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Bromocryptine is effective in reducing milk production in ewes during lactation, but has no additional effect during drying off

Published online by Cambridge University Press:  02 September 2010

N. Buys
Affiliation:
Laboratory of Comparative Endocrinology, Catholic University of Leuven, Naamsestraat 61, B-3000 Leuven, Belgium Department of Animal Husbandry, Catholic University of Leuven, Kardinaal Mercierlaan 92E, B-3001 Heverlee, Belgium
D. Vanmontfort
Affiliation:
Department of Animal Husbandry, Catholic University of Leuven, Kardinaal Mercierlaan 92E, B-3001 Heverlee, Belgium
R. Peeters
Affiliation:
Department of Animal Husbandry, Catholic University of Leuven, Kardinaal Mercierlaan 92E, B-3001 Heverlee, Belgium
J. van Isterdael
Affiliation:
Department of Animal Husbandry, Catholic University of Leuven, Kardinaal Mercierlaan 92E, B-3001 Heverlee, Belgium
E. Decuypere
Affiliation:
Department of Animal Husbandry, Catholic University of Leuven, Kardinaal Mercierlaan 92E, B-3001 Heverlee, Belgium
E. R. Kühn
Affiliation:
Laboratory of Comparative Endocrinology, Catholic University of Leuven, Naamsestraat 61, B-3000 Leuven, Belgium
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Abstract

The effect of bromocryptine on milk production was investigated in 32 crossbred ewes (Flemish Milksheep х Suffolk) with one sucking lamb, during lactation and during drying off. After weaning the lambs, all ewes were hand milked twice daily for 3 days. From day 4 onwards, the ewes were divided into four groups with equal mean daily milk production. Ewes of groups A and B were hand milked twice daily during the following 9 days. Ewes of groups C and D were dried off by reducing the milking frequency. They were milked on days 5, 8 and 12. In groups B and D, bromocryptin (1 ml of 1 g/l ethanol 50%) was injected intramuscularly twice daily while control ewes (groups A and C) received 1 ml ethanol 50%. Blood samples were taken by venipuncture prior to each injection and were assayed for prolactin, growth hormone, thyrotropin and cortisol.

Bromocryptine decreased plasma prolactin levels but did not alter growth hormone or cortisol concentrations during lactation or drying off. Thyrotropin levels were elevated by bromocryptine during drying off but were unaffected during galactopoiesis.

During lactation the daily milk production remained unchanged in control ewes while in bromocryptine-treated ewes a proportional decrease of 0·5 was observed. In all ewes the decrease in milk production occurring at drying off could not be accelerated or stimulated by bromocryptine.

It is concluded that prolactin plays an important role in galactopoiesis in ewes but its role is comparatively unimportant compared with other factors during mammary involution.

Type
Research Article
Copyright
Copyright © British Society of Animal Science 1995

