A method of examining the cyclic changes occurring in the sheep ovary using endoscopy

Boyd, J. Morton; Ducker, M. J.

doi:10.1136/vr.93.2.40

Cited by 27 publications

(15 citation statements)

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“…Onset of puberty was defined as the date of the first progesterone value above 0.5 ng/ml in a series of three or more samples above 0.5 ng/ ml that included one above 1 ng/ml. Presence of CL on the ovaries of lambs was confirmed by laparoscopy [19] carried out when progesterone concentrations in two consecutive blood samples were higher than 0.5 ng/ml. Differences in lamb birth weight, date of birth, and average daily gain were examined by ANOVA.…”

Section: Methodsmentioning

confidence: 99%

Effect of Photoperiod Before and After Birth on Puberty in Ewe Lambs1

Sunderland

O'Callaghan

Boland

et al. 1995

Biology of Reproduction

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Previous studies have shown that exposure to long days followed by short days after 12 wk of age advances the onset of puberty in ewe lambs. The aim of this experiment was to determine whether or not puberty would be advanced by exposure of lambs to such a photoperiodic regime when the long days were given before birth and the short days immediately after birth. Ewes kept in natural photoperiod (NP) were housed on January 15 and allocated at random to one of four treatments: 1) NP/NP, natural photoperiod before and after parturition (n = 26); 2) SD/SD, short days (SD; 9L:15D) before and after parturition (n = 27); 3) LD/NP, long days (LD; 18L:6D) before parturition and NP after parturition (n = 27); and 4) LD/SD, LD before parturition and SD after parturition (n = 26). Mean (+/- SEM) birth date for all lambs was March 20 +/- 1 day, and the number of days of exposure to long and short days prior to parturition was 64 +/- 2 and 67 +/- 2 days, respectively. From ewes on the four treatments, 24, 20, 14, and 16 female lambs, respectively, were reared. Lambs were weighed at birth and at weekly intervals after weaning. Reproductive activity in ewe lambs was assessed from serum progesterone concentrations in blood samples collected twice weekly from August 1 until puberty was reached or the experiment terminated on November 17 (34 wk after birth).(ABSTRACT TRUNCATED AT 250 WORDS)

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Section: Methodsmentioning

confidence: 99%

Effect of Photoperiod Before and After Birth on Puberty in Ewe Lambs1

Sunderland

O'Callaghan

Boland

et al. 1995

Biology of Reproduction

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“…The ovaries of all the ewes were examined using a peritoneoscope with a forward oblique field of vision. Both the equipment and the method of operation are described fully by Boyd and Ducker (1973). The number of corpora lutea present on both ovaries was counted to measure ovulation rate exactly.…”

Section: Collection Of Datamentioning

confidence: 99%

The effect of body size and body condition on the ovulation rate of ewes

Ducker

Boyd

1977

Anim. Sci.

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Link to this article: http://journals.cambridge.org/abstract_S0003356100011880How to cite this article: M. J. Ducker and J. S. Boyd (1977). The effect of body size and body condition on the ovulation rate of ewes. SUMMARYBody size was estimated for 255 Greyface ewes using five linear body dimensions. On the basis of this calculated measure combined with a subjective measure of body size 50 small and 50 large ewes were selected for use in the experiment. Precise ovulation data were obtained by endoscopy and this technique allowed the ewes to be mated subsequently. Body size did not affect the mean ovulation rate of the ewes although, at the same level of body condition, the large ewes were 25 % heavier than the small ewes. The ovulation rates and the numbers of lambs born were influenced by changes in live weight and body condition. For these reasons live weight per se was not a good indicator of ovulation rate as ewe live weight was a combination of both body size and body condition. At the same live weight small ewes in improving body condition had a significantly higher ovulation rate than large ewes in reducing body condition. The onset of the breeding season of the ewes was not affected by their body size. The mean date of onset of oestrous activity for both large and small ewes was 17 October 1972 at a latitude 55° 52' N.

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“…The basic laparoscopic technique has been described elsewhere (Boyd and Ducker, 1973). An ovulation rate of three or more was diagnostic of 'carrier' status.…”

Section: Methodsmentioning

confidence: 99%