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2009 | 53 | 3 |

Tytuł artykułu

Changes in growth hormone and prolactin secretions in ewes used for milk under different photoperiodic conditions

Warianty tytułu

Języki publikacji

EN

Abstrakty

EN
The aim of the present experiment was to determine the growth hormone (GH) and prolactin (PRL) secretions in relation to the milk yield of lambed sheep used for milk under different photoperiodic conditions. The study was carried out at the Experimental Station of the Department of Sheep and Goat Breeding of the Agricultural University in Krakow, using 60 Polish Long-wool sheep assigned to three groups. Sheep, which had lambed in January in group I (n=20) and in June in group II (n=20) were exposed to natural changes in the length of the photoperiod. In group III (n=20), sheep were lambed in June and kept under a long photoperiod (16L:8D) until the end of lactation. In the group I, the highest milk yield (0.43 ±0.08 l) was found in the first month of milking (May). Growth hormones and PRL concentrations in the blood were also the highest (5.49 ±4.2 and 312.6 ±24.3 ng/mL, respectively). In the group III, as in the group II, the milk yield consistently decreased from August to November. The highest GH concentration was found in August (18.22 ±1.3 ng/mL) and the lowest in October (4.1 ±0.6 ng/mL) (P<0.05). The results show that the GH secretion in sheep entering lactation during the shortening photoperiod is higher than in lambed sheep used for milk during the lengthening photoperiod.

Słowa kluczowe

Wydawca

-

Rocznik

Tom

53

Numer

3

Opis fizyczny

p.389-393,fig.,ref.

Twórcy

autor
  • Biotechnology and Genomic Laboratory, Department of Sheep and Goat Breeding, Agricultural University in Krakow, 30-274 Krakow, Poland
autor
  • Institute of Animal Physiology and Nutrition, Polish Academy of Sciences, 05-110 Jablonna n.Warsaw, Poland
  • Institute of Animal Physiology and Nutrition, Polish Academy of Sciences, 05-110 Jablonna n.Warsaw, Poland
autor
  • Biotechnology and Genomic Laboratory, Department of Sheep and Goat Breeding, Agricultural University in Krakow, 30-274 Krakow, Poland
autor
  • Biotechnology and Genomic Laboratory, Department of Sheep and Goat Breeding, Agricultural University in Krakow, 30-274 Krakow, Poland

Bibliografia

  • 1. Ciuryk S., Molik E., Bonczar G.: Current state of the use of sheep for milk in the Cracow region based on studies performed at the Department of Sheep and Goat Breeding of the Agricultural University in Cracow. Zesz Nauk Fundacja Rozwój (SGGW Warszawa) 1999, 3, 61- 69.
  • 2. Dahl G.E., Buchanan B.A., Tucker H.A.: Photoperiodic effects on dairy cattle: a review. J Dairy Sci 2000, 83, 885-893.
  • 3. Dvorak P., Becka S., Krejci P., Chrpova M.: Radioimmunoassay of bovine growth hormone. Radiochemical Radioanal Lett 1978, 34, 160-166.
  • 4. Lincoln G.A., Clarke I.J.: Photoperiodically-induced cycles in the secretion of prolactin in hypothalamo- pituitary disconnected rams: evidence for translation of the melatonin signal in the pituitary gland. J Neuroendocrinol 1994, 6, 251-260.
  • 5. Lincoln G.A., Clarke I.J.: Role of the pituitary gland in the development of photorefractoriness and generation of long-term changes in prolactin secretion in rams. Biol Reprod 2000, 62, 432-438.
  • 6. Lincoln G.A., Tortonese D.J.: Prolactin replacement fails to inhibit reactivation of gonadotropin secretion in rams treated with melatonin under long days. Biol Rep 1999, 60, 602-610.
  • 7. Misztal T., Romanowicz K., Barcikowski B.: Seasonal changes of melatonin secretion in relation to the reproductive cycle in sheep. J Anim Feed Sci 1996, 56, 35-48.
  • 8. Molik E., Misztal T., Romanowicz K., Wierzchoś E.: Dependence of the lactation duration and efficiency on the season of lambing in relation to the prolactin and melatonin secretion in ewes. Livestock Sci. 2007, 107, 220-226.
  • 9. Norms, 1993. Nutrient requirements for cattle and sheep in the traditional system. IZ Kraków, Poland.
  • 10. Peters R.R., Chapin L.T., Leining K.B., Tucker H.A.: Supplemental lighting stimulates growth and lactation in cattle. Science 1978, 199, 911-912.
  • 11. Reksen O., Tverdal A., Landsverk K., Kommisrud E., Boe K.E., Ropstad E.: Effects of photointensity and photoperiod on milk yield and reproductive performance of Norwegian Red cattle. J Dairy Sci 1999, 82, 810-816.
  • 12. Reiter R. J.: Neuroendocrinology of melatonin. In: Melatonin Clinical Perspectives. Editors: Miles A., Philbrick D.R.S., Thomson C., Oxford University Press, Oxford, 1988, pp. 1-42.
  • 13. Robinson J.J.S., Wigzell R.P., Aitken J.M., Wallace S., Robertson I.S.: Daily oral administration of melatonin from March onwards advances by 4 months the breeding season of ewes maintained under the ambient photoperiod at 57° N. Anim Reprod Sci 1992, 27, 141-160.
  • 14. Romanowicz K., Misztal T., Barcikowski B.: The effects of intracerebroventricular infusion of prolactin on luteinizing hormone, testosterone and growth hormone secretion in male sheep. Anim Reprod Sci 2004, 81, 261- 271.
  • 15. Tucker H.A.: Lactation and its hormonal control. In: The Physiology of Reproduction. Edited by Knobil E., Neill J.D. New York Raven Press, 1994, pp. 1065-1098.
  • 16. Tucker H.A.: Hormones, mammary growth and lactation: a 41-year perspective. J Dairy Sci 2000, 83, 874-884.
  • 17. Wolinska E., Polkowska J., Domanski E.: The hypothalamic centers involved in the control of production and release of prolactin in sheep. J Endocrinol 1977, 73, 21-29.

Typ dokumentu

Bibliografia

Identyfikatory

Identyfikator YADDA

bwmeta1.element.agro-34331def-d12e-4e23-a45e-953685e72071
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