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Food intake regulation in late pregnancy and early lactation

Published online by Cambridge University Press:  27 February 2018

K. L. Ingvartsen ,
N. C. Friggens  and
P. Faverdin
K. L. Ingvartsen
Affiliation:
Danish Institute of Agricultural Sciences, Research Centre Foulum, PO Box 50, 8830 Tjele, Denmark
N. C. Friggens
Affiliation:
Danish Institute of Agricultural Sciences, Research Centre Foulum, PO Box 50, 8830 Tjele, Denmark
P. Faverdin
Affiliation:
INRA, Station de Recherches sur la Vache Laitière, 35590 Saint-Gilles, France
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Abstract

The dip in food intake, which starts in late pregnancy and continues into early lactation, has traditionally been interpreted as a depression in intake due to physical constraints. However, the rôle of physical constraints on intake has been overemphasized, particularly in early lactation. There is mounting evidence that the presence and mobilization of body reserves in early lactation play an important rôle in regulating intake at this time.

Conceptually, the dip in intake in early lactation observed when cows have access to non-limiting foods can be accounted for by assuming that the cow has a desired level of body reserves. When the cow is not compromised, the changes with time in body reserves and the dip in intake represent the normal case and provide the basis against which to assess true depressions in intake which may occur when the cow is compromised by limiting nutrition or environment.

The regulation of body reserves and intake in the periparturient cow is orchestrated through nervous and hormonal signals. Likely factors that are involved in intake regulation are reproductive hormones, neuropeptides, adrenergic signals, insulin and insulin resistance and leptin. Furthermore, oxidation of NEFA in the liver may result in feedback signals that reduce intake. The relative importance of these is discussed. A better understanding of the physiological signals involved in intake regulation and their interrelations with body weight regulation may provide important indicators of the degree of compromise that periparturient cows may experience.

Type
Research Article
Information
BSAP Occasional Publication , Volume 24: Metabolic stress in dairy cows , 1999 , pp. 37 - 54
Copyright
Copyright © British Society of Animal Science 1999

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References

Allen, M. S. 1996. Physical constraints on voluntary intake of forages by ruminants. Journal of Animal Science 74: 3063–3075.Google Scholar
Anil, M. H. and Forbes, J. M. 1980. Feeding in sheep during intraportal infusions of short-chain fatty acids and the effect of liver denervation. Journal of Physiology 298: 407–414.Google Scholar
Anil, M. H. and Forbes, J. M. 1987. Neural control and sensory functions of the liver. Proceedings of the Nutition. Society 46: 125–133.CrossRefGoogle ScholarPubMed
Arase, K., York, D. A., Shimizu, H., Shargill, N. and Bray, G. 1988. Effect of corticotropin releasing factor on food intake and brown adipose tissue thermogenesis in rats. American Journal of Physiology 255: E255–E259.Google Scholar
Baile, C. A. and Martin, H. F. 1971. Hormones and amino acids as possible factors in the control of hunger and satiety in sheep. Journal of Dairy Science 54:897–905.CrossRefGoogle ScholarPubMed
Balch, C. C. and Campling, R. C. 1962. Regulation of voluntary food intake in ruminants. Nutrition Abstracts and Reviews 32:669–682.Google Scholar
Bareille, N. and Faverdin, P. 1996a. Lipid metabolism and intake behavior of dairy cows: effects of intravenous lipid and beta-adrenergic supplementation. Journal of Dairy Science 79:1209–1220.Google Scholar
Bareille, N. and Faverdin, P. 1996b. Modulation of the feeding response of lactating dairy cows to peripheral insulin administration with or without a glucose supply. Reproduction, Nutrition, Development 36: 83–93.Google Scholar
Bareille, N., Faverdin, P. and Hay, M. 1997. Modification of feed intake response to a beta(2)-agonist by bovine somatotropin in lactating dairy cows. Journal of Dairy Science 80:52–66.CrossRefGoogle Scholar
Bauman, D. E. and Currie, W. B. 1980. Partitioning of nutrients during pregnancy and lactation: a review of mechanisms involving homeostasis and homeorhesis. Journal of Dairy Science 63:1514–1525.Google Scholar
