Heat stress in lactating dairy cows: a review

Livestock Production Science - Tập 77 - Trang 59-91 - 2002
C.T Kadzere1, M.R Murphy1, N Silanikove2, E Maltz2
1Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
2Agricultural Research Organization, The Volcani Center, P.O. Box 6, Bet Dagan 50 250, Israel

Tài liệu tham khảo

Abdel-Bary, 1992, Effects of season and month of calving on estrous performance, services conception and milk yield of Friesian cows in Egypt, Egypt. J. Anim. Prod., 29, 229, 10.21608/ejap.1992.120964 Aganga, 1990, Response to water deprivation by Yankasa ewes under different physiological states, Small Rumin. Res., 3, 109, 10.1016/0921-4488(90)90086-L 1980 Akari, 1984, The effect of level of lactation diurnal temperature patterns of dairy cattle in hot environments, J. Dairy Sci., 67, 1752, 10.3168/jds.S0022-0302(84)81501-5 Akari, 1987, Diurnal temperature sensitivity of dairy cattle in a naturally cycling environment, J. Therm. Biol., 12, 23, 10.1016/0306-4565(87)90019-2 Albright, 1972, Effects of varying the environment upon performance of dairy cattle, J. Anim. Sci., 32, 566, 10.2527/jas1971.323566x Alexander, 1974, Heat loss from sheep, 187 Al-Katanani, 1998, Factors affecting seasonal variation in non-return of lactating dairy cows, J. Dairy Sci., 81, 217 Allen, 1962, Responses of Zebu, Jersey and Zebu and Jersey crossbred heifers to rising temperatures with particular reference to sweating, Aust. J. Agric. Res., 13, 165, 10.1071/AR9620165 Alvarez, 1973, Environmental heat exposure on cattle plasma catecholamine and glucocorticoids, J. Dairy Sci., 56, 189, 10.3168/jds.S0022-0302(73)85145-8 Anderson, 1985, Effects of drinking water temperature on water intake and milk yield of tied up dairy cows, Livest. Prod. Sci., 12, 329, 10.1016/0301-6226(85)90132-0 Armstrong, 1957, The heat increment of steam-volatile fatty acids in fasting sheep, Br. J. Nutr., 11, 247, 10.1079/BJN19570044 1966 Attenberry, 1968, Effect of environmental temperature, controlled feeding and fasting on rumen motility, J. Anim. Sci., 29, 734, 10.2527/jas1969.295734x Badinga, 1993, Effect of environmental heat stress on follicular development and steroidogenesis in lactating Holstein cows, Theriogenology, 39, 797, 10.1016/0093-691X(93)90419-6 Bandaranayaka, 1976, Changes in the composition of milk and rumen contents in cows exposed to a high ambient temperature with controlled feeding, Trop. Anim. Health Prod., 8, 38, 10.1007/BF02383364 Barash, 1996, Effect of season of birth on milk, fat, and protein production of Israeli Holsteins, J. Dairy Sci., 79, 1016, 10.3168/jds.S0022-0302(96)76453-6 Beede, 1986, Potential nutritional strategies for intensively managed cattle during thermal stress, J. Anim. Sci., 62, 543, 10.2527/jas1986.622543x Beede, 1985, Effects of warm climates on milk yield and composition (short-term effects), 322 Berman, 1968, Nychthermeral and seasonal patterns of thermoregulation in cattle, Aust. J. Agric. Res., 19, 181, 10.1071/AR9680181 Berman, 1985, Upper critical temperatures and forced ventilation effects for high-yielding dairy cows in a tropical climate, J. Dairy Sci., 68, 488, 10.3168/jds.S0022-0302(85)80987-5 Bianca, 1959, Acclimatization of calves to hot, humid environment, J. Agric. Sci., 52, 305, 10.1017/S0021859600029609 Bianca, 1964, Thermoregulatory responses of the dehydrated ox to drinking cold and warm water in a warm environment, Res. Vet. Sci., 5, 75, 10.1016/S0034-5288(18)34827-6 Bianca, 1965, Reviews of the progress in dairy science. Cattle in hot environment, J. Dairy Res., 