tissue. Bioscience Reports 3, 431–441.
| The thermogenic mechanism of brown adipose tissue.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaL3sXksFSrsr4%3D&md5=3e0a46d2e000a91112d7dbc58e2511c3CAS | 6882887PubMed |
Nicholls DG, Locke RM (1984) Thermogenic mechanisms in brown fat. Physiological Reviews 64, 1–64.
Purser AF, Karam HA (1967) g. Animal Production 9, 75–85.
| g.Crossref | GoogleScholarGoogle Scholar |
Sack J, Beaudry M, DeLamater PV, Oh W, Fisher DA (1976) Umbilical cord cutting triggers hypertriiodothyroninemia and nonshivering thermogenesis in the newborn lamb. Pediatric Research 10, 169–175.
| Umbilical cord cutting triggers hypertriiodothyroninemia and nonshivering thermogenesis in the newborn lamb.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaE28XhslOnurk%3D&md5=eb77789c513f49e12b8737bfccfd8a42CAS | 1250646PubMed |
Samson DE, Slee J (1981) Factors affecting resistance to induced body cooling in newborn lambs of 10 breeds. Animal Production 33, 59–65.
| Factors affecting resistance to induced body cooling in newborn lambs of 10 breeds.Crossref | GoogleScholarGoogle Scholar |
Sawa R, Asakura H, Power G (1991) Changes in plasma adenosine during simulated birth of fetal sheep. Journal of Applied Physiology 70, 1524–1528.
Sawalha RM, Conington J, Brotherstone S, Villanueva B (2007) Analysis of lamb survival of Scottish Blackface sheep. Animal 1, 151–157.
| Analysis of lamb survival of Scottish Blackface sheep.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BC38vptFCqsA%3D%3D&md5=17900900905cdabb222b566921e3959bCAS | 22444218PubMed |
Schermer SJ, Bird JA, Lomax MA, Shepherd DA, Symonds ME (1996) Effect of fetal thyroidectomy on brown adipose tissue and thermoregulation in newborn lambs. Reproduction, Fertility and Development 8, 995–1002.
| Effect of fetal thyroidectomy on brown adipose tissue and thermoregulation in newborn lambs.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DyaK2s%2FltFaqtA%3D%3D&md5=9e3f70abc425d9c0b9027253ec28af2aCAS |
Silva JE (1995) Thyroid hormone control of thermogenesis and energy balance. Thyroid 5, 481–492.
| Thyroid hormone control of thermogenesis and energy balance.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DyaK28vgtlyhsQ%3D%3D&md5=9b02192bc8b880b2773ac5616e4c5dd8CAS | 8808101PubMed |
Silva JE, Larsen PR (1983) Adrenergic activation of triiodothyronine production in brown adipose tissue. Nature 305, 712–713.
| Adrenergic activation of triiodothyronine production in brown adipose tissue.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaL3sXmtVKkt7k%3D&md5=c001c6d0f000e9bbfbe4ec5d78666b18CAS | 6633638PubMed |
Simpson SP, Slee J (1988) The inheritance of non-response to noradrenaline in newborn scottish blackface lambs. Genetical Research 51, 65–69.
| The inheritance of non-response to noradrenaline in newborn scottish blackface lambs.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaL1cXhvFyrsLw%3D&md5=488802b0a7bcf7e658f39e7a1c81ea51CAS | 3366382PubMed |
Slee J (1981) A review of genetic aspects of survival and resistance to cold in newborn lambs. Livestock Production Science 8, 419–429.
| A review of genetic aspects of survival and resistance to cold in newborn lambs.Crossref | GoogleScholarGoogle Scholar |
Slee J, Simpson SP (1991) Description of the effects of a single gene which inhibits the normal metabolic response of newborn lambs to exogenous noradrenaline. Research in Veterinary Science 51, 34–39.
| Description of the effects of a single gene which inhibits the normal metabolic response of newborn lambs to exogenous noradrenaline.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DyaK3Mzns1emtg%3D%3D&md5=450886bed00ecc1b6cb8c70705997c6bCAS | 1896628PubMed |
Slee J, Stott AW (1986) Genetic selection for cold resistance in Scottish blackface lambs. Animal Production 43, 397–404.
| Genetic selection for cold resistance in Scottish blackface lambs.Crossref | GoogleScholarGoogle Scholar |
Slee J, Griffiths RJ, Samson DE (1980) Hypothermia in newborn lambs induced by experimental immersion in a water bath and by natural exposure outdoors. Research in Veterinary Science 28, 275–280.
