Animal Reproduction Science 86 (2005) 131–141 Uterine and fetal asphyxia monitoring in parturient sows treated with oxytocin Daniel Mota-Rojas a,1 , Julio Mart´ ınez-Burnes b , Ma. Elena Trujillo c , Alfonso L ´ opez d , Ana M. Rosales a , Ramiro Ram´ ırez a , H´ ector Orozco a , Angeles Merino a , Mar´ ıa Alonso-Spilsbury a,∗ a Laboratorio de Etolog´ ıa y Producci´ on Porcina, Universidad Aut´ onoma Metropolitana-Xochimilco, Calzada del hueso 1100, Col. Villa Quietud, D.F. 04960, M´ exico b Divisi´ on de Estudios de Posgrado e Investigaci´ on, FMVZ, Universidad Aut´ onoma de Tamaulipas, Carretera Victoria-Mante Km 5, CP 87000, Cd. Victoria Tamaulipas, M´ exico c Departamento Producci´ on Animal: Cerdos, FMVZ, Universidad Nacional Aut´ onoma de M´ exico, Ciudad Universitaria, D.F. 04510, M´ exico d Atlantic Veterinary College, University of Prince Edward Island, 550 University Ave., Charlottetown, PEI, Canada C1A4P3 Received 20 February 2004; received in revised form 27 May 2004; accepted 16 June 2004 Abstract Oxytocin is used to induce and control parturition, nevertheless, the increase of uterine contractions decreases blood flow and gaseous exchange through the womb predisposing to intra-partum mortality. The objective of the present study was to evaluate the effect of oxytocin on myometrial activity, fetal intrauterine hypoxia and postnatal asphyxia in sows during farrowing. Hybrid (n = 120) sows approaching the time of farrowing were randomly assigned in two groups of 60 animals each. Group I (G 1 : control) was treated IM with saline solution and Group II (G 2 ) was injected IM with oxytocin (1 IU/6 kg LW) as a single dose at birth of the first piglet. Both average number of myometrial contractions and intensity in G 2 were greater (P < 0.01) as compared with G 1 . The mean of intra- partum stillbirths (IPS’s) and those where fetal cardiac frequency (FCF) or heart beats, could not be detected after birth, were greater (P < 0.01) in G 2 as compared with G 1 . The average decelerations of FCF known as dips II, which indicate severe hypoxia, was greater in G 2 (P < 0.01) as compared with ∗ Corresponding author. Tel.: +52 55 5483 7535; fax: +52 55 5483 7535. E-mail addresses: maspilsbury@hotmail.com, marilu@cueyatl.uam.mx (M. Alonso-Spilsbury). 1 This study is part of the preliminary advances from the first co-author Ph.D. studies from the Doctorate Program in Biological Sciences at the Universidad Aut´ onoma Metropolitana Iztapalapa-Xochimilco, Mexico. 0378-4320/$ – see front matter © 2004 Published by Elsevier B.V. doi:10.1016/j.anireprosci.2004.06.004