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References

Besser, G. M., Parke, L., Edwards, C. R. W., Forsyth, I. A. and McNeilly, A. S. 1972. Galactorrhoea: successful treatment with reduction of plasma-prolactin levels by bromo-ergocryptine. British Medical Journal 3: 669672.CrossRefGoogle Scholar
Buys, N. 1992. The endocrinological background of the artificial inhibition of lactation in sheep. PhD.thesis, K.U. Leuven.Google Scholar
Buys, N., Peeters, R., Clerck, B. de, Isterdael, J. van, Kϋhn, E. R. and Decuypere, E. 1990. Seasonal variations in prolactin, growth hormone and thyroid hormones and the prolactin surge at ovulation do not affect litter size of ewes during pregnancy in the oestrus or the anoestrus season. Journal of Reproduction and Fertility 90: 4753.CrossRefGoogle Scholar
Collu, R., Jéquier, J-C., Leboeuf, G., Letarte, J. and Ducharme, J. R. 1975. Endocrine effects on pimozide, a specific dopaminergic blocker. Journal of Clinical Endocrinology and Metabolism 41: 981984.CrossRefGoogle ScholarPubMed
Elsasser, T. H. and Bolt, D. J. 1987. Dopaminergic-like activity in toxic fescue alters prolactin but not growth hormone or thyroid stimulating hormone in ewes. Domestic Animal Endocrinology 4: 259269.CrossRefGoogle ScholarPubMed
Fell, L. R., Chandler, N. J. and Goding, J. R. 1974. Effects of inhibition of prolactin secretion by 2-bromo-α-ergocryptine at parturition and during lactation in dairy cows. Journal of Reproduction and Fertility 36: 480481.CrossRefGoogle Scholar
Flϋckiger, E., Marko, M., Doepfner, W. and Niederer, W. 1976. Effect of ergot alkaloids on the hypothalamic pituitary axis. Postgraduate Medical Journal 52: 5761.Google Scholar
Fraker, P. J. and Speck, J. C. 1978. Protein and cell-membrane iodinations with a sparingly soluble cloramide l,3,4,6-tetraclore-3A,6A-diphenylglycoluril. Biochemical Biophysical Research Communications 80: 849857.CrossRefGoogle Scholar
Fulkerson, W. J. 1981. Hormonal control of lactation, volume 2. Annual research reviews, series (ed. Horrobin, D. F.). Eden Press, Churchill Livingstone.Google Scholar
Hall, T. R., Harvey, S. and Scanes, C. G. 1986. Control of growth hormone secretion in the vertebrates: a comparative survey. Comparative Biochemistry and Physiology 84A: 231253.CrossRefGoogle Scholar
Hart, I. C. 1973. Effect of 2-bromo-α-ergocryptine on milk yield and the level of prolactin and growth hormone in the blood of the goat at milking. Journal of Endocrinology 57: 179180.CrossRefGoogle Scholar
Hökfelt, T. and Fuxe, K. 1972. Effects of prolactin and ergot alkaloids on the tubero-infundibular dopamine neurones. Neuroendocrinology 9: 100122.CrossRefGoogle Scholar
Hooley, R. D., Campbell, J. J. and Findlay, J. K. 1978. The importance of prolactin for lactation in the ewe. Journal of Endocrinology 79: 301310.CrossRefGoogle ScholarPubMed
Kann, G. 1976. Inhibition of prolactin secretion in the ewe by 2-bromo-α-ergocryptine during pregnancy or early lactation; effect on milk yield. Proceedings of the fifth international congress on endocrinology, Hamburg, abstr. 611.Google Scholar
Karg, H., Schams, D. and Reinhardt, V. 1972. Effects of 2-br-α-ergocryptine on plasma prolactin level in milk yield in cows. Experienta 28: 574576.CrossRefGoogle Scholar
Knight, C. H., Foran, D. and Wilde, C. J. 1990. Interaction between autocrine and endocrine control of milk yield; trice-daily milking of bromocryptine-treated goats. Journal of Reproduction and Fertility Abstract series 5: 20.Google Scholar
McNeilly, A. S. and Land, R. B. 1979. Effect of suppression of plasma prolactin on ovulation, plasma gonadotrophins and corpus luteum function in LHRH treated anoestrus ewes. Journal of Reproduction and Fertility 56: 601609.CrossRefGoogle Scholar
Miyai, K., Onishi, T., Hosokawa, M., Ishiobashi, K. and Kumahara, Y. 1974. Inhibition of thyrotropin and prolactin secretions in primary hypothyroidism by 2-br-α-ergocryptine. Journal of Clinical Endocrinology and Metabolism 39: 391394.CrossRefGoogle Scholar
Niswender, G. D. 1974. Influence of 2-bromo-α-ergocryptine on serum levels of prolactin and the oestrus cycle in sheep. Endrocrinology 94: 612615.CrossRefGoogle Scholar
Peeters, R., Buys, N., Robijns, L., Vanmontfort, D. and Isterdael, J. van. 1992. Milk yield and milk composition of Flemish Milksheep, Suffolk and Texel ewes and their crossbreeds. Small Ruminant Research 7: 279288.CrossRefGoogle Scholar
Pozo, E. del, Brun del Re, R., Varga, L. and Friesen, H. 1972. The inhibition of prolactin secretion in man by CB-154. Journal of Clinical Endocrinology and Metabolism 35: 768771.CrossRefGoogle Scholar
Sherman, L. and Kolodny, H. D. 1971. The hypothalamus, brain catecholamines, and drug therapy for gigantism and acromegaly. Lancet i: 682685.CrossRefGoogle Scholar
Smith, V. G., Beck, T. W., Convey, E. M. and Tucker, H. A. 1974. Bovine serum prolactin, growth hormone, cortisol and milk yield after ergocryptine. Neuroendocrinology 15: 172181.CrossRefGoogle ScholarPubMed
Statistical Analysis Systems Institute. 1985. SAS users' guide, statistics, version 5 edition. SAS Institute Inc., Cary, NC.Google Scholar