Slee J, Simpson SP, Woolliams JA (1987) Metabolic-rate responses to cold and to exogenous noradrenaline in newborn Scottish blackface lambs genetically selected for high or low resistance to cold. Animal Production 45, 69–74.
| Metabolic-rate responses to cold and to exogenous noradrenaline in newborn Scottish blackface lambs genetically selected for high or low resistance to cold.Crossref | GoogleScholarGoogle Scholar |
Slee J, Alexander G, Bradley LR, Jackson N, Stevens D (1991) Genetic aspects of cold resistance and related characters in newborn Merino lambs. Australian Journal of Experimental Agriculture 31, 175–182.
| Genetic aspects of cold resistance and related characters in newborn Merino lambs.Crossref | GoogleScholarGoogle Scholar |
Smith SB, Carstens GE, Randel RD, Mersmann HJ, Lunt DK (2004) Brown adipose tissue development and metabolism in ruminants. Journal of Animal Science 82, 942–954.
Stafford KJ, Kenyon PR, Morris ST, West DM (2007) The physical state and metabolic status of lambs of different birth rank soon after birth. Livestock Science 111, 10–15.
| The physical state and metabolic status of lambs of different birth rank soon after birth.Crossref | GoogleScholarGoogle Scholar |
Stott AW, Slee J (1985) The effect of environmental-temperature during pregnancy on thermoregulation in the newborn lamb. Animal Production 41, 341–347.
| The effect of environmental-temperature during pregnancy on thermoregulation in the newborn lamb.Crossref | GoogleScholarGoogle Scholar |
Stott AW, Slee J (1987) The effect of litter size, sex, age, body weight, dam age and genetic selection for cold resistance on the physiological responses to cold exposure of scottish blackface lambs in a progressively cooled water bath. Animal Production 45, 477–491.
| The effect of litter size, sex, age, body weight, dam age and genetic selection for cold resistance on the physiological responses to cold exposure of scottish blackface lambs in a progressively cooled water bath.Crossref | GoogleScholarGoogle Scholar |
Symonds ME (2013) Brown adipose tissue growth and development. Scientifica 2013, 305763
| Brown adipose tissue growth and development.Crossref | GoogleScholarGoogle Scholar | 24278771PubMed |
Symonds ME, Stephenson T, Gardner DS, Budge H (2007) Long-term effects of nutritional programming of the embryo and fetus: mechanisms and critical windows. Reproduction, Fertility and Development 19, 53–63.
| Long-term effects of nutritional programming of the embryo and fetus: mechanisms and critical windows.Crossref | GoogleScholarGoogle Scholar |
Thompson GE, Jenkinson DM (1969) Nonshivering thermogenesis in the newborn lamb. Canadian Journal of Physiology and Pharmacology 47, 249–253.
| Nonshivering thermogenesis in the newborn lamb.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaF1MXnsFOjtg%3D%3D&md5=7ba72ec40e56aaa14d20f0140aae3134CAS | 5767242PubMed |
Thompson MJ, Briegel JR, Thompson AN, Adams NR (2006) Differences in survival and neonatal metabolism in lambs from flocks selected for or against staple strength. Australian Journal of Agricultural Research 57, 1221–1228.
| Differences in survival and neonatal metabolism in lambs from flocks selected for or against staple strength.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD28XhtFeqsr7P&md5=ae299374394ee90caf50a07776956b0aCAS |
Trayhurn P (1993) Brown adipose tissue: from thermal physiology to bioenergetics. Journal of Biosciences 18, 161–173.
| Brown adipose tissue: from thermal physiology to bioenergetics.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK3sXltlKju7Y%3D&md5=7920ffa4d55755b5219135626f5380e5CAS |
Wolff JE, Baker RL, Dobbie PM, Ford AJ, Jordan RB (1987) Genetic aspects of cold resistance in new-born lambs. Proceedings of the New Zealand Society of Animal Production 47, 93–98.
