Hostname: page-component-586b7cd67f-dsjbd Total loading time: 0 Render date: 2024-11-23T10:39:42.877Z Has data issue: false hasContentIssue false
  • English
  • Français

The contribution of science to the improvement of hill sheep production

Published online by Cambridge University Press:  02 September 2010

I. A. M. Lucas
I. A. M. Lucas
Affiliation:
Department of Agriculture, University College of North Wales, Memorial Buildings, Bangor, Gwynedd LL57 2UW
Get access

Extract

Hill farms vary greatly in size, soil and climate and each has its particular problems. The task of the scientist is to investigate each facet of production from the hill and to provide information which will improve the overall understanding of the potentials and limitations to output. From that understanding, the solutions to the problems of the individual farms may be derived.

Type
59th Meeting, Bangor, 16 to 19 September 1974: Report of Meeting on Meat from the Hills
Information
Proceedings of the British Society of Animal Production (1972) , Volume 4 , January 1975 , pp. 45 - 67
Copyright
Copyright © British Society of Animal Production 1975

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Agricultural Development and Advisory Service. 1972. A System For Welsh Mountain Sheep. MAFF Publications, Pinner, Middx.Google Scholar
Agricultural research council. 1965. The Nutrient Requirements of Farm Livestock. No. 2. Ruminants. Agricultural Research Council, London.Google Scholar
Alcock, M. B. 1975. The contribution of science to the improvement of hill pasture production. Proc. Sr. Soc. Anim. Prod. 4; 25–43.Google Scholar
Alexander, G. 1964. Lamb survival: physiological considerations. Proc. Aust. Soc. Anim. Prod. 5: 113–122.Google Scholar
Alliston, J. C. 1974. A study of the effects of environment on Welsh Mountain ewes. Ph.D. Thesis, Univ. Coll. N. Wales, Bangor.Google Scholar
Armitage, P. L. 1972. The significance of mountain grazing in Wales. B.Sc.(Hons.) Dissertation, Univ. Coll. N. Wales, Bangor.Google Scholar
Armstron, R. H. and Eadie, J. 1973a. Lamb growth on grass and clover diets. Proc. Br. Soc. Anim. Prod. 2; 68 (Abstr.).Google Scholar
Armstrong, R. H. and Eadie, J. 1973b. Some aspects of the growth of hill lambs. Rep. Hill Farming Res. Org. 6: 57–68.Google Scholar
Baker, R. D., Large, R. V. and Speeding, C. R. W. 1973. Size of animal in relation to productivity with special reference to the ruminant—economic aspects. Proc. Br. Soc. Anim. Prod. 2: 35–42.Google Scholar
Barnicoat, C. R., Murray, P. F., Roberts, E. M. and Wilson, G. S. 1956. Milk secretion studies with New Zealand Romney ewes. Parts V-XI. J. agric. Sci., Camb. 48: 9–35.Google Scholar
Bastiman, B. 1972. Effect of inwintering on the number of lambs born. Proc. Br. Soc. Anim. Prod. 1: 147 (Abstr.).Google Scholar
Black, J. S. 1967. The digestibility of indigenous hill pasture species. Rep. Hill Farming Res. Org. 4: 33–37.Google Scholar
Blaxter, K. L. 1963. Problems of cold environments. Proc. 6th int. Congr. Nutr., Edinburgh, pp. 227–242.Google Scholar
Blaxter, K. L., Wainman, F. W. and Wilson, R. S. 1961. The regulation of food intake by sheep. Anim. Prod. 3: 51–61.Google Scholar
Broadbent, J. S. and Watson, J. H. 1966. Factors governing the shape of the growth curve of body weight and the age at slaughter of Suffolk x Welsh lambs. Anim. Prod. 8: 435–444.Google Scholar
Clarke, E. A. 1954. Early weaning of lambs on hill country. J. Dep. Agric. N.Z. 89: 471–476.Google Scholar
Coop, I. E. 1961. The energy requirements of sheep. Proc. N.Z. Soc. Anim. Prod. 21: 79–91.Google Scholar
Coop, I. E. 1964. Live weight, flushing and ewe fertility. Proc. Ruakura Fmrs' Conf. Week, pp. 69–81.Google Scholar