32, 291, 10.1017/S0022029900018665 Bianca, 1962, The effect of thermally-induced hyperpenea on the acid–base status of the blood of calves, Res. Vet. Sci., 3, 38, 10.1016/S0034-5288(18)34926-9 Bitman, 1984, Circadian and ultradian temperature rhythms of lactating dairy cows, J. Dairy Sci., 67, 1014, 10.3168/jds.S0022-0302(84)81400-9 Blaxter, 1961, The utilization of the energy of foods by ruminants, 211 Blaxter, 1961, Environmental temperature and the energy metabolism and heat emission of steers, J. Agric. Sci. (Camb.), 46, 81, 10.1017/S0021859600023832 Blaxter, 1964, The effect of increased air movement on the heat production and emission of steers, J. Agric. Sci. (Camb.), 62, 207, 10.1017/S0021859600060822 Blaxter, 1959, Environmental temperature, energy metabolism and heat regulation in sheep. II. The partition of heat losses in closely clipped sheep, J. Agric. Sci. (Camb.), 52, 25, 10.1017/S0021859600035644 Blazquez, 1994, Rate of discharge and morphology of sweat glands in the perineal, lumbodorsal and scrotal skin of cattle, Res. Vet. Sci., 57, 277, 10.1016/0034-5288(94)90118-X Bligh, 1973, 351 Bloom, 1978, Gut hormones, Proc. Nutr. Soc., 37, 259, 10.1079/PNS19780037 Bouchard, 1973, Sulfur requirement of lactating dairy cows. I. Sulfur balance and dietary supplementation, J. Dairy Sci., 56, 1276, 10.3168/jds.S0022-0302(73)85347-0 Bouchard, 1974, Sulfur metabolism and nutritional changes in lactating cows associated with supplemental sulfate and methionine hydroxy analog, Can. J. Anim. Sci., 54, 587, 10.4141/cjas74-071 Brody, 1945 Brosh, 1988, Physiochemical conditions in the rumen of Bedouin goats: effect of drinking, food quality and feeding time, J. Agric. Sci. (Camb.), 111, 147, 10.1017/S0021859600082940 Burfening, 1968, Embryonic survival subsequent to culture of rabbit spermatozoa at 38 and 40 °C, J. Reprod. Fertil., 15, 87, 10.1530/jrf.0.0150087 Carter, 1990, A review of the physiological significance of hypertonic body fluids on feed intake and ruminal function salivation, motility and microbes, J. Anim. Sci., 68, 2811, 10.2527/1990.6892811x Cavestany, 1985, Effect of season and high environmental temperature on fertility of Holstein cattle, J. Dairy Sci., 68, 1471, 10.3168/jds.S0022-0302(85)80985-1 Cena, 1975, Transfer processes in animal coats. 1. Radiative transfer, Proc. R. Soc. Lond. B, 188, 377, 10.1098/rspb.1975.0026 Chiaiyabutr, 1987, Effect of acute heat stress on changes in the rate of liquid flow from the rumen and turnover of swamp buffalo, J. Agric. (Camb.), 108, 549, 10.1017/S0021859600079934 Christopherson, 1976, Effects of prolonged cold and the outdoor winter environment on apparent digestibility in sheep and cattle, Can. J. Anim. Sci., 56, 201, 10.4141/cjas76-024 Christopherson, 1983, Effect of thermal environment on digestion in ruminants, Can. J. Anim. Sci., 63, 447, 10.4141/cjas83-058 Clark, 1978, Uptake and metabolism of nitrogenous components by the lactating mammary gland, Fed. Proc., 37, 1233 Cohen, 1972, Acid–base balance and sodium chloride ratios in diets of laying hens, J. Nutr., 102, 1, 10.1093/jn/102.1.1 Collier, 1982, Influences of environment and its modification on dairy animal health and production, J. Dairy Sci., 65, 2213, 10.3168/jds.S0022-0302(82)82484-3 Collins, 1968, Endocrinological aspects of exposure to high environmental temperature, Physiol. Rev., 48, 785, 10.1152/physrev.1968.48.4.785 Coppock, 1978, Feeding energy to dairy cattle, 265 Coppock, 1982, Lactating dairy cow responses to dietary sodium, chloride, and bicarbonate during hot weather, J. Dairy