Active immunization of ewes against ovine placental lactogen increases birth weight of lambs and milk production with no adverse effect on conception rate

H. Leibovich, A. Gertler, F. W. Bazer, E. Gootwine*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

22 Scopus citations

Abstract

In two experiments, 16 Booroola-Assaf and 35 Assaf ewe-lambs were actively immunized at 5 months of age against recombinant ovine placental lactogen (oPL). At 9 months of age, the ewe-lambs were mated for the first time and then introduced into a frequent mating-system. Anti-oPL antibody titers, reproductive performance, maternal serum levels of oPL during pregnancy, lamb birth weight and milk production of the ewes were followed in the immunized ewes and in their non-immunized control counterparts. All the immunized ewes developed anti-oPL antibodies, which interfered with oPL bioactivity in an in vitro cell proliferation assay. Conception rates did not differ (P > 0.05) between immunized and non-immunized ewes Abundant antibody-bound non-active oPL detected in sera of immunized ewes by western blotting indicated enhanced oPL production by the placenta following immunization. An increase (P < 0.02) in serum oPL bioactivity, but not immunoreactivity, was observed in the immunized ewes in late gestation relative to control ewes. The average litter size was 1.83 and 1.32 lambs born per ewe lambing in the first and second experiments, respectively. Average birth weights of lambs born to the immunized ewes were higher (P < 0.01) than for lambs born to control ewes by 10, 17 and 39% for those born as singles, twins and triplets, respectively. Immunized ewes produced 19 and 33% more milk (P < 0.02) than the control ewes in the first 3.5 months of the first and second lactations, respectively. These findings do not suggest a role for oPL in maternal recognition of pregnancy, but they strongly suggest important roles for oPL in fetal growth and mammogenesis. Immunization of ewes against oPL may thus represent a novel practical technique for enhancing birth weights of lambs born to prolific sheep, as well as milk production by both dairy and mutton ewes. (C) 2000 Elsevier Science B.V.

Original languageEnglish
Pages (from-to)33-47
Number of pages15
JournalAnimal Reproduction Science
Volume64
Issue number1-2
DOIs
StatePublished - 1 Dec 2000

Keywords

  • Immunization
  • Lamb production
  • Milk production
  • Placental lactogen
  • Sheep-placenta

Fingerprint

Dive into the research topics of 'Active immunization of ewes against ovine placental lactogen increases birth weight of lambs and milk production with no adverse effect on conception rate'. Together they form a unique fingerprint.

Cite this