Coop, I. E. and Cark, V. R. 1969. The influence of nutritional level in early pregnancy of the ewe. J. agric. Sci., Camb. 73: 387–394.Google Scholar
Cocker, B. H. 1958. A method of estimating the botanical composition of the diet of sheep. N.Z. Jl. agric. Res. 2: 72–85.Google Scholar
Crocker, K. P. and Lindsamy, D. R. 1972. A study of the mating behaviour of rams when joined at different proportions. Aust. J. exp. Agric. Anim. Husb. 12: 13–18.Google Scholar
Dalton, D. C. 1962. Characters of economic importance in Welsh Mountain sheep. Anim. Prod. 4: 269–278.Google Scholar
Davies, G. M. 1954–1955. Wintering ewe lambs. Some Welsh trials. Scott. Agric. 34: 149–153.Google Scholar
Davies, R. O., Jones, D. T. H. and Milton, W. E. 1959. Factors influencing the composition and value of herbage from fescue and Molinia areas. J. agric. Sci., Camb. 53: 268–285.Google Scholar
Donald, H. P., Read, J. L. and Russell, W. S. 1963. Heterosis in crossbred hill sheep. Anim. Prod. 5: 289–299.Google Scholar
Donald, H. P., Read, J. L. and Russell, W. S. 1968. A comparative trial of crossbred ewes by Finnish Landrace and other sires. Anim. Prod. 10: 413–421.Google Scholar
Donald, H. P. and Russell, W. S. 1970. The relationship between live weight of ewe at mating and weight of newborn lamb. Anim. Prod. 12: 273–280.Google Scholar
Doney, J. M. 1963. The effects of exposure in Blackface sheep with particular reference to the role of the fleece. J . agric. Sci., Camb. 60: 267–273.Google Scholar
Doney, J. M. 1966. Inbreeding depression in grazing Blackface sheep. Anim. Prod. 8: 261–266.Google Scholar
Doney, J. M. and Munro, J. 1962. The effect of suckling, management and season on sheep milk production as estimated by lamb growth. Anim. Prod. 4: 215–220.Google Scholar
Ducker, M. J. and Fraser, J. 1973. A note on the effect of level of husbandry at lambing on lamb viability and subsequent performance. Anim. Prod. 16: 91–94.Google Scholar
Eadie, J. 1967. The nutrition of grazing hill sheep: utilisation of hill pastures. Rep. Hill Farming Res. Org. 4: 38–45.Google Scholar
Eadie, J. 1973. Sheep production systems development on the hills. Potassium Institute Ltd., Colloquium Proc. No. 3, pp. 131–137.Google Scholar
Edgar, D. G. 1961. Talking about tupping. Proc. Ruakura Fmrs' Conf. Week, pp. 6–13.Google Scholar
Everitt, G. C. 1967a. Residual effects of prenatal nutrition on the postnatal performance of Merino sheep. Proc. N.Z. Soc. Anim. Prod. 27: 52–68.Google Scholar
Everitt, G. C. 1967b. Prenatal development of uniparous animals with particular reference to the influence of maternal nutrition in sheep. InGrowth and Development of Mammals (ed.Lodge, G. A. and Lamming, G. E.), pp. 131–157. Butterworth, London.Google Scholar
Foot, J. Z. 1972. A note on the effect of body condition on the voluntary intake of dried grass wafers by Scottish Blackface ewes. Anim. Prod. 14: 131–134.Google Scholar
Foot, J. Z. and Greenhalgh, J. F. D. 1970. A note on the relation between weights of the alimentary tract contents, body fat and uterus in Blackface ewes. Anim. Prod. 12: 669–671.Google Scholar
Forbes, J. M. 1969. A note on the voluntary feed intake of lactating ewes, their milk yield and the growth rate of their lambs. Anim. Prod. 11: 263–266.Google Scholar
Forbes, J. M. 1970. The voluntary food intake of pregnant and lactating ruminants: a review. Br. vet.J. 126: 1–11.CrossRefGoogle ScholarPubMed
Forbes, T. J. and Robinson, J. J. 1967. The effect of source and level of dietary protein on the performance of in-lamb ewes. Anim. Prod. 9: 521–530.Google Scholar
Forbes, T. J. and Singleton, A. G. 1964. Ovine pregnancy toxaemia: a review. Br. vet. J. 120: 56–68.CrossRefGoogle Scholar
Gibb, M. J., Treacher, T. T. and Joicey, S. A. 1972. A case of rejection by lambs of regrowths from previously grazed ryegrass swards. Proc. Br. Soc: Anim. Prod. 1: 148 (Abstr.).Google Scholar
