Recent advances in sheep breeding
2003
Hanif, M. (Directorate of Planning and Evaluation, Lahore (Pakistan)) | William, H.L.
The effects of melatonin and Light treatments on the reproductive performance of yearling Suffolk rams were investigated. The two groups (A, n = 8; B, n = 8) were given a priming period of long days (18 h Light (L): 6 h dark (D) during 1st February to 14th March. During 14th March to 9th September, group A was exposed to local light + melatonin Implants (Regulin) at 5 weekly intervals, group B was exposed to local light + melatonin Fed (M- 5250) alongwith the feed. The group (C, n = 8) in the local light during 1st February to 14th March and during 14th March to 9th September remained on local light + melatonin implants (Regulin) at 5-weekly intervals. However, the group (D, n=8) was treated as control and kept on local light environment (Lat. 51 degree 43'N) throughout the experiment. Testis diameter, sexual behaviours and semen quality were used to assess reproductive performances. The treatment to group A & B resulted in a significant advancement in high reproductive performance. The treatment to group C indicated that the abrupt application of melatonin in mid March resulted in a weak response in terms of all the criteria of assessment. The investigation indicated that seasonal fluctuations in reproductive behaviour and semen quality may be rephrased by the application of light and melatonin treatments and that these treatments may be considered for the preparation of rams for out of season breeding.
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