PAPERS & ARTICLES Changes in the feed intake, pH and osmolality of rumen fluid, and the position of the abomasum of eight dairy cows during a diet- induced left displacement of the abomasum S. C. L. VAN WINDEN, C. R. BRATTINGA, K. E. MOLLER, J. TH. SCHONEWILLE, J. P. T. M. NOORDHUIZEN, A. C. BEYNEN During the last six weeks of the dry period, eight Holstein-Friesian cows were fed a restricted amount of grass silage; after calving, a mixture of maize silage and concentrates was offered in a feeding regimen designed to induce a displacement of the abomasum. In the first month after calving, the cows were monitored for the following variables: feed intake and composition, milk production, the position of the abomasum, and the pH and osmolality of the rumen contents. In five of the eight cows, a left displacement of the abomasum occurred between four and 21 days after calving in the absence of other diseases. The displacement was temporary, lasting between five and 36 consecutive hours and one or two days in two of the cows (floaters), and for three or more days in the other three. Before these three cows developed the displacement, their abomasum was 4-3 to 7-9 cm higher, its contents had a higher mean osmolality (+19-2 mosmol/kg), and the ratio of roughage to concentrates in their feed was lower (-0-87) than in the three cows that did not develop clinical signs of a displaced abomasum. There were no significant differences in these variables between the floaters and the healthy cows. Veterinary Record (2004) 154, 501-504 S. C. L. Van Winden, DVM, MSc, PhD, K. E. Muller, DVM, PhD, J. P. T. M. Noordhuizen, DVM, PhD, Department of Farm Animal Health, J. Th. Schonewille, BSc, PhD, A. C. Beynen, MSc, PhD, Department of Nutrition, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 7, 3584 CL Utrecht, The Netherlands C. R. Brattinga, DVM, MSc, Department of Animal Sciences, Animal Husbandry Group, Wageningen University, PO Box 338, 6700 AH Wageningen, The Netherlands A DISPLACEMENT of the abomasum, usually to the left side, most often occurs during the first month after calving, pre- dominantly in Jersey, Guernsey and Holstein-Friesian cows (Constable and others 1992, Stengarde and Pehrson 2002). The condition is associated with a high level of rapidly fer- mentable components in the ration supplied after calving (Martens 2000), a small roughage mat in the rumen (Goff and Horst 1997), an energy-dense feed provided before calving (Coppock 1974) and a low feed intake after calving (Dirksen 1962, 0stergaard and Grohn 2000). Conditions which com- monly affect high-producing cows in early lactation, such as a severe negative energy balance, hypocalcaemia and infec- tious diseases, have been shown to be risk factors for the development of a displaced abomasum (Massey and others 1993, Heuer and others 1999). In dairy cows, the estimated average incidence of the condition is 5 per cent, but it can range from 0 to 20 per cent on different farms (Kane 1983, Dawson and others 1992, Jacobsen 1995). The aim of this study was to induce a displaced abomasum and to evaluate the changes in feed intake, the ratio of roughage to concentrate in the cows' voluntarily ingested feed, the position of the abomasum, and the pH and osmolality of the rumen contents before it developed. It has recently been shown that even in apparently healthy cows the position of the abomasum changes after calving (Van Winden and oth- ers 2002), and it was expected that larger changes would occur in cows that develop the condition. Eight dry pregnant cows were fed a dietary regimen designed to induce a displaced abomasum, modified from that used by Coppock and oth- ers (1972), and differences in the selected variables were eval- uated between the cows that did or did not develop a clinical displaced abomasum. MATERIALS AND METHODS Animals and nutrition The study took place under the supervision and with approval of the Ethical Review Committee of Animal Experimentation of the Faculty of Veterinary Medicine, Utrecht University in the Netherlands. Eight multiparous Holstein-Friesian cows were used; they weighed between 612 and 723 kg six weeks before calving. The cows were housed on stands with sawdust bedding. During the last six weeks of the dry period, they were fed individually according to the Dutch recommendations for energy requirements (Centraal Veevoeder Bureau 1998) and received 53 MJ NEl/day. The ration consisted of 7-7 kg dry matter (DM) of grass silage which was given once daily at 10.00. Immediately after they calved they were offered 5 kg DM of a mixture of concentrates for two hours; after the leftover con- centrates were removed and weighed, they were provided with 10 kg DM of maize silage to which they had access until 08.00 the next day. During the following days they were fed increas- ing amounts of concentrates, with a maximum of 13-5 kg DM/day, between 10.00 and 13.00, and between 13.00 and 08.00 the next day they were provided with maize silage ad libitum; before the next supply of concentrates at 10.00 the animals had no access to feed. The leftover quantities of both the mixture of concentrates and the maize silage were weighed and recorded, and their daily feed intake of each was calculated. Details of the feeding regimen are shown in Table 1. The cows were milked at 12.00 and 24.00 and their yield at each milking was recorded. Clinical examination Each day at 08.00, 11.00,13.00,15.00 and 17.00 the cows were examined for the presence of a left or right displaced aboma- sum. If the abomasum was found to be displaced at 17.00 the cow was re-examined at 23.00. The examination was made by percussion auscultation in an attempt to evoke the charac- teristic 'steelband' sound on the left or right side of the cow. Any suspected displaced abomasum was confirmed by an ultrasonographic survey (Winter and Hofmann 1996). A visual check for mastitis was made on the first milk of each milking period. The involution of the uterus was checked each week by rectal palpation and a vaginal discharge was used as a criterion to diagnose endometritis. If a cows was sus- pected of having milk fever, a blood sample was collected to determine blood calcium concentration. The Veterinary Record, April 17, 2004 group.bmj.com on May 27, 2012 - Published by veterinaryrecord.bmj.com Downloaded from