with some modifications. The assay reagent and HRP-labelled progesterone were diluted in saline solution 1:2. Standards were diluted in zero-plasma supplied in the kit to
produce a standard curve ranging between 0.25 and 8 nmolrl. Serial dilutions of porcine plasma produced displacement curves parallel to the standard curve. The intra-assay
coefficients of variation calculated from 10 assays were below 10 for concentrations between 0.25 and 8 nmolrl. The inter-assay coefficient of variation for one control
Ž .
sample was 11 2 nmolrl . The average detection limit of the assay was 0.2 nmolrl. 2.7. Statistical methods
Motility and hormonal observations were grouped into 12 4-h periods according to Ž
. recordingrsampling time with respect to ovulation three before and nine after . All
Ž .
observations at the time of ovulation time 0 were included in the y3 to 0 h period. For each sow and 4-h period, mean values were calculated for motility and hormonal
observations. Two sows were removed from the analyses due to missing hormonal or pressure values. The calculated mean values were analysed by analysis of variance
Ž according to the GLM-procedure in the SAS package Statistical Analysis Systems
. Ž
. Institute, 1989 . The statistical model included the effects of sow 13 and the 4-h period
Ž .
12 . There were 156 observations in the analyses and the number of observationsrsow ranged from 3 to 12.
3. Results
The implantation of the pressure transducer into the porcine isthmus, as shown in Fig. 1, permitted the monitoring of oviductal motility on one of the Polyviewe chart
monitors. In all cases, the pressure transducer was in the correct position in the isthmus as checked at the time of slaughter and no macroscopic lesions were observed on the
isthmic lumen. The isthmic motility patterns from one sow are shown in Fig. 2. The isthmic motility patterns were regular before ovulation but then changed to wave
patterns during the peri-ovulatory period and eventually to irregular patterns after ovulation.
The levels of significance of the effects included in the statistical model are presented Ž
. in Table 1. There was an influence p - 0.001 of the sow on the amplitude, frequencies
Ž .
of phasic pressure fluctuations frequencyrmin , oestradiol-17b and progesterone. On
Table 1 Significance of the effects included in the statistical model
Variable Sow
New time Frequencyrmin
Ž .
Amplitude mm Hg Ž
. Oestradiol 17b pmol
Ž .
Progesterone nmol p- 0.01.
p- 0.001.
A.M. Mwanza
et al.
r Animal
Reproduction
Science 62
2000 309
– 320
316
Table 2 Ž
. Ž
. Ž
. Ž
. LSmean SEM values of the isthmic frequencies of phasic pressure fluctuations frequenciesrmin , amplitudes mm Hg , plasma oestradiol-17b E
and
2
Ž .
Ž .
Ž .
progesterone P levels in sows n s13 in relation to the time of ovulation time 0 s ovulation
4
Ž . Time-ao h
y11 to y8 y7 to y4 y3 to 0
1 to 4 5 to 8
9 to 12 13 to 16
17 to 20 21 to 24
25 to 28 29 to 32
33 to 36
a ab
a ab
bc cd
de df
efg gh
hi i
Frequencyr 421.5
411.3 421.3
411.4 381.3
371.5 341.4
341.8 291.9
261.6 231.9
201.8 min
a ab
ab b
bc c
cd c
de ef
ef f
Amplitude 1327.3
1286.2 1275.9
1136.5 1106.2
1086.8 946.5
1118.4 819.0
677.8 609.0
568.4 Ž
. mm Hg
a b
bc bc
bc bc
bc c
bc bc
bc c
Ž .
E pmolrl
182.4 102.0
71.9 52.2
52.0 42.3
42.2 22.7
52.9 32.6
22.9 22.7
2 a
a a
ab bc
cd ce
ef fg
g g
h
Ž .
P nmolrl 10.4
10.3 20.3
20.3 30.3
30.3 30.3
40.4 50.4
60.4 60.4
80.4
4
Ž .
Values without a common superscript within the same row differ significantly p- 0.05 .
Ž .
the other hand, the 4-h period had a significant p - 0.001 effect on the amplitude,
Ž .
frequencies of phasic pressure fluctuations frequenciesrmin , progesterone and oestra- Ž
. diol-17b
p - 0.01 . Ž
. The LSmean SEM values for the frequencies of phasic pressure fluctuations,
Ž .
amplitudes mm Hg , plasma oestradiol-17b and progesterone levels during the 12 4-h periods in relation to ovulation are presented in Table 2. The frequencies of phasic
pressure fluctuations were 42.9 1.5 approximately 8 to 11 h before ovulation and Ž
. remained high during the subsequent periods before decreasing significantly p - 0.05
to 38.4 1.3 during the period between 5 and 8 h after ovulation. The frequencies of phasic pressure fluctuations then gradually decreased over time to 20.6 1.8 between
Ž .
33 and 36 h after ovulation. The amplitudes decreased significantly p - 0.05 from
132 7.3 mm Hg 8 to 11 h before ovulation to 113.6 6.5 mm Hg between 1 and 4 h after ovulation. Amplitudes then gradually decreased over time to 56 8.4 mm Hg 33 to
36 h after ovulation. Ž
. Plasma progesterone levels increased significantly
p - 0.05 from 2 0.3 nmolrl between 3 and 0 h before ovulation to 3 0.3 nmolrl 5 to 8 h after ovulation.
Progesterone then increased over time to 8 0.4 nmolrl. Oestradiol-17b was 18 2.4 pmolrl between 8 and 11 h before ovulation and
Ž .
decreased significantly p - 0.05
to 10 2.0 pmolrl 4 to 7 h before ovulation. Oestradiol-17b then continued to decrease during the subsequent periods reaching its
Ž .
lowest value of 2.2 2.7 pmolrl below detection limit 17 to 20 h after ovulation. The frequencies of phasic pressure fluctuations and the amplitudes were highest at the
time when oestradiol-17b levels were highest and when progesterone levels were low.
4. Discussion