Spontaneous recovery or persistence of postpartum endometritis and risk factors for its persistence in Holstein cows G. Gautam, T. Nakao * , K. Koike, S.T. Long, M. Yusuf, R.M.S.B.K. Ranasinghe, A. Hayashi Laboratory of Theriogenology, Department of Veterinary Medicine, Faculty of Agriculture, Yamaguchi University, Yamaguchi, Japan Received 3 July 2009; received in revised form 8 August 2009; accepted 24 August 2009 Abstract It has been stated that postpartum endometritis in dairy cows has a tendency to cure without intervention. The objectives of this field study, therefore, were to determine the proportions of cows with spontaneous clinical recovery or persistence of postpartum endometritis and to determine some risk factors for its persistency in dairy cows (Bos taurus). Holstein-Friesian cows (n = 441 lactations) from seven dairy herds were examined monthly by vaginoscopy and transrectal palpation. A cow was considered to have ‘‘postpartum endometritis’’ if it had pus in the cervico-vaginal discharge at the first postpartum examination during Days 15 to 60 (Day 0 = day of calving); this was classified as mild, mucopurulent, or purulent endometritis, or endometritis with fluid in uterus. Furthermore, a cow with evidence of endometritis at least once during Days 61 to 150 was considered to have ‘‘persistence (or recurrence) of endometritis.’’ A total of 104 (23.6%) lactations had postpartum endometritis, of which 25.3% had persistence or recurrence of clinical endometritis. Cows with persistence or recurrence of endometritis became pregnant at a slower rate (hazard ratio [HR] = 0.28; P < 0.001) than those with no endometritis until Day 150. Calving in summer (odds ratio [OR] = 7.00; P = 0.04), early postpartum complications (OR = 6.58; P = 0.05), moderate (OR = 4.03; P = 0.08) and severe (OR = 30.99; P = 004) degrees of urovagina, and mucopurulent (OR = 9.54; P = 0.02) and purulent (OR = 5.70; P = 0.04) endometritis were risk factors for the persistence or recurrence of endometritis. Furthermore, 10.6% of cows that had not shown signs of postpartum endometritis had a new diagnosis of endometritis during Days 61 to 150. Some risk factors for the new diagnosis of endometritis beyond Day 60 were early postpartum complications (OR = 2.82; P = 0.03) and moderate (OR = 5.00; P = 0.001) or severe (OR = 12.63; P < 0.001) degrees of urovagina. In conclusion, approximately one quarter of cows with postpartum endometritis had persistence of endometritis until or beyond the breeding period. Risk factors for the persistence of clinical endometritis were summer calving, early postpartum complications, clinically relevant urovagina, and clinically relevant endometritis within 2 mo postpartum. # 2010 Elsevier Inc. All rights reserved. Keywords: Endometritis; Holstein cows; Spontaneous recovery; Urovagina; Vaginoscopy 1. Introduction Postpartum uterine diseases have been described as a leading cause of reproductive inefficiency in dairy cattle [1–17]. Uterine diseases, postpartum endometritis in particular, reduce the reproductive efficiency of cows by extending the calving to conception interval, increasing the number of inseminations per conception [5,7– 9,15,16], and increasing culling rates [5,7,8]. The prevalence of endometritis in 43 studies ranged from 2.2% to 37.3%, with a median of 10.1% [18]. In some herds, 40% of postpartum cows may be diagnosed and treated for uterine infections [17]. www.theriojournal.com Available online at www.sciencedirect.com Theriogenology 73 (2010) 168–179 * Corresponding author. Tel.: +81 83 933 5935; fax: +81 83 933 5935. E-mail address: tnakao@yamaguchi-u.ac.jp (T. Nakao). 0093-691X/$ – see front matter # 2010 Elsevier Inc. All rights reserved. doi:10.1016/j.theriogenology.2009.08.010