Bauman, D. E. and Vernon, R. G. 1993. Effect of exogenous bovine somatotropin on lactation. Annual Review of Nutrition 13:437–461.Google Scholar
Beede, D. K., Sanchez, W. K. and Wang, C. 1992. Macrominerals. In Large dairy herd management (ed. Van Horn, H. H. and Wilcox, C. J.), pp. 272–286. American Dairy Sciences Association, Champaign, IL, USA.Google Scholar
Bell, A. W. 1995. Regulation of organic nutrient metabolism during transition from late pregnancy to early lactation. Journal of Animal Science 73:2804–2819.CrossRefGoogle ScholarPubMed
Bertalanffy, L. von. 1968. General system theory, revised edition. George Braziller, New York.Google Scholar
Bines, J. A. 1979. Voluntary food intake. In Feeding strategy for the high yielding dairy cow (ed. Broster, W. H. and Swan, H.), pp. 23–48. Wageningen.Google Scholar
Bines, J. A. and Morant, S. V. 1983. The effect of body condition on metabolic changes associated with intake of food by the cow. British Journal of Nutrition 50:81–89.Google Scholar
Bines, J. A., Suzuki, S. and Balch, C. C. 1969. The quantitative significance of long-term regulation of food intake in the cow. British Journal of Nutrition 23:695–704.Google Scholar
Blaxter, K. L., Wainman, F. W. and Wilson, R. S. 1961. Regulation of food intake by sheep. Animal Production 3: 51–61.Google Scholar
Boden, G., Chen, G., Mozzoli, M. and Rayan, I. 1996. Effect of fasting on serum leptin in normal human subjects. Journal of Clinical Endocrinology and Metabolism 81: 3419–3423.Google Scholar
Broster, W. H. and Broster, V. A. 1998. Body score of dairy cows. Journal of Dairy Research 65:155–173.Google Scholar
Butera, P. C. and Beikirch, R. J. 1989. Central implants of diluted estradiol: independent effects on ingestive and reproductive behaviours of ovariectomized rats. Brain Research 491: 266–273.CrossRefGoogle ScholarPubMed
Campfield, L. A., Smith, F. J., Guisez, Y., Devos, R. and Burn, P. 1995. Recombinant mouse OB protein: evidence for a peripheral signal linking adiposity and central neural networks. Science 269: 546–549.Google Scholar
Carpenter, R. G. and Grossman, S. P. 1983. Plasma fat metabolites and hunger. Physiology and Behavior 30:57–63.CrossRefGoogle ScholarPubMed
Castonguay, T. W. 1991. Glucocorticoids as modulators in the control of feeding. Brain Research Bulletin 27:423–428.Google Scholar
Chen, G., Koyama, K., Yuan, X., Lee, Y., Zhou, Y.-T., O’Doherty, R., Newgard, C. B. and Unger, R. H. 1996. Disappearance of body fat in normal rats induced by adenovirus-mediated leptin gene therapy. Proceedings of the National Academy of Sciences of the United States of America 93: 14795–14799.CrossRefGoogle ScholarPubMed
Chen, H., Charlat, O., Tartaglia, L. A., Woolf, E. A., Weng, X., Ellis, S. J., Lakey, N. D., Culpepper, J., Moore, K. J., Breitbart, R. E., Duyk, G. M., Tepper, R. I. and Morgensten, J. P. 1996. Evidence that the diabetis gene encodes the leptin receptor: identification of a mutation in the leptin receptor gene in db/db mice. Cell 84:491–495.Google Scholar
Chien, E. K., Hara, M., Rouard, M., Yano, H., Philippe, M., Polonsky, K. S. and Bell, G. I. 1997. Increase in serum leptin and uterine leptin receptor messenger RNA levels during pregnancy in rats. Biochemical and Biophysical Research Communications 2237: 476–480.Google Scholar
Chilliard, Y., Bocquier, F., Delavaud, C., Guerre-Millo, M., Bonnet, M., Martin, P., Faulconnier, Y. and Ferlay, A. 1998. Leptin in ruminants: effects of species, breed, adiposity, photopheriod, beta-agonists and nutritional status. Nutrition conference for feed manufacturers, 1998, pp. 1–10.Google Scholar
Coffey, K. P., Paterson, J. A., Saul, C. S., Coffey, L. S., Turner, K. E. and Bowman, J. G. 1989. The influence of pregnancy and source of supplemental protein on intake, digestive kinetics and amino acid absorption by ewes. Journal of Animal Science 67:1805–1814.Google Scholar
Coleman, D. L. 1973. Effects of parabiosis of obese with diabetes and normal mice. Diabetologia 9:294–298.CrossRefGoogle ScholarPubMed
Coleman, D. L. and Hummel, K. P. 1969. Effects of parabiosis of normal with genetically diabetic mice. American Journal of Physiology 217: 1298–1304.Google Scholar
Conrad, H. R., Pratt, A. D. and Hibbs, J. W. 1964. Regulation of feed intake in dairy cows. 1. Change in importance of physical and physiological factors with increasing digestibility. Journal of Dairy Science 47:54–62.Google Scholar
