Submitted to: Journal of Animal and Veterinary Advances
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 9, 2004
Publication Date: February 22, 2004
Citation: Strauch, T.A., Carroll, J.A., Berg, E.L., Salfen, B.E. 2004. Zeranol administration to gestating sows alters sow blood serum IGF-1 concentrations and improves piglet performance. Journal of Animal and Veterinary Advances. 3(5): 270-277. Interpretive Summary: A study was conducted to determine the effects administration of the growth implant Ralgro to sows during gestation on subsequent performance of the sows and piglets. Sows were implanted with Ralgro, an estrogenic compound commonly administered to cattle, at day 60 of gestation, and sows were farrowed at approximately 115 days of gestation. Blood and milk samples were collected from sows, and blood samples were collected from piglets. Analysis of serum from the blood of both sows and piglets at parturition/birth revealed increases in an important growth factor (insulin-like growth factor-I). Accordingly, piglet average daily gain and body weight at weaning was greater for piglets whose sows were treated with Ralgro during gestation. This study provides a potential method to enhance growth performance in young pigs with a relatively simple administration of a growth promotant to the sow. This information will be of interest to individuals working in the area of swine productivity, including scientists, extension personnel, and swine producers.
Technical Abstract: Objectives were to determine the effects of an estrogenic compound (Ralgro; R) on sow and piglet performance, and components of the somatotrophic axis. Treated sows were administered 36 mg R subcutaneously in the ear on d 60 of gestation, and control (C) sows were administered a sham implant. There was no difference (P > 0.38) in serum growth hormone (GH) between C and R sows, but there was a trend for increased (P < 0.12) insulin-like growth factor-I (IGF-I) in R sows. There was no difference (P < 0.14) in litter size, number born alive, or piglet survival to weaning; however, there was a trend (P < 0.11) for a greater total litter weight in C sows. There was no difference (P > 0.47) in piglet weight at birth, but there was a treatment effect (P < 0.002) on average daily gain (ADG) to 7 d of age, with increased ADG in R piglets, and the increased ADG continued until weaning (P < 0.02). Treatment did not affect piglet serum concentrations of GH at birth (P > 0.18) or weaning (P > 0.64), and increased (P < 0.0006) serum concentrations of IGF-I in R pigs at birth, but not weaning (P > 0.31). Hypothalamic mRNA expression of growth hormone releasing hormone tended (P < 0.07) to be greater in R pigs. These data indicate that R implantation in gestating sows increases circulating concentrations of IGF-I, and improves pre-weaning ADG of pigs exposed to R in utero.