Sci., 65, 566, 10.3168/jds.S0022-0302(82)82234-0 Croom, 1982, High levels of NaCl in beef cattle diets, Can. J. Anim. Sci., 62, 217, 10.4141/cjas82-022 Cummins, 1998, Bedding plays role in heat abatement, Dairy Herd Manage., 35, 20 Curtis, 1981 Dale, 1954, Thermal stress and acid–base balance in dairy cattle, Missouri Agric. Exp. Stat. Res. Bull. No. 562 Davis, 1956, Comparative measurements of Holsteins, Ayrshire, Guernsey, and Jersey females from birth to 7 years, Nebraska Agric. Exp. Stat. Res. Bull. No. 179 Diven, 1975, Bicarbonate in ruminant nutrition and physiology. Part I, 21 Dmi’el, 1980, Is the black coat in the desert a means of saving metabolic energy, Nature, 283, 761, 10.1038/283761a0 Dmi’el, 1979, Sweat gland secretion in the black Bedouin goat, Physiol. Zool., 52, 558, 10.1086/physzool.52.4.30155946 Dobson, 1984, Blood flow and absorption from the rumen, Q. J. Exp. Physiol., 69, 599, 10.1113/expphysiol.1984.sp002846 Dowling, 1955, The hair follicle and apocrine gland populations of Zebu (Bos indicus L.) and Shorthorn (Bos taurus L.) cattle skin, Aust. J. Agric. Res., 6, 645, 10.1071/AR9550645 DuBois, 1980, Increased incidence of retained placenta associated with heat stress in dairy cows, Theriogenology, 13, 115, 10.1016/0093-691X(80)90120-X El-Nouty, 1980, Aldosterone and ADH response to heat and dehydration in cattle, J. Appl. Physiol., 48, 249, 10.1152/jappl.1980.48.2.249 Elvinger, 1992, Interactions of heat stress and bovine somatotropin affecting physiology and immunology of lactating cows, J. Dairy Sci., 75, 449, 10.3168/jds.S0022-0302(92)77781-9 Escobosa, 1984, Effects of dietary sodium bicarbonate and calcium chloride in physiological responses of lactating dairy cows in hot weather, J. Dairy Sci., 67, 574, 10.3168/jds.S0022-0302(84)81341-7 Esdale, 1972, Manipulation of rumen fermentation. IV. Effect of altering ruminal pH on volatile fatty acid production, J. Dairy Sci., 55, 964, 10.3168/jds.S0022-0302(72)85603-0 Esmay, 1969 Ferguson, 1955, The functions of cattle sweat glands, Aust. J. Agric. Res., 6, 640, 10.1071/AR9550640 Finch, 1976, An assessment of the energy budget of Boran cattle, J. Therm. Biol., 1, 143, 10.1016/0306-4565(76)90004-8 Finch, 1986, Body temperature in beef cattle: its control and relevance to production in the tropics, J. Anim. Sci., 62, 531, 10.2527/jas1986.622531x Findlay, 1950, The sweat glands and Ayrshire cattle, J. Agric. Sci., 40, 126, 10.1017/S0021859600045573 Flatt, 1965, Energy balance studies with dry, non-lactating dairy cows consuming pelleted forages, 131 Flatt, 1969, Energy utilization by high producing dairy cows. I. Experimental design, ration composition, digestibility data, and animal performance during energy balance trial Frisch, 1977, Food intake, eating rate, weight gains, metabolic rates and efficiency of feed utilization in Bos taurus and Bos indicus cross-breed cattle, Anim. Prod., 25, 353, 10.1017/S0003356100016755 Fuquay, 1981, Heat stress as it affects animal production, J. Anim. Sci., 32, 164, 10.2527/jas1981.521164x Fuquay, 1979, Modifications in free stall housing for dairy cows during summer, J. Dairy. Sci., 62, 566, 10.3168/jds.S0022-0302(79)83293-2 Gat, 1999 Gonsalez, 1978, Indices of thermoregulatory strain for moderate exercise in the heat, J. Appl. Physiol., 44, 889, 10.1152/jappl.1978.44.6.889 Gordon, 1968 Graham, 1959, Environmental temperature, energy metabolism and heat regulation in sheep. I. Energy metabolism in closely clipped sheep, J. Agric. Sci. (Camb.), 52, 13, 10.1017/S0021859600035632 Greene, 1983, Effect of dietary potassium on absorption of magnesium and other macro-elements in sheep fed different levels of magnesium, J. Anim. Sci., 56, 1208, 10.2527/jas1983.5651208x Grovum, 1981, Factors affecting the voluntary intake of food by sheep. 