Changes

confinement with ''ad libitum'' access to hay on gastric ulceration in horses.  ''Am J Vet Res'', 57:1599-1603.</ref>  However, when comparing solitary stable confinement with stabling next to a companion, and finally turn out in a paddock, Husted and colleagues (2008) found that the environmental situation had no effect on mucosal acid exposure in the equine stomach.<ref>Husted, L, Sanchex, L.C, Olsen, S.N, Baptiste, K.E, Merritt, A.M (2008) Effect of paddock vs. stall housing on 24 hour gastric pH within the proximal and ventral equine stomach.  ''Equine Vet J'', 40(4):337-41.</ref>  Thus the reason for a higher prevalence of EGUS in stabled animals is unclear.  '''Transport''' has also been shown to induce squamous mucosal ulceration in horses, by as yet, unidentified mechanisms.<ref>McClure, S.R, Carithers, D.S, Gross, S.J, Murray, M.J (2005) Gastric ulcer development in horses in a simulated show or training environment.  ''J Am Vet Med Assoc'', 227:775-777.</ref>

confinement with ''ad libitum'' access to hay on gastric ulceration in horses.  ''Am J Vet Res'', 57:1599-1603.</ref>  However, when comparing solitary stable confinement with stabling next to a companion, and finally turn out in a paddock, Husted and colleagues (2008) found that the environmental situation had no effect on mucosal acid exposure in the equine stomach.<ref>Husted, L, Sanchex, L.C, Olsen, S.N, Baptiste, K.E, Merritt, A.M (2008) Effect of paddock vs. stall housing on 24 hour gastric pH within the proximal and ventral equine stomach.  ''Equine Vet J'', 40(4):337-41.</ref>  Thus the reason for a higher prevalence of EGUS in stabled animals is unclear.  '''Transport''' has also been shown to induce squamous mucosal ulceration in horses, by as yet, unidentified mechanisms.<ref>McClure, S.R, Carithers, D.S, Gross, S.J, Murray, M.J (2005) Gastric ulcer development in horses in a simulated show or training environment.  ''J Am Vet Med Assoc'', 227:775-777.</ref>

*'''Diet and feeding regime:'''  '''Feed deprivation''' encourages gastric ulceration in three ways: (1) it precludes the buffering capacity of protein leading to a reduced gastric pH<ref>Murray, M.J, Schusser, G.F (1993) Measurement of 24-h gastric pH using an indwelling pH electrode in horses unfed, fed and treated with ranitidine.  ''Equine Vet J'', 25:417-421.  In: Sandin, A, Skidell, J, Haggstrom, J, Nilsson, G (2000) ''Postmortem'' findings of gastric ulcers in Swedish horses older than age one year: a retrospective study of 3715 horses (1924–1996).  ''Equine Vet J'', 32(1):36-42.</ref> and (2) it empties the stomach and exposes the squamous mucosa to the more mobile gastric juice<ref name="Sandin">Sandin, A, Skidell, J, Haggstrom, J, Nilsson, G (2000) ''Postmortem'' findings of gastric ulcers in Swedish horses older than age one year: a retrospective study of 3715 horses (1924–1996).  ''Equine Vet J'', 32(1):36-42.</ref> and (3) it permits the accumulation of bile salts, which, together with HCl, cause greater squamous mucosal damage than HCl alone.<ref>  It is unsurprising, therefore, that an alternating feed-fast protocol would produce a consistent model of ulcer induction in the equine squamous mucosa.<ref>Murray, M.J, Schusser, G.F (1993) Measurement of 24-h gastric pH using an indwelling pH electrode in horses unfed, fed and treated with ranitidine.  ''Equine Vet J'', 25:417-421.  In: Sanchez, L.C (2010) 'Diseases Of The Stomach' in  Reed, S.M, Bayly, W.M. and Sellon, D.C (2010) '''Equine Internal Medicine''' (Third Edition), Saunders, Chapter 15.</ref><ref>Murray, M.J (1994) Equine model of inducing ulceration in alimentary squamous epithelial mucosa.  ''Dig Dis Sci'', 39:2530-2535.  In: Sanchez, L.C (2010) 'Diseases Of The Stomach' in  Reed, S.M, Bayly, W.M. and Sellon, D.C (2010) '''Equine Internal Medicine''' (Third Edition), Saunders, Chapter 15.</ref>  Despite this, feed deprivation is not a prerequisite for gastric ulceration in the horse.<ref name="Vatistas thesis">Vatistas, N.J (1998) Gastric Ulceration in the Racing Thoroughbred.  ''PhD Thesis''.  In: Vatistas, N.J, Sifferman, R.L, Holste, J, Cox, J.L, Pinalto, G, Schultz, K.T (1999) Induction and maintenance of gastric ulceration in horses in simulated race training.  ''Equine Vet J Suppl'', 29:40-44</ref>  Diets that are plentiful in roughage prolong the mastication process and the production of salivary bicarbonate that protects the gastric mucosa.  A diet of '''high grain and low roughage''' thus predisposes to EGUS.<ref name="Nadeau"> In: Nadeau, J.A, Andrews, F.M (2009) ''Science: Overviews'' Equine gastric ulcer syndrome: The continuing conundrum.  ''Equine Vet J'', 41(7):611-615.</ref>  This sort of diet is commonly fed to racehorses but dietary components have also been shown to influence EGUS risk in nonracehorses.<ref>Luthersson, N, Nielson, K.H, Harris, P, Parkin, T.D (2009) Risk factors associated with equine gastric ulceration syndrome (EGUS) in 201 horses in Denmark.  ''Equine Vet J'', 41(7):625-30.</ref>  Ponies fed a '''concentrate diet''' had a greater prevalence of gastric ulcers than ponies fed hay alone.<ref name="Vatistas 2">Vatistas, N.J, Sifferman, R.L, Holste, J, Cox, J.L, Pinalto, G, Schultz, K.T (1999) Induction and maintenance of gastric ulceration in horses in simulated race training.  ''Equine Vet J Suppl'', 29:40-44</ref> and this may be because grain and pelleted feeds are asssociated with increased serum gastrin.<ref>Smyth, G.B, Young, D.W, Hammond, L.S (1988) Effects of diet and feeding on post-prandial serum gastrin and insulin concentrations in adult horses.  ''Equine Vet J Suppl'' 7:56-59.</ref>  '''High starch meals''' are also a risk because they are fermented to VFAs and lactic acid and are emptied from the stomach relatively slowly.<ref>Mètayer, N, Lhôte, M, Bahr, A, Cohen, N.D, Kim, I, Rousell, A.J, Julliand, V (2004) Meal size and starch content affect gastric emptying in horses.  ''Equine Vet J'', 36:434-440.  In: Nadeau, J.A, Andrews, F.M (2009) ''Science: Overviews'' Equine gastric ulcer syndrome: The continuing conundrum.  ''Equine Vet J'', 41(7):611-615.</ref><ref>Taharaguchi, S, Okai, K, Orita, Y, Kuwano, M, Ueno, T, Taniyama, H (2004) Relation between amounts of concentrated feed given mares and gastric ulcers in foals.  ''J Japan Vet Med Ass'', 57:366-370.  In: Nadeau, J.A, Andrews, F.M (2009) ''Science: Overviews'' Equine gastric ulcer syndrome: The continuing conundrum.  ''Equine Vet J'', 41(7):611-615.</ref><ref>Boswinkel, A.M, Ellis, A.D, Sloet van Oldruitenborgh-Oosterbaan, M.M (2007) The influence of low versus high fibre haylage diets in combination with training or pasture rest on equine gastric ulceration syndrome (EGUS).  ''Pferdeheilkunde'', 23:123-130.  In: Nadeau, J.A, Andrews, F.M (2009) ''Science: Overviews'' Equine gastric ulcer syndrome: The continuing conundrum.  ''Equine Vet J'', 41(7):611-615.</ref>