Giles, J. R. 1968. The effect of different levels of nutrition from weaning to seventeen months of age on the lifetime production of Merino ewes. Aust. J. exp. Agric. Anim. Husb. 8: 149–157.Google Scholar
Griffiths, J. G. 1968. Observations on neonatal changes of body temperature in Blackface lambs. Anim. Prod. 10: 319–323.Google Scholar
Griffiths, J. G. 1970. A note on patterns of behaviour and grazing in hill sheep. Anim. Prod. 12: 521–524.Google Scholar
Griffiths, J. G. and Doney, J. M. 1969. Physiological adjustment to repeated wind exposure in sheep. Anim. Prod. 11: 493–498.Google Scholar
Griffiths, J. G., Gunn, R. G. and Doney, J. M. 1970. Fertility in Scottish Blackface ewes as influenced by climatic stress. J. agric. Sci., Camb. 75: 485–488.Google Scholar
Griffiths, J. R., Bennett, R. J. and Bush, R. M. R. 1970. The effect of cobalt supplementation, as an oral drench or pasture treatment, on the growth of lambs. Anim. Prod. 12: 89–94.Google Scholar
Grunes, D. L., Stout, P. R. and Brownell, J. R. 1970. Grass tetany in ruminants. Adv. Agron. 12: 331–374.Google Scholar
Gunn, R. G. 1964a. Levels of first winter feeding in relation to performance of Cheviot hill ewes. I. Body growth and development during treatment period. J. agric. Sci., Camb. 62: 99–122.Google Scholar
Gunn, R. G. 1964b. Levels of first winter feeding in relation to performance of Cheviot hill ewes. II. Body growth and development during the summer after treatment, 12-18 months. J. agric. Sci., Camb. 62: 123–149.Google Scholar
Gunn, R. G. 1967a. A note on hill ewe mortality. Anim. Prod. 9: 263–264.Google Scholar
Gunn, R. G. 1967b. Levels of first winter feeding in relation to performance of Cheviot hill ewes. IV. Growth and development from 18 months to maturity. J. agric. Sci., Camb. 69: 341–344.Google Scholar
Gunn, R. G. 1968. Levels of first winter feeding in relation to performance of Cheviot hill ewes. VI. Lifetime production from the hill. J. agric. Sci., Camb. 71: 161–166.Google Scholar
Gunn, R. G. 1969. The effects of calcium and phosphorus supplementation on the performance of Scottish Blackface hill ewes, with particular reference to the premature loss of permanent incisor teeth. J. agric. Sci., Camb. 72: 371–378.Google Scholar
Gunn, R. G. 1970. A note on the effect of broken mouth on the performance of Scottish Blackface hill ewes. Anim. Prod. 12: 517–520.Google Scholar
Gunn, R. G. 1972. Growth and lifetime production of Scottish Blackface hill ewes in relation to the level of feeding during rearing. Anim. Prod. 14: 343–349.Google Scholar
Gunn, R. G. and Doney, J. M. 1973. A note on the influence of the pattern of live weight and body condition recovery between weaning and mating on food consumption and reproductive performance of Scottish Blackface ewes. J. agric. Sci., Camb. 81: 189–191.Google Scholar
Gunn, R. G. and Doney, J. M. 1974. Reproductive response to variation in body condition at mating in three breeds of hill sheep. Proc. Br. Soc. Anim. Prod. 3: 96 (Abstr.).Google Scholar
Gunn, R. G., Doney, J. M. and Russel, A. J. F. 1969. Fertility in Scottish Blackface ewes as influenced by nutrition and body condition at mating. J. agric. Sci., Camb. 73: 289–294.Google Scholar
Gunn, R. G., Doney, J. M. and Russel, A. J. F. 1972. Embryo mortality in Scottish Blackface ewes as influenced by body condition at mating and by post mating nutrition. J. agric. Sci., Camb. 79: 19–25.Google Scholar
Gunn, R. G. and Robinson, J. F. 1963. Lamb mortality in Scottish hill flocks. Anim. Prod. 5: 67–75.Google Scholar
Hadjipieris, G. and Holmes, W. 1966. Studies on feed intake and food utilization by sheep. I. The voluntary intake of dry, pregnant and lactating ewes. J. agric. Sci., Camb. 66: 217–224.Google Scholar