3. The effect of intravenous infusions of gastrin, cholecystokinin and secretin on motility of the reticulo-rumen intake, Br. J. Nutr., 45, 183, 10.1079/BJN19810091 Guerrini, 1981, Food intake of sheep exposed to hot humid, hot dry and cool humid environments, Am. J. Vet. Res., 42, 658 Gwazdauskas, 1981, Rates of conception by artificial insemination of dairy cattle, J. Dairy Sci., 64, 358, 10.3168/jds.S0022-0302(81)82575-1 Hales, 1984, Redistribution of cardiac output and skin AVA activity in sheep during exercise and heat stress, J. Therm. Biol., 9, 113, 10.1016/0306-4565(84)90048-2 Hales, 1968, The oxygen cost of thermally-induced and CO2-induced hyperventilation in the ox, Respir. Physiol., 4, 353, 10.1016/0034-5687(68)90040-6 Hamada, 1971, Estimation of lower critical temperatures for dry and lactating dairy cows, J. Dairy Sci., 54, 1704, 10.3168/jds.S0022-0302(71)86093-9 Hammel, 1968, Regulation of internal body temperature, Annu. Rev. Physiol., 30, 641, 10.1146/annurev.ph.30.030168.003233 Hansen, 1997, Effects of environment on bovine reproduction, 403 Hansen, 1999, Strategies for managing reproduction in heat-stressed dairy cows, J. Dairy. Sci., 82, 36 Hayssen, 1985, Basal metabolic rates in mammals: taxonomic differences in the allometry of BMR and body mass, Comp. Biochem. Physiol., 81A, 741, 10.1016/0300-9629(85)90904-1 Heinrichs, 1987, Standards of weight and height for Holstein heifers, J. Dairy Sci., 70, 653, 10.3168/jds.S0022-0302(87)80055-3 Hormer, 1954, Rumen temperature. I. Temperature gradients during feeding and fasting, Cornell Vet. J., 44, 368 Huhnke, 1976, Physiologic responses of preparturient and postparturient Holstein-Friesian cows to summer heat stress in Arizona, Am. J. Vet. Res., 37, 1301 Igono, 1992, Environmental profile and critical temperature effects on milk production of Holstein cows in desert climate, Int. J. Biometeorol., 36, 77, 10.1007/BF01208917 Igono, 1990, Physiological stress index of lactating dairy cows based on diurnal pattern of rectal temperature, J. Interdiscip. Cycle Res., 21, 303, 10.1080/09291019009360091 Igono, 1988, Effect of season on milk temperature, milk growth hormone, prolactin, and somatic cell counts of lactating cattle, Int. J. Biometeorol., 32, 194, 10.1007/BF01045279 Ingraham, 1974, Relationship of temperature and humidity to conception of Holstein cows in tropical climate, J. Dairy Sci., 54, 476, 10.3168/jds.S0022-0302(74)84917-9 Isaacson, 1975, Efficiency of energy utilization by mixed rumen bacteria in continuous culture, J. Dairy Sci., 58, 1645, 10.3168/jds.S0022-0302(75)84763-1 1997 Ittner, 1951, Water consumption of Hereford and Brahman cattle and the effect of cooled drinking water in a hot climate, J. Anim. Sci., 10, 742, 10.2527/jas1951.103742x Johnson, 1976, World climate and milk production, Biometeorology, 6, 171, 10.1007/BF01553975 Johnson, 1980, Depressed chemical thermogenesis and hormonal functions in heat, 3 Johnson, 1988, Short-term heat acclimation effects on hormonal profile of lactating cows Johnson, 1991, Effects of somatotropin on milk yield and physiological responses during summer farm and hot laboratory conditions, J. Dairy Sci., 74, 1250, 10.3168/jds.S0022-0302(91)78281-7 Johnson, 1987, Bioclimate effects on growth, reproduction and milk production, 35 Johnson, 1976, Effects