Influence of SLA haplotype on ovulation rate and litter size in miniature pigs.
Systemic blood was collected from and surgery performed on sows of 3 strains of miniature swine bred for specific SLA (swine MHC) haplotypes (a, c and d) from Day 2 to Day 6 after mating (first day of mating = Day 0). Ovulation rate was determined by counting corpora lutea and embryos were flushed from the uterus. Progesterone, oestradiol-17 beta and oestrone were quantitated in blood plasma and uterine flushings by RIA. SLAd/d females had a higher ovulation rate than SLAa/a or SLAc/c females (11.50 +/- 0.87 vs 9.11 +/- 0.68 and 8.17 +/- 0.83, respectively; P less than 0.01). Oestrone was higher than oestradiol-17 beta in systemic plasma (56.5 +/- 6.4 vs 33.0 +/- 4.7 pg/ml, P less than 0.01) while oestradiol-17 beta was higher than oestrone in uterine flushings (19.8 +/- 1.4 vs 14.9 +/- 1.5 pg/horn, P less than 0.10). Systemic progesterone concentration was correlated with day after mating (r = 0.93, P less than 0.01). There was no effect of haplotype on any of the hormone concentrations measured. Litter size was analysed from 99 matings amongst SLAa/a, SLAa/c, SLAa/d, SLAd/c and SLAd/d sires and dams. Litter size from -/d and d/d sows or from d/d boars were larger (P less than 0.05) than for all other matings. Although ovulation rate was higher in SLAd/d sows, the significant effect of sire SLA genotype on litter size suggests an additional effect of the d haplotype on embryonic survival.
Conley
A J
AJ
Department of Animal Science, Iowa State University, Ames 50011.
Jung
Y C
YC
Schwartz
N K
NK
Warner
C M
CM
Rothschild
M F
MF
Ford
S P
SP
D000818:Animals; D004958:Estradiol / Q000097:blood; D004970:Estrone / Q000097:blood; D005260:Female; D005805:Genes, MHC Class I; D006239:Haplotypes; D008098:Litter Size; D010060:Ovulation; D011247:Pregnancy; D011374:Progesterone / Q000097:blood; D013552:Swine; D013556:Swine, Miniature / Q000235:genetics*
D004970:Estrone; D011374:Progesterone; D004958:Estradiol