Halliday, R. 1968a. Serum γ-globulin levels in dead lambs from hill flocks. Anim. Prod. 10: 177–182.Google Scholar
Halliday, R. 1968b. Serum protein concentrations in 2-day-old Finnish Landrace, Scottish Blackface, Merino and Merino x Cheviot lambs. J. agric. Sci., Camb. 71: 41–45.Google Scholar
Halliday, R. 1971. Total serum protein and immunoglobulin concentrations in Scottish Blackface and Merino lambs at birth and during the first two days of suckling. J. agric. Sci., Camb. 77: 463–466.Google Scholar
Halliday, R., Sykes, A. R., Slee, J. and Field, A. C. 1969. Cold exposure of Southdown and Welsh Mountain sheep. 4. Changes in concentrations of free fatty acids, glucose, acetone, protein bound iodine, protein and antibody in the blood. Anim. Prod. 11: 479–491.Google Scholar
Hight, G. K. and Jury, K. E. 1970. Lamb mortality. Proc. Ruakura Fmrs' Conf. Week, pp. 78–92.Google Scholar
Hughes, R. E., Milner, C. and Dale, J. 1964. Selectivity in grazing. In Grazing in Terrestrial and Marine Environments (ed. Crisp, D. J.), pp. 189–202. Blackwell, Oxford.Google Scholar
Hunter, R. F. 1962. Hill sheep and their pasture: a study of sheep grazing in south-east Scotland. J. Ecol. 50: 651–680.Google Scholar
Hunter, R. F. 1964. Home range behaviour in hill sheep. In Grazing in Terrestrial and Marine Environments (ed. Crisp, D. J.), pp. 155–171. Blackwell, Oxford.Google Scholar
Hunter, R. F. and Davies, G. E. 1963. The effect of method of rearing on the social behaviour of Scottish Blackface hoggets. Anim. Prod. 5: 183–194.Google Scholar
Inglis, J. S. S., Weipers, M. and Pearce, P. J. 1959. Hypomagnesaemia in sheep. Vet. Rec. 71:755–763.Google Scholar
Inkster, I. J. 1956. Management at mating. Proc. Ruakura Fmrs' Conf. Week, pp. 20–27.Google Scholar
Jones, LL. I. 1967. Studies on hill land in Wales. Welsh Plant Breeding Station Tech. Bull. No. 2.Google Scholar
Joyce, J. P. and Blaxter, K. L. 1964. The effect of air movement, air temperature and infra red radiation on the energy requirements of sheep. Br. J. Nutr. 18: 5–27.Google Scholar
Lambourne, L. J. 1956. Mating behaviour. Proc. Ruakura Fmrs' Conf. Week, pp. 16–20.Google Scholar
Langlands, J. P., Corbett, J. L., Mcdonald, I. and Reid, G. W. 1963. Estimates of the energy required for maintenance by adult sheep. 2. Grazing sheep. Anim. Prod. 5: 11–16.Google Scholar
Large, R. V. 1970. The biological efficiency of meat production in sheep. Anim. Prod. 12: 393–401.Google Scholar
Lawrence, N. G. 1974. A. Rep. Trawscoed Exp. Husb. Fm.Google Scholar
Lindsay, D. R. and Robinson, T. J. 1961a. Studies on the efficiency of mating in sheep. I. The effect of paddock size and number of rams. J. agric. Sci., Camb. 57: 137–140.Google Scholar
Lindsay, D. R. and Robinson, T. J. 1961b. Studies on the efficiency of mating in sheep. n. The effect of freedom of the rams, paddock size and age of the ewes.J. agrlc. Set., Comb. 57: 141–145.Google Scholar
Mcclelland, T. H. and Forbes, T. J. 1969. A study of the effect of energy and protein intake during late pregnancy on the performance of housed Scottish Blackface ewes. Rec. agric. Res. (N. Ir.) 17: 131–139.Google Scholar
Mcclelland, T. H. and Forbes, T. J. 1970. Nitrogen utilisation in Scottish Blackface ewes during late pregnancy. Rec. agric. Res. (N. Ir.) 18: 1–7.Google Scholar
Mcclelland, T. H. and Forbes, T. J. 1971. A study of protein requirements of housed Scottish Blackface ewes during late pregnancy. Anim. Prod. 13: 643–651.Google Scholar
Mcclelland, T. H. and Forbes, T. J. 1973. The effect of level and pattern of energy intake during late pregnancy on the performance of housed Scottish Blackface ewes. Anim. Prod. 16: 165–171.Google Scholar