*'''Diet and feeding regime:'''  '''Feed deprivation''' encourages gastric ulceration in three ways: (1) it precludes the buffering capacity of protein leading to a reduced gastric pH,<ref>Murray, M.J, Schusser, G.F (1993) Measurement of 24-h gastric pH using an indwelling pH electrode in horses unfed, fed and treated with ranitidine.  ''Equine Vet J'', 25:417-421.  In: Sandin, A, Skidell, J, Haggstrom, J, Nilsson, G (2000) ''Postmortem'' findings of gastric ulcers in Swedish horses older than age one year: a retrospective study of 3715 horses (1924–1996).  ''Equine Vet J'', 32(1):36-42.</ref> (2) it empties the stomach and exposes the squamous mucosa to the more mobile gastric juice<ref name="Sandin">Sandin, A, Skidell, J, Haggstrom, J, Nilsson, G (2000) ''Postmortem'' findings of gastric ulcers in Swedish horses older than age one year: a retrospective study of 3715 horses (1924–1996).  ''Equine Vet J'', 32(1):36-42.</ref> and (3) it permits the accumulation of bile salts, which, together with HCl, cause greater squamous mucosal damage than HCl alone.<ref>Berschneider, H.M, Blikslager, A.T, Roberts, M.C (1999) Role of dudodenal relfux in nonglandular gastric ulcer disease of the mature horse.  ''Equine Vet J Suppl'', 29:24-29.</ref>  It is unsurprising, therefore, that an alternating feed-fast protocol would produce a consistent model of ulcer induction in the equine squamous mucosa.<ref>Murray, M.J, Schusser, G.F (1993) Measurement of 24-h gastric pH using an indwelling pH electrode in horses unfed, fed and treated with ranitidine.  ''Equine Vet J'', 25:417-421.  In: Sanchez, L.C (2010) 'Diseases Of The Stomach' in  Reed, S.M, Bayly, W.M. and Sellon, D.C (2010) '''Equine Internal Medicine''' (Third Edition), Saunders, Chapter 15.</ref><ref>Murray, M.J (1994) Equine model of inducing ulceration in alimentary squamous epithelial mucosa.  ''Dig Dis Sci'', 39:2530-2535.  In: Sanchez, L.C (2010) 'Diseases Of The Stomach' in  Reed, S.M, Bayly, W.M. and Sellon, D.C (2010) '''Equine Internal Medicine''' (Third Edition), Saunders, Chapter 15.</ref>  Despite this, feed deprivation is not a prerequisite for gastric ulceration in the horse.<ref name="Vatistas thesis">Vatistas, N.J (1998) Gastric Ulceration in the Racing Thoroughbred.  ''PhD Thesis''.  In: Vatistas, N.J, Sifferman, R.L, Holste, J, Cox, J.L, Pinalto, G, Schultz, K.T (1999) Induction and maintenance of gastric ulceration in horses in simulated race training.  ''Equine Vet J Suppl'', 29:40-44</ref>  Diets that are plentiful in roughage prolong the mastication process and the production of salivary bicarbonate that protects the gastric mucosa.  A diet of '''high grain and low roughage''' thus predisposes to EGUS.<ref name="Nadeau"> In: Nadeau, J.A, Andrews, F.M (2009) ''Science: Overviews'' Equine gastric ulcer syndrome: The continuing conundrum.  ''Equine Vet J'', 41(7):611-615.</ref>  This sort of diet is commonly fed to racehorses but dietary components have also been shown to influence EGUS risk in nonracehorses.<ref>Luthersson, N, Nielson, K.H, Harris, P, Parkin, T.D (2009) Risk factors associated with equine gastric ulceration syndrome (EGUS) in 201 horses in Denmark.  ''Equine Vet J'', 41(7):625-30.</ref>  Ponies fed a '''concentrate diet''' had a greater prevalence of gastric ulcers than ponies fed hay alone.<ref name="Vatistas 2">Vatistas, N.J, Sifferman, R.L, Holste, J, Cox, J.L, Pinalto, G, Schultz, K.T (1999) Induction and maintenance of gastric ulceration in horses in simulated race training.  ''Equine Vet J Suppl'', 29:40-44</ref> and this may be because grain and pelleted feeds are asssociated with increased serum gastrin.<ref>Smyth, G.B, Young, D.W, Hammond, L.S (1988) Effects of diet and feeding on post-prandial serum gastrin and insulin concentrations in adult horses.  ''Equine Vet J Suppl'' 7:56-59.</ref>  '''High starch meals''' are also a risk because they are fermented to VFAs and lactic acid and are emptied from the stomach relatively slowly.<ref>Mètayer, N, Lhôte, M, Bahr, A, Cohen, N.D, Kim, I, Rousell, A.J, Julliand, V (2004) Meal size and starch content affect gastric emptying in horses.  ''Equine Vet J'', 36:434-440.  In: Nadeau, J.A, Andrews, F.M (2009) ''Science: Overviews'' Equine gastric ulcer syndrome: The continuing conundrum.  ''Equine Vet J'', 41(7):611-615.</ref><ref>Taharaguchi, S, Okai, K, Orita, Y, Kuwano, M, Ueno, T, Taniyama, H (2004) Relation between amounts of concentrated feed given mares and gastric ulcers in foals.  ''J Japan Vet Med Ass'', 57:366-370.  In: Nadeau, J.A, Andrews, F.M (2009) ''Science: Overviews'' Equine gastric ulcer syndrome: The continuing conundrum.  ''Equine Vet J'', 41(7):611-615.</ref><ref>Boswinkel, A.M, Ellis, A.D, Sloet van Oldruitenborgh-Oosterbaan, M.M (2007) The influence of low versus high fibre haylage diets in combination with training or pasture rest on equine gastric ulceration syndrome (EGUS).  ''Pferdeheilkunde'', 23:123-130.  In: Nadeau, J.A, Andrews, F.M (2009) ''Science: Overviews'' Equine gastric ulcer syndrome: The continuing conundrum.  ''Equine Vet J'', 41(7):611-615.</ref>

*'''Other ailments:''' Conditions that produce abdominal pain and/or inappetance are likely to reduce food intake and predipose to gastric ulcers.<ref name="Sandin">Sandin, A, Skidell, J, Haggstrom, J, Nilsson, G (2000) ''Postmortem'' findings of gastric ulcers in Swedish horses older than age one year: a retrospective study of 3715 horses (1924–1996).  ''Equine Vet J'', 32(1):36-42.</ref>  This may be the reason that '''colic''' and other gastrointestinal disorders have been associated with EGUS.<ref>Furr, M.O, Murray, M.J (1989) Treatment of gastric ulcers in horses with histamine type 2 receptor antagonists.  ''Equine Vet J Suppl'', 7:77-79.</ref>  Alternatively, EGUS may be part of a more general gastrointestinal disease complex.<ref name="Vatistas 2">Vatistas, N.J, Sifferman, R.L, Holste, J, Cox, J.L, Pinalto, G, Schultz, K.T (1999) Induction and maintenance of gastric ulceration in horses in simulated race training.  ''Equine Vet J Suppl'', 29:40-44</ref> Gastrointestinal disorders: especially those resulting in delayed gastric emptying.<ref>Mertz, H.R, Walsh, J.H, (1991) Peptic ulcer pathophysiology.  ''Med Clin North Am'', 75:799-814. In: Sanchez, L.C (2010) ''Diseases Of The Stomach'' in Reed, S.M, Bayly, W.M. and Sellon, D.C (2010) '''Equine Internal Medicine''' (Third Edition), Saunders, Chapter 15.</ref>

*'''Other ailments:''' Conditions that produce abdominal pain and/or inappetance are likely to reduce food intake and predipose to gastric ulcers.<ref name="Sandin">Sandin, A, Skidell, J, Haggstrom, J, Nilsson, G (2000) ''Postmortem'' findings of gastric ulcers in Swedish horses older than age one year: a retrospective study of 3715 horses (1924–1996).  ''Equine Vet J'', 32(1):36-42.</ref>  This may be the reason that '''colic''' and other gastrointestinal disorders have been associated with EGUS.<ref>Furr, M.O, Murray, M.J (1989) Treatment of gastric ulcers in horses with histamine type 2 receptor antagonists.  ''Equine Vet J Suppl'', 7:77-79.</ref>  Alternatively, EGUS may be part of a more general gastrointestinal disease complex.<ref name="Vatistas 2">Vatistas, N.J, Sifferman, R.L, Holste, J, Cox, J.L, Pinalto, G, Schultz, K.T (1999) Induction and maintenance of gastric ulceration in horses in simulated race training.  ''Equine Vet J Suppl'', 29:40-44</ref> Gastrointestinal disorders: especially those resulting in delayed gastric emptying.<ref>Mertz, H.R, Walsh, J.H, (1991) Peptic ulcer pathophysiology.  ''Med Clin North Am'', 75:799-814. In: Sanchez, L.C (2010) ''Diseases Of The Stomach'' in Reed, S.M, Bayly, W.M. and Sellon, D.C (2010) '''Equine Internal Medicine''' (Third Edition), Saunders, Chapter 15.</ref>