Economic Efficacy of Ileitis Vaccination in European Farms

Ileitis Symposium, Hamburg, June 28th 2004 Economic Efficacy of Ileitis Vaccination in European Farms Dr. Torsten Hardge, Dr. Knut Elbers, Dr. Ulrike Langbein, Dr. Björn Schröder Boehringer Ingelheim Animal Health GmbH, Binger Str. 173, 55216 Ingelheim, Germany Introduction of age in farm B. The treatments were blinded to the investigators. The pigs of all treatment groups were kept in pens of 10 to 12 Porcine proliferative enteropathy (PPE), often named Ileitis, is a pigs each under identical housing and feeding conditions common enteric disease of swine. The disease is characterized (liquid feed). There were no in-feed antibiotics applied in farm by thickening of the ileum and proximal part of the large in- B. In farm A, antibiotics were only used parenterally at weaning testine due to crypt cell proliferation in association with the and in-feed during the first 18 nursery days (pulsed). presence of the gram-negative bacterium Lawsonia intracellu- The body weight (at begin and end of fattening), the slaughter laris (Gebhardt and McOrist, 1999). There are two forms of the weight and mortality has been recorded. Feed intake has been disease – acute and chronic. The acute form frequently includes measured in farm A only. fatal haemorrhagic diarrhoea typically seen in end fatteners The animal performance data were analysed by using a General and in gilts freshly introduced into the breeding herd (porcine Linear Model taking into account the effects of the treatment haemorrhagic enteropathy – PHE). The chronic form (porcine and weekly delivery batch. In order to account for differences intestinal adenomatosis – PIA) affects grow-finishing pigs and in the initial body weight between treatment and control is associated with mild diarrhoea, weight loss and increased groups the body weight at vaccination was used as covariate. body weight variation. The most common presentation of Ileitis The statistical significance of farm-economic parameters was in European production systems is the chronic form in an often evaluated using Students t-test and Chi2-test as appropriate. subclinical presentation. The development of a modified live vaccine for oral administration (Enterisol® Ileitis, Boehringer Ingelheim Vetmedica Results and discussion GmbH) allows now to build up protective immunity to control Ileitis in strategic health management. Both farms were tested positive for Lawsonia intracellularis in The economic efficacy of this vaccine has been investigated at weaning, breeding and fattening units by PCR and IFAT but two commercial farms in Germany in accordance with good they did not show any clinical signs apart from increased clinical practice (GCP) conditions. growth variation around the 18th week of life in farm B. This is typical for the subclinical form of the disease which is defined as an infection with Lawsonia intracellularis in the absence of Material and methods clinical signs of the disease such as PPE related mortality and diarrhoea. Gross or microscopic lesions of PPE are usually Two farrow to finishing farms – farm A with 6,000 sows and present but of insufficient severity to result in overt clinical farm B with 1,500 sows – were chosen for the trials. In total signs. Nevertheless, farms with subclinical presentation of 1,650 pigs from 2 (farm A) and 4 (farm B) successive weekly Ileitis experience suboptimal growth, reduced feed intake and delivery batches were included. There were 3 experimental loss of homogenicity in body weights (Jacobson et al., 2003; groups (Table 1). The first group received an oral 2 ml dose of Guedes, 2004). the vaccine (Enterisol® Ileitis, Lyophilized form) by using a In both study farms the performance of the vaccinated groups drenching pistol (Drench). In the second group the vaccine was was better than the controls (Table 1). Vaccinated pigs consumed given orally via water in troughs during a period of 4 hours more, grew faster and achieved considerably higher end weights (Trough). The third group which served as control (Control) than non-vaccinated pigs when slaughtered at the same day. received 2 ml isotonic saline solution orally by drench (Control). The feed intake was numerically higher in pigs receiving the Piglets were vaccinated at 7 weeks of age in farm A and 3 weeks vaccine via drench and was significantly increased in the 1 Boehringer Ingelheim Ileitis Symposium trough-vaccinated pigs. The differences between the groups The analysis of the economic impact of vaccination was based with respect to mortality were not statistically significant. The on the gross margin which considers the carcase value minus numerically higher mortality of the Drench-group in farm B the cost of piglets and feed. The effect of mortality was included was mainly due to increased incidence of respiratory diseases in the analysis by calculating all cost components per pig sold. including PCV2, Pasteurella multocida and injury due to canni- It can be clearly seen from Table 2 that vaccinated pigs yielded balism. In both farms there was a higher average daily weight a considerably higher gross margin between € +3.1 and € +5.85 gain (ADWG) in