Martin, D. J. 1955. Features on plant cuticle: An aid to the analysis of the natural diet of grazing animals with especial reference to Scottish hill sheep. Trans. bot. Soc., Edinb. 36: 278–288.Google Scholar
Meat and Livestock Commission. 1972. Sheep improvement. Rep. Sci. Study Group.Google Scholar
Michael, D. T. 1957. A survey of pregnancy toxaemia and allied disorder in North Wales—Winter, 1955. Vet. Rec. 69: 595–599.Google Scholar
Miller, G. R. 1968. Some responses of hill ewes and lambs to artificial shelter. Anim. Prod. 10: 59–66.Google Scholar
Mudd, A. J. and Mackie, I. L. 1972. The effect of vitamin E and selenium on pregnant ewes. Proc. Br. Soc. Anim. Prod. 1: 145 (Abstr.).Google Scholar
Munro, J. 1962a. A study of the milk yield of three strains of Scottish Blackface ewes in two environments. Anim. Prod. 4: 203–213.Google Scholar
Munro, J. 1962b. The use of natural shelter by hill sheep. Anim. Prod. 4: 343–349.Google Scholar
Munro, J. M. M., Davies, D. A. and Morgan, T. E. H. 1972. Research on pasture improvement potential at Pant-y-Dŵr hill centre. Rep Welsh Plant Breeding Station, pp. 209–235.Google Scholar
Owen, J. B. 1957. A study of the lactation and growth of hill sheep in their native environment and under lowland conditions. J. agric. Sci., Camb. 48: 387–412.Google Scholar
PeAart, J. N. 1967. The effect of different levels of nutrition during late pregnancy on the subsequent milk production of Blackface ewes and on the growth of their lambs. J. agric. Sci., Camb. 68: 365–371.Google Scholar
Peart, J. N. 1968a. Lactation studies with Blackface ewes and their lambs. J. agric. Sci., Camb. 70: 87–94.Google Scholar
Peart, J. N. 1968b. Some effects of live weight and body composition on the milk production of Blackface ewes. J. agric. Sci., Camb. 70: 331–338.Google Scholar
Peart, J. N. 1970a. Factors influencing lactation in hill ewes. Rep. Hill Farming Res. Org. 5: 55–69.Google Scholar
Peart, J. N. 1970b. The influence of live weight and body composition on the subsequent milk production of Blackface ewes following a period of undernutrition in early lactation. J. agric. Sci., Camb. 75: 459–469.Google Scholar
Purser, A. F. 1965. Repeatability and heritability of fertility in hill sheep. Anim. Prod. 7: 75–82.Google Scholar
Purser, A. F. and Hall, J. G. 1974. Fertility and survival in hill sheep in relation to their haemoglobin type. Proc. Br. Soc. Anim. Prod. 3: 95 (Abstr.).Google Scholar
Purser, A. F. and Karam, H. A. 1967. Lamb survival, growth and fleece production in relation to birthcoat type among Welsh Mountain sheep. Anim. Prod. 9: 75–85.Google Scholar
Purser, A. F. and Roberts, R. C. 1959. The relationship of hogg weight to the subsequent performance of Scottish Blackface ewes. Anim. Prod. 1: 107–111.Google Scholar
Purser, A. F. and Roberts, R. C. 1965. The effect of treatment during first winter on the subsequent performance of Scottish Blackface ewes. Anim. Prod. 6: 273–284.Google Scholar
Purser, A. F. and Young, G. B. 1959. Lamb survival in two hill flocks. Anim. Prod. 1: 85–91.Google Scholar
Purser, A. F. and Young, G. B. 1965. Mortality among twin and single lambs. Anim. Prod. 6: 321–329.Google Scholar
Pwllpeiran Experimental Husbandry Farm. 1969. Farm Guide and Report. MAFF, London.Google Scholar
Pwllpeiran Experimental Husbandry Farm. 1970. Farm Guide and Report. MAFF, London.Google Scholar
Robinson, J. J. and Forbes, T. J. 1967. A study of die protein requirements of the mature breeding ewe. 2. Protein utilization in the pregnant ewe. Br. J. Nutr. 21: 879–891.Google Scholar
Robinson, J. J. and Forbes, T. J. 1968. The effect of protein intake during gestation on ewe and lamb performance. Anim. Prod. 10: 297–309.Google Scholar
Robinson, J. J., Fraser, C., Corse, Elizabeth, L. and Gill, J. C. 1970. The effect of pattern of protein intake and level of energy intake on the performance and nitrogen utilization of the ewe. J. agric. Set, Camb. 75: 403–411.Google Scholar
