Early-weaned sows: altrenogest therapy, estrus, ovulation, and reproductive performance.
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.
dos Santos
José Maurício Gonçalves
JM
Centro Universitário de Maringá-Av. Guedner 1610-87050-390, Maringá, PR, Brazil. jmgds@cesumar.br
Wentz
Ivo
I
Bortolozzo
Fernando Pandolfo
FP
Barioni
Waldomiro
W
D000818:Animals; D000831:Animals, Newborn; D004971:Estrus / Q000502:physiology*; D004972:Estrus Detection; D005260:Female; D007315:Insemination, Artificial / Q000662:veterinary; D016018:Least-Squares Analysis; D008098:Litter Size; D008297:Male; D010060:Ovulation / Q000187:drug effects / Q000502:physiology*; D010061:Ovulation Detection; D011247:Pregnancy; D045167:Progesterone Congeners / Q000494:pharmacology*; D011897:Random Allocation; D013552:Swine / Q000502:physiology*; D014204:Trenbolone Acetate / Q000031:analogs & derivatives* / Q000494:pharmacology*; D014886:Weaning
D045167:Progesterone Congeners; C023445:altrenogest; D014204:Trenbolone Acetate