Considine, R. V. and Caro, J. F. 1997. Leptin and the regulation of body weight. International Journal of Biochemistry and Cell Biology 29:1255–1272.Google Scholar
Considine, R. V., Sinha, M. K., Heiman, M. L., Kriauciunas, A., Stephens, T. W., Nyce, M. R., Ohannesian, J. P., Arko, C. C., McKee, L. J., Bauer, T. L. and Caro, J. F. 1996. Serum immunoreactive-leptin concentrations in normal-weight and obese humans. New England Journal of Medicine 334: 292–295.Google Scholar
Costa, A., Poma, A., Martignoni, E., Nappi, G., Ur, E. and Grossman, A. 1997. Stimulation of corticotrophin-releasing hormone release by the obese (ob) gene product, leptin, from hypothalamic explants. NeuroReport 8:1131–1134.Google Scholar
Dado, R. G. and Allen, M. S. 1995. Intake limitations, feeding behavior and rumen function of cows challenged with rumen fill from dietary fiber or inate bulk. Journal of Dairy Science 78:118–133.Google Scholar
Deetz, L. E. and Wangsness, P. J. 1980. Effect of intrajugular administration of insulin on feed intake, plasma glucose and plasma insulin of sheep. Journal of Nutrition 110: 1976–1982.Google Scholar
Drackley, J. K. 1998. Transitional period nutrition management explored. Feedstuffs 70: 12–16 Google Scholar
Dubuc, G. R., Phinney, S. D., Stern, J. S. and Havel, P. J. 1998. Changes of serum leptin and endocrine and metabolic parameters after 7 days of energy restriction in men and women. Metabolism 47:429–434.Google Scholar
Dyer, C. J., Simmons, J. M., Matteri, R. L. and Keisler, D. H. 1997. Leptin receptor RNA is expressed in ewe anterior pituitary and adipose tissue and is differentially expressed in hypothalamic regions of well-fed and restricted ewes. Domestic Animal Endocrinology 14: 119–128.Google Scholar
Ellis, L. A., Mastro, A. M. and Picciano, M. F. 1997. Do milk-borne cytokines and hormones influence neonatal immune cell function? Journal of Nutrition 127: 985S–988S.Google Scholar
Emery, R. S., Liesman, J. S. and Herdt, T. Н. 1992. Metabolism of long chain fatty acids by ruminant liver. Journal of Nutrition 122: 832–837.Google Scholar
Faverdin, P., Baumont, R. and Ingvartsen, K. L. 1995. Control and prediction of feed intake in ruminants. In Recent developments in the nutrition of herbivores (ed. Journet, M., Grenet, E., Farce, M.-H., Theriez, M. and Demarquilly, C.), pp. 95–120. INRA Editions, Paris.Google Scholar
Foot, J. Z. 1972. A note on the effect of body condition on the voluntary food intake of dried grass wafers by Scottish Blackface ewes. Animal Production 14:131–134.Google Scholar
Forbes, J. M. 1968. The physical relationship of the abdominal organs in the pregnant ewe. Journal of Agricultural Science, Cambridge 70:171–177.Google Scholar
Forbes, J. M. 1969. The effect of pregnancy and fatness on the volume of rumen content in the ewe. Journal of Agricultural Science, Cambridge 72: 119–121.Google Scholar
Forbes, J. M. 1974. Feeding in sheep modified by intraventricular estradiol and progesterone. Physiology and Behavior 12: 741–747.Google Scholar
Forbes, J. M. 1986. The effects of sex hormones, pregnancy and lactation on digestion, metabolism and voluntary food intake. In Control of digestion and metabolism in ruminants (ed. Milligan, L. P., Grovum, W. L. and Dobson, A.), pp. 420–435. Prentice-Hall, Englewood Cliffs.Google Scholar
Forbes, J. M. 1988. Metabolic aspects of the regulation of voluntary food intake and appetite. Nutrition Research Reviews 1:145–168.Google Scholar
Forbes, J. M. 1995a. Voluntary food intake and diet selection in farm animals. CAB International, Wallingford.Google Scholar
Forbes, J. M. 1995b. Voluntary intake: a limiting factor to production in high yielding dairy cows? In Breeding and feeding the high genetic merit dairy cow (ed. Lawrence, T. L. J., Gordon, F. J. and Carson, A.), pp. 13–19. British Society of Animal Science occasional publication no. 19. Google Scholar
Forbes, J. M. 1996. Integration of regulatory signals controlling forage intake in ruminants. Journal of Animal Science 74:3029–3035.CrossRefGoogle ScholarPubMed
Friggens, N. C., Emmans, G. C., Kyriazakis, I., Oldham, J. D. and Lewis, M. 1998. Feed intake relative to stage of lactation for dairy cows consuming total mixed diets with a high or low ratio of concentrate to forage. Journal of Dairy Science 81:2228–2239.Google Scholar