Robinson, W. I., Brown, W. and Lucas, I. A. M. 1973. Effects of shelter, exposure and level of feeding over winter on the productivity of Welsh Mountain ewes and lambs. Anim. Prod. 17: 21–32.Google Scholar
Russel, A. J. F., Doney, J. M. and Reid, R. L. 1967. The use of biochemical parameters in controlling nutritional state in pregnant ewes, and the effect of undernourishment during pregnancy on lamb birth weight. J. agric. Set, Camb. 68: 351–358.Google Scholar
Russel, A. J. F., Gunn, R. G. and Doney, J. M. 1968. Components of weight loss in pregnant hill ewes during winter. Anim. Prod. 10: 43–51.Google Scholar
Rutter, W. 1970. A comparison of the performance of suckled lambs with lambs weaned at seven weeks of age and either grazed or given concentrates. Anim. Prod. 12: 543–549.Google Scholar
Rutter, W., Laird, T. R. and Broadbent, P. J. 1971. The effects of clipping pregnant ewes at housing and of feeding different basal roughages. Anim. Prod. 13: 329–336.Google Scholar
Rutter, W., Laird, T. R. and Broadbent, P. J. 1972. A note on the effect of clipping pregnant ewes at housing. Anim. Prod. 14: 127–130.Google Scholar
Schinckel, P. G. 1963. The potential for increasing efficiency of feed utilisation through newer knowledge of animal nutrition (c) sheep and goat. Proc. 1st World Conf. Anim. Prod. 1: 199–239.Google Scholar
Schinckel, P. G. and Short, B. F. 1961. The influence of nutritional level during prenatal and early post-natal life on adult fleece weight and body characters. Aust. J. agric. Res. 12: 176–202.Google Scholar
Sheehan, W. and Lawlor, M. J. 1972. Energy supplementation of silage for ewes in late pregnancy. Anim. Prod. 15: 29–37.Google Scholar
Slee, J. 1966. Variation in the responses of shorn sheep to cold exposure. Anim. Prod. 8: 425–434.Google Scholar
Slee, J. 1968. Body temperature and vasomotor responses in Scottish Blackface and Tasmanian Merino Sheep subjected to slow cooling. Anim. Prod. 10: 265–282.Google Scholar
Slee, J. 1970. Resistance to body cooling in male and female sheep and the effects of previous exposure to chronic cold, acute cold and repeated short cold shocks. Anim. Prod. 12: 13–.Google Scholar
Slee, J. 1972. Habituation and acclimatization of sheep to cold following exposures of varying length and severity. J. Physiol. 227: 51–70.Google Scholar
Slee, J. and Halliday, R. 1968. Some effects of cold exposure, nutrition and experimental handling on serum-free fatty-acid levels in sheep. Anim. Prod. 10: 67–76.Google Scholar
Slee, J. and Sykes, A. R. 1967. Acclimatisation of Scottish Blackface sheep to cold. 1 Rectal temperature responses. Anim. Prod. 9: 333–347.Google Scholar
Sykes, A. R. and Field, A. C. 1972a. Effects of dietary deficiencies of energy, protein and calcium on the pregnant ewè. I. Body composition and mineral content of the ewes. J. agric. Set, Camb. 78: 109–117.Google Scholar
Sykes, A. R. and Field, A. C. 1972b. Effects of dietary deficiencies of energy, protein and calcium on the pregnant ewe. II. Body composition and mineral content of the lamb. J. agric. Set, Camb. 78: 119–125.Google Scholar
Sykes, A. R. and Field, A. C. 1972c. Effects of dietary deficiencies of energy, protein and calcium on the pregnant ewe. III. Some observations on the use of biochemical parameters in controlling energy undernutrition during pregnancy and on the efficiency of utilisation of energy and protein for foetal growth. J. agric. Set, Camb. 78: 127–133.Google Scholar
Sykes, A. R. and Slee, J. 1968. Acclimatisation of Scottish Blackface sheep to cold. 2. Skin temperature, heart rate, respiration rate, shivering intensity and skinfold thickness. Anim. Prod. 10: 17–35.Google Scholar
