Litter size and piglet traits of gilts with different prolactin receptor genotypes.
Seventy-seven Large White x Meishan F2 crossbred gilts with prolactin receptor (PRLR) genotype AA (n = 26), AB (n = 36) and BB (n = 15) were compared for teat number (FTm), age at first estrus, gestation length (GL), litter size, and litter means of functional teat number (FTp), birthweight (BW), and pre-weaning growth rate (GR). Own placental information was available for 88% of 620 live-born piglets (62 gilts), since placentae were labeled during farrowing. The effect of PRLR genotype of the mother on average placenta weight (PLW) and placenta efficiency (EFF = BW/PLW), was therefore, also analyzed, PRLR genotype significantly (P < 0.05) affected age at first estrus and, as a result (since the gilts were inseminated at a fixed estrus number), age and bodyweight at insemination. Furthermore, PRLR genotype affected total number of piglets born (TNB, P = 0.056) and number of piglets born alive (NBA, P = 0.072), but it did not affect (P > 0.3) GL, BW or GR, neither before nor after correction for litter size. BB gilts were significantly younger at first estrus and younger and lighter at insemination than AA gilts (P < 0.05). AA gilts had larger TNB (P = 0.047) and tended to have a larger NBA (P = 0.062) than BB gilts. TNB was 11.4 +/- 0.7, 10.8 +/- 0.6, and 8.8 +/- 0.9; NBA was 11.1 +/- 0.6, 10.5 +/- 0.6, and 8.7 +/- 0.9; BW was 1309 +/- 40, 1277 +/- 34, and 1290 +/- 53 g; and GL was 113.6 +/- 0.3, 113.8 +/- 0.3, and 113.5 +/- 0.4 days for AA, AB and BB gilts, respectively. The effects on litter size and age at first estrus are independent effects. PRLR affected PLW (P = 0.050) and EFF (P = 0.066), resulting in a difference between AA and BB gilts. PLW was 160 +/- 9, 181 +/- 7 and 196 +/- 11 g and EFF was 7.6 +/- 0.2, 7.3 +/- 0.2 and 6.7 +/- 0.3 for AA (n = 19), AB (n = 29) and BB (n = 14) gilts, respectively. After correction for TNB, the differences disappeared. Functional teat number of the AA. AB and BB gilts was 15.35 +/- 0.22, 15.53 +/- 0.18, and 15.60 +/- 0.29, respectively, and was not affected by PRLR genotype (P = 0.7). Functional teat number of piglets from AA, AB and BB mothers was 14.20 +/- 0.10, 14.37 +/- 0.08, and 14.63 +/- 0.13, respectively. Piglets from BB mothers had on average larger numbers of functional teats compared to piglets from AA mothers (P = 0.028). In conclusion, PRLR gene is a major gene or marker for age at first estrus, litter size, and litter average of number of functional teats in the Large White x Meishan F2 crossbred gilts studied. The favorable allele for litter size (A allele) is the unfavorable allele for age at first estrus and for litter mean of functional teat number.
van Rens
Birgitte T T M
BT
Animal Breeding and Genetics Group, WIAS, Wageningen University, The Netherlands. birgitte.vanrens@alg.vf.wag-ur.nl
van der Lende
Tette
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D000375:Aging; D000483:Alleles; D000818:Animals; D000831:Animals, Newborn / Q000254:growth & development / Q000502:physiology*; D001724:Birth Weight; D001835:Body Weight; D004971:Estrus; D005260:Female; D005838:Genotype; D005865:Gestational Age; D008098:Litter Size / Q000235:genetics; D008297:Male; D009929:Organ Size / Q000235:genetics; D010920:Placenta / Q000033:anatomy & histology; D011247:Pregnancy; D011981:Receptors, Prolactin / Q000235:genetics*; D012741:Sexual Maturation / Q000235:genetics; D013552:Swine / Q000033:anatomy & histology / Q000235:genetics*
D011981:Receptors, Prolactin