Garnsworthy, P. C. 1988. The effect of energy reserves at calving on performance of dairy cows. In Nutrition and lactation in the dairy cow (ed. Garnsworthy, P. C.), pp. 157–170. Butterworths, London.Google Scholar
Garnsworthy, P. C. and Topps, J. H. 1982. The effect of body condition of dairy cows at calving on their food intake and performance when given complete diets. Animal Production 35:113–119.Google Scholar
Gettys, T. W., Harkness, P. J. and Watson, P. M. 1996. The beta3-adrenergic receptor inhibits insulin-stimulated leptin secretion from isolated rat adipocytes. Endocrinology 137: 454–457.CrossRefGoogle Scholar
Griinari, J. M., McGuire, M. A., Dwyer, D. A., Bauman, D. E. and Palmquist, D. L. 1997. Role of insulin in the regulation of milk fat synthesis in dairy cows. Journal of Dairy Science 80:1076–1084.Google Scholar
Grossman, S. P. 1986. The role of glucose, insulin and glucagon in the regulation of food intake and body weight. Neuroscience and Biobehavior Reviews 10:295–315.Google Scholar
Grovum, W. L. 1995. Mechanisms explaining the effect of short chain fatty acids on feed intake in ruminants - osmotic pressure, insulin and glucagon. In Ruminant physiology: digestion, metabolism, growth and reproduction (ed. Engelhardt, W. v., Leonhard-Marek, S., Breves, G. and Giesecke, D.), pp. 173–198. Ferdinand Enke Verlag, Stuttgart.Google Scholar
Grummer, R. R. 1993. Etiology of lipid-related metabolic disorders in periparturient dairy cows. Journal of Dairy Science 76:3882–3896.Google Scholar
Grummer, R. R. 1998. Transition cow energy, protein nutrition examined. Feedstuffs, September, pp. 11–12.Google Scholar
Grummer, R. R., Bertics, S. J., Lacount, D. W., Snow, J. A., Dentine, M. R. and Stauffacher, R. H. 1990. Estrogen induction of fatty liver in dairy cattle. Journal of Dairy Science 73:1537–1543.CrossRefGoogle ScholarPubMed
Gunter, S. A., Judkins, M. B., Krysi, L. J., Broesder, J. T., Barton, R. K., Rueder, B. R., Hallford, D. M. and Holcombe, D. W. 1990. Digesta kinetics, ruminal fermentation characteristics and serum metabolites of pregnant and lactating ewes fed chopped alfalfa hay. Journal of Animal Science 68:3821–3831.Google Scholar
Halaas, J. L., Gajiwala, K. S., Maffei, M., Cohen, S. L., Chait, B. T., Rabinowitz, D., Lallone, R. L., Burley, S. K. and Friedman, J. M. 1995. Weight-reducing effects of the plasma protein encoded by the obese gene. Science 269: 543–546.Google Scholar
Hamann, A. and Matthaei, S. 1996. Regulation of energy balance by leptin. Experimental and Clinical Endocrinology of Diabetes 104: 293–300.Google Scholar
Harris, R. B. S. and Martin, R. J. 1984. Specific depletion of body fat in parabiotic partners of tube-fed obese rats. American Journal of Physiology 247: R380–R386.Google Scholar
Harris, R. B. S. and Martin, R. J. 1990. Site of action of putative lipostatic factor: food intake and peripheral pentose shunt activity. American Journal of Physiology 259: R45–R52.Google Scholar
Head, H. H., Thatcher, W. W., Wilcox, C. J. and Bachmann, K. C. 1976. Effect of a synthetic corticoid on milk yield and composition and on blood metabolites and hormones in dairy cows. Journal of Dairy Science 59: 880–888.Google Scholar
Hervey, G. R. 1959. The effects of lesions in the hypothalamus in parabiotic rats. Journal of Physiology 145: 336–352.Google Scholar
Hotta, M., Shibasaki, T., Yamauchi, N., Ohno, H., Benoit, R., Ling, N. and Demura, H. 1991. The effects of chronic central administration of corticotropin-pituitary-adrenocortical hormones. Life Sciences 48:1491.Google Scholar
Houpt, T. R. 1974. Stimulation of food intake in ruminants by 2-deoxy-D-glucose and insulin. American Journal of Physiology 227: 167.Google Scholar
Houseknecht, K. L., Dwyer, D. A., Lanna, D. P. D. and Bauman, D. E. 1995. Effect of somatotropin on adipose tissue metabolism: ontogeny of the enhanced response to adrenergic challenge in the lactating cow. Domestic Animal Endocrinology 12: 105–113.Google Scholar
Houseknecht, K. L., Mantzoros, C. S., Kuliawat, R., Hadro, E., Flier, J. S. and Kahn, B. B. 1996. Evidence for leptin binding to proteins in serum of rodents and humans: modulation with obesity. Diabetes 45:1638–1643.CrossRefGoogle ScholarPubMed
Illius, A. W. and Jessop, N. S. 1996. Metabolic constraints on voluntary intake in ruminants. Journal of Animal Science 74:3052–3062.Google Scholar
Ingvartsen, K. L. 1994. Models of voluntary food intake. Livestock Production Science 39: 19–38.Google Scholar