Sykes, A. R. and Slee, J. 1969a. Cold exposure of Southdown and Welsh Mountain sheep. 1. Effects of breed, plane of nutrition and previous acclimatisation to cold upon skin temperature, heart rate, shivering and respiration rate. Anim. Prod. 11: 65–76.Google Scholar
Sykes, A. R. and Slee, J. 1969b. Cold exposure of Southdown and Welsh Mountain sheep. 2. Effects of breed, plane of nutrition and previous acclimatisation to cold upon skin temperature, heart rate, shivering and respiration rate. Anim. Prod. 11: 77–89.Google Scholar
Sykes, A. R. and Slee, J. 1969C. Cold exposure of Southdown and Welsh Mountain sheep. 3. Changes in plasma calcium, phosphorus, magnesium, sodium and potassium levels. Anim. Prod. 11: 91–99.Google Scholar
Treacher, T. T. 1970. Effects of nutrition in late pregnancy on subsequent milk production in ewes. Anim. Prod. 12: 23–36.Google Scholar
Treacher, T. T. 1971. Effects of nutrition in pregnancy and in lactation on milk yield in ewes. Anim. Prod. 13: 493–501.Google Scholar
Treacher, T. T. and Crabtree, J. R. 1973. The effect of plane of nutrition of the ewe during the first and second months of lactation on the growth rate of twin lambs. Proc. Br. Soc. Anim. Prod. 2: 80 (Abstr.).Google Scholar
Turner, H. N. 1969. Genetic improvement of reproduction rate in sheep. Anim. Breed. Abstr. 37: 545–563.Google Scholar
Wallace, L. R. 1955. Factors influencing the efficiency of food conversion by sheep. Proc. Nutr. Soc. 14: 7–13.Google Scholar
Wallace, L. R. 1958. Breeding Romneys for better lambing percentages. Proc. Ruakura Fmrs' Conf. Week, pp. 62–73.Google Scholar
Wallace, L. R. 1961. Influence of liveweight and condition on ewe fertility. Proc. Ruakura Fmrs' Conf. Week, pp. 14–25.Google Scholar
Wallace, L. R. 1964. The effect of selection for fertility on lamb and wool production. Proc. Ruakura Fmrs' Conf. Week, pp. 25–38.Google Scholar
Wardrop, I. D., Tribe, D. E. and Coombe, J. B. 1960. An experimental study of early weaning of lambs. J. agric. Set, Camb. 55: 133–136.Google Scholar
Watson, J. H. 1971. Development in the cross breeding and hybridisation of sheep for maximum meat production. In Lamb Production, pp. 47–62. US Feed Grains Council, London.Google Scholar
Welsh Plant Breeding Station. 1971. Report for 1971, pp. 66 and 99.Google Scholar
Welsh Plant Breeding Station. 1972. Report for 1972, pp. 114 and 116.Google Scholar
White, R. G. 1931. The importance of hardiness in Welsh Mountain sheep. Jl. R. Welsh agric. Soc., pp. 99102.Google Scholar
Wiener, G. 1966. The effect of breed and of farm of origin on body size, fleece weight and reproductive performance of sheep. Anim. Prod. 8: 357 (Abstr.).Google Scholar
Wiener, G. 1967. A comparison of the body size, fleece weight and maternal performance of five breeds of sheep kept in one environment. Anim. Prod. 9: 177195.Google Scholar
Wiener, G., Deeble, F. K., Broadbent, J. S. and Talbot, M. 1973. Breed variation in lambing performance and lamb mortality in commercial sheep flocks. Anim. Prod. 17: 229243.Google Scholar
Williams, G. L. 1965. Wintering of mountain ewe lambs. NAAS Q. Rev. No. 70 pp. 6169.Google Scholar
Winfield, C. J., Brown, W. and Lucas, I. A. M. 1968. Some effects of compulsory exposure over winter on in-lamb Welsh Mountain ewes. Anim. Prod. 10: 451463.Google Scholar
Winfield, C. J., Brown, W. and Lucas, A. A. M. 1969. Sheltering behaviour at lambing by Welsh Mountain ewes. Anim. Prod. 11; 101106.Google Scholar
Young, B. A. and Corbett, J. L. 1972. Maintenance energy requirement of grazing sheep in relation to herbage availability. I. Calorimetric estimates. Aust. J. agric. Res. 23: 5776.Google Scholar
Young, N. E. and Newton, J. E. 1974. A note on the intake of lactating ewes at pasture. J . Br. Grassld Soc. 29: 117119.Google Scholar