Short communication The effect of feeding a low- or high-starch diet on equine faecal parameters Jo-Anne MD Murray a,n , Annette Longland b , Meriel Moore-Colyer c , Catherine Dunnett d , Annette Longland b a Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Roslin, Midlothian EH25 9RG, UK b Institute of Grassland and Environmental Research, Plas Gogerddan, Aberystwyth SY23 3EB, Wales, UK c Institute of Rural Sciences, University of Wales, Aberystwyth, Llanbadarn Campus, Aberystwyth, SY23 3AL Wales, UK d Dengie Crops Limited, Heybridge Business Centre,110 The Causeway, Maldon, Essex CM9 4ND, UK article info Article history: Received 6 February 2013 Received in revised form 11 October 2013 Accepted 13 October 2013 Keywords: Equine Starch Faeces Diet abstract Seven mature Welsh-cross pony geldings provided the faecal inocula in a cross-over design experiment, consisting of two 14-day periods. In period 1, four ponies (group 1) were fed a low-starch fibre-mix (LS), and three (group 2) were fed a conventional high- starch coarse-mix (HS), both groups were fed these mixes in a 50:50 ratio with mature grass hay, to give a total daily dry matter (DM) intake of 17.5g/kg live weight per day. Diets were then switched in period 2. At the end of each experimental period freshly voided faeces were collected from each animal and analysed for cellulolytic and amylolytic bacterial numbers, volatile fatty acid (VFA) and lactate concentration. There was no effect of diet on the number of cellulolytic and amylolytic bacteria, VFA or lactate present in the faeces of the experimental ponies. Consequently, it would appear that the effect of feeding LS or HS on faecal parameters is minimal; however, further work is required to determine the accuracy of faeces as a model for changes in the hindgut environment of the horse. & 2013 Elsevier B.V. All rights reserved. 1. Introduction Horses have evolved to survive on a diet consisting of large quantities of low-quality fibre, ingested on an almost continual basis. However, the nutrient, and in particular energy demands of performance horses have necessitated the incorporation of large amounts of energy-dense cereal grains in the diets of these animals, which are high in starch and low in fibre. It is well known that the small intestine of the horse has a limited capacity for starch digestion (Kienzle et al., 1994; Meyer et al., 1995) and thus when high levels of starch are fed in a single meal, undigested starch enters the hindgut. Excess starch enter- ing the hind-gut favours the proliferation of Gram positive lactic acid producing bacteria in the hindgut of the horse at the expense of the Gram negative fibre-degrading bacterial population. The increase in lactate, volatile fatty and acids (VFA) and consequent reduction in gut pH elicited through feeding high-starch diets can cause a number of intestinal and metabolic disorders in horses such as colic and laminitis (Rowe et al., 1994). Therefore, the present study was undertaken to examine the effects of feeding a low- or high-starch diet on faecal parameters. 2. Materials and methods 2.1. Experimental design Seven mature Welsh-cross pony geldings (280 kg7 17.6 LW) provided the faecal inocula in a cross-over design experiment whereby four ponies (group 1) were fed a low- starch fibre-mix (LS) containing 186 g/kg DM of starch, and Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/livsci Livestock Science 1871-1413/$ - see front matter & 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.livsci.2013.10.017 n Corresponding author. Fax: þ44 131 650 6588. E-mail address: Jo-Anne.Murray@ed.ac.uk (J.-A. Murray). Livestock Science 159 (2014) 67–70