Ingvartsen, K. L., Andersen, H. R. and Foldager, J. 1992. Effect of sex and pregnancy on feed intake capacity of growing cattle. Acta Agriculturae Scandinavica, Section A, Animal Science 42: 40–46.Google Scholar
Ingvartsen, K. L., Danfær, A. Andersen, P. H. and Foldager, J. 1995a. Prepartum feeding of dairy cattle: a review of the effect on periparturient metabolism, feed intake, production and health. In Proceedings of the 46th annual meeting of the European Association for Animal Production, pp. 1–18.Google Scholar
Ingvartsen, K. L., Foldager, J., Aaes, O. and Andersen, P. H. 1995b. [Effect of feeding level in the last 24 weeks prepartum on intake, production and metabolism in heifers and cows.] In Transition to lactation: feeding and physiology of the dairy cow during pregnancy and around parturition, pp. 38–48. Danish Institute of Animal Science.Google Scholar
Janowitz, H. D. and Ivy, A. C. 1948. Role of blood sugar levels in spontaneous and insulin-induced hunger in man. Journal of Applied Physiology 1:643–645.Google Scholar
Kaske, M. and Groth, A. 1997. Changes in factors affecting the rate of digesta passage during pregnancy and lactation in sheep fed on hay. Reproduction, Nutrition, Development 37: 573–588.Google Scholar
Kennedy, G. C. 1953. The role of depot fat in the hypothalamic control of food intake in the rat. Proceedings of the Royal Society of London, Series B, Biological Sciences 139: 578–592.Google Scholar
Kennedy, G. C. 1967. Ontogeny of mechanisms controlling food and water intake. In Alimentary canal, volume 1. Control of food and water intake (ed. Code, C. F.), pp. 337–352. American Society, Washington.Google Scholar
Kolaczynski, J. W., Nyce, M. R., Considine, R. V., Boden, G., Nolan, J. J., Henry, R., Mudaliar, S. R., Olefskiy, J. and Caro, J. F. 1996a. Acute and chronic effects of insulin on leptin production in humans. Diabetes 45: 701.Google Scholar
Kolaczynski, J. W., Ohannesian, J. P., Considine, R. V., Marco, C. C. and Caro, J. F. 1996b. Response of leptin to short-term and prolonged overfeeding in humans. Journal of Clinical Endocrinology and Metabolism 81:4162–4165.Google Scholar
Krahn, D. D., Gosnell, B. A., Levine, A. S. and Morley, J. E. 1984. Localization of the effects of corticotropin releasing factor on feeding. Proceedings of the Socety for Neurescience 10:302 (abstr.).Google Scholar
Kronfeld, D. 1976. The potential importance of the proportions of glucogenic, lipogenic and aminogenic nutrients in regard to the health and productivity of dairy cows. Advances in Animal Physiology and Animal Nutrition 7: 5–26.Google Scholar
Lagerlof, N. 1929. Investigations of the topography of the abdominal organs in cattle and some clinical observations and remarks in connection with the subject. Skandinavisk Veterinærtidsskrift 19:253–265.Google Scholar
Langhans, W., Egli, G. and Scharrer, E. 1985a. Regulation of food intake by hepatic oxidative metabolism. Brain Research Bulletin 15:425–428.Google Scholar
Langhans, W., Egli, G. and Scharrer, E. 1985b. Selective hepatic vagotomy eliminates the hypophagic effect of different metabolites. Journal of the Autonomie Nervous System 13:255–262.Google Scholar
Langhans, W., Pantel, K. and Scharrer, E. 1985c. Ketone kinetics and D-(-)-3-hydroxybutyrate induced inhibition of feeding in rats. Physiology and Behavior 34:579–582.Google Scholar
Langhans, W. and Scharrer, E. 1987. Evidence for a vagally mediated satiety signal derived from hepatic fatty acid oxidation. Journal of the Autonomie Nervous System 18:13–18.Google Scholar
Lehman, F. 1941. Die Lehre von Ballast. Zeitschrift für Tierernahrung und Futtermittelkunde 5:155–173.Google Scholar
Leitch, J. 1987. Don’t skate on thin ice. Dairy Farmer, November, pp. 55–56.Google Scholar
Leng, R. A. 1989. Some factors influencing the efficiency of feed utilization by ruminants with special reference to the tropics. In Recent advances in animal nutrition in Australia (ed. Farell, D. J.), pp. 75–85. University of New England, Annidale, Australia.Google Scholar
Levine, A. S., Rogers, B., Kneip, J., Grace, M. and Morley, J. E. 1983. Effect of centrally administered corticotropin releasing factor (CRF) on multiple feeding paradigms. Neuropharmacology 22: 337–339.Google Scholar
McCann, J. P., Bergman, E. N. and Beermann, D. H. 1992. Dynamic and static phases of severe dietary obesity in sheep: food intakes, endocrinology and carcass and organ chemical composition. Journal of Nutrition 122: 496–505.Google Scholar
