Fec carriers and non-carriers. In the model, the crossbred type and the fecundity-gene status were considered as fixed-crossed effects, and the ewe was taken as a random
Ž .
effect Dagnelie, 1975 . The Scheffe test was used to compare group means when the
´
Ž .
main or interaction effects were significant P - 0.01 and P - 0.05 . Values relating to OR and the rate of follicle atresia were logarithmically transformed before analysis.
3. Results
3.1. OÕulation rate Ž
. The results for OR are summarized in Table 1. The OR was higher P - 0.05 in Fec
Ž gene carriers ewes than in non-carriers. The carriers of either the Booroola BGM and
. Ž
. BT or Cambridge CC, CT and CS fecundity gene did not have significantly different
OR means. The same observations were realized with the non-carriers. Also, the OR data did not differ between purebred CC and its crossbred CS and CT ewes; nor between
CT and BT with a fecundity gene of different origin, and between CS and CT with the same fecundity gene.
The OR values did not significantly differ before, at the end of, or 1 month after a 5-day period of laparoscopy, except for the comparison between the 2nd and the 3rd
Ž .
cycles for CS F q P - 0.05 . 3.2. Follicular parameters
Data on the follicular parameters are presented in Table 2. Whatever the type of breed, the number of small, medium and large growing follicles did not differ between
Ž .
carriers and non-carriers, despite the higher P - 0.05 number of ovulating follicles in carrier ewes. The number of small growing follicles did not differ among the five
Ž .
experimental breeds. The number of medium-sized follicles was lower P - 0.05 in CC and CT than in CS, BT and BGM crossing irrespective of the fecundity gene status. The
Ž .
number of large growing follicles was lower P - 0.05
in the CT than in other Cambridge ewes and Booroola crossings. Values did not differ between BT and BGM.
The atresia rate for small follicles did not differ between carriers and non-carriers, Ž
. except for the BT ewes 19 5 F q vs. 47 5 qq, P - 0.05 . This rate also did
Ž .
not differ among type of crossbred, except for high P - 0.05 values in the CT and BT qq ewes. The atresia rate for medium follicles did not differ between carriers and
Ž .
non-carriers and among type of crossbred, with exception of high P - 0.05 values in CS crossbred.
Ž .
The atresia rates were higher P - 0.05 for large follicles in non-carriers than in
carriers, whatever the experimental crossbreed group. Also, they were higher in Booroola Ž
. crossings than in the Cambridge crossbred
Table 3 ; they were not significantly different among the three Cambridge groups, nor between the two Booroola crossings.
S.N.M. Mandiki
et al.
r Animal
Reproduction
Science 63
2000 77
– 88
82
Table 1 Ovulation rate in the CC, CS, CT, BT and BGM ewes
Ž .
Ž .
Values are meansS.E. a–b P - 0.05 or b–c P - 0.01 : significantly different means between carriers and non-carriers within each breed or crossbred. Data with Ž
. no letter indication are not significantly different P 0.05 .
Genotype CC
CS CT
BT BGM
Ž .
Ž .
Ž .
Ž .
Ž .
Ž .
Ž .
Ž .
Ž .
Ž .
Fq ns 5 qq ns 5
Fq ns 5 qq ns 5
Fq ns6 qq ns 5
Fq ns6 qq ns6
Fq ns 5 qq ns 5
a b
a b
a b
a b
Ovulation rate, 3.60.4
2.00.3 2.80.4
2.20.2 3.30.3
2.00.0 3.50.2
1.80.3 3.80.6
2.40.3 1st cycle
a b
a b
a b
a b
a b
Ovulation rate, 3.20.4
1.80.4 3.60.3
2.20.2 3.00.2
2.00.3 3.00.4
1.80.4 3.60.3
2.00.3 2nd cycle
a b
a b
b c
a b
a b
Ovulation rate, 3.00.3
1.80.4 2.60.2
1.60.2 3.30.2
1.50.2 3.00.2
1.80.3 3.80.2
1.80.2 3rd cycle
Mean 3.30.4
1.90.4 3.00.3
2.00.2 3.20.2
1.80.2 3.20.3
1.80.3 3.70.4
2.10.3
S.N.M. Mandiki
et al.
r Animal
Reproduction
Science 63
2000 77
– 88
83 Table 2
Follicular parameters in the CC, CS, CT, BT and BGM ewes Ž
. Ž
. Values are meansS.E. a–b P - 0.05 or b–c P - 0.01 : significantly different means between carriers and non-carriers within each breed or crossbred.
Genotype CC
CS CT
BT BGM
Ž .
Ž .
Ž .
Ž .
Ž .
Ž .
Ž .
Ž .
Ž .
Ž .
Fq ns 5 qq ns 5
Fq ns 5 qq ns 5
Fq ns6 qq ns 5
Fq ns6 qq ns6
Fq ns 5 qq ns 5
Number of small 12.60.6
12.21.0 14.61.5
16.01.4 12.20.9
14.41.3 13.01.7
15.31.2 15.21.6
16.80.2 follicles
a b
Ž . Atresia rate
355 313
275 347
515 543
195 475
327 326
Number of medium 8.20.7
8.40.8 10.61.2
10.41.1 5.80.3
6.60.6 10.31.2
8.21.1 10.00.9
11.41.0 follicles
Ž . Atresia rate
309 356
484 541
346 417
363 335
234 329
Number of large 5.60.5
4.60.8 5.40.4
4.80.6 3.80.3
3.80.4 6.50.6
5.50.9 7.60.5
8.20.6 follicles
a b
a b
a b
a b
a b
Ž . Atresia rate
427 579
325 517
208 4413
528 617
516 755
a b
a b
Diameter of ovulating 6.60.2
5.60.3 6.20.1
6.10.5 6.30.2
6.60.4 5.20.2
6.50.8 6.20.1
6.30.1 Ž
. follicles mm
Ž .
Values represent the percentages of shrincking large follicles as compared with the OR during the 2nd oestrous cycle Table 1 . Data with no letter indication are Ž
. not significantly different P 0.05 .
Table 3 Comparison between Booroola and Cambridge crossings
Genotype Cambridge ewes
Booroola ewes Ž
. Ž
. Ž
. Ž
. Fq ns16
qq ns15 Fq ns11
qq ns11 Number of small
13.11.0 14.21.2
14.11.7 16.10.7
follicles Ž .
Atresia rate 37.74.9
39.74.3 25.55.8
39.55.8 Number of medium
8.20.7 8.50.8
10.21.1 9.81.1
follicles Ž .
Atresia rate 37.36.4
414.8 29.53.5
32.57.3 Number of large
4.90.4 4.40.6
7.10.6 6.90.8
follicles
a b
a b
Ž . Atresia rate
31.36.6 50.79.7
52.07.0 68.06.4
Diameter of ovulating 6.40.2
6.10.4 5.70.2
6.40.5 Ž
. follicles mm
Ovulation rate 3.20.3
1.90.3 3.50.5
2.00.3 Duration of oestrous
16.00.6 16.20.7
16.70.5 17.00.0
cycle
The diameter of ovulatory follicles did not differ among type breeds and between Ž
carriers and non-carriers, except in the BT ewes 5.2 0.4 mm F q vs. 6.5 0.2 mm .
Ž .
qq, P - 0.05 and in the CC ewes 6.6 0.4 mm F q vs. 5.6 0.6 q q, P - 0.05 .
4. Discussion
