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Table 3 Mean dates ± S.E.M. in days, for onset and end of ovulatory activity in Black-Belly ewes maintained under two different photoperiodic conditions.

From: Seasonal ovulatory activity exists in tropical Creole female goats and Black Belly ewes subjected to a temperate photoperiod

 

1st breeding season 1998–1999

2nd breeding season 1999–2000

3rd breeding season 2000–2001

 

onset

end

onset

end

onset

end

Temperate regimen

NA

22/04 ± 7

15/09 ± 3

25/04 ± 12

22/09 ± 5

NA

Tropical regimen

NA

09/04 ± 4

05/08*** ± 5*

22/04 ± 4*

13/09 ± 3

NA

  1. Two groups of Black-Belly ewes were maintained in light-proof rooms and subjected to either simulated temperate photoperiodic conditions (TE, 12 ewes, 8 to 16 hours of light per day from winter to summer solstice) or simulated tropical photoperiodic conditions (TR, 12 ewes, 11 to 13 hours of light per day from winter to summer solstice) for 25 months. Ovulatory activity was assessed by determinations of plasma progesterone by radioimmunoassay. Means and variances were compared between groups within each column. Significant differences between means and between variances are indicated by asterisks (*:p < 0.05, ***: P < 0.001). NA: not available.
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BMC Physiology

ISSN: 1472-6793

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