McGowan, M. K., Andrews, K. M. and Grossman, S. P. 1992. Chronic intrahypothalamic infusions of insulin or insulin antibodies alter body weight and food intake in the rat. Physiology and Behavior 51: 753–766.Google Scholar
McGuire, M. A., Dwyer, D. A., Harrel, R. J. and Bauman, D. E. 1995a. Insulin regulates circulating insulin-like growth factor and some of their binding proteins in lactating cows. American Journal of Physiology 269: E723–E730.Google Scholar
McGuire, M. A., Griinari, J. M., Dwyer, D. A. and Bauman, D. E. 1995b. Role of insulin in the regulation of mammary synthesis of fat and protein. Journal of Dairy Science 78:816–824.Google Scholar
McNamara, J. 1995. Role and regulation of metabolism in adipose tissue during lactation. Journal of Nutritional Biochemistry 6:120–129.Google Scholar
Maffei, M., Fei, H., Lee, G. H., Dani, C., Leroy, P., Zhang, Y., Proenca, R., Negrel, R., Ailhaud, G. and Friedman, J. M. 1995a. Increased expression in adipocytes of ob RNA in mice lesions of the hypothalamus and with mutations at the db locus. Proceedings of the National Academy of Sciences of the United States of America 92: 6957–6960.Google Scholar
Maffei, M., Halaas, J., Ravussin, E., Pratley, R. E., Lee, G. H., Zhang, Y., Fei, H., Kim, S., Lallone, R., Ranganathan, S., Kern, P. A. and Friedman, J. M. 1995b. Leptin levels in human and rodent: measurement of plasma leptin and ob RNA in obese and weight-reduced subjects. Nature Medicine 1:1155–1161.Google Scholar
Mantzoros, C. S., Qu, D., Frederich, R. C., Susulic, V. S., Lowell, B. B., Maratos-Flier, E. and Flier, J. S. 1996. Activation of ß3 adrenergic receptors suppresses leptin expression and mediates a leptin-independent inhibition of food intake in mice. Diabetes 45:909–914.Google Scholar
Masuzaki, H., Ogawa, Y., Isse, N., Satoh, N., Okazaki, T., Shigemoto, M., Mori, K., Tamura, N., Hosoda, K., Yoshimasa, Y., Jingami, H., Kawada, T. and Nakao, K. 1995. Adipocyte-specific expression and regional differences in the adipose tissue. Diabetes 44:855–858.Google Scholar
Mäkelä, A. 1956. Studies on the question of bulk in the nutrition of farm animals with animals with special reference to cattle. Acta Agralia Fennica 85: 130 Google Scholar
Mertens, D. R. 1994. Regulation of forage intake. In Forage quality, evaluation and utilization (ed. Fahey, G. C.), pp. 450–493. American Society of Agronomists, Madison.Google Scholar
Miner, J. L. 1992. Recent advances in the central control of intake in ruminants. Journal of Animal Science 70:1283–1289.Google Scholar
Mistry, A. M., Swick, A. G. and Romsos, D. R. 1997. Leptin rapidly lowers food intake and elevates metabolic rates in lean and ob/ob mice. Journal of Nutrition 127: 2065–2072.Google Scholar
Mook, D. G., Kenny, N. J., Roberts, S., Nussbaum, A. I. and Rodier, W. I. 1972. Ovarian-adrenal interaction in regulation of body weight by female rats. Journal of Comparative Physiology and Psychology 81:198–211.Google Scholar
Muir, L. A., Hibbs, J. W., Conrad, H. R. and Smith, K. L. 1972. Effect of estrogen and progesterone on feed intake and hydroxyproline excretion following induced hypocalcemia in dairy cows. Journal of Dairy Science 31: 145–148.Google Scholar
Nielsen, B. L. 1998. Perceived welfare issues in dairy cows, with special emphasis on metabolic stress. In Metabolic stress in dairy cows (ed. Oldham, J. D., Simm, G., Groen, A. F., Nielsen, B. L., Pryce, J. E. and Lawrence, T. L. J.), pp. 1–7. British Society of Animal Science occasional publication no. 24. Google Scholar
Nishizawa, Y. and Bray, G. A. 1980. Evidence for a circulating ergostatic factor: studies on parabiotic rats. American Journal of Physiology 239: R344–R351.Google Scholar
Oldham, J. D. and Emmans, G. C. 1989. Prediction of responses to required nutrients in dairy cows. Journal of Dairy Science 72:3212–3229.Google Scholar
Parameswaran, S. V., Steffens, A. B., Hervey, G. R. and De Ruiter, L. 1977. The involvement of a humoral factor in the regulation of body weight in parabiotic rats. American Journal of Physiology 232: R150–R157.Google Scholar
Pedron, O, Cheli, F., Senatore, E., Baroli, D. and Rizzi, R. 1993. Effect of body condition score at calving on performance, some blood parameters and milk fat composition in dairy cows. Journal of Dairy Science 76: 2528–2535.Google Scholar
