Early-weaned sows: altrenogest therapy, estrus, ovulation, and reproductive performance

Anim Reprod Sci. 2004 Sep;84(3-4):407-13. doi: 10.1016/j.anireprosci.2004.02.011.

Abstract

Early weaning is a technique used to increase swine health status, and may cause consequences in reproductive performance of sows. An experiment was performed to evaluate these effects in a herd of sows, with weaning at 9 or 10 days post-farrowing, located in west of Minas Gerais, Brazil. Large-White sows (n=102), with three or four previous parturitions were randomly allocated to three treatment groups: T1: artificial insemination (AI) at first post-weaning estrus of the sows; T2: AI at second post-weaning estrus, T3: AI at first estrus, after an administration of a daily individual dose of 20 mg of altrenogest from 5 to 8 days post-weaning. The duration of the first post-weaning estrus did not differ among treatment groups; however, the second estrus of the T2 group was of shorter duration relative to the other treatment groups (P< or =0.035). Ovulation occurred earlier at the second estrus of the T2 group, compared with the T1 and T3 groups (P< or =0.027), being similar to that at the first estrus of T2 group (P=0.177). The relationship of the timing between ovulation and estrus was similar among treatment groups (P> or =0.221). There was no difference in farrowing rate among treatment groups (P> or =0.313). The T2 group produced a mean of 2.5 more piglets per litter (P=0.002). In conclusion, the use of altrenogest did not increase the reproductive performance of early-weaned sows.

MeSH terms

  • Animals
  • Animals, Newborn
  • Estrus / physiology*
  • Estrus Detection
  • Female
  • Insemination, Artificial / veterinary
  • Least-Squares Analysis
  • Litter Size
  • Male
  • Ovulation / drug effects
  • Ovulation / physiology*
  • Ovulation Detection
  • Pregnancy
  • Progesterone Congeners / pharmacology*
  • Random Allocation
  • Swine / physiology*
  • Trenbolone Acetate / analogs & derivatives*
  • Trenbolone Acetate / pharmacology*
  • Weaning*

Substances

  • Progesterone Congeners
  • altrenogest
  • Trenbolone Acetate