pigs vaccinated via trough compared to pigs in the Drench and Trough groups, respectively. This is mainly vaccinated via drench. This was unexpected but may be related based on higher slaughter sales due to increased end weights to lower vaccination stress and the better distribution of the (Table 2). vaccine in the digestive tract due to higher fluid intake in the Trough-group (Table 1). Table 1: Least Squares Means for growth performance*1 in the three experimental groups on each of the farms Farm A Vaccination groups Trait/group Drench Trough Pigs (n) 278 277 ADWG (g) a a Feed conv. (kg/kg) End weight (kg) 2.67 96.8 Mortality*2 (%) c 721 1.88ab Feed intake (kg/day) a 4.98 Control 278 b 702 Farm B Vaccination groups Drench Trough 273 273 a 674 692 713 682a - 1.85b - - a 2.74a - - a 97.8 3.62 94.1 b 112.9 4.68 271 b 1.98a 2.75 Control ab 115.3 7.35 a 3.30 110.5b 3.68 *Different letters indicate significant differences between treatments within the respective farm; *1 from weaning to slaughter; *2Fishers exact test: farm A, p = 0.81; farm B, p = 0.06; Table 2: Financial returns, costs and gross margins of pigs vaccinated with Enterisol® Ileitis compared to non-vaccinated controls*1 Economic trait/group Drench Trough Control (€/pig) 103.73a 110.48b 98.58a Piglet costs (€/pig) 48.97ab 51.73a 47.80b Feed costs (€/pig) 34.17ab 36.01a 33.68b (€/pig) ab a 13.51b Financial returns Sales (slaughter house) Costs Gross margin 16.61 19.36 *Different letters indicate significant differences between treatments within the respective farm *1For the calculation of the slaughter sales and weight discounts the Euro-Reference grading grid with base price of € 1.4 has been applied. A feed price of 175 €/t and piglet prices depending on the weight (18.0 kg – 28 kg = € 49,7; > 28 kg = € 58,7; < 18 kg = 32,6 kg) were assumed. Mortality was considered in calculating all costs per pig sold. The pen was considered as experimental unit. Ileitis Symposium Boehringer Ingelheim 2 Animal Health In addition to the higher end weight, the variation in body variation at the end of fattening. It can therefore be assumed weight was lower in vaccinated pigs than in the controls that vaccination with Enterisol® Ileitis provides protective (Figure 1). Furthermore, the percentage of lightweights and the immunity to prevent subclinical Ileitis. The results agree with percentage of pigs outside the optimal weight window were also laboratory challenge experiments with virulent field isolates lower for Drench (26.3 %) and Trough (13.4 %) in comparison to showing higher daily weight gain of pigs vaccinated with the Control group (36.8 %). This finally resulted in significantly Enterisol® Ileitis compared to challenge-control pigs (Kroll et reduced weight discounts per pig (Drench: € -1.24; Trough: al., 2004a; Kroll et al. 2004b). The better performance of vacci- € -0.61; Control: € -1.98) and to a higher end-price per kg nated pigs resulted in higher economic gross margins ranging, slaughter weight (Figure 1). under the conditions of this study, from € +3.1 (Drench) to € +5.85 (Trough). The results show that subclinical infection with Lawsonia intracellularis reduced feed intake and growth and is related to It is concluded that vaccination with Enterisol® Ileitis is an increased slaughter weight variation. Vaccinated piglets had a economically efficient tool to control sub-clinical Ileitis and to higher feed intake, increased weight gain and less body weight allow a better exploitation of the genetic growth potential. Figure 1: Slaughter weight distribution in vaccinates and controls in farm A Percent observations 52 % 43 % Vaccinated group Control group 35 % 26 % Lightweights p < 0.001 17 % 9% 0% 20 30 40 50 60 70 80 90 100 110 Slaughter weight (kg) Ileitis Symposium Boehringer Ingelheim 3 Animal Health References Gebhart, C. J.; McOrist, S. (1999): Porcine Proliferative Enteropathies. Diseases of Kroll, J. J.; Roof, M. B.; McOrist, S. (2004a): Evaluation of protective immunity in Swine, 8 Edition / Editors: Leman A.D., Straw B.E. 38, 521 - 534 pigs following oral aministration of an avirulent live vaccine of Lawsonia intracel- Guedes, R. (2004): Update on epidemiology and diagnosis of porcine proliferative lularis. Am. J. Vet. Res. 65, 559 - 565 th enteropathy. Kroll, J. J.; Roof; M. B. Elbers, K.; P. Utley (2004b): The safety and increased efficacy Journal of Swine Health and Production 12 (3), 134 - 138 of vaccinating pigs with Enterisol Ileitis in the drinking water. Proc. of the Jacobson, M.; Hard af Segerstad, C.; Fellstroem, C.; Gunnarsson, A.; De Verdier 18th IPVS, Hamburg 2004 Klingenberg, K.; Wallgreen, P.; Jensen-Waern, M. ( 2003 ): Diarrhoea in the growing pig – a comparison of clinical, morphological and microbial findings between animals from good and poor performance herds . Research in Veterinary Science 74, 163 - 169 Ileitis Symposium Boehringer Ingelheim 4 Boehringer Ingelheim Animal Health GmbH Binger Straße 173 55216 Ingelheim am Rhein Germany Phone +49 (0) 61 32 77-9 27 22 Fax +49 (0) 61 32 77-9 81 83 [email protected] 6-232457-4 © Boehringer Ingelheim Animal Health GmbH, June 2004; Subject in alteration without notice. www.boehringer-ingelheim.com