Pelleymounter, M. A., Cullen, M. J., Baker, M. B., Hecht, R., Winters, D., Boone, T. and Collins, F. 1995. Effects of the obese gene product on body weight regulation in oblob mice. Science 269:540–543.Google Scholar
Peterson, A. D. and Baumgardt, B. R. 1976. Influence of level of energy demand on the ability of rats to compensate for diet dilution. Journal of Nutrition 101: 1069–1074.Google Scholar
Plata-Salaman, C. R. and Oomura, Y. 1986. Effect of intra-third ventricular administration of insulin on food intake after food deprivation. Physiology and Behavior 37: 735–739.Google Scholar
Pond, C. M. 1984. Physiological and ecological importance of energy storage in the evolution of lactation: evidence for a common pattern of anatomical organization of adipose tissue in mammals. In Physiological strategies in lactation (ed. Peaker, M., Vernon, R. G. and Knight, C. H.), pp. 1–29. Zoological Society of London, London, UK.Google Scholar
Ponsky, K. S., Given, B. D., Hirsch, L., Shapiro, E. T., Tillil, H., Beebe, C., Galloway, J. A., Frank, B. H., Karrison, T. and Cauter, E. van. 1988. Quantitative study of insulin secretion and clearance in normal and obese subjects. Journal of Clinical Investigation 81: 435–441.Google Scholar
Richard, D. 1998. Involvement of corticotropin-releasing factor in the control of food intake and energy expenditure. Annals of the New York Academy of Science 697: 155–172.Google Scholar
Roseler, D. K., Fox, D. G., Chase, L. E. P., Pell, A. N. and Stone, W. C. 1997. Development and evaluation of equations for prediction of feed intake for lactating Holstein dairy cows. Journal of Dairy Science 80: 878–893.Google Scholar
Rowland, N. E., Morien, A. and Li, B.-H. 1996. The physiology and brain mechanisms of feeding. Nutrition 12: 626–639.Google Scholar
Ruckebusch, Y. and Malbert, C. H. 1986. Stimulation and inhibition of food intake in sheep by centrally-administered hypothalamic releasing factors. Life Sciences 38: 929–934.Google Scholar
Ruegg, P. L. and Milton, R. L. 1995. Body condition scores of Holstein cows on Prince Edward Island, Canada: relationships with yield, reproductive performance and disease. Journal of Dairy Science 78: 552–564.Google Scholar
Sahu, A. 1998. Evidence suggesting that galanin (GAL), melanin-concentrating hormone (MHC), neurotensin (NT), proopiomelanocortin (POMC) and neuropeptide Y (NPY) are targets of leptin signaling in the hypothalamus. Endocrinology 139: 795–798.Google Scholar
Satoh, N., Ogawa, Y., Katsuura, G., Tsuji, T., Masuzaki, H., Hiraoka, J., Okazaki, T., Tamaki, M., Hayase, M., Yoshimasa, Y., Nishi, S., Hosoda, K. and Nakao, K. 1997. Pathophysiological significance of the obese gene product, leptin, in ventromedial hypothalamus (VMH)-lesioned rats: evidence for loss of its satiety effect in VMH-lesioned rats. Endocrinology 138: 947–954.Google Scholar
Sauvant, D. 1992. La modélisation systémique nutrition. Reproduction, Nutrition, Development 32: 217–230.Google Scholar
Sauvant, D. 1994. Modelling homeostatic and homeorhetic regulations in lactating animals. Livestock Production Science 39:105–113.Google Scholar
Scharrer, E. and Langhans, W. 1986. Control of food intake by fatty acid oxidation. American Journal of Physiology 250: R1003–R1006.Google Scholar
Scharrer, E. and Langhans, W. 1988. Matabolic and hormonal factors controlling food intake. International Journal of Vitamin and Nutrient Research 58: 249–261.Google Scholar
Scharrer, E. and Langhans, W. 1990. Mechanisms for the effect of body fat on food intake. In The control of body fat content (ed. Forbes, J. M. and Hervey, G. R.), pp. 63–86. Smith-Gordon, London.Google Scholar
Schwartz, M. W., Baskin, D. G., Bukowski, T. R., Kuijper, J. L., Foster, D., Lasser, G., Prunkard, D. E., Porte, D., Woods, S. C., Seeley, R. J. and Weigle, D. S. 1996a. Specificity of leptin action on elevated blood glucose levels and hypothalamic neuropeptide Y gene expression in ob/ ob mice. Diabetes 45:531–535.Google Scholar
Schwartz, M. W., Seeley, R. J., Campfield, L. A., Burn, P. and Baskin, D. G. 1996b. Identification of targets of leptin action in rat hypothalamus. Journal of Clinical Investigation 98:1101–1106.Google Scholar
Schwartz, M. W., Sipol, A. J., Kahn, S. E. and et al. 1990. Kinetics and specificity of insulin uptake from plasma into cerebrospinal fluid. American Journal of Physiology 259: E378–E383.Google Scholar
Sinha, M. K. and Caro, J. F. 1998. Clinical aspects of leptin. Vitamins and Hormones 54:1–30.Google Scholar