of environmental and other stressors on blood hormone patterns in lactating animals, J. Dairy Sci., 59, 1603, 10.3168/jds.S0022-0302(76)84413-X Johnston, 1959, Summer climate and its effect on dairy cattle in the Southern region Kamal, 1962, Metabolic reactions during thermal stress in dairy animals acclimated to 50 and 80 °F, Univ. Missouri Agric. Exp. Stat. Res. Bull. No. 785 Kelly, 1967, Effect of environmental temperature on ruminal VFA levels with controlled feed intake, J. Dairy Sci., 50, 531, 10.3168/jds.S0022-0302(67)87460-5 Kibler, 1964, Thermal effects of various temperature–humidity combinations on Holstein cattle as measured by eight physiological responses, Univ. Missouri Agric. Exp. Stat. Res. Bull. No. 862 Kibler, 1951, Environmental physiology with special reference to domestic animals. XVIII. Influence of increasing temperature on heat production and cardiorespiratory activities in Brown Swiss and Brahman cows and heifers, Univ. Missouri Agric. Exp. Stat. Res. Bull. No. 475 Kibler, 1952, Relative efficiency of surface evaporative, respiratory evaporative and non-evaporative cooling in relation to heat production in Jersey, Holstein, Brown Swiss and Brahman cattle, 50 to 105 °F, Univ. Missouri Agric. Exp. Stat. Res. Bull. No. 497 Kibler, 1954, Effects of temperature, 50 to 105 °F and 50 to 90 °F on heat production and cardiorespiratory activities in Brahman, Jersey and Holstein cows, Univ. Missouri Agric. Exp. Stat. Res. Bull. No. 464 Kibler, 1954, Influence of radiation intensity on evaporative cooling, heat production and cardio-respiratory activities in Jersey, Holstein and Brahman cows, Univ. Missouri Agric. Exp. Stat. Res. Bull. No. 574 Kleiber, 1932, Body size and metabolism, Hilgardia, 6, 315, 10.3733/hilg.v06n11p315 Lanham, 1986, Effects of drinking water temperature on physiological responses of lactating Holstein cows in summer, J. Dairy Sci., 69, 1004, 10.3168/jds.S0022-0302(86)80495-7 Leach, 1979, Dietary electrolytes: story with many facets, 19 Ledger, 1959, A possible explanation for part of the heat tolerance exhibited by Bos taurus and Bos indicus beef cattle, Nature (Lond.), 184, 405, 10.1038/1841405c0 Lee, 1965, Climatic stress indices for domestic animals, Int. J. Biometeorol., 9, 29, 10.1007/BF02187306 Lemerle, 1986, Assessment of heat stress in dairy cattle in Papua New Guinea, Trop. Anim. Health Prod., 18, 232, 10.1007/BF02359540 Little, 1978, A note on the individuality of the intake of drinking water by dairy cows, Anim. Prod., 26, 225, 10.1017/S0003356100039659 Lu, 1989, Effect of heat stress on goat production, Small. Rumin. Res., 2, 151, 10.1016/0921-4488(89)90040-0 MacFarlane, 1972, Comparative water and energy economy of wild and domestic mammals, Symp. Zool. Soc. Lond., 31, 261 Maltz, 1996, Kidney function and nitrogen balance of high-yielding dairy cows at the onset of lactation, J. Dairy Sci., 79, 1621, 10.3168/jds.S0022-0302(96)76525-6 Maltz, 1984, Homeostatic response to water deprivation or hemorrhage in lactating and non lacating Bedouin goats, Comp. Biochem. Physiol., 77A, 79, 10.1016/0300-9629(84)90015-X Maltz, 1994, Diurnal fluctuations in plasma ions and water intake of dairy cows as affected by lactation in warm weather, J. Dairy Sci., 77, 2630, 10.3168/jds.S0022-0302(94)77204-0 Maltz, 1982, Energy cost and water requirement of black Bedouin goats at different levels of production, J. Agric. Sci. Camb., 98, 499, 10.1017/S0021859600054253 Masero, 1977 McArthur, 1988, Body temperature of homeotherms and the conservation of energy and water, J. Therm. Biol., 