View Full Table | Close Full ViewTable 1.

Summary statistics of sows, corpus luteum and litter characteristics

 
Variables n Mean SD Min Max
Experiment 1
    Parity 45 7.3 3.2 2 13
    TUS pregnancy age, d 45 23.4 2.9 20 28
    Slaughter pregnancy age, d 45 29.8 1.9 27 32
    Ovulation rate by TUS 45 23.4 5.8 13 34
    Ovulation rate after dissection 45 24.1 5.3 13 37
    Average CL diameter TUS1, mm 25 10.3 0.73 8.4 11.7
    Average CL diameter DISS2, mm 25 10.3 0.64 8.7 11.5
    Average CL weight DISS3, g 25 0.40 0.07 0.22 0.56
    Total average CL diameter4, mm 25 9.8 0.7 7.8 11.0
    Total average CL weight4, g 25 0.38 0.1 0.20 0.51
    Total luteal mass5, g 25 7.9 1.5 5.2 10.7
Experiment 2
    Parity 100 5.0 1.9 2 9
    TUS pregnancy age, d 100 23.8 2.4 21 29
    Gestational length, d 100 115 1.7 111 120
    Average CL diameter TUS1, mm 100 8.4 0.8 5.5 10.5
    Litter size6 100 17.9 3.0 9 26
    Number of live born 100 16.3 2.9 6 23
    Number of stillborn 100 1.53 1.8 0 9
    Number of mummies 100 0.42 0.8 0 5
    Average piglet BW7, g 100 1277 165 914 1618
    SD BW7, g 100 303 76 161 555
    Average live born piglets BW7, g 100 1299 167 933 1674
    SD BW live born7, g 100 292 76 115 492
    Litter BW, kg 100 23 4.0 15 30
1Average calculated based on the diameter of the 5 biggest corpora lutea in each ovary (10 per sow) measured by Transrectal ultrasonography (TUS).
2Average calculated based on the diameter of the 5 biggest corpora lutea in each ovary (10 per sow) measured with caliper rule after slaughter of the sows and ovarian dissection.
3Average weight of the 5 corpora lutea in each ovary (10 per sow) that had the highest diameter measured after ovarian dissection.
4Average diameter and weight calculated based on the measurement of all corpora lutea dissected from each ovary.
5Sum of the weight of all the corpora lutea dissected from the ovaries.
6Litter size is the sum of piglets born alive (live born) and stillborn piglets.
7Piglets were weighed within 24 h after birth.



View Full Table | Close Full ViewTable 2.

Relationship between average corpora lutea diameter measured by transrectal ultrasonography (DIAMTUS) and litter characteristics at birth

 
DIAMTUS1, mm
Litter size
Parity
Dependent variables β (SEM) P-value P-value P-value
Gestational length, d 0.48 (0.26) 0.06 ns2 ns
Litter size3 –0.098 (0.43) 0.82 ns
Number of live born –0.084 (0.43) 0.84 ns
Number of stillborn4 –0.015 (0.22) 0.95 0.02 0.01
Number of mummies –0.013 (0.10) 0.90 ns ns
Average piglet BW5, g 37.57 (17.84) 0.04 < 0.0001 ns
SD BW5, g 24.25 (10.37) 0.02 ns ns
Average live born piglets BW5, g 32.98 (18.41) 0.08 < 0.0001 ns
SD BW live born5, g 27.33 (10.52) 0.01 ns ns
Litter BW, kg 0.81 (0.47) 0.09 < 0.0001 ns
1Average calculated based on the diameter of the 5 biggest corpora lutea in each ovary (10 per sow) measured by TUS.
2ns = P > 0.05.
3Litter size is the sum of piglets born alive (live born) and stillborn piglets.
4Interaction between parity (PC) and litter size (LS) classes (P = 0.002): PC1 × LS1 (n = 9): 0.67 ± 0.55b; PC2 × LS1 (n = 12): 0.48 ± 0.48b; PC3 × LS1 (n = 6): 1.54 ± 0.47ab; PC2 × LS2 (n = 12): 1.02 ± 0.49b; PC2 × LS2 (n = 12): 2.01 ± 0.49b; PC3 × LS2 (n = 11): 0.92 ± 0.49ab; PC1 × LS3 (n = 13): 0.81 ± 0.66b; PC2 × LS3 (n = 12): 1.58 ± 0.51ab; PC3 × LS3 (n = 13): 3.83 ± 0.47a.
5Piglets were weighed within 24 h after birth (BW).



Abbreviations Description
TUS Transrectal ultrasonography
OR Ovulation rate, i.e. the total number of CL present in both ovaries
CL Corpora lutea
ORTUS Total number of corpora lutea counted on both ovaries with transrectal ultrasonography
E1 Transrectal ultrasonography examiner one
E2 Transrectal ultrasonography examiner two
DIAMTUS The average diameter of the 10 biggest corpora lutea measured by transrectal ultrasonography in a sow
ORDIS Total number of corpora lutea counted after slaughter and dissection of the ovaries for individual corpora lutea
DIAMDIS The average diameter of the 10 biggest corpora lutea measured with a caliper rule after slaughter and dissection of the ovaries for individual corpora lutea
WTDIS The average weight of the 10 biggest corpora lutea measured after slaughter and dissection of the ovaries for individual corpora lutea
LS Litter size, i.e. the sum of the number of piglets born alive and dead
BW Piglet birth weight