Sinha, M. K., Ohannesian, J. P., Heiman, M. L., Kriauciunas, A., Stephens, T. W., Magosin, S., Marco, C. and Caro, J. F. 1996a. Nocturnal rise of leptin in lean, obese and non-insulin-dependent diabetes mellitus subjects. Journal of Clinical Investigation 97: 1344–1347.Google Scholar
Sinha, M. K., Opentanova, I., Ohannesian, J. P., Kolaczynski, J. W., Heiman, M., Hale, J., Becker, G. W., Bowsher, R. R., Stephens, T. W. and Caro, J. F. 1996b. Evidence of free and bound leptin in human circulation. Journal of Clinical Investigation 98: 1277–1282.Google Scholar
Sinha, M. K., Sturis, J., Ohannesian, J. P., Magosin, S., Stephens, T. W., Heiman, M. L., Polonsky, K. S. and Caro, J. F. 1996c. Ultradian oscillations of leptin secretion in humans. Biochemical and Biophysical Research Communications 228: 733–738.Google Scholar
Slonaker, J. R. 1924. The effect of copulation, pregnancy, pseudopregnancy and lactation on the voluntary activity and food consumption of the albino rat. American Journal of Physiology 71:362–394.Google Scholar
Stephens, T. W., Basinski, M., Bristow, P. K., Bue-Valleskey, J., Burgett, S. G., Craft, L., Hale, J., Hoffmann, J., Hsiung, H. M., Kriauciunas, A., MacKellar, W., Rosteck, P. R. Jr, Schoner, B., Smith, D., Tinsley, F. C., Zhang, X.-Y. and Heiman, M. 1995. The role of neuropeptide Y in the antiobesity action of the obese gene product. Nature 377: 530–532.Google Scholar
Tartaglia, L. A., Dembski, M., Weng, X., Deng, N., Culpepper, J., Devos, R., Richards, G. J., Campfield, L. A., Clark, F. T., Deeds, J., Muir, C, Sanker, S., Moriarty, A., Moore, K. J., Smutko, J. S., Mays, G. G., Woolf, E. A., Monroe, C. A. and Tepper, R. I. 1995. Identification and expression cloning of a leptin receptor, OB-R. Cell 83: 1263–1271.Google Scholar
Tarttelin, M. F. and Gorski, R. A. 1973. The effect of ovarian steroids on food and water intake and body weight in the female rat. Acta Endocrinologica 73:551–568.Google Scholar
Thompson, J. M. and Parks, J. R. 1983. Food intake, growth and mature size in Australian Merino and Dorset Horn sheep. Animal Production 36: 471–479.Google Scholar
Tucker, H. A. 1985. Endocrine and neural control of the mammary gland. In Lactation (ed. Larson, B.L.), pp. 39–79. Iowa State University Press,Google Scholar
Vandermeerschen-Doizé, F., Bouchat, J.-C., Bouckoms-Vandermeir, M.-A. and Paquay, R. 1983. Effects of long-term ad libitum feeding on plasma lipid components and blood glucose, ß-hydroxybutyrate and insulin concentrations in lean adult sheep. Reproduction, Nutrition, Développement 23:51–63.Google Scholar
Vandermeerschen-Doizé, F., Bouckoms-Vandermeir, M.-A. and Paquay, R. 1982. Effects of long-term ad libitum feeding on the voluntary food intake, body weight, body composition and adipose tissue morphology of lean adult sheep. Reproduction, Nutrition, Développement 22:1049–1060.Google Scholar
Vandermeerschen-Doizé, F. and Paquay, R. 1984. Effects of continuous long-term intravenous infusion of long-chain fatty acids on feeding behaviour and blood components of adult sheep Appetite 5:137–146.Google Scholar
Vanderweele, D. A., Xavier, P. F., Novin, D. and Bush, M. J. 1980. Chronic insulin infusion suppresses food ingestion and body weight gain in rats. Brain Research Bulletin 5:5–11.Google Scholar
Vernon, R. G. and Pond, C. M. 1997. Adaptations of maternal adipose tissue to lactation. Journal of Mammary Gland Biology and Neoplasia 2:231–241.Google Scholar
Wade, G. N. 1975. Some effects of ovarian hormones on food intake and body weight in female rats. Journal of Comparative Physiology and Psychology 88:183–193.Google Scholar
Wade, G. N. and Gray, J. M. 1972. Gonadal effects on food intake and adiposity: a metabolic hypothesis. Physiology and Behavior 22:583–593.Google Scholar
Webster, A. J. F. 1995. Cattle and other ruminants. In Animal welfare: a cool eye towards Eden, p. 167. Blackwell Science Ltd, Oxford, UK.Google Scholar
Woods, S. C., Porte, D. Jr, Bobbioni, E., Ionescu, E., Sauter, J.-F., Rohner-Jeanrenaud, F. and Jeanrenaud, B. 1985. Insulin: its relationship to the central nervous system and to the control of food intake and body weight. American Journal of Clinical Nutrition 42:1063–1071.Google Scholar
Zhang, Y., Proenca, R., Maffei, M., Barone, M., Leopold, L. and Friedman, J. M. 1994. Positional cloning of the mouse obese gene and its human homologue. Nature 372:425–432.Google Scholar