3, 9, 10.1016/0306-4565(88)90003-4 McBride, 1984, The effect of lactation on ouabain-sensitive respiration of duodenal mucosa of cows, Can. J. Anim. Sci., 64, 817, 10.4141/cjas84-095 McDowell, 1976, Effects of climate on performance of Holsteins in first lactation, J. Dairy Sci., 59, 965, 10.3168/jds.S0022-0302(76)84305-6 McGuire, 1991, Effects of acute thermal stress and amount of feed intake on concentrations of somatotropin, insulin-like growth factor (IGF)-I and IGF-II, and thyroid hormones in plasma of lactating Holstein cows, J. Anim. Sci., 69, 2050, 10.2527/1991.6952050x McLean, 1963, The partition of insensible losses of body weight and heat from cattle under various climatic conditions, J. Physiol. (Lond.), 167, 427, 10.1113/jphysiol.1963.sp007160 Milam, 1985, Effects of drinking water temperature on production responses in lactating Holstein cows in summer, J. Dairy Sci., 69, 1013, 10.3168/jds.S0022-0302(86)80496-9 Miller, 1974, Effect of thyroid status on digestive tract fill and flow rate of undigested residues in cattle, J. Dairy Sci., 57, 193, 10.3168/jds.S0022-0302(74)84859-9 Milligan, 1986, The biological basis of maintenance and its relevance to assessing responses to nutrients, Proc. Nutr. Soc., 45, 185, 10.1079/PNS19860053 Mishra, 1970, Effect of diet and ambient temperature–humidity and ruminal pH, oxidation–reduction potential, ammonia and lactic acid in lactating cows, J. Anim. Sci., 31, 1023, 10.2527/jas1970.3061023x Mitra, 1972, Effect of prolonged thermal exposure on growth hormone (GH) secretion in cattle, J. Anim. Sci., 34, 776, 10.2527/jas1972.345776x Moe, 1970, Partial efficiency of energy use for maintenance, lactation, body gain and gestation in the dairy cow, 65 Moe, 1971, Energetics of body tissue mobilization, J. Dairy Sci., 54, 548, 10.3168/jds.S0022-0302(71)85886-1 Moe, 1972, Net energy value of feeds for dairy cattle, J. Dairy Sci., 55, 945, 10.3168/jds.S0022-0302(72)85601-7 Mongin, 1980, Electrolytes in nutrition: review of basic principles and practical application in poultry and swine, 1 Montgomery, 1984, The effects of thermal stimulation on the ultra-structure of the human atrichial sweat gland. 1. The fundus, Br. J. Dermatol., 110, 319, 10.1111/j.1365-2133.1984.tb04652.x More, 1983, Effect of level of water intake on water, energy and nitrogen balance and thyroxine secretion in sheep and goat, Aust. J. Agric. Res., 34, 441, 10.1071/AR9830441 Muller, 1993, Effect of summer climatic conditions on different heat tolerance indicators in primiparous Friesian and Jersey cows, S. Afr. J. Anim. Sci., 23, 98 Muller, 1979 Mullick, 1960, Effect of humidity and exposure to sun on the pulse rate, respiration rate, rectal temperature and haemoglobin level in different sexes of cattle and buffalo, J. Agric. Sci., 54, 391, 10.1017/S002185960002133X Murphy, 1992, Water metabolism of dairy cattle, J. Dairy Sci., 75, 326, 10.3168/jds.S0022-0302(92)77768-6 Murphy, 1982, Factors affecting water consumption by Holstein cows in early lactation, J. Dairy Sci., 66, 35, 10.3168/jds.S0022-0302(83)81750-0 1989 Nebel, 1997, Use of a radio frequency data communication system, HeatWatch®, to describe behavioral estrus in dairy cattle, J. Dairy Sci., 80, 179 Niles, 1980, Effects of heat stress on rumen and plasma metabolites and plasma hormone concentrations of Holstein cows, J. Anim. Sci., 51, 152 Omar, 1996, Effect of water spray followed by forced ventilation on some physiological status and milk production of post calving Friesian cows, Alex. J. Agric. Res., 4, 71 Pavlicek, 1989, Uticaj visokih ljetnjih temperatura na proizvodnju mlijeka, zdravlje krava 1 plodnost, Vet. Glasnik, 43, 397 Prosser, 1969 Purwanto, 1990, Diurnal patterns of heat production and HR under thermoneutral conditions in Holstein Friesian cows differing in milk production, J. Agric. Sci. (Camb.), 114, 139, 10.1017/S0021859600072117 Ragsdale, 1934, Growth standards for dairy cattle Richards, 1985, Milk production of Friesian cows subjected to high daytime temperatures when allowed food either ad lib or at nighttime only, Trop. Anim. Health Prod., 17, 141, 10.1007/BF02355873 Robertshaw, 1981, The environmental physiology of animal production, 3 Robertshaw, 1980, Scrotal thermoregulation of the bull (Bos spp.), Aust. J. Agric. Res., 31, 401, 10.1071/AR9800401 Roenfeldt, 1998, You can’t afford to ignore heat stress, Dairy Manage., 35, 6 Rogers, 1980, Effects of increasing rumen fluid dilution rate with mineral salts on water consumption, ruminal degradation of dry matter and production of volatile fatty acids, J. Dairy Sci., 63, 147 Rogers, 1982, Alteration of rumen fermentation, milk fat synthesis and nutrient utilization with mineral salts in dairy cows, J. Dairy Sci., 65, 577, 10.3168/jds.S0022-0302(82)82235-2 Salem, 1982, Physiology of sheep and goats in the tropics, 148 Schmidt-Nielsen, 1964 Schneider, 1988, Nycterohemeral patterns of acid–base status, mineral concentrations and digestive function of lactating cows in natural or chamber heat stress environments, J. Anim. Sci., 66, 112, 10.2527/jas1988.661112x Scott, 1983, Effect of programmed diurnal temperature cycles on plasma thyroxine level, body temperature, and feed intake of Holstein dairy cows, Int. J. Biometeorol., 27, 47, 10.1007/BF02186300 Shalit, 1991, Water, Na, K, and Cl metabolism of dairy cows at onset of lactation in hot weather, J. Dairy Sci., 74, 1874, 10.3168/jds.S0022-0302(91)78353-7 Sharma, 1983, Climatological and genetic effects on milk composition and yield, J. Dairy Sci., 66, 119, 10.3168/jds.S0022-0302(83)81762-7 Shearer, 1990, Thermoregulation and physiological responses of dairy cattle in hot weather, Agri-Practice, 11, 5 Shkolnik, 1980, The role of the ruminant’s digestive tract as a water reservoir, 731 Silanikove, 1989, Role of the rumen and saliva in the homeostatic response to rapid re-hydration in cattle, Am. J. Physiol., 256, R816 Silanikove, 1992, Effects of water scarcity and hot environment on appetite and digestion in ruminants: a review, Livest. Prod. Sci., 30, 175, 10.1016/S0301-6226(06)80009-6 Silanikove, 1994, The struggle to maintain hydration and osmoregulation in animals experiencing severe dehydration and rapid rehydration: the story of ruminants, Exp. Physiol., 79, 281, 10.1113/expphysiol.1994.sp003764 Silanikove, 1989, Rumen volume, saliva flow rate and systemic fluid homeostasis in dehydrated cattle, Am. J. Physiol., 256, R809 Silanikove, 1997, Water, Na, K and Cl metabolism in high yielding dairy cows at the onset of lactation, J. Dairy Sci., 80, 949, 10.3168/jds.S0022-0302(97)76019-3 Silanikove, 1998, Metabolic and productive response of dairy cows to increased ion supplementation at early lactation in hot weather, J. Dairy Sci. Res., 65, 529, 10.1017/S0022029998003185 Singh, 1990, Cardio-respiratory activity in Zebu and their F1 crosses with European breeds of dairy cattle at different ambient temperatures, Livest. Prod. Sci., 24, 119, 10.1016/0301-6226(90)90072-E Singh, 1978, Acclimatization of young calves to high temperatures: physiological responses, Am. J. Vet. Res., 39, 795 Stewart, 1954, Effect of radiation intensity on hair and skin temperatures and on respiration rates of Holstein, Jersey and Brahman cattle at air temperatures 45, 70 and 80 °F Stott, 1972, Reproductive health program for cattle subjected to high environmental temperatures, J. Am. Vet. Med. Assoc., 16, 1339 Sugiyama, 1999 Taylor, 1986, Inter-breed relationship of maintenance efficiency to milk yield in cattle, Anim. Prod., 43, 37, 10.1017/S0003356100018328 Thatcher, 1974, Effects of season, climate and temperature on reproduction and lactation, J. Dairy Sci., 57, 360, 10.3168/jds.S0022-0302(74)84894-0 Thompson, 1973, Review of the progress of dairy science: climate physiology of cattle, J. Dairy Res., 40, 441, 10.1017/S0022029900014813 Thompson, 1949, Influence of temperature, 50 to 105 °F, on water consumption in dairy cattle Tucker, 1988, Influence of dietary cation–anion balance on milk, blood, urine and rumen fluid in lactating dairy cattle, J. Dairy Sci., 71, 346, 10.3168/jds.S0022-0302(88)79563-6 Van Es, 1969, Energy, carbon and nitrogen balance experiments with lactating cows, 209 Wagner, 1974, Controlled parturition in cattle, J. Anim. Sci., 38, 485, 10.2527/jas1974.383485x Warren, 1974, Digestibility and rate of passage by steers fed tall fescue, alfalfa and orchard grass hay in 18 and 32 °C ambient temperature, J. Anim. Sci., 39, 93, 10.2527/jas1974.39193x Waterman, 1991, Nutrition, feeding and calves: role of magnesium in the DCAB equation for ruminants, J. Dairy Sci., 74, 1866, 10.3168/jds.S0022-0302(91)78352-5 Wayman, 1962, Effect of ad libitum or force-feeding of two rations on lactating dairy cows subject to temperature stress, J. Dairy Sci., 45, 1472, 10.3168/jds.S0022-0302(62)89658-1 Webster, 1976, Origins of the heat increment of feeding in sheep, 45 Webster, 1975, The influence of food intake on portal blood flow and heat production in the digestive tract of sheep, Br. J. Nutr., 34, 125, 10.1017/S0007114575000165 Weldy, 1964, Responses of winter-conditioned heifers under prolonged heat stress, J. Dairy Sci., 47, 691 West, 1987, Potassium carbonate as a potassium source and dietary buffer for lactating cows during heat stress, J. Dairy Sci., 70, 309, 10.3168/jds.S0022-0302(87)80012-7 Wiestra, 1976, Effects of cold on digestibility, retention time digesta, reticulum motility and thyroid hormones in sheep, Can. J. Anim. Sci., 56, 699, 10.4141/cjas76-083 Wilson, 1978, Colonic and tail-skin temperature responses of the rat at selected running speeds, J. Appl. Physiol., 44, 571, 10.1152/jappl.1978.44.4.571 Wilson, 1998, Effects of controlled heat stress on ovarian function of dairy cattle. 2. Heifers, J. Dairy Sci., 81, 2132, 10.3168/jds.S0022-0302(98)75789-3 Wolfenson, 1997, Seasonal and acute heat stress effects on steroid production by dominant follicles in cows, Anim. Reprod. Sci., 47, 9, 10.1016/S0378-4320(96)01638-7 Wolfenson, 1995, Effect of heat stress on follicular development during estrus cycle in lactating dairy cattle, Biol. Reprod., 52, 1106, 10.1095/biolreprod52.5.1106 Woodford, 1984, Water dynamics of dairy cattle as by the initiation of lactation and feed intake, J. Dairy Sci., 67, 2336, 10.3168/jds.S0022-0302(84)81582-9 Young, 1976, Effects of cold environments on nutrient requirements of ruminants, 491 Young, 1959, Body temperature and heat exchange during treadmill running in dogs, J. Appl. Physiol., 14, 839, 10.1152/jappl.1959.14.5.839 Yousef, 1985, Vol. 1 Yousef, 1966, Calorigenesis of dairy cattle as influenced by thyroxine and environmental temperature, J. Anim. Sci., 25, 150